Due to cardiovascular and oncological diseases, the most a large number of people. Scientists at the National Cancer Institute and the International Heart Association in the United States have teamed up to scientifically compile a list of foods that can be a good backdrop to curbing diseases such as heart attack, stroke, and cancer.

The study of scientists, which began in 1997, was attended by 400 thousand people aged 25 to 65 years. Each of the volunteers was forced to keep a food diary and transfer its data to scientists once a year. Also, each of the participants underwent a complete medical examination every year.

20 years later, scientists have compiled a list of foods that were present in the diet of people who do not suffer from cardiovascular and oncological diseases. The list started at 100, but after studying the effect of a particular food product in laboratory conditions, scientists reduced it to 15.

15 scientifically proven foods

The first place was taken by tomatoes

They are able to inhibit the development of prostate cancer, Bladder and heart attack.

The second place was given to broccoli and its active substance sulforaphane

Already, many heart medicines have been created on the basis of this substance.

Vegetable unrefined oils and nuts

Omega-3 polyunsaturated fatty acids, which are rich in olive, sesame, pumpkin, sea buckthorn, flaxseed oils, as well as nuts and fish of the northern seas (not to be confused with artificially grown salmon) are able to inhibit the growth of "bad" cholesterol, strengthen the heart muscles and prevent the development of some forms of cancer.

Beet

According to scientists, the daily presence of beets in the diet significantly reduces the risk of stroke.

Legumes rounded out the top five

Boiled red and black beans have been scientifically proven to reduce the risk of breast cancer.

Unprocessed whole grains unlock the top 5 healthiest foods

Cereals such as buckwheat, oats, brown rice and millet protect blood vessels from atherosclerotic plaques and help to lose weight, and obesity today causes 8 forms of cancer!

The berries on this list took their seventh lucky place.

The most useful of them, scientists called blueberries, cranberries, black currants, sea buckthorn and blackberries. All of them fight free radicals and are delicious cancer prevention.

The experts took the eighth place with greenery

Chlorophyll, which is rich in parsley, green salads, dill, cilantro, spinach and basil, neutralizes the harmful effects of certain foods and also has antioxidant properties.

The ninth place went to dried apricots

It has been scientifically proven that consuming 2-3 dried apricots daily can protect the heart from heart attacks.

The top ten superfoods are closed by vegetables and fruits

400 grams per day, no less. Otherwise they lose their useful property... Among the large variety of vegetables and fruits, scientists have identified (in addition to the above-named tomatoes, beets and broccoli) - other crucifers, carrots, young potatoes and sweet potatoes, pumpkin, apples,

Eleventh place went to green tea and dark chocolate

Catechins, which are found in real green tea and dark chocolate, inhibit the division of cancer cells and significantly reduce the risk of developing colon, stomach, lung and liver cancers. In addition, green tea is one of the top three so-called heart superfoods.

Scientists cautiously put a glass of dry red wine in twelfth place

Why caution, because exceeding 150 grams per day will turn the "medicine" into poison.

Thirteenth place went to turmeric due to its active substance called curcumin.

In moderation, it protects the heart from developing a heart attack and inhibits the growth of cancer cells.

Fourteenth place was taken by shiitake mushrooms

Mushrooms have immunostimulatory effects and protect against the development of breast, ovarian and uterine cancers. Vegetables and fruits.

Fermented milk products closed the list of useful products

According to scientists, half a liter of kefir or yogurt a day will strengthen the immune system and protect against the development of cardiovascular and oncological diseases.

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What is cheat meal, and how permissiveness in food will help you lose weight

Surely everyone who has lost weight at least once in his life knows about the concept of "cheat meal". It is believed that against the background of long-term restrictions, relaxation in nutrition suits the body as a kind of "shake-up", which even helps the process of losing weight. Professional trainer Paul Carter explained how to overeat to lose weight.

If on the first day of the diet you are already waiting for a cheat meal, you are probably not yet ready for restrictions and you should reconsider your attitude. But in general, cheat meals are quite common in sports and nutrition.

Cheat meal (meal) is a planned violation of the diet (or habitual eating plan), which helps to relieve tension from too strict dietary restrictions. Cheat meal gives you the right to eat whatever your heart desires, but only in one meal once every 7 days (most often the interval is just that).

But if you feel that you do not need such a ritual and hold on perfectly well without it, you may well successfully lose weight and build muscle mass, and without cheat meals.

Problems only appear when people insist on having a weekly cheat meal too much. Sometimes, patients even make claims to nutritionists, because they do not include cheat meals in their meal plan.

Cheat meals and refeeds are a reward option for dieters and professional athletes preparing for competition. In a word, very many are accustomed to arranging this weekly "holiday" for themselves.

A refeed is like a cheat meal, but its main purpose is to load the body with carbohydrates. The results are about the same as the cheat meal. Let's try to figure out what the differences are.

Cheat meal and refeed

A cheat meal is a deliberate violation of the diet that is scheduled in advance for a specific day. For many it is like a “breath of fresh air” amid constant restrictions. It is also convenient to schedule it for weekends and holidays.

But refeeds appear in the diet only if necessary, if the situation requires it: striving for a certain appearance and figure, athletic achievements, performance in training, etc. That is, refeeds are never planned in advance. Most often, a refeed occurs when an athlete has been eating for a long time with restrictions and his glycogen reserves are very scarce.

Their number and composition is determined individually, since it all depends on how fast the body processes carbohydrates into glucose.

For example, bodybuilders resort to refeeding when muscle mass is “deflated” and needs to be “refilled”. In addition, the refeed maintains muscle mass, since during the depletion of glycogen reserves in the body, the process of gluconeogenesis begins, which, in a calorie deficit, negatively affects the condition of the muscles. And more often than not, the refeed is much more restrained and "cleaner" than the cheat meal. Although cheat meal gives almost the same effect (replenishes glycogen levels).

The importance of cheat meals and refeeds

When you limit your calorie intake, your body produces less leptin and slows down your metabolism. That is why people who diet for too long simply stop losing weight over time. The body changes its metabolism and begins to retain fat so as not to harm health - this is a standard defense mechanism.

In fact, our body only thinks about reproduction and survival, and it does not care about your abs or preparing for the beach season. If you could explain to your body that a beautiful relief will help it in procreation, the reaction to sports and dieting would probably be completely different.

In addition, it is important to understand that a lack of calories for a long time is quite stressful for the body, in response to which the level of cortisol increases, so it becomes much more difficult for you to lose weight. But with a cheat meal, even psychological relaxation helps lower cortisol levels.

Cheat meal, as it were, helps the body to distract itself, so that later it can continue to effectively lose weight and burn fat. The body suddenly realizes that hunger has not come, which means that you can continue to lose weight.

Is it necessary or not

Cheat meals and refeeds are appropriate for people who have already spent quite a lot of time on a diet and have been able to lose weight. But if you are losing weight for only 5-6 days, then by and large your body does not need a cheat meal.

How to determine when it is time to "eat"? The longer you lose weight, the higher the chance that a cheat meal and refeed will help you. If you are a man and you have more than 15% body fat (for women this figure is 25%), then don't even think about cheat meal. Once your body fat has dropped to 10% (or 15% for women), you may want to consider adding a cheat meal to your diet.

But here a second logical question arises - how to determine how many percent of fat is present in your body? Of course, you can go through special procedures, but there is an easier option. Take off your clothes, stand in front of a mirror and start jumping.

If almost the whole body is shaking noticeably, it is too early for you to think about indulging your diet.

If the shaking is moderate (and you have been restricting your diet for quite some time), you can schedule a cheat meal.

If you have almost nothing shaking, then cheat meals and refeeds will only benefit you.

How and when

The effect of the "forbidden fruit" will be most noticeable immediately after an active workout (when the muscles are using the maximum glycogen). Choose low-protein carbohydrates for your refeed, such as sushi, pasta, or steak with baked potatoes. Remember that a cheat meal is just one meal, not a whole day of permissiveness.

You shouldn't get too hung up on the portion size for a cheat meal (remember that this is also a psychological relief), but of course, you should not absorb food in buckets. Just relax, indulge yourself in a delicious meal and get the most out of this meal. And most importantly, after a cheat meal, you should feel a sense of happiness and satisfaction, not remorse.

Important: if you feel that after cheat meals it is difficult for you to return to your usual diet, try temporarily deleting them from your diet. And even if you have a breakdown after the cheat meal, learn your lessons from it and continue to eat according to your plan.

Safe food: everything you wanted to know

Nutrition is an important part of human life. Indeed, in the world a billion people are undernourished, and 2 billion people, on the contrary, overeat and suffer from various diseases associated with obesity. Agree, such an imbalance is alarming. And it is important to understand that this concerns each of us and starts with what is in your refrigerator.

Today we will talk about nutrition and its safety with the Deputy Chief Physician of the Republican Center for Nutrition, Hygiene, Epidemiology and Public Health Lyudmila Konstantinovna Naroichik.

Lyudmila Konstantinovna, let's start with why food safety is so important for all of us?

Food safety is a very serious topic, as diarrheal diseases kill an estimated 2 million people worldwide each year. Moreover, most of the victims are children. And it is good that on the scale of our republic there is no such problem as mass infectious diseases. But this topic is always relevant, since risks exist in any case. The most important thing here lies in the hygienic aspects. If we compare the level of hygiene and the standard of living in African countries and take the developed civilized countries, then this is certainly incomparable, and therefore European countries do not even think about such problems.

I would like to add that if you delve deeper into the historical aspect of this problem, you will notice that Europe, which today is proud of its cleanliness, until recently was much dirtier than the lands where we live today. And the principles of their life were completely different, and we were ahead, and then at some stage, we were a little behind and we also had certain problems with hygiene. Coming back to the topic, let's go over the basic principles of food safety.

If we talk about infectious diseases, then the very first and most important principle voiced by WHO is the observance of cleanliness. That is, all foods that we plan to eat must be stored in appropriate conditions.

But the concept of cleanliness is different for everyone. For a surgeon who washes his hands for 10 minutes - one thing, but for ordinary people - another. Maybe you can give more specific examples that pose a threat to the life and health of people?

I do suggest, however, to start with five basic principles and then discuss each of them in more detail.

The first principle, as we said, is cleanliness. Second: you should never combine ready-made and raw foods, since the latter can be contaminated with a large number of dangerous bacteria. Further, heat treatment is the most important condition, it not only brings the product to readiness, but also kills all dangerous microorganisms. The fourth principle is storage conditions. Many people neglect this rule, but in vain, because each product has a shelf life, and even in the refrigerator you cannot store food for a very long time. And the last principle is freshness of food and clean drinking water. Dangerous pathogens can also enter the body with water.

By the way, on the eve of the holiday season, I want to tell everyone that water is a very important point of your safety and you should be especially careful on vacation. It is best to drink bottled water; this is the safest option. The same goes for cocktails served with ice. If it is made of running water, then you are at great risk too.

But here again. Ask any passer-by if he keeps clean and he will confidently answer you "yes". And for some, washing hands is just getting them wet.

Yes, specifically hand washing is also an important point. Hands should be washed as often as possible when preparing food. There are no trifles here, you should always remember this. All appliances must be washed, cutting boards must be separate for different types food. Yes, in our country there are no outbreaks and epidemics, but every year about 2-3 thousand Salmonella diseases are registered. Moreover, 30% are children, and this already suggests that mothers do not always carefully observe the basic rules of hygiene.

Let's be specific. What rules do mothers fail to follow and thereby endanger the health of their children?

Speaking specifically about salmonellosis, it is most often spread through meat or infected raw eggs... This, again, is washing hands, washing knives and cutting boards, thorough heat treatment of meat and eggs before eating.

What can you say about eating raw eggs?

If you buy eggs from private farmers, you know the owner, you know what the bird eats and how the bird lives, and if you wash them well before eating, then your risk is of course minimized. But this only applies to adults, children are different. Their intestines are not yet ready to meet the causative agent of intestinal infections and cannot adequately respond to them. Remember this.

And who is more dangerous if we talk about the likelihood of infection, large producers or private farms? Whom to trust?

You need to trust yourself. And of course, you need to carefully process the eggs (fry or boil) before cooking.

With hygiene, everything seems to be clear. And if we talk about the rule of not combining raw and cooked food. Is it just about the refrigerator or not just about it?

We are talking about all stages of food preparation. Again, boards, it is better that you have different ones for raw and ready-made products (especially if they are wooden). The same storage, if they come into contact, it is enough for infection. This is an elementary rule of hygiene that should not be neglected.

As for the heat treatment rule. Everything is clear here, there is only one caveat - microwave ovens. If you cook in them, then remember that they heat food rather unevenly and it is important to withstand the required cooking time.

The next principle is storage conditions. In the refrigerator +4, in the freezer -18. Does it ever happen that food in the freezer spoils?

There are microorganisms that tolerate low temperatures very well, and if the meat has been contaminated with any pathogens, then nothing will happen to them in the freezer. And when defrosting, the product will become dangerous again. There are a lot of such examples. I want to remind you that in the age of globalization, it is rather difficult to foresee and control everything, but still try to observe all the rules of hygiene.

What else is worth paying attention to, besides the 5 principles that we have already voiced?

Again, these are very simple things. So you come to the store and see what you buy, read the information on the packaging: expiration dates, packaging integrity, product storage conditions, study the composition. And only then make your choice. The manufacturer will do everything to sell, but you have to think if you need it. Each person always has a choice. Here I would like to touch upon the topic with which we started. Indeed, in food safety, not only hygiene and cleanliness are important, but also what and in what quantities a person eats. After all, if someone receives food in excess, and someone in short supply, this is bad in both cases.

I propose to answer some of the questions of our readers.

Are products from your site safer than those in the store?

Safety and utility should not be confused here. The products in the store are safe for your health, but if we talk about the benefits, then what is grown in your garden always wins. The stores have a control system at several levels at once and of course you should not be afraid of products.

Is alcohol dangerous for worms?

For example, helminth trichinillosis, which is quite common and often found in hunters. So they killed the infected boar, shared it with friends and the spread of infections began. And alcohol does not save anyone in this case.

Can you eat raw meat such as carpaccio?

Well, this particular dish is most often served in restaurants of a certain level, which are very worried about their reputation. This means they have high-quality raw materials, plus spices are used in the preparation, which can disinfect the product a little. Therefore, for lovers, this dish may be acceptable.

Why do you need to change boards? After all, bacteria quickly die in the atmosphere?

Bacteria in the environment can live from several days to several months, so this is a big misconception.

Can I drink tap water?

Our water is supplied of guaranteed quality. But on chemical composition there may be nuances in some places. Therefore, it is still better to drink filtered or bottled water, especially for children.

Your final parting words to our readers.

Remember that a person is responsible for his own health. And if he wants to live long and improve the quality of his life, he will not be irresponsible about his health. Today we talked about elementary norms that should be observed by everyone, without exception. After all, food is one of the most important aspects of our life.

A team of experts from Drexel University has created a cognitive computer game that relieves people of sugar cravings, which means it helps to lose weight. The game called "Diet DASH" helps to train the parts of the brain that control impulsive behavior, helping a person to make the right choices, in particular, to refuse to buy sweets.

The main task of the player is to walk around the virtual supermarket as quickly as possible, collecting useful products in the cart and refusing harmful ones. When a player makes the right choice, points are awarded to him, says psychology professor Evan Foreman.

The authors tested the effectiveness of their development on 106 volunteers who were very fond of sweets and suffered from obesity and excess weight. But before the start of the game, all the volunteers attended a special seminar, where they were told about the dangers of sugar, which foods are harmful and which are useful, and how to organize proper nutrition.

Then all the participants in the experiment played the game for six weeks for several minutes a day. And then they continued to play once a week for another two weeks. As a result, in 8 weeks more than half of the participants lost almost 3% of their body weight. In an interview with scientists, they said that daily play helped them cope with acute attacks of sugar cravings and admitted that they will continue to play it in the future.

Does meat cause cancer or not? Can adults drink milk or not? Low-fat foods - solid good or evil embodied? Research says one thing or the other. And so the scientists themselves told why such a mess is going on in nutrition science.

Once upon a time, the study of nutrition was a simple matter. In 1747, Scottish doctor James Lind decided to find out why so many sailors suffer from scurvy, a disease that leads to wasting and anemia, bleeding gums and tooth loss. So Lind set up the first clinical study of 12 patients with scurvy.

The sailors were divided into six groups, each with a different treatment. People who ate lemons and oranges eventually recovered. An irrefutable result that revealed the cause of the disease, that is, a shortage.

Something like this was solved the problem of nutrition in the pre-industrial era. Many diseases, significant for that time, such as pellagra, scurvy, anemia, endemic goiter, appeared as a result of a lack of one or another element in food. Doctors put forward hypotheses and set up experiments until they experimentally found the missing piece of the puzzle in the diet.

Unfortunately, the study of nutritious nutrition is not so easy now. During the 20th century, medicine has learned to cope with most diseases caused by an unbalanced diet. In developed countries, this is no longer a problem for most people.

Overeating has become the biggest problem today. People consume too many calories and low quality food, which leads to chronic diseases such as cancer, obesity, diabetes, or cardiovascular disease.

Unlike scurvy, these diseases are not so easy to deal with. They do not appear acutely overnight, but develop over the years. And buying a box of oranges cannot get rid of them. It is necessary to study the entire diet and lifestyle of the patient in order to weed out all risk factors leading to the disease.

This is how nutritional science became imprecise and confusing. A sea of ​​conflicting studies has emerged, in which a host of inaccuracies and limitations are easily discovered. The confusion in this area makes nutritional advice confusing. Scientists cannot agree in any way, protect tomatoes from cancer or provoke it, red is useful or harmful, and so on. Therefore, journalists writing about nutrition often sit in a puddle, describing the next report.

To get an idea of ​​how difficult it is to study nutrition, Julia Belluz interviewed eight researchers. And this is what they said.

There is no point in doing a randomized trial to find answers to common nutritional questions

Michael Stern / Flickr.com

The gold standard of evidence-based medicine is a randomized controlled trial. Scientists recruit test takers and then randomly assign them to two groups. One gets the medication, the other gets a placebo.

The implication is that, due to random sampling, the only significant difference between the groups is the drug intake. And if research results differ, it is concluded that the drug is the cause (which is how Lind calculated that fruits cured scurvy).

The point is, for most critical nutritional questions, this approach does not work. It is too difficult to assign different groups to several groups, which will be strictly observed for a long time, in order to determine which food affects which disease.

In an ideal world, I would take 1,000 newborn babies to study and divide them into two groups. To feed one group only fresh fruits and vegetables for the rest of their lives, and the other with bacon and fried chicken... And then I would measure in which group they were more likely to have cancer, heart disease, who would grow old and die earlier, who would be smarter, and so on. But I would have to keep them all in jail, because there is no other way to make 500 specific people not try anything other than fruits and vegetables.

Ben Goldacre, physiologist and epidemiologist

It's wonderful that scientists cannot imprison people and force them on a diet. But this means that existing clinical trials are cluttered and unreliable.

Take, for example, one of the most expensive and large-scale studies by Women’s Health Initiative magazine. The women were divided into two groups, one of which followed a regular diet and the other a low-fat diet. It was assumed that the subjects would eat in this way for several years.

What is the problem? When the researchers collected the data, it turned out that no one followed the recommendations. And both groups ended up eating the same.

Billions were wasted and the hypothesis was never tested.

Walter Willett, physiologist, nutritionist at Harvard University

Rigorous, randomized, placebo-controlled trials can be performed within a short time frame. Some nutritional supplementation studies allow subjects to stay in the laboratory for days or weeks and monitor what they eat.

But such studies have nothing to say about the effects of long-term diets that can be followed for decades. All we can learn is fluctuations in blood cholesterol levels, for example. Researchers only make assumptions that something will affect health in the long term.

Researchers have to rely on observational data full of unknown variables

Instead of randomized trials, scientists have to use data from observational studies. They have been held for years, a huge number of people participate in them, who already eat the way the researchers need. Checks are periodically carried out among them to detect, for example, the development of cancer or diseases of the cardiovascular system.

This is how scientists learn about the dangers of smoking or the benefits of exercise. But due to the lack of control, as in experiments, these studies lack precision.

Let's say you're going to compare people who have eaten a lot of red meat for decades versus people who do. The first catch is that the two groups can differ in other ways. Nobody even distributed them at random. Maybe fish lovers have a higher income or better education, maybe they look after themselves more. And it is one of these factors that will influence the results. Or maybe meat lovers smoke more often.

Researchers may try to control these confounding factors, but it is not realistic to track them all.

giphy.com

Many observational (and non-observational) studies rely on survey data. Scientists cannot stand behind each person's shoulder for decades and watch what he eats. I have to ask.

An obvious problem appears. Do you remember what you ate for lunch yesterday? Crumbled nuts into a salad? And then you had something to eat? And how many grams, in grams, have you eaten this week?

Most likely, you will not be able to answer these questions with the required accuracy. But a huge amount of research uses this data: people themselves tell what they remember.

When the researchers decided to test these memory-based nutritional assessment methods for the Mayo Clinic Proceedings, they found the data "fundamentally wrong and hopelessly flawed." After reviewing a nearly 40-year national study of population health and nutrition, which was based on self-reported dietary reports, the researchers concluded that the reported calories reported by 67% of women could not physiologically match objective data on their body mass index.

Maybe this happened due to the fact that everyone lies and gives those answers that will be approved by public opinion. Or maybe the memory fails. Whatever the reason, it doesn't make it easier for researchers. I had to create protocols that take into account some errors.

I need a camera, gastric and intestinal implants, as well as a device in the toilet that will collect all your secretions, instantly process them and send information about their full composition.

Christopher Gardner

Christopher Gardner, a Stanford researcher, says that in some studies, he provides food for participants. Or it involves nutritionists who closely monitor the diet of the subjects, checking their weight and health status to confirm the purity of the experiment. He calculates an error that can be kept in mind when analyzing other results.

But researchers dream of better instruments, such as sensors that detect chewing and swallowing movements. Or trackers that will display the movement of the hand from the plate to the mouth.

Ray Bouknight / Flickr.com

As if there were few problems with the accuracy of the data ... Scientists have learned that different bodies react differently to the same food. This is another factor that makes it difficult to study the effects of diet on health.

In a recent study published in the journal Cell, Israeli scientists monitored 800 participants for a week, constantly collecting blood sugar data to understand how the body responds to the same food. Each individual's response was different, suggesting that universal dietary guidelines are of limited benefit.

It is clear that the impact of nutrition on health cannot be viewed only in terms of what a person consumes. Much depends on how nutrients and other bioactive food components interact with the genes and gut microflora of each individual.

Rafael Perez-Escamilla, Professor of Epidemiology and Public Health at Yale University

Let's complicate the problem. Foods that appear to be the same actually differ in composition nutrients... Locally grown farm carrots will contain more nutrients than the mass-produced carrots on supermarket shelves. The diner burger will be higher in fat and sugar than

Marion Nestle

Sponsored research tends towards results that are beneficial to sponsors. For example, out of 76 sponsored studies conducted from March to October 2015, 70 drew the conclusions that food manufacturers needed.

"Mostly independent studies find a link between sugary drinks and poor health, but those that soda makers paid to do are not," Nestlé writes.

No matter what, nutritional science is alive

chotda / Flickr.com

The complexities of studying nutrition create the feeling that it is generally unrealistic to find out something unambiguous about the effect of diet on health. But this is not the case. Researchers have used all of these imperfect tools for years. The slow and careful approach pays off.

Without these studies, we would never have known that a lack of folate during pregnancy leads to the development of fetal malformations. We wouldn't know that trans fats have a negative effect on the heart. We wouldn't know that soda in large quantities increases the risk of diabetes and fatty liver disease.

Frank B. Hu, Professor of Public Health and Nutrition, Harvard University

The researchers discussed how they determine which data to trust. In their opinion, it is necessary to evaluate all available studies on one issue, and not isolated reports.

They also recommend looking at different types of research that focus on the same subject: clinical research, observational data, laboratory research. Different work with different introductory, different methods, leading to the same results, is an objectively good indicator that there is a connection between diet and changes in the body.

You need to pay attention to the source of research funding. Independents are funded by government and public funds and are more credible, in particular because the research plan has fewer constraints.

Good researchers never say they've found a superfood, or advise them to skip a particular food entirely, or make bold claims about the effects of eating a particular fruit or type of meat, and limit themselves to suggesting that a particular diet might be beneficial.

These tips reflect the general consensus of a group of researchers who have recently discussed nutrition and health issues. Here are the conclusions of their meeting:

A healthy diet consists of lots of vegetables, fruits, whole grains, seafood, legumes, nuts, and low fat; you should also moderate your consumption of alcohol, red meat, and processed meats. And there is also less sugar and processed grains. It is not necessary to completely cut out any food group or stick to a strict diet to achieve the positive effect. You can combine foods in many ways to create a balanced diet. The diet should take into account individual needs, preferences and cultural traditions.

The statements that cabbage or, for example, kill humanity cannot be called the voice of science. Because, as we understood, science simply cannot prove anything like that.

Where do people get their information about the benefits or dangers of food?

Doubtful claims about nutritional issues have always existed, but in the internet age they have become much easier to face. You enter a query, and on this side of the screen people appear, expressing their opinion, as if they know for sure that it is true.

Unfortunately, there is a long list of questions in the field of nutrition, which still have not been answered. For example, no one knows if vegans have higher, lower, or similar rates of cancer compared to those who consume animal products. Nobody knows because no relevant research has been done.

When I hear an unexpected nutritional statement, I ask myself:

• Does this sound too good to be true? If so, then it is probably not true.
• Does this sound too bad to be true? If so, then it is probably not true.
• How does the person claiming this know that it is true?

Answering the third question can save you a lot of time. Often, after reading a popular article or book, people begin to claim that what they have learned is true. Information can be based:

• on research in vitro (which is practically useless for use in everyday life),
• on animals (the same),
• their own experiences with patients (which can be quite biased)
• or handed down from generation to generation traditions.

Given the myriad of theories and facts about nutrition these days, none of the above sources of information provide sufficient evidence to pique my interest.

Selection bias occurs when people become part of the study group because they have responded well to treatment. For example, a doctor may take a group of patients into Program X. For those who are not eligible for Program X, the doctor stops observing, and the remaining patients end up with a high positive response. If we evaluate only those patients who have completed the course of treatment, then the formation of such a group is based on an independent choice. AND the results obtained in this group may not coincide with the results obtained in the general population (population).

Introduction

For every nutritional claim these days, there are various theories to support it. In this article, I will explain which studies provide evidence for a theory. When we, as vegetarians, base our arguments on concrete evidence, we can prevent exaggeration against us and at the same time understand and operate with facts.

You don't have to be a biochemist

Before going into the basic details of nutrition research, I would like to point out that logic alone (for example, A reduces the likelihood of B, B causes C, so A decreases the likelihood of C) to answer nutritional questions. Logic can give you an idea of ​​a possible cause. But you cannot claim to know all the variables, so a logic check is necessary.

The disadvantage of this approach is that you simply cannot remember the numerous physiological mechanisms that occur in the body, take into account all the relationships between them and establish the truth without first checking. There are many biochemical chains in the body, and each has its own characteristics of interaction with others. Nobody can know all of them. This puts people who know biochemistry and physiology on a par with those who do not have such knowledge. Any theory needs to be tested, no matter how many details a person knows about an organism or food. When the test results are well explained, people with no knowledge of nutritional science or biochemistry can understand them.

The problem of iron absorption is an example in relation to vegetarianism. We often hear from doctors that a person cannot get iron from a vegetarian diet. Iron is essential for optimal health and is not readily absorbed from plant sources as well as from meat. Since vegetarians don't eat meat, it's logical to assume that their health should not be as good as those who eat it, right? Not necessary. Lower iron levels can reduce insulin sensitivity (a risk factor for diabetes), and higher levels are associated with some types of cancer. Knowing this, can we argue that vegetarians have a lower incidence of diabetes and cancer? Not necessary. To find out if vegetarians are healthier than meat eaters, we must compare their rates of disease. Everything else will be just guesswork.

Because of this, don't be fooled by fancy biochemical explanations. Whenever you hear something new about nutritional issues, look at what studies have been done, paying attention to the actual results.

Study types

Obtaining basic results on the influence of the type of nutrition on the development of chronic diseases, which take a long period of time to obtain, is a difficult work combining a large amount of different information. And often, a lot of research is needed to verify which product or component affects the risk of developing a disease.

Research usually focuses on only one disease. In order to accurately know the impact of a particular eating habit, we must consider the risk of all diseases (and possibly quality of life too, which is even more difficult to test). Naturally, some of this information seeps into society. Which of these should be taken seriously?

Nutrition studies can be divided into 2 main categories:

• Those that show which areas of research are worth spending more time and money, but they themselves do not provide concrete evidence;
• Those that provide concrete evidence.

Confusion often arises when the results of only a few studies are reported. And, especially when these studies are the ones that do not provide concrete evidence. Below is a short description different types research in nutrition.

Table 1. Summary of Evidence-Based Studies

Inconclusive (provide information on which variables to investigate further)

In vitro

On animals

Ecological

Thematic

More evidence-based

Retrospective ("case-control")

Crossover

Prospective (cohort)

Case-control cohort

anomized controlled trial (RCT)

Most convincing

Meta-analysis of retrospective or randomized controlled trials

In vitro

These studies examine (outside the body) the interactions between food components and cells in other tissues. What happens outside the body can be very different from what happens when food is eaten, metabolized, and transported to different parts of the body. The food or organism may have factors that counteract the positive or negative properties of the food that cannot be accounted for in the test tube.

On animals

People differ from other species in physiology, psychology, size and lifestyle. This means that the influence exerted by food on an animal is not reliable in order to make recommendations to a person on its basis. Nutritionists rarely (or never) base their nutritional recommendations on in vitro or animal studies. Common food that has been used over the years is generally considered safe until proven otherwise in human studies.

An exception is the testing of synthetic nutritional supplements for their ability to cause cancer. The assumption is that if a new substance causes cancer in any organism, then it doesn't make sense to take risks in humans. Some nutritional supplements were banned due to the results of animal studies, although this is a controversial decision.

Environmental (regional)

Environmental studies compare data on food consumption and disease rates of a group of people in one geographic region versus another; or in the same region for a long time. These studies generate assumptions that can then be tested by observing the habits of individuals rather than the entire group.

Migration Studies are environmental studies that look at what happens to a group of people when they move to another region and develop new dietary habits (and other lifestyle changes). This provides clues as to whether their diseases are primarily genetic.

Studies like this run into problems. The environment and behavior of people from region to region often change along with the diet. It is also possible that more or less certain foods are consumed in the region, but people with diseases actually act in the opposite way to the norms for this region.

Thematic (case study)

A case study is the publication in a scientific journal of the history, characteristics, and outcome of a single person's disease. When case studies are not published in a scientific journal, they are considered casuistry. There are a great many such casuistic-contradictory cases, and this is the reason why research with strict criteria is necessary.

Disease markers

Many studies look at markers of diseases, not the disease itself. An example would be research on the effect of food on cholesterol levels, rather than on the development of heart disease. A particular diet can lower total cholesterol, but also increase the ratio of "bad" to "good" cholesterol, or increase triglyceride levels (also considered a risk factor for heart disease). If you are investigating the outcome of a disease, the results may be inconclusive.

Retrospective ("case-control")

Retrospective studies find people with the disease and compare their past dietary habits with those who do not. These are usually case-control studies because a certain number of people with a disease (case) are compared to a similar number of people without a disease (control).

Case-control studies are relatively inexpensive. It does not take long to follow up until people develop the disease. They allow the study of diseases that are quite rare in the population for prospective studies (described below).

The disadvantage of this type of study is that the occurrence of illness often affects people's memories of their previous diet, and the control group may be more concerned about their health (as expressed in their desire to participate in the study), the difference in habits in this case can be misinterpreted as a factor influencing the disease.

Crossover

Cross-sectional studies observe dietary preferences and disease at the same time and are often case-control studies. They can be biased, especially because the "cases" may have recently changed their diet due to their current illness.

Prospective (cohort)

Prospective studies follow a large number of people who are (usually) healthy when research begins. The diet is evaluated at the beginning and sometimes during the study to ensure that it has not changed. As the population adheres to the diet, the eating habits of those who are sick are compared to those who are not.

One of the benefits of cohort studies is that participants eat normally, which allows the results to be applied to some extent to real life.

To be effective, cohort studies must be large and long-term, long enough for some people to develop the disease under study. They are rarely large enough to study rare diseases. Cohort studies show associations, but not necessarily causes. Cohort studies can lead to misleading results when large numbers of people use the same measures to improve their health. If some of these behaviors reduce the risk of disease, then the outcome for all models will lead to a decrease in risk. Another problem is this: people who know that they are at risk can do what they believe will be aimed at preventing the disease. If they do get sick, this behavior will become associated with the disease. All of these variables must be considered.

Case-control cohort study

Sometimes a case-control study is conducted using subsetting of participants from a prospective study. All participants in the study who did not get sick are compared with the same number of those who did not get sick (instead of comparing with all who did not get sick, as is done in a prospective study). This frees researchers from analyzing the diet or blood samples of each person participating in the study. The case-control cohort study eliminates the bias associated with people's memories of their previous diet, which is common in other case-control studies.

Randomized controlled trial (RCT)

An RCT randomly places people either in a group that is instructed to follow a prescribed diet or in a control group. And then the results are compared.

Whenever possible, RCTs should be double-blind to reduce bias. This means that neither the researchers nor the participants know who is in which group. This is important for equality among groups. For example, if only one group is instructed about nutrition, this may result in a placebo effect in only that group.

Variables can be manipulated much better than cohort studies, and this can provide a better understanding of cause and effect. The disadvantage of this type of study is that the participants may not follow the directions and the study may not take long enough to notice the difference between the groups.

Overview

A review is a study of scientific literature on a specific topic in order to draw a conclusion from this. They usually do not use any statistical methods to quantify the results of various studies. Reviews can range from short to very detailed.

Meta-analysis

Meta-analyzes examine the scientific literature and usually employ a method to quantify a research subject. Methods can range from simply graphing study results for easy comparison, to collecting relevant unpublished information from each study and performing new analyzes on all data.

Other Nutrition Research Questions

Treatment of diseases

A successful, recognized method of treating a disease in some people can prevent the disease, and in some it cannot. This is undoubtedly worth taking into account, but they are two different phenomena. Renal failure is a striking example showing that the method of treatment cannot always serve as prevention. For those whose kidneys are no longer functioning (i.e. in the case of kidney dialysis), a diet should be high in protein and low in fruits and vegetables. This is the opposite good nutrition to prevent kidney failure.

Common problems in analyzing dietary preferences

The main obstacle to studying dietetics is the difficulty in determining what people actually eat. The most common methods are:

• Duplicate portions. Participants submit equivalent portions of the food they consume to be analyzed for their nutrient content. It is very expensive and very rarely done.
• Food diaries. Participants write down everything they ate over the course of several days. Analyzing this data is a long process and is not usually used in large studies.
• Frequency of food consumption questionnaires. Participants are asked how often they eat each item on the list.

If duplicate portions are not analyzed for their nutrient content, the food is checked against the nutrient database to determine this. This can lead to some errors because the researchers have to match the food eaten by the study participants with the food in the database, which is not always easy. This method is also based on the accuracy of information from the database, which may not be correct for all products.

When you add up all the possible errors, you can see that researchers often play with general trends rather than specific numbers, especially in large studies.

Examining certain groups that do not eat certain foods (eg, vegans) can provide some research benefits, given that you can be confident that the amount of food consumed in some categories is zero.

Lack of results

It is to be expected that for any subject matter of study, some studies will not find the same relationship (correlation) found in others. One reason for this is that, among some populations, dietary habits do not change enough to reveal a relationship. The small sample size can also make it difficult to identify existing relationships.

Researcher bias

There is always the possibility that a particular researcher or group of researchers may be biased. They can be confident that the previous research they did was correct and want to provide further evidence of this. They can be funded by companies or organizations that have a financial interest in a particular outcome. Overall, I believe that personal bias influences scientific research less than it influences ideas about nutrition in more social circles.

Publisher bias

There may be bias in the scientific literature for studies that have not found relationships (between variables). Some evidence suggests that researchers are less likely to submit papers with negative results and that journals may delay publication of such studies.

Adjusting Results After Adjusting Variables

While very little is known about the subject under study, the results will be adjusted for various variables, which will affect the outcome of the study. For example, in a study on fat and obesity, the total amount of calories consumed can influence the outcome, so that the result will be adjusted for differences in calorie intake. Typically, the adjustment and post-adjustment mechanisms are communicated in advance. Since the result after the adjustment may disappear altogether, this does not necessarily mean that it was incorrect.

Statistical significance

If someone did research on 1000 people and found that 20 people who ate more avocados developed cancer, then that means that avocados cause cancer, right? Not so fast. Any group of people with cancer will have their own range of avocado consumption. By coincidence, those who developed cancer may have eaten more avocados than those who did not develop cancer. In order to establish whether the found match is really true or is it just an accident, statistical methods are used. As a rule, the establishment of a fact in which the probability of its accidental occurrence is less than 5% is considered statistically significant.

Conclusion

The main idea of ​​this article is that in order to know something with confidence about nutrition, each question must be fully and thoroughly studied. Indirect methods, which are often resorted to, lead only to guesswork.

Applicable to vegetarian diets

Now that you are familiar with the basics of nutritional research, you know that in order to understand the health of vegetarians, you must study their rates of disease versus non-vegetarians. By examining these studies, you will have a strong case for balancing your diet, and you will have something to argue against the claims of people who claim that vegetarianism is an unhealthy diet based on several possible disadvantages.

Summing up the results of the outgoing year, one cannot ignore the scientific discoveries in the field of nutrition made by scientists from different countries in 2015. Perhaps not all of them became a breakthrough and turned the scientific world upside down, but they all certainly deserve that we learn about them.

We decided to tell you about the scientific discoveries of the outgoing year, which make you take a fresh look at the well-known products.

1. Night snacks impair memory

American scientists from the University of California have stated that nighttime snacks can cause memory impairment. They came to this conclusion after an experiment conducted on mice. For 2 weeks, one group of experimental subjects was fed only at night, and the other only during the day.

Despite the fact that the mice in both control groups slept for the same amount of time, the rodents in the first group soon developed sleep problems and decreased production of proteins responsible for memory and learning. As a result, mice that were fed only at night became much worse on memory tests.

2. Healthy foods can cause obesity

Scientists at the Cornell University Nutrition Lab have come to an unexpected conclusion. It turns out that obesity can be caused not only by fast food and fatty foods, but also by completely harmless "healthy" foods with low calorie content.

The researchers conducted an experiment in which a control group of 100 volunteers was offered a healthy low-calorie cookie as a snack during a movie show. The results of the study showed that if a person is confident that he is eating dietary products, he forgets about the sense of proportion and as a result overeats.

3. Apples burn fat

This is the conclusion reached by a group of researchers from the University of Iowa led by Dr. Christopher Adams. In the course of the experiments, scientists found that regular consumption of apples increases muscle mass by 15%, while reducing the amount of body fat by almost 50%.

According to scientists, it's all about the ursolic acid contained in apples, which increases the activity of signals that stimulate muscle growth and reduce the amount of white fat in the body. Along the way, researchers found that apples help lower cholesterol and blood sugar levels.

4. Chocolate contains opiates

As a result of numerous experiments, scientists have found that the cocoa beans, of which our favorite chocolate is composed, contains a substance vandanamide, which affects the human brain and causes it to be addictive.

However, there is a small caveat: for at least a minimal effect, you need to eat at least 30 kilograms of natural dark chocolate. So do not deny yourself your favorite delicacy, just know when to stop.

5. Cheese is addictive

In addition to dark chocolate, cheese can also cause addiction in a person - this is the conclusion reached by American scientists from the universities of Michigan and Colorado. They conducted a study that found that cheese is addictive in humans.

The fact is that the composition of this product includes casein protein, which, in the process of digestion, releases casomorphins. It is they who, interacting with dopamine receptors, trigger the mechanism of addiction formation.

6. Champagne improves memory

A group of researchers from the University of Reading (UK) has discovered in the composition of the grapes Pinot Noir and Pinot Meunier, from which champagne is produced, a plant compound that improves memory and reduces the risk of brain diseases.

Researchers believe that for age-related memory problems and prevention senile dementia just 3 glasses of brut a week is enough. So far, the experiment was carried out only on laboratory mice, but soon scientists plan to test their discovery in humans, inviting a control group of volunteers over the age of 65 to participate in the research.

7. Spicy food prolongs life

This is the conclusion reached by Chinese scientists. In a 7-year study, they examined the diets of more than 500,000 people aged 30 to 79 and found that among those who ate at least 3 times a week of spicy food, early mortality was almost 14% lower than among those who didn't eat it at all. The best scores were for those who ate fresh chili peppers, which are high in capsaicin.

8. The size of the glasses affects the amount of alcohol consumed

A group of researchers from the University of Cambridge concluded that in the same situations, people drink much more alcohol if they drink from large glasses.

The experiment was carried out in the Cambridge bar The Pint Shop, where for 16 weeks, visitors were offered the same portion of alcohol in 175 milliliters in containers of different sizes - 250, 300 or 370 milliliters. It turned out that the larger the glass, the more often customers order an additional portion of the drink.

According to study leader Teresa Marteau, this phenomenon is known as a block of displacement: large dishes give a person the illusion that they have drunk only half of their norm, and they order an additional portion.

9. Salty foods don't make you thirsty

Professor Mika Leshem from the University of Haifa conducted a study, during which it turned out that the use of salty foods has nothing to do with the appearance of a person's thirst.

The experiment was carried out in a control group of 58 students. They were divided into 3 subgroups: the first ate salted nuts, the second - unleavened, and the third - candied. 2 hours before the experiment, the students were asked not to smoke or drink water, and for several hours after - every 15 minutes to record the level of thirst in a special questionnaire.

The results of the study showed that after eating salted, plain and sweet nuts, students wanted to drink the same way. This means that salt does not affect the onset of thirst.

10. Coffee Reduces the Risk of Liver Cancer

Researchers at the World Cancer Foundation and the American Institute for Cancer Research have found coffee to be effective in preventing liver cancer.

The experiment involved 8,000,000 people from around the world, 24,000 of whom were diagnosed with liver cancer at various stages. After analyzing data from 34 studies conducted as part of the experiment, scientists found that people who drink 1 cup of coffee daily have a 29% lower chance of cancer than those who do not drink coffee at all.

Russian scientists conducted an experiment in which almost 250 volunteers ate for two weeks according to the recommendations of experts and donated samples of the intestinal microbiome before and after the study. A press release from Novosibirsk State University calls this work "the largest study on the effect of diet on gut microbiota." The results were published in the journal Nutrients.

The question of what is proper nutrition and what effect certain dietary interventions have on the body are very much discussed these days. However, most of the scientific research in this direction is devoted to the study of the effect of individual nutrients under tightly controlled conditions. At the same time, the question remains open, what changes occur in the human body, which begins to adhere to healthy eating without changing the usual rhythm of your life.

To answer this question, a group of scientists from the Laboratory of Theoretical and Applied Functional Genomics of NSU, the Atlas Research Company and ITMO University conducted a study in which 248 volunteers followed the nutritionist's recommendations for two weeks, aimed at increasing the amount of useful plant fiber and reduced empty calories.

Scientists were interested in how diet can change the composition of the bacterial community (microbiota) of the intestines of volunteers. For this, two microbiota samples were collected from each volunteer - before and after following the recommendations. These samples were analyzed using metagenomic DNA sequencing.

Intestinal bacteria are mostly human symbionts: they protect us from infections, produce vitamins and butyric acid necessary for intestinal cells, decompose complex polysaccharides and participate in the formation of immunity. When the balance of the microbiota and the human body is imbalanced, the number of opportunistic bacteria increases, causing inflammation in the intestines and other health problems.

In a community, each microbe performs certain functions, representing a link in a complex metabolic network, and the composition of nutrients coming from outside with food largely determines which microbes will gain a competitive advantage. On the other hand, health conditions often also affect the composition of the community: the presence of diseases such as type 2 diabetes, coronary heart disease and inflammatory bowel disease can be predicted with relatively high accuracy from the human microbiota. The composition of the microbiota varies widely among people and allows one to judge both their dietary preferences and health status.

The presence of fermenting bacteria that convert complex polysaccharides into short-chain fatty acids useful for humans is one of the important signs of a healthy microbiota. The study showed that after the participants in the experiment began to follow the recommendations of a nutritionist, they had significantly more of these bacteria in their intestines. This suggests that even two weeks of healthy eating have a beneficial effect on the microbiota of his intestines.

However, against the background of an increase in the number of microbes associated with a healthy state of the body, some destabilization of the intestinal community was also observed. First of all, this was expressed in the fact that the diversity of microorganisms in the intestine decreased. The more diverse a community is, the more resilient it is to external influences such as stress or antibiotics. The diversity-reducing effect observed in the study was quite small. Apparently, it is associated with the fact that the microbiota did not have time to "recover" from a fairly rapid change in diet.

“The study materials formed the basis of the microbiota test, and the study's conclusion is very practical: it is possible to improve gut health by increasing the amount of dietary fiber. And it works not only in rigorous clinical trials, but also at home, ”said Dmitry Alekseev, senior researcher at the Laboratory of Theoretical and Applied Functional Genomics at NSU.

Another interesting observation was that in different people the microbiota reacted with different strengths to the diet: in some people, the composition of the community changed more. The groups did not differ in terms of diet before the study, or according to the recommendations of a dietitian, however, they could be predicted with fairly high accuracy from the composition of the microbiota before the diet. This observation suggests that in order to increase the effectiveness of dietary recommendations, it is important to take into account not only the person's current diet, but also the composition of his intestinal community.

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