10 Zinc Foods You Should Include in Your Diet

Don't skip breakfast. Cut down on fats. Avoid gluten. Drink at least eight glasses of water a day. Drink less coffee. Sound familiar? Let's figure out whether you need to follow these tips based on scientific achievements.

Scientist and doctor Tim Spector, author of the book “Mandatory Breakfast, Bad Coffee and Dangerous Fast Food,” dispels myths about “healthy” eating, based on scientific advances. He touches on diet food, veganism, eating fish, caffeine, vitamin supplements, and organic foods. Tim Spector is Professor of Genetic Epidemiology at King's College London and Director of the TwinsUK Registry. Since 1992, he has been proving that many diseases are related not only to diet and environment, but also to genetics. He has published more than 700 articles in scientific journals, including Science and Nature. He is the director of the Human Microbiome Research Project and the author of several books and an academic award winner. She also conducts research in the field of epigenetics - the science of how our genes are influenced by the environment. We publish an excerpt from his book.

Myth: Breakfast is the most important meal of the day.

“A proper breakfast is the key to a good day!”, “Eat breakfast like a king!”
- the idea that a morning meal is mandatory and is the key to energy, concentration and good mood throughout the day is hammered into us like a mantra from early childhood. Over the last half century, we have been bombarded with messages extolling the health benefits of dry processed cereals, muesli and oatmeal. But what exactly do we mean by breakfast? A British mountain of various fried things? Or a typical Italian breakfast consisting of cappuccino and a cigarette? After all, cappuccino contains milk and sugar, which means it contains all three macronutrients - carbohydrates, fats and proteins - and will have the same effect on metabolism as a serving of food: it will break our overnight fast.
What about black espresso or tea without sugar? It contains fiber and polyphenols, but no carbohydrates, which provide energy. Many people who say they don't eat breakfast actually start their mornings with tea or coffee with milk - which means they still consume something.

Signs of Zinc Deficiency

Zinc deficiency has negative consequences for the body:

• deterioration of central vision;
• disruptions in the functioning of the immune system;
• complications during pregnancy (early birth, disturbances in fetal development).

With a lack of zinc, there is often an excessive tendency to pneumonia and diarrhea. Deficiency of this vitamin at the initial stage does not have specific symptoms. In some cases, insomnia develops, hair begins to fall out, night vision deteriorates, mood decreases, and skin lesions take a long time to heal.

If you have such symptoms, you should consult a doctor.

What is breakfast?

The lack of a good definition of what breakfast is is one of the reasons why there has been little research in this area.
In Anglo-Saxon culture, breakfast is considered an essential part of life. However, most modern fad diets, particularly the Paleo diet, tend to follow the example of our ancestors, who lived thousands of years ago and led a nomadic lifestyle. But as applied to breakfast, this topic is rarely discussed. When I visited the Tanzanian Hadza tribe (the last true hunter-gatherers remaining in East Africa), I noticed that they do not have breakfast in their daily routine, although they go to bed and get up at approximately the same time. They don’t even have a special word in their language for morning meal. Usually, when men wake up, they go hunting on an empty stomach - later they can pick and eat some berries along the way. Women remain in or near the camp and may sometimes prepare simple food such as baobab porridge or eat stored honey, but usually not before 10 am. This means that during the day they do not eat anything for 14 or 15 hours, including sleep at night, which contrasts with the Western habit: our night fast lasts only 8-10 hours.

Pumpkin seeds

What other foods contain zinc? 100 g of pumpkin seeds contain 7.8 mg of this microelement, and when fried, its concentration does not decrease much. Pumpkin seeds are rich in antioxidants that prolong youth and beauty, and they owe these properties to zinc. With a lack of the mineral, the brain is deprived of nutrition, so memory deteriorates, and senile dementia develops in old age. Once you add zinc to your diet, your memory clears up.

Pumpkin seeds can not only be fried in a frying pan, but also dried in the oven until they become golden brown. They are used to decorate salads, soups, cereals, casseroles, baked goods, sweet pastries and fruit desserts. Pumpkin seeds are also used to make vegan candy and raw cheese.

Oatmeal or roti?

Historians who study human eating habits may disagree with me, but I believe that breakfast probably became widespread during the Victorian era.
Before that, in the morning we usually ate the leftovers of yesterday's dinner. Breakfast also stands out because it is the only meal in which people all over the world eat the same thing day after day, year after year, and do not get bored. They even feel lost if they don't eat their usual breakfast one morning; be it two pieces of toast, a boiled egg, oatmeal, or (on another continent) dim sum, roti or saag aloo (dim sum - light snacks in Chinese cuisine, usually served with tea; roti - traditional Indian bread; saag aloo - Indian green dish, potatoes and spices). I remember how difficult it was for me to adjust to curry and vegetables for breakfast when I was working in a hospital in Nairobi as a medical student. Japanese and Korean breakfasts are also completely opposite from Western ones and usually include rice, vegetables, miso soup, pickled vegetables, spicy kimchi or fermented soybeans.

One of the reasons why breakfast may depend on the culture and history of a people, and not be something common to all humanity, is perhaps that the food must somehow be preserved overnight, and then time and effort must be spent on preparing it. in the morning. This means that before the invention of refrigerators, only rich people who had servants could have breakfast. This all changed with the advent of cheap, processed food that can be stored for a long time and is easy to prepare. Kellogg's Corn Flakes became the first major breakfast cereal brand. They were invented in 1894 and were initially considered a very healthy product. Millions of bowls of this cereal are now eaten every day around the world. They are made from refined corn flour and have a very high glycemic index of 81, even higher than potatoes (78).

After removing the nutritious fat-containing parts of the grain, the remaining part is heated in pressure cookers for several hours, and then it is rolled out flat and fried. The result consists mostly of fried starch, which has virtually zero nutritional value. Therefore, various chemicals, including vitamins, are added to corn flakes. Profit margins for breakfast cereals are over 40%; This allows manufacturers to spend approximately 25% of their breakfast revenue on advertising to brainwash children and teenagers and influence the opinions of adults - the general public and nutritionists - about the nutritional value of the cereal. Due to the popularity and profitability of breakfast cereals, there are now 5,000 different brands of breakfast cereals produced in the United States alone.

Products

The best sources of zinc are animal products, including seafood. Oysters, mussels and shrimp are rich in microelements; it is found in fish - salmon, trout. By eating 50 grams of oysters, you will provide your body with a valuable mineral for a day.

It is found in smaller quantities in red meat, for example, 100 g of beef or lamb provides up to 65 percent of the daily value. Pumpkin and watermelon seeds are equivalent in zinc content. But it is impossible to compensate for the body’s needs for microelements at the expense of berries, vegetables and fruits. They contain zinc, but in order for an adult to get the required amount, for example, from apples or currants, they will need to eat at least ten kilograms.

Table - list of foods rich in zinc

Products high in zinc are available at any store. But the microelement is absorbed differently. Best from seafood, meat, hard cheeses, offal. Worse - from grains and soybeans. In addition to fiber, which inhibits absorption, they contain phytic acid, which “binds” the microelement. Therefore, yeast bread will not be useful, but baking from wholemeal flour with sourdough will benefit the body, since the phytic compounds in it are destroyed.

Does breakfast “kick start” your metabolism?

Some beliefs about breakfast are so widely held that most people never think to question them. For example, the fact that breakfast somehow “starts” our metabolism in the morning, allowing us to more efficiently digest food throughout the day. And also the fact that if you skip breakfast, you will get hungry, then overeat and, as a result, gain weight. Despite the lack of evidence, these ideas are presented as scientific facts.

In Britain, for example, they were included in National Health Service guidelines developed by civil servants from the Public Health Service, a committee of specialist scientists who receive data from the food industry. Similar statements are found in the US Department of Agriculture's recommendations for Americans and in the Australian government's current healthy eating guidelines. The same statements about the need for breakfast can be found in the recommendations of health authorities in other countries, as well as in the press and the Internet around the world. But what if we were misled? What if this is just another nutrition myth?

In 2021, a systematic review and meta-analysis of studies looking at the effects of skipping breakfast was finally published in the British Medical Journal. The review authors reviewed 52 studies and rejected most of them because they were poorly designed and lacked proper randomization (in other words, the results of the studies could not possibly be objective), and four because they were conducted in low-income countries. Of the remaining 11 randomized clinical trials that qualified, the majority were conducted in the US and UK and only one in Japan.

The studies varied in both length (from one day to six weeks) and quality. Seven of the studies tracked participants' changes in weight as well as variations in their energy intake, which was determined by measuring their metabolic rate. The conclusion of this meta-analysis was the same as previous reviews based on less information: there is no evidence that skipping breakfast makes you gain weight or lower your basal metabolic rate. In fact, evidence shows that the opposite is true: skipping breakfast may be a successful strategy for weight loss. Why were nutritionists of the past so wrong and why didn’t they point out the lack of quality data sooner?

There may be several reasons, and they all relate to traditional beliefs about nutrition and food.

Daily consumption rate

It is 10 – 15 mg, increases during pregnancy, with severe psycho-emotional stress, prolonged physical activity.

The daily norm of zinc for women is 10 - 13 mg, the norm of zinc for men should be at least 13 - 15 mg per day.

For infants and newborns, the daily requirement of zinc should be no more than 5 mg, for children under 10 years old - no less than 10 mg, for children under 18 years old - from 8 to 12 mg.

It is recommended that women take at least 15 to 19 milligrams during pregnancy or breastfeeding, and they should increase their serving size of foods containing these micronutrients.

Professional athletes can introduce foods rich in minerals and dietary supplements into their diet. They need to use at least 20 - 35 mg daily.

It is recommended to combine these substances with other minerals, calcium, vitamins B 6, B 12, C.

Often and little by little

Lately, nutritionists have been advising eating little and often to avoid stress on the body: when digesting a hearty meal, the body secretes insulin, sometimes in large quantities, and this can ultimately lead to the development of insulin resistance and diabetes.
They say following this advice is especially important in the afternoon, when glucose and insulin levels peak higher and your metabolic rate drops. This advice is based on the results of studies conducted on small animals, as well as data from a few and short-term experiments in humans. The groundbreaking study - which changed the minds of all doctors and nutritionists - was published more than 30 years ago in the prestigious New England Journal of Medicine.

In the study, participants were given the same food in the same quantities per day, but in the first two weeks they received it throughout the day in the form of 17 small meals. After the break, the same amount of the same food was divided into three servings. The experimenter found that in the group that ate small meals, blood insulin levels decreased by 27% and a stress marker (cortisol) decreased by 20%. This is all very impressive until you realize that this famous study only had seven participants, so the results may well be due to chance and definitely should not be generalized to all people and all dietary needs.

Binge eating

The concern that skipping breakfast may lead to overeating the rest of the day is theoretically justified: those who skip breakfast tend to eat more at lunch and also tend to be less active.
As for metabolism, it is triggered by an interesting process called food thermogenesis: eating itself stimulates the formation of heat in the body. But the main point is that these cunning compensatory mechanisms, even together, are not able to compensate for the calorie deficit resulting from skipping breakfast. Some misconceptions about breakfast, based on rumors and unreliable research, are firmly entrenched as tenets of nutrition science, even among experts. Nutritionists, doctors and food industry workers, as well as the general public, have been deceived by big headlines based on few observations. These studies found that people who skip breakfast are more likely to be overweight. But skipping breakfast is not the cause of excess weight. The skewed results are due to poor study design. Those who skipped breakfast were, on average, more likely to have lower incomes and therefore have a poorer overall diet than those who ate breakfast. All of these social factors were independently associated with excess weight, which was therefore not a result of skipping breakfast. Research has also shown that overweight people were more likely to diet, crash, and then feel guilty and try to skip meals.

Breakfast cereals

Despite obvious flaws in design and a steady increase in the number of randomized controlled trials with contrary results, the belief that skipping meals is harmful has been around for decades and is still one of the eight principles of healthy eating in the UK National Health Service guidelines, as well as in current USDA and Australian Dietary Guidelines.
Thriving food conglomerates have huge marketing budgets and great influence over government officials; it allows food corporations to influence public policy—so much so that long-debunked principles find their way into government-sanctioned guidelines. When you think about how much money a multibillion-dollar industry would lose if, for example, people stopped eating breakfast cereal, it's easy to see why myths about breakfast are so common and persistent.

So what good do we get from skipping breakfast? A number of positive effects likely stem from the fact that we fast for longer periods of time as a result. There is now growing evidence that limiting the window during which we eat and extending the window during which we don't eat may help lower insulin levels and help some people lose weight. Some of these recent, seemingly counterintuitive discoveries can be understood when considered in the context of the GI microbiome. This community of 100 trillion microbes, found primarily in the large intestine, behaves like an additional organ of the body, influencing our health and metabolism. Many microbes have circadian rhythms similar to ours, and microorganisms differ greatly in composition and function when they are hungry versus when they are fed.

Although the discipline is relatively new, some evidence suggests that microbial communities suffer from long periods of fasting, but short periods of fasting—such as skipping breakfast—may benefit them. After 4-6 hours without food, certain types of microbes begin to multiply and feed on carbohydrates from the layer of mucus lining the intestines, essentially cleaning it out, resulting in a more efficient and healthier intestinal barrier. It's possible that microbial communities, like ourselves, also need to relax and rest as part of their circadian rhythm, which is why rest is important for our gut health.

Cereals

Oatmeal is another food that is high in zinc. 100 g of oatmeal contains about 4 mg of mineral, and it can be prepared in different ways - with vegetables, fruits or berries. Rolled oats make delicious pancakes with carrots and apples, potato pancakes, honey bars with nuts and dried fruits, pies, cookies, crumble, puddings, soups, casseroles, muffins, bread and other baked goods.

Zinc takes an active part in the functioning of the immune system, fights harmful bacteria and viruses, participates in the production of one hundred enzymes in the body, and also improves the functioning of the sense of smell and taste buds. In addition, it normalizes vision and regulates blood sugar levels. However, oatmeal is also beneficial due to its fiber, which lowers cholesterol levels and takes care of the proper intestinal microflora.

Breakfast and memory

In addition to the false promise of weight loss, another common argument used to market breakfast cereals is that children won't be able to concentrate in school without breakfast.
There are many tales about how children, supposedly deprived of breakfast, freak out in class or perform poorly on assignments due to low blood glucose levels. Again, this evidence is based largely on outside observation and is likely to be biased in the same way as corresponding studies on adults. Some independent reviews have looked at many studies in this area and found them to be of poor quality. Twenty-one studies looked at just the effect of eating breakfast on a child's ability to pay attention that day. Only eight studies found a positive effect of breakfast. In the rest, the effect appeared only in boys suffering from malnutrition. Similar results were found when memory ability was tested, and no consistent patterns associated with breakfast type could be identified. In general, these were artificial scenarios that are difficult to extrapolate to the real world. To examine a longer-term picture of the impact of breakfast on academic performance, 11 studies were conducted involving long-term school breakfast programs.

In seven out of eight, no clear increase in concentration was found. Four out of five also showed no positive effect of breakfast on memory. This means that there is no authoritative scientific evidence that children should be forced to eat breakfast if they are eating normally. Some children and teenagers simply don't feel hungry in the morning.

Is it possible to skip breakfast?

Many people in developed countries around the world regularly skip breakfast.
Concrete data is difficult to come by, although the oatmeal and breakfast cereal industry has persistently sponsored studies that have found skipped breakfast rates to reach "dangerous" levels of 50% in countries like the UK. As people get older, they are less likely to skip breakfast and generally fall into the routine prescribed by their culture. Many others, including myself, eat breakfast regularly and enjoy it. I don't want to say that absolutely everyone who is overweight can lose weight if they start skipping breakfast. Some people naturally tend to prefer earlier meals, while others prefer later ones. This may be due to the unique metabolism and special composition of the intestinal microbiome of each person. I repeat once again: there is no universal solution to the question of whether and when to have breakfast. Skipping breakfast a few times definitely won't hurt; and I encourage readers to experiment to see how it makes them feel, both in the short term in terms of mood and tone, and in the long term. You could, for example, skip breakfast for a month and see if that leads to weight gain or loss. If it becomes too difficult, try skipping meals every now and then. I sometimes do this to boost my metabolism, as well as extend my overnight fast and help my germs. Breakfast may indeed be the most important meal of the day, but it's clearly not for everyone.

Based on materials from the book “Mandatory Breakfast, Harmful Coffee and Dangerous Fast Food”