What to eat to actually feel better
Scientists are gathering increasing evidence that diet can be used to influence the psyche and even alleviate the symptoms of many diseases.
The gut interacts with the brain through what is known as the gut-brain axis, a system for transmitting signals between organs. Germs in the gut produce neurotransmitters, such as serotonin and dopamine, which regulate our mood and emotions. Now there is a growing body of research showing that through these mechanisms, nutrition can influence mental health.
As psychiatrist Drew Ramsey says, this is good news for all of us: "We can't control our genes, we can't choose our parents or whether traumatic events will happen to us. But we can control what we eat and thus take care of our brains on a daily basis."
Of course, Ramsay's words cannot be relied upon completely: one cannot always control one's diet, if only because of financial problems. In addition, research on the relationship between microbes in the gut and the brain has its limitations.
For example, it is not known exactly whether the relationship between nutrition and the brain is causal or correlational. Is it the microbiome that affects the mental state or vice versa? More research is needed for mental health organizations to start making clear dietary recommendations for mental health. Nevertheless, the first conclusions can already be drawn.
Here are some of the conclusions scientists have reached in recent studies.
Mediterranean diet may reduce symptoms of depression
This is not even a diet, but a whole cuisine based on the usual foods of the inhabitants of Greece, Italy, and Spain. Instead of animal fats, vegetable fats, preferably olive oil. Instead of pork and beef, chicken and fish. Plus lots of legumes, whole grains, fruits, vegetables and dairy products. Studies show that people with depression are healed from it faster on the Mediterranean diet.
Here's how it was tested: American scientists gathered 67 people with clinical depression and divided them into two groups. One group was counseled by a dietitian: he taught the participants the principles of the Mediterranean diet. The second group - a social support worker, who did not give any dietary recommendations. All participants continued to take antidepressants, if prescribed.
The dietitian's group made serious dietary changes. They ate granola and oatmeal, small amounts of lean meat and fish, and lots of vegetables, fruits, and cereals. They also gave up pizza, cereal, sausage, and ham.
After 12 weeks, all participants took depression tests. In both groups, there was a reduction in symptoms of the illness. But progress was more marked in the dietitian's group, with 30 percent of the participants no longer experiencing symptoms of depression. In the second group, there were only 8%.
This was not the only positive effect the participants observed. They spent an average of $138 a week on food before going on the diet, and $112 after. The hamburgers, pizza and sweets they ate before were more expensive.
Later, other studies have shown the effectiveness of the Mediterranean diet for depression. But exactly what makes it work is not yet known. Perhaps it's tryptophan - an amino acid, which is rich in many "Mediterranean" products: cheese, nuts, yogurt, fish, soybeans and vegetables. This amino acid is necessary for the brain to produce serotonin.
That said, switching to a Mediterranean diet does not appear to be necessary for a positive effect: even small changes will have an effect. One six-year study monitored the mental state of 12,400 people who increased their consumption of fruits and vegetables. After two years of the experiment, almost all participants rated their level of life satisfaction significantly higher. But what mattered was exactly how much fruit and vegetables they ate. The greatest positive effect on mental health was observed when respondents ate eight servings a day.
Excess sugar can affect productivity and concentration
The WHO recommends reducing the amount of added sugar in the diet - primarily sweets and sodas. But it's not just about the risks of obesity and tooth decay.
The WHO Guidelines on Sugar Intake in Adults and Children.
The main carrier of calories in sugar is glucose. Our cells use it in combination with oxygen to produce energy. But glucose molecules cannot get through the cell membranes on their own, this requires the hormone insulin - it tells the cells to let the glucose in from the blood. If too much glucose comes with food, the body does not have time to produce enough insulin and excess glucose continues to circulate in the blood. One hypothesis is that this, among other things, leads to inflammation. And inflammation can negatively affect cognitive abilities.
In 2019, Chinese scientists analyzed the effects of added sugar on children ages 6 to 12. Tests showed that students who drank sugary sodas or tea with sugar twice a week or more often performed 1.62 times worse on schoolwork than their peers who avoided such drinks. In addition, sugary drinkers were more likely to suffer from attention deficit hyperactivity disorder.
In another experiment, scientists fed rats standard foods and foods high in sugars. Those fed sugary foods showed signs of inflammation in the hippocampus. Apparently, the same mechanism works in humans.
But at least up to a certain point, these changes are reversible if a person switches to a low-sugar diet, such as the Mediterranean diet. Participants who switched to this type of diet and exercise significantly improved their cognitive abilities and especially their memory over three years. But the effect can come even faster. Some researchers have pointed out that even seven weeks without added sugar improves memory.
Highly processed foods may increase the risk of depression
The diet that is commonly referred to as a Western diet - with lots of refined foods, processed foods, and saturated fats - increases the risks of a large number of mental disorders, including depression. This has already been confirmed by many studies with large-scale samples.
For example, French scientists tracked the fate of 27,000 people who were not depressed at the start of the study. Every six months, participants had to submit three daily nutrition reports. From these, the scientists identified typical patterns of eating behavior. Separately, they paid attention to heavily processed foods - with various flavor enhancers and sauces, pizza, burgers, sweets, instant noodles, and ready-to-eat supermarket meals that only need to be heated up.
Examples of minimally and heavily processed products
Minimal processing Beans: soybeans, peas, chickpeas, lentils
Nuts: unsalted peanuts, walnuts, almonds, macadamia nuts and others
Vegetables: tomatoes, cucumbers, carrots, eggplant, zucchini, spinach, kale, arugula
Home-made red meats: pork and beef
House made chicken
Fish: sardines, tuna, salmon
Strong processing Chocolate beverages and yogurt with additives
Carbonated beverages and reconstituted juices
Noodles and instant soups
Processed meat products: hamburger meatballs, frankfurters, cooked sausage, salami, ham, turkey breast
Frozen meat products: pizza, nuggets, French fries
Bread, hamburger rolls, hot dog rolls, sweet rolls
Sweets: candy, chewing gum, ice cream, jelly, and chocolate
As a result, in the course of the experiment, 8% of the participants were diagnosed with depression. And many of them ate mostly processed foods. The researchers estimate that a 10 percent increase in processed foods in the diet increases the risk of depressive symptoms by 21 percent. Still, the study has limitations. For example, the researchers cannot completely rule out other factors influencing the development or reduction of depression symptoms. They could have been caused by events in the participants' lives, not by their diets.
But, as usual, scientists don't fully understand exactly why processed foods might be detrimental to health. One of the main hypotheses is that the body lacks important nutrients and that the processes in which these substances are involved are impaired. Zinc deficiency creates problems in transporting dopamine, which affects a person's mood and mental stability.
Another problem is the non-nutrients that are used in cooking: for example, emulsifiers and molecules that are formed during the intense heating of food. These impoverish the intestinal microbiome and cause inflammation, which can eventually affect the central nervous system and cause symptoms of depression.
Boredom can lead to obesity
When a person has a boring, uninteresting job, he often takes a break for a snack. The same is true of people whose lives are monotonous and boring. If a person is apathetic, he is not interested in anything, he looks for meaning in food.
Why does this happen? The fact that in order to maintain a good mood, a person needs dopamine, which the body produces at the moment of receiving a subjectively pleasant experience.
If the work you do is interesting and you enjoy it, then the process of doing it stimulates the production of dopamine. If you don't like your work, you will look for that stimulus on the side. The easiest way to get pleasure is through delicious food.
The result is an increase in body weight. Researchers from Ireland and England say: obesity is more common among those who regularly experience boredom, and not other negative emotions. The researchers asked the participants for a week every day to write in a diary answers to the questions of how easy it was for them to focus on work today, whether they had a good day. The degree of satisfaction had to be rated in points. Positive and negative emotions of the day were evaluated and a food diary was kept.
It turned out that when the level of boredom increased by about 1.3 times, the participants of the experiment consumed 100 kilocalories more per day.
Of course, a week is too short a period to draw far-reaching conclusions, but other experiments by these scientists, also small, confirmed these findings. One of them involved 44 students who were divided into two groups: one was shown a sad movie, the other - a boring video clip. And they were offered a choice of eating sweet crackers or cherry tomatoes while watching it. Those who watched the boring video were more likely to choose cookies than cherries. That is, apparently, boredom induces a desire to eat "unhealthy" food, which is enjoyable, rather than "healthy" food, which itself is rated as "boring."
The microbiome may affect feelings of fear
A key element of gut health is a rich microbiome, that is, a great variety of bacteria that live there. Monotonous and heavily processed food leads to an impoverished microbiome. This, in turn, can greatly affect the mental state and, as recent studies have shown, the feeling of fear.
The study was done on mice. Some of them had a normal microbiome, while others had a depleted one. Scientists made the mice feel frightened: they turned on a beep, followed by an electric shock. But they soon stopped using the current and just turned on the signal. The mice with normal microbiomes quickly stopped responding, while those with depleted microbiomes continued to freeze when they heard the sound.
Then the researchers looked at what the medial prefrontal cortex looked like in these mice: it's the one responsible for fear reactions. In those of them with a depleted microbiome, some of the neurons looked different: they had fewer special spikes associated with learning. Scientists suggested that mice with a depleted microbiome could not learn not to be afraid.
Later, a small study on children confirmed these results. Scientists tracked how one-year-old children reacted to the appearance of a stranger wearing a mask. Children who had a depleted microbiome at one month of age were more afraid of him.
More research is needed to confirm the pattern between microbiome diversity and infant fear, and to rule out the influence of other factors on the child's reactions.
Overall, the authors of the study suggest that this fear may cause the development of depression and anxiety, as well as problems with expressing emotions.
A baby's microbiome depends on many factors, but that includes the mother's diet during pregnancy and breastfeeding. Yogurt, kimchi, and kombucha help maintain a diversity of bacteria in the gut. This diversity can bring many benefits to a baby's health, from an effectively functioning immune system to a reduced risk of psychological disorders. And, of course, it can increase a mother's stress tolerance.