Diet and mental health: is there a link?

Gesunde Ernährung

According to the Austrian Health Report 2016, 8 percent of the population suffer from a diagnosed depression or consider themselves depressed. Since there is still a stigmatization of mental illnesses in our country, it can be assumed that the number of unreported cases is much higher. Many people in this country are afraid to seek help, do not want to take medication or do not even realize that they would benefit from help.

The trend is clearly upwards; more and more young people suffer from burnout, chronic overload, are less resilient or stress-resistant and go through depressive phases. Where does this trend come from?

For some time there have been efforts to increase public awareness of mental and psychological illnesses and thus to remove the taboo, but nobody really seems to be concerned with where this negative trend comes from. In this discussion, mental health is almost never discussed in the context of nutrition. As you read on you will learn why nutrition should be one of the first and most important strategies to treat mental illness and episodes.

gut-brain axis and mental health

There is a strong connection between mental health and nutrition through a complex structure in the body - the gut-brain axis. The gut-brain axis is a two-way communication network between our central nervous system (consisting of the brain and spinal cord), the enteric nervous system (in our digestive tract) and the billions of microbes (bacteria, fungi and viruses) primarily found in our gut are. To make things even more complicated and complex, there are also interfaces with the endocrine (hormone-producing) systems, the gut/microbiome, and the immune system.

Signaling molecules and messenger substances produced by the intestinal bacteria and cells in our intestinal wall act as information for our body. They are practically a kind of guide for our cells and influence our emotional and mental behavior. This reaction also works in the other direction. Probably everyone of us knows the situation that a queasy stomach occurs when you are nervous, you get digestive problems under stressful situations or you have a changed feeling of hunger when you are in a bad mood or when you are over-stressed.

If you become aware of these complex relationships, it is actually not a big surprise that nutrition is closely related to mental health.

How do microbes affect our mental health?

Researchers have shown repeatedly over the past few years and decades that microbes produce several messenger substances that affect our bodies.

  • Neurotransmitters such as GABA (gamma aminobutyric acid), serotonin, norepinephrine (noradrenaline) and dopamine.

  • Short chain fatty acids such as butyrate and propionate

  • Indoles (formed from the amino acid tryptophan) act as mediators of anxiety

  • bile acids

  • Choline metabolites

  • Lactate

  • Vitamins (including vitamin B12 and biotin/vitamin B7)

Once these messenger substances have been produced, there are 3 ways in which they can affect our body.

  1. They stimulate the vagus nerve, which originates in the gut and connects it to the brain

  2. They stimulate the immune system in the gut and blood This fact also helps to understand the connection between dysfunction in the immune system, chronic inflammation and mental health.

  3. They can also enter the blood directly and affect other organs (e.g. the brain).

9 factors in nutrition that affect your mental health

After birth and throughout life, there are a number of factors that can affect mental health. These include:

  • The meanwhile typical "Western" diet (consisting of processed foods, fast food, lots of carbohydrates and vegetable fats)

  • gut imbalances

  • reduced ability of the body to control blood sugar levels

  • pro-inflammatory nutrients

  • a deficiency in vitamins and minerals/trace elements

1. western diet

Also called "Standard American Diet" (SAD) - the abbreviation SAD in particular (in German: sad) is extremely significant in many ways. Above all, it is characterized by a high proportion of highly processed foods (if you can still call them that). This includes all ready meals, deep-frozen processed meat products (schnitzel, nuggets, lasagne, burger patties and co.), French fries and the like, snacks and sweets, soft drinks, but also meat substitutes, vegetables in sauces, etc. and everything else that is known as " convenient food " - i.e. practical food - applies.

There are several factors how this SAD affects our mental health:

  • It drives chronic inflammatory processes in the gut, which result in the gut-brain axis being disrupted
  • It leads to a lack of nutrients that are particularly important for brain health (more on this further down in the blog)
  • It leads to a leaky gut - this means that substances get into our blood that actually shouldn't be there and thus disrupt the entire body system (including the brain).

Studies are now linking ultra-processed foods to anxiety and depression.

2. gut imbalances

As mentioned before, our gut is populated by billions of bacteria and other microbes. These can work for or against us. They do this by absorbing parts of our food that our body cannot process itself/fast enough/or insufficiently and produce metabolites from them.

Too much processed food, especially fast-acting simple sugars and carbohydrates like starches, creates an excess food supply for microbes to work against us. The bacteria that would benefit our health literally starve to death.

This leads to a variety of problems caused by an imbalance of good versus bad bacteria - a gut imbalance. This entails many problems (indigestion is obvious) - among other things, it also affects our mood, mental health and cognitive abilities.

Frequent, long-term consumption of antibiotics can also lead to an imbalance, because the antibiotics also kill our intestinal bacteria. They cannot distinguish between good and bad.

Disrupted signals from a gut imbalance can lead to anxiety, depression, bipolar disorder, schizophrenia and anorexia.

3. insufficient blood sugar regulation

Of course - the first thing you probably think of is diabetes. But chronically high blood sugar levels not only lead to diabetes and metabolic syndrome (a collective term for several diseases, all of which are associated with obesity, high blood sugar levels and cardiovascular problems) in the long (or shorter term - depending on the individual genetic predisposition) but cause chronic inflammation (throughout the body - hotspots depending on genetic predisposition in the gut, brain, joints, skin, etc.).

And as we've read a few times now, chronic inflammation is related to mental health.

It even goes so far that Alzheimer's is now referred to in the professional world as type 3 diabetes or insulin resistance in the brain. But not only serious diseases in the brain (Alzheimer's, Parkinson's and dementia) are associated with insulin resistance in the brain. Insulin resistance in our brain means that dopamine - one of the happiness hormones - is broken down more quickly, resulting in a deficiency. This then leads to depression and mood swings.

What to do about it?

Reading all of this scares and worries you. (And trust me, this is just a high-level overview - a lot of research here is still in its infancy and this is just the tip of the iceberg).

Thankfully, there's tons of scientific evidence on how to eat for optimal cognitive and mental health. And before you think to yourself: "Oh great - the next thing I have to look out for in a healthy diet... this is getting more and more complicated" - here comes the salvation:

What is healthy for your brain is also optimal and healthy for the rest of your body.

So here are the most important strategies and pillars of a healthy, balanced and brain-friendly diet.

4. Genetically adapted diet

Don't worry - I'm definitely not talking about some modern genetic test that promises to give you several hundred euros of information about what kind of metabolism you are, what supplements you need, etc.

There are such tests. They are not necessarily highly scientific and meaningful. And period - I don't even want to start writing about that now ... that's probably a topic for another blog.

So what do I mean by customized?

Adapted means nothing other than "traditional" - NOOOOO, not a traditional schnitzel or Kaiserschmarrn.

Traditional in the sense of "original" - some also call it Paleo or who knows what names they have come up with for it. In the end, it's about the fact that we humans have developed with our environment over time. This is what made us the complex creatures we are. We can boast an incredibly extensive repertoire of possibilities, especially with regard to food utilization.This results from the fact that in the course of our development history we were constantly confronted with phases of hunger (drought, seasons, hunting cessations, migration of peoples, etc.). Our bodies often had to learn to get by without (sufficient) food over long distances. Long story short - before I get too bogged down here (if I'm not already) - Numerous studies and observations show that the diets of indigenous and indigenous peoples are clearly associated with better mental and cognitive ability and health.

The nutrition of these primitive peoples is not 1:1 the same (depending on where these peoples live, they have different food sources available). However, they all have some things in common and are based on the following foods:

  • non-starchy vegetables (preferably at least 3-4 kinds daily)
  • Fruit in moderation
  • quality meat, poultry, fish, seafood and eggs
  • moderate amounts of starchy vegetables: (sweet) potatoes, squash, parsnips, turnips, etc.
  • Nuts and seeds
  • Sprouted and/or cooked legumes and cereals
  • full fat dairy

This offers the body a wealth of nutrients, vitamins and minerals that it needs to be and stay healthy.

5. Minerals and vitamins

There are a handful of minerals and some vitamins that are essential to brain health. They are needed to produce neurotransmitters (messenger substances) for our brain and to support metabolic processes for repair processes in the brain.


Iron deficiency impairs brain development and is associated with depression, anxiety, bipolar disorder, and attention-deficit/hyperactivity disorder (ADHD) in children and adults. Iron deficiency also prevents the production of serotonin, dopamine and norepinephrine.

The form of iron that we can best utilize is found in meat and animal products. Iron found in plants is not used as efficiently by our body.


Zinc is the second most abundant mineral in the body after iron. It is found in particularly high concentrations in the brain areas that are important for emotional processing (hippocampus and frontal cortex). This also explains why zinc deficiency is associated with mood disorders.

Studies have even found that zinc supplementation in addition to antidepressants works synergistically (meaning both drugs/treatments together have shown more effect than the sum of the individual treatments). The effect of zinc is also related, at least in part, to its anti-inflammatory effect.


Magnesium is the mineral known to make us "calm and relaxed". Magnesium as a dietary supplement can be helpful in combating mild to moderate depression in adults and can work wonders in treating mood swings and anxiety.

Magnesium is required by over 300 metabolic processes in the body. Among other things, the breakdown of activating signals in the brain that put us in "fight and flight mode" (engl: fight or flight) (norepinephrine and epinephrine aka noradrenaline and adrenaline). This helps the brain relax and get into "rest and digest" mode.

folic acid (vitamin B9)

Folic acid is one of the B vitamins and is mainly found in green leafy vegetables, liver and legumes. It is also added to some foods (this is because pregnant women in particular have a higher need for B9 to carry healthy babies ).

Folic acid is important for so-called methylation processes in the body and a deficiency during pregnancy leads to defects in brain and nervous system development. A deficiency is also associated with depression. If you want to supplement, you should rely on the methyl form (L-methylfolate).

vitamin B12 (cobalamin)

Together with vitamin B9 (folic acid), vitamin B12 helps with methylation processes in the body and metabolic processes with neurotransmitters. A deficiency leads to cognitive loss, irritability, personality changes, depression and psychosis. Vitamin B12 is found almost exclusively in animal foods (meat, poultry, fish, eggs and dairy products).

vitamin B6 (pyridoxal)

Vitamin B6 is an important cofactor for the production of serotonin, dopamine and epinephrine. Therefore, a deficiency is also a reason for depression and anxiety. Good sources of vitamin B6 are pork, poultry, fish, eggs and avocados.

choline (the lost B vitamin)

Choline, originally categorized as a B vitamin, is actually not strictly a vitamin. Nevertheless, it is absolutely essential for us. It is a critical component of cell membranes, keeping them in a condition that allows nutrients to enter cells and waste products to exit. Choline is found primarily in egg yolks, meat and, to a lesser extent, in vegetables (cruciferae).

vitamin C

Some studies claim vitamin C directly helps against bad mood. This could be because vitamin C acts as an antioxidant, protecting the brain and neurons (brain cells) from oxidative stress.

vitamin D

More and more studies are showing the positive effects of vitamin D on mood and mental health. Vitamin D supplementation reduces depression.

Vitamin D is generally produced in our skin when we are exposed to the sun (without sunscreen). That's why most people don't have enough - at least here in Central Europe we live at a latitude and in a climate zone where we certainly don't get enough sunlight on our skin between October and April to produce enough vitamin D.

Apart from vitamin D supplements (make sure to take vitamin D3 - best in combination with vitamin K2 and in an oil capsule. Alternatively (if no oil capsule or in drop form) simply add a little oil to one take a meal), vitamin D is also found in eggs and wild fish (but in much lower amounts than we would produce ourselves from sun exposure).

6. Essential Fatty Acids

When we talk about essential fatty acids or fats, we mean omega-3 and omega-6 fats. In a nutshell: we need both to ensure an appropriate response from our immune system. Omega-6 fats are needed to produce pro-inflammatory substances. Omega-3 fats do exactly the opposite: they are involved in the production of anti-inflammatory substances in the body.

We practically don't have to worry about omega-6.They are often found in food and with our modern diet we automatically consume (more than) enough of them. Omega-3 fatty acids, on the other hand, we are only too happy to neglect. They are mainly found in fatty fish (salmon, mackerel, sardines, anchovies, anchovies) but also in seaweed (for vegans). The two specific fatty acids we produce from omega-3 fats are DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid) and have many beneficial properties for brain health. The ideal dose of EPA per day is 1-2 g. The ratio of EPA to DHA should be 2:1 to 3:1.

Omega-3 fatty acids protect our brain and contribute to mental health by keeping neuron cell walls flexible enough to allow nutrient transport and signaling.

There are no direct vegan sources of DHA and EPA except in algae oil.

Omega 3 fatty acids are also found in some seeds (flaxseed, chia seeds,..), but the ALA (alpha LInolenic Acid) present there must first be converted into DHA and EPA - which is relatively low-efficiency in our body happened. This means you would have to eat a lot more plant-based omega 3 to end up with just as much DHA and EPA than fatty fish or fish/algal oil.

7. Phytonutrients/phytonutrients

Phytonutrients - also called phytonutrients - are substances produced by plants to protect themselves from predators, fungal and bacterial infections and to withstand extreme situations (drought, etc.).

As a result, we are exposed to slight stress when we consume these substances with the plants. This light stress (hermetic stress) has the consequence that our body activates signaling pathways, which then help us to deal better with stronger stress in the future and to endure it more easily. Among other things, this also leads to the production of BDNF (brain derived neurotropic factor) and GABA (a hormone that contributes to relaxation).

Phytonutrients that have been particularly well researched include:

  • Curcumin: found in turmeric - it helps against depression and also has an anti-inflammatory effect
  • L-theanine: found in green tea leaves - it works against anxiety
  • Glucoraphine and sulforaphane: found in cruciferous plants - works against depression through its antioxidant effects
  • Cocoa flavonoids: found in dark (>75%) chocolate - reduces stress and inflammation in the brain and can thus counteract depression.

8. probiotics and prebiotics

As briefly mentioned, gut health is fundamental to a well-functioning brain, cognitive abilities, and mental health. Research into how probiotics affect mental health has led to the term "psychobiotics." These include the following bacterial strains:

  • Lactobacillus rhamnosus - these bacteria produce GABA (the calming neurotransmitter)
  • Lactobacillus plantarum - reduces stress and anxiety while improving memory.
  • Lactobacillus helveticus - is involved in shutting down the HPA axis (hypothalamic - pituitary-adrenal) which leads to chronic stress and subsequent intestinal inflammation.

Bacteria have to eat too - preferably fiber. These are a type of carbohydrates that our body cannot use itself directly because we lack the mechanisms to break them down into smaller components.These dietary fibers primarily include fructo-oligosaccharides and galacto-oligosaccharides. These have been shown in studies to alleviate depression and stress.

9. Coffee, tea and caffeine

Depending on your individual gene variant, stimulating drinks like coffee and tea can also have a calming effect on you. The best way to do this is to observe how you react to these drinks. If you're feeling jittery or high after a cup of coffee, you should probably refrain from drinking coffee regularly.

Finally, I would like to briefly mention vegetarian and vegan lifestyles . There are many reasons why people choose to become vegetarian or vegan. There is nothing wrong with that, as long as the diet is well thought out and planned. Purely from the point of view of mental, psychological and cognitive health and performance, it is rather difficult to reach an optimal level with these forms of nutrition.

This results from the fact that not eating animal foods often indicates a lack or low status of the following factors that are important for the brain:

* Iron * Zinc * Choline * Vitamin D * Vitamin B12 * Vitamin B6 * Omega 3 FA *

While nutrition is an essential factor in mental health, one must not forget that it is only one of the pillars. Other factors are lifestyle factors such as sleep, stress management, sport and exercise.

Diet and other lifestyle factors are THE primary factors for a healthy and disease-free life. Integrating a healthy, balanced diet prevents chronic diseases and can even reverse them (at least in part).


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