Nutrition and Mental Health - What's the relationship?

In all the information written about our New Zealand statistics on suicide, there is one aspect that gets very little attention. We talk a little about relationships, connection, support and recovery, we talk a lot about raising the awareness of depression and mental health issues and people are generously sharing personal stories on social media about their experiences of mental illness. 

However very rarely do I see what I believe maybe a significant contributing factor being addressed...

What are we feeding ourselves?

Do we ever discuss the diet of the nation? The diet of young people? Whether they suffer from malnutrition - even though they may consume an overabundance of calories?

Effect of diet

In 2017 a study was published to answer the question "If I eat better, will I feel better?" It was aptly called the 'SMILES' study (2) and it turned out, that for over 30% of depressed people, the answer was yes, it does. 32% of depressed people who changed their diet went into remission - ie no longer suffered from depression.

Other studies (3, 4) suggest that simply increasing probiotic foods has the possibly to decrease anxiety and depression.

In New Zealand it is estimated that 27% of people are below recommended blood level of vitamin D - although this is more of a hormone (made with the assistance of sunlight on the skin) than a nutrient, it is not routinely tested in those suffering from depression or mental illness.

New Zealand soils are known to deficient in selenium, colbolt and iodine as well as other trace minerals - resulting in these elements being deficient in New Zealanders. Iodine and selenium are essential for adequate thyroid function. Deficiencies can have not only an impact on mental health but on other areas of health and well-being. According to a recent review in the Lancet, a low selenium status is associated with an increased risk of mortality, poor immune function and cognitive decline.

The last National Nutrition survey found about 11% of New Zealand women had low iron stores, iron deficiency or iron deficiency anemia with a higher prevalence among Maori. A 2001 study found that 45 per cent of adolescent women were at risk of low dietary intakes or iron and that up to 13 per cent of women aged 15-49 years had sub-optimal iron levels. (See more: here.) Low iron can cause poor sleep and extreme fatigue, often mimicking the symptoms of depression. Folate deficiency is found to be common in those suffering from depression. Magnesium and Zinc deficiencies and lack of the B complex vitamins can contribute to a low mood.

Our modern day sedentary lifestyle, with infrequent exercise, pollution (noise, air, food and water supply) and stress of a physical or mental nature, can contribute to a poor nutrient intake, poor absorption of food, a sluggish thyroid and disrupted hormones resulting in poor cellular function, often causing a vicious cycle of low energy, low mood, poor eating habits and sedentary lifestyle.

What's needed to make neurotransmitters?

Below is a simplified diagram of how food is converted into neurotransmitters in our body and brain. It doesn't take into account many other variants which might contribute to our health, such as the state of our microbes, the ability to digest and absorb these nutrients, genetics and other disease states which may interfere with our health. But the diagram shows how amino aids (the building blocks of protein) - for example tryptophan - metabolises with the help of folate, B6 and zinc to become serotonin. It also shows other amino acids and their conversions and the co-factors necessary.



Serotonin known as the happy, feel good chemical is often thought to be deficient in those suffering from depression and is the primary neurotransmitter that many of the modern antidepressants (SSRI's - Serotonin Reuptake Inhibitors) target (they help to keep levels of serotonin higher in the brain). Dopamine is less known - but is known as the motivating, reward neurotransmitter - often suggested to be enhanced in when people satisfy cravings and low levels are implicated in addictions. GABA - is a calming, relaxing neurotransmitter.

For all of these processes to take place - you need the entire cascade to be working properly. Ie, you need the intake of amino acids (such as tryptophan contained in meat, egg and dairy - but can also be found in vegetarian based protein sources such as legumes and nuts, quinoa and soy). You need adequate magnesium (found in spinach, yogurt, almonds) which supports the enzymes needed to transform the amino acids. You also need folate (green leafy veges), B6 (beef, advocado, tuna) and zinc (lamb, pumpkin seeds, beef, chickpeas), Vitamin C...the list goes on.

Serotonin is also converted into melatonin, which is necessary for sleep. Dopamine is also converted into adrenaline and noradrenaline for the get up and go response we all need from time to time.

When a person is depressed/anxious and they first present to their GP or other health professional - does the health professional question, examine or support the persons diet? Do they look at the quality or nutrient dense food intake, perhaps offer to work with this, offer extra supplements as we all know that even if we eat very well we are unlikely to get all the nutritional requirements - especially if we have been deplete for sometime.

Anecdotally, I have seen an enormous positive response in people who chose to 'nutrify' their diets (with food and/or supplements), cut out the poor quality, nutrient deficient food, add loads of greens, cut out alcohol or other substances which may be depleting vitamins and minerals. I've seen how anxiety reduces significantly and mood improves substantially.

Unfortunately the modern diet too often consists of low nutrient processed food and drinks which provide very little of the substances needed for us to be well. We allow major fast food companies to sponsor sports and other nationally held events and influence what our young children are exposed to. We may be - nutritionally speaking - starving ourselves to death and contributing to the poor state of mental health in this country.

Nutrition may only be a small part of the puzzle when it comes to recovery from mental illness. But if we think it can't possibly be as simple as 'eat well and feel better', the Smiles Study clearly shows for 32% of depressed people, this is indeed the case. And for those 32% I am sure that meant an awful lot.

if you want to learn more about nutrition and other ways to support your mental health - enrol in the free four week mental health care course


(1) axis How the microbiome influences anxiety and depression_Tran .pdf