We all know that what we eat plays a big role in how happy or otherwise we are, but did you know you could (almost literally) eat yourself happy?
I’m not talking about eating for pleasure, the transient state that’s achieved when devouring some delicious dessert or your favourite food. I’m talking about eating in away that enables the production of serotonin, the neurotransmitter in our brain responsible for our wellbeing (along with helping us feel relaxed and calm).
Four dietary factors are incredibly important for our overall happiness. The first thing that is important is ensuring the health of our gut. Though some serotonin is produced in the brain (centrally), over 90 per cent is produced in the gut and there is an emerging body of research investigating the inflammatory basis of depression.
Inflammation inhibits our ability to produce or uptake serotonin and affects the frontal cortex of our brain, which is responsible for emotional expression.
If there is a disruption to our gut functioning, this can cause the release of inflammatory cytokines. Our gut wall is less than paper-thin, so it is easy to see how even the smallest disruption can begin an inflammatory cascade that has consequences far beyond digestive issues.
The second nutritional factor important in serotonin production is tryptophan. Tryptophan is an amino acid found in protein-based foods and is necessary to produce serotonin in the brain. It is known as an “essential” amino acid, meaning we can’t produce it ourselves and must obtain it from our diet.
However, tryptophan is one of the least abundant amino acids in the food supply and it competes with other amino acids for the same receptors in the brain to be transported over the blood-brain-barrier. Though we find tryptophan in protein-containing foods (such as eggs, red meat, fish, lentils, almonds and pumpkin seeds to name a few), these are also plentiful in other amino acids.
For some people, the decrease in tryptophan levels in the brain reduces serotonin levels to that which affects overall mood state. Carbohydrate levels in the diet also affect our level of tryptophan.
Sometimes, people who adopt a lower carbohydrate approach may drop too low in tryptophan, and their mood consequently suffers.
Omega 3 fatty acids are another dietary constituent essential for brain health and mood. We find these in the most useful forms of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in fatty fish such as salmon, mackerel and sardines, along with small amounts in red meat and omega-3 enriched eggs.
EPA inhibits the production of E2 prostaglandins, molecules that play a key role in generating an inflammatory response in the brain, inhibiting the release of serotonin. DHA increases cell membrane fluidity, making serotonin receptors in the brain more accessible.
Dietary intake at a population level is difficult to come by in New Zealand, however a recent study revealed that 30 per cent of pregnant women did not meet the recommendations for DHA, which is in line with findings of Australian research in healthy adults.
Fructose is the last food constituent which affects the level of serotonin in the brain, and a high fructose-containing diet has been found to reduce the protein transporters responsible for serotonin reuptake. Though fructose is the main type of sugar found in fruit, that isn’t the type of fructose I’m talking about.
Unlike fruit, which also delivers fibre and vitamins, isolated fructose in processed food is the type that is best minimised. Much of the research into added fructose has been conducted in diets containing high fructose corn syrup — a cheap by-product of the grain industry that is added to many foods.
In New Zealand, we find it in some imported foods, however our main source of added sugar in the diet is in the form of sucrose. Though they are different molecules, the chemical structure of high fructose corn syrup and sucrose are very similar.
In high fructose corn syrup, 55 per cent of the sugar comes from fructose, whereas sucrose contains 50 per cent. Studies investigating levels of fructose in the diet and adverse health outcomes usually provide fructose at levels well in excess of normal intakes.
However, I think it is still worth mentioning as the mechanism for it to affect overall happiness exists. In addition, free sugar is lurking in a lot of foods we don’t necessarily think of when it comes to sugar. One only needs to watch That Sugar Film to see how easy it is to consume levels more than the World Health Organisation’s recommended maximum of six teaspoons (or 24g) of free sugar per day.
Practical tips to eat yourself happy
Incorporate some “healthy gut” strategies everyday to protect your digestive tract and minimise inflammatory disruption. Fermented foods such as sauerkraut, kimchi, water kefir or yoghurt provide bacteria to support your gut microbiome, and including good amounts of vegetable fibres help feed the bacteria.
Salads such as roasted beetroot with kombucha vinaigrette will be a tasty way to maintain your gut wall integrity, incorporating elements of gut health awesomeness.
Incorporate a wide variety of protein-containing foods that are a good source of tryptophan. Try this chicken and kumara bake.
Include at least 2-3 meals per week that are good sources of omega 3 fatty acids, such as this sardine dish.
Make sauces from scratch to minimise added sucrose. See Ray McVinnie's how to make an Italian tomato sauce video here.
A savoury stuffed baked potato is a good way to incorporate carbohydrate foods that will include fibre too — helping both our gut integrity and tryptophan levels.