When it comes to our dietary habits, our body reacts in very different ways when we are stressed, anxious or depressed. Sometimes our stomachs close completely and we don't feel like eating anything, feeling even nauseous; other times is the opposite, and we feel more peckish than usual. What's usually a common ground is that we feel like we are low in energy levels.
We can "cheat" a little bit on our body by eating. Sometimes low mood can trigger loss of appetite and, in severe cases, the lack of nutrition in itself can perpetuate the low mood. I know it can be tricky to eat if you don't feel like it but in those cases you can probably try a smaller portion and split your intake into lots of small snacks along the day.
Although there's evidence that a healthy diet is vital to reduce our health problems, it's fair to mention that the research on this area is still undergoing and there are no firm conclusions on whether it is actually good for mental health. Bearing in mind physical health and mental health are pretty much the same thing and you cannot have a healthy brain without a healthy rest of the body is it fair to assume nutrition is an important aspect of mental wellbeing.
Five Mood Foods
Before we go into this it is important to point out that what has been shown to happen is that if you are malnourished or your levels of these nutrients are low your risk of developing depression and anxiety disorders is higher. This does not mean that if you are suffering from depression and your levels are normal you will necessarily treat your symptoms by taking extra amounts of these nutrients. It just does not work that way. So remember, this is only useful if you lack any of these nutrients. If you have enough taking in extra is not likely to help.
-Tryptophan, an essential amino acid (amino acids are the building blocks of proteins), is a basic component of the neurotransmitter serotonin which is essential to maintain a healthy mood. This paper by Ogawa and colleagues outlines the evidence of tryptophan deficit being linked to depression. You can find Tryptophan in chocolate, oats, dried dates, milk, yogurt, cottage cheese, red meat, eggs, fish, poultry, sesame, chickpeas, sunflower seeds, pumpkin seeds, spirulina, bananas, and peanuts.
-Vitamin B12 is essential to maintain a healthy brain function. It can affect both mood and memory and its deficit is one of the essential things to screen for when doctors are worried about someone's memory. This paper outlines its role in mood disorders. As you can see it is particularly important in older adults. You can find B12 in meat, salmon, cod, milk, cheese, eggs, some fortified breakfast cereals and shellfish.
-Omega 3 and 6 fatty acids: have been shown to be beneficial for the cardiovascular system, for the heart, for mental health and memory, to improve attention and for joint health. Here's a recent review of their role in depression. Any fish works but those rich in omega 3 would be salmon, mackerel, tuna, and some canned fish like sardines. If you don't like fish, you can replace this intake with food supplements but try to find one without vitamin A. If you are a vegetarian, try taking a flat seed supplement . Do not overdo it. 4 portions for an adult per week is more than enough and same goes to supplements. Our bodies cannot absorb more than certain amounts of omega 3. If you have a diet rich in the foods that contain these you are fine, don't buy unnecessary supplements!
-Vitamin D has been shown to be linked to depression when the person is running low on it. Here is a link to a very thorough review that also proves that if you have the right amount of vit D taking in any extra does not seem to do much but if you are running low you really need it. You can get vit D from oily fish, such as salmon, sardines and mackerel, egg and some fortified breakfast cereals.
-Antioxidant Vitamins (A, C and E). Once again it is their deficit that is linked to depression. You would need to test your levels before using supplements as they would only be helpful if you are running low. Vit A in particular is dangerous as if you take too much of it, it can be very harmful. Here is a paper that reviews their link to depression and anxiety. Good and safe sources of these vitamins tend to be vegetables and fruit. The precursor to Vit A, beta carotene is found in orange, yellow and green vegetables and fruits. This is quite safe to eat as opposed to the supplements. For Vit E you would also want wholegrain cereals and nuts.
What Not to Do
On the flip side, you may want to avoid products with high levels of refined sugars (bakery, biscuits, sugary fizzy drinks, snacks), alcohol or processed foods in general. When humans first evolved 200,000 years ago the stress reaction was triggered usual by a physical imminent danger, such as a tiger in the bush. The mind and body are pre-programmed to get ready to fight or run away. Because these are activities that demand a lot of energy it stands to reason that we would crave foods with a lot of quick and easy energy. Fast forward to the modern era when food with countless calories is readily available and there are no tigers in the bush. The stress reaction is the same and we still crave that quick hit, but there is no running away or fighting our mortgages, the bank or the tax man, hence the problem. We need to learn to curb our instincts and substitute those high energy, sugary foods, for the more healthy, nutrient rich, alternatives.
Change doesn't come immediately. You have to persist a bit in keeping these habits but from personal experience I can tell you that within a month you can make a massive change. No kidding! If you can regulate your eating, make a few changes in your diet and combine it with a few daily exercises, both physical like walking or biking, and mental like meditation or calm breathing, you've got the perfect recipe for a balanced life!
You can get some more tips reading this paper about Healthy eating and depression by the Mental Health Foundation.