Last time, we talked a bit about depression. This time, we are going to talk about how changing your diet can help. Depression is a disease with many causes. It is a very complicated illness with a wide range of symptoms and a broad spectrum of severity—from mild to severe.

Depression can also be a chronic illness for many people. Similar to other chronic illnesses, such as heart disease and diabetes, nutrition is one of the lifestyle factors that can worsen or improve the illness.

Serotonin, a brain chemical (neurotransmitter), plays an important role in the cause and treatment of depression. The level of serotonin in the brain is low in people experiencing depression. Nutrition is one of many factors that affect the level of serotonin in the brain.

The brain is unable to produce serotonin unless an amino acid (protein) called tryptophan is available. It would seem logical to say, “Let’s make sure we eat foods high in tryptophan.” However, eating foods high in tryptophan is not an easy answer to meet this need.

The transport system that carries tryptophan to the brain also carries other large amino acids which compete with tryptophan as they are carried to the brain. A meal containing a higher ratio of these other large amino acids prevents the transport of the tryptophan to the brain.

Foods containing animal proteins, such as meat and dairy products, contain low levels of tryptophan in proportion to the other amino acids. Therefore, meat and dairy products reduce the flow of tryptophan to the brain. Examples of foods that are higher in tryptophan than the other amino acids are soybeans, nuts—such as walnuts and hazel nuts—pumpkin seeds, tofu, almonds and sesame seeds.

Essential fatty acids also play a crucial role in the function of brain chemicals, particularly serotonin. Studies have shown that low levels of omega-3 fatty acids (linolenic acid) or a high ratio of omega-6 fatty acids to omega-3 fatty acids may be associated with depression. In fact, the lower the ratio of omega-3 to omega-6, the higher the rate of depression.

The American diet is typically high in omega-6 fatty acids (found in certain vegetable oils, such as soybean and corn oils) and low in omega-3 fatty acids. Regularly eating foods rich in omega-3 fatty acids will help to maintain an appropriate balance of omega-6 to omega-3 fatty acids. Plant sources containing omega-3 (linolenic acid) are flax seeds (ground or flaxseed oil), walnuts, green soybeans, spinach, sesame seeds and almonds.

Vitamin B deficiencies have been linked to depression. Vitamin B6 is necessary for the conversion of tryptophan to serotonin. Folate or folic acid deficiency can be a direct cause of depression. Evidence from recent studies has also shown that individuals with low blood levels of folate had a poor response to some forms of anti-depressive medications. Examples of excellent sources of folate are garbanzos, black-eyed peas, lentils, red kidney beans, okra, navy beans and spinach.

Low levels of vitamin C, vitamin D, calcium and magnesium have been associated with depressive symptoms. Even a low level of iron in the blood resulting in anemia is often accompanied by depression.

Maybe you are feeling overwhelmed thinking about all the nutrients you need to include in your daily diet. Just remember this: a balanced diet which includes fruits and vegetables, whole grains, legumes (beans and peas), nuts and seeds will supply the nutrients needed for healthy brain function. Eat for a happy, healthy mind!