Depression is a debilitating but widespread condition involving low mood, low self-esteem, and loss of interest or pleasure in normally enjoyable activities. Nutrition may have the potential to affect a person’s risk of depression, its symptoms and its severity. The link is frequently explored in research studies, but the results are not yet conclusive.
Some aspects of nutrition that may be associated with depression include omega-3 fatty acids, vitamins C and E, folate, alcohol, caffeine, and overall style of diet such as the “western” diet containing processed foods.
Some people eat more when they are depressed, while others eat less. In any case, it is likely that a depressed person will not prioritize healthy eating all the time. Fast food or comfort food can seem more appealing. However, sustaining food is needed to maintain stable blood sugar levels. Although the brain needs glucose to enable it to perform effectively, very sugary foods cause blood sugar levels to shoot up and then plummet, leading to lethargy. This can trigger another sweet craving, and the cycle continues.
Certain foods increase the physical stress on your body by making digestion more difficult, or by denying the brain essential nutrients. Drinks can have just as great an effect: caffeine and alcohol both put a considerable strain on the body, and sometimes the mind.
Relying on caffeine for energy is not a good idea. It raises stress hormones and can cause insomnia and dehydration, having a negative impact on the body. Yet the link appears somewhat complex. A very recent study in Finland looked at the connection between caffeine and depression. Based on 2,232 middle-aged men, it found that depression was significantly less likely in heavy coffee drinkers (more than 813ml per day), than non-drinkers. Tea and overall caffeine intake were not linked to depression.
Heavy consumption of alcohol will have unpleasant effects the following day and perhaps in the longer-term. This does not mean that depressed people need to avoid alcohol completely, but it is not a healthy coping technique.
Foods That May Help Fight Depression
Regarding omega-3 fatty acids, experts suggest they may affect depression because they are widespread in the brain. Dr. Rossella Liperoti and colleagues at from the Catholic University of the Sacred Heart in Rome, Italy, explain that the omega-3 fatty acids eicosapentaeoic acid (EPA) and docosahexaenoic acid (DHA) are the most common polyunsaturated fatty acids in the brain.
These compounds help regulate cell membranes, dopamine and serotonin levels, communication between brain cells, and brain glucose metabolism. “Increasing evidence from animal and human research shows omega-3 depletion may play a role in several disorders,” say the team.
“In particular, an association between omega-3 and depression was repeatedly suggested in observational and experimental studies on populations affected by major depression, depressed mood or postpartum depression,” they add. But they point out that larger and more sophisticated studies are needed to provide “convincing evidence of a causal relationship” and to show a benefit from supplementation.
In any case, omega-3s are found in high concentrations in oily fish such as salmon, herring, mackerel, anchovies and sardines, as well as flax seeds and walnuts–all generally considered “healthy” additions to the diet.
Earlier this year, an Australian study found that a “traditional” dietary pattern characterized by vegetables, fruit, meat, fish, and whole grains was associated with lower risk of depression than a “western” diet of processed or fried foods, refined grains, sugary products and beer. But the researchers say a direct association cannot be confirmed.
A 2009 study from the University of Minnesota investigated whether depressed women had a higher consumption of sweet foods. Dr. Robert W. Jeffery and colleagues say that stress and depression are associated with cravings for sweets, and chronic sweet consumption may reduce levels of the “stress hormone” cortisol. Individuals with seasonal affective disorder also show a preference for sugar-rich foods in the winter months.
They did find that depressive symptoms were associated with sweet food intake, which is “consistent with the hypothesis that eating sweet foods reduces negative mood.” Of course, this coping technique could backfire, as it is well established that depression is more common among overweight and obese people.
However weak or strong the effects of nutrition are on depression, providing the body with the nutrition it needs is a positive step individuals can take toward combating their condition. With adequate nutrition, we are all better prepared to face the challenges of the day.
Ruusunen, A. et al. Coffee, tea and caffeine intake and the risk of severe depression in middle-aged Finnish men: the Kuopio Ischaemic Heart Disease Risk Factor Study. Public Health Nutrition, April 2010, in press.
Liperoti, R. et al. Omega-3 polyunsaturated fatty acids and depression: a review of the evidence. Current Pharmaceutical Design, Vol. 15, December 2009, pp. 4165-72.
Jacka, F. N. et al. Association of Western and traditional diets with depression and anxiety in women. The American Journal of Psychiatry, Vol. 167, March 2010, pp. 305-11.
Jeffery, R. W. et al. Reported Food Choices in Older Women in Relation to BMI and Depressive Symptoms. Appetite, Vol. 52, February 2009, pp. 238-40.