Diet and Depression: Is There a Link? Can it Hurt to Try?

Biology 103
2001 Second Web Report
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Diet and Depression: Is There a Link? Can it Hurt to Try?

Kat Fallon

Just as there are a plethora of conditions which can generally be referred to as depression of one kind or another, there are a myriad of factors which cause or contribute to such depression. Despite the tendency to disregard depressive behavior as temporary and insignificant, A World Health Organization report recently identified depression as the "No. 1 cause of disability in the US and the third biggest, behind heart disease and strokes, in Europe " (1). With depression's increasing incidence throughout the United States and the rest of the world, more studies are being conducted every day to identify possible causes and treatments. One such approach is that of diet therapy, which is based upon the idea that "illness may be treated by providing the body and the brain with the correct amount of nutrients" (2).

Several dietary supplements are considered important to mental functionality. Tryptophan is thought to be instrumental in treating depression in those patients who have not responded well to other antidepressants (2). Tryptophan is a natural relaxant, reducing anxiety and depression. It performs many useful duties in the healthful functioning of the body, but it also significantly increases levels of seratonin (3). Laboratory studies have shown that "patients who are depressed, particularly those with suicidal behaviour, are deficient in the neurotransmitter serotonin," which is produced by the amino acid tryptophan (2).

Omega-3's are also thought to be absolutely necessary to healthy mental functioning. A lack of essential fatty acids and an excess of saturated fats and animal fatty acids leads to "the formation of cell membranes that are much less fluid than normal" (4). The brain is "the richest source of fatty acids in the human body," and so "alterations in membrane fluidity impact behavior, mood, and mental function" (4). In fact, studies in London have shown that giving schizophrenic patients omega-3 fatty acids can correct membrane abnormalities (5).

Essential fatty acids are necessary to humans, and yet we cannot produce our own. We must make obtain these essential fatty acids through the foods we consume (4). This is problematic in that these essential fatty acids tend to be removed from our food supply in order to improve its shelf life (4). To prevent flour from spoiling, for instance, a miller will remove the germ which contains almost all of the omega-3 fatty acids before he grinds it into flour (5). Omega-3's, then, are found most often found in oily, deep-water fish. Interestingly, depression is shown to be sixty times more common in New Zealand (6 per cent) than in Japan (.12 per cent), where far more fish is eaten (5).

While these dietary factors are thought to help alleviate depression, other foods are speculated to have negative effects on the human psyche. Most of these are typically considered to be good for one's mood, but the contrary is actually true. Alcohol, for instance, is oftentimes used as an escape from depression, but in actuality, alcohol can lead to vitamin deficiencies which can contribute to depression (6). Similarly, some foods suggested in aiding depression can be double-edged swords. Caffeine, for instance, can help to increase energy levels, leading to a temporary emotional high. In the long-run, however, "this dietary measure can backfire" (6). Caffeine can lead to sleeping problems, whether it be full-fledged insomnia or the inability to fall into the deep sleep necessary for a healthy disposition. Caffeine can lead to overstimulation of the nervous system, which raises anxiety levels, and "anxiety and depression often go hand-in-hand, mak[ing] recovery more difficult" (6). A diet rich in carbohydrates is thought to lead to a brighter disposition, as it increases levels of seratonin in the brain (6). It is fascinating, too, to recognize the inclination of depressed people to unconsciously increase their carbohydrate intakes during bad spells (6). However, a diet too rich in carbohydrates can lead to unwanted weight gain, which can lead to negative body image, which often results in a kind of depression of its own.

One of the largest debates in diet therapy is one of which-came-first-the-chicken-or-the-egg proportions. It appears as though depression can lead to a poor diet, as depression leads to a decrease in appetite and an increase in craving sugars and alcoholic substances. However, when looked at the other way around, it also becomes evident that poor diets can be a contributing factor to depression, as explained by the side effects of deficiencies in the minerals and foods mentioned above. So, which is it, then? Does depression lead to a poor diet, or does a poor diet result in depression? Can the two be separated from one another, either way?

Diet therapy was first suggested in the 1950's, and although there is little evidence to support the use of diet therapy for people with depression as of yet, there is a great deal of evidence which maintains that many nutrients are necessary for the correct functioning of brain chemistry (2). It is important to recognize, however, that even if diet therapy proves to be only mildly helpful in aiding chemical depression, the diet prescribed in an attempt to alleviate depression can generally only lead to a healthy existence. Diet therapy suggests a diet balanced in nutrients and vitamins, which are essential for normal functioning of the body in any case. B1, for instance, is essential for energy production and nerve cell function (7). B6 is important in maintaining hormone balance, Vitamin C increases immune system functions in general, and many other suggested foods such as bitter greens and endives help to cleanse the liver and improve digestion (2). More research is being done every day on this fairly new theory of nutritionally-affected depression, but in the meantime, it can't hurt to make sure your diet is a balanced one.

WWW Sources

2)Diet Therapy

3)Essential Amino Acids

4)Essential Fatty Acids

5)Diet May Treat Depression and Schizophrenia

6) Diet and Depression

7) B Vitamins