Sunday, March 23, 2014

A Diet For Depression

If you are chronically depressed, tired, forgetful, or just plain bad tempered, chances are you deserve a break today. If you suffer depression, the break you need and deserve, however, may be a break from too much food rather than a break for fast food. Minimal mental problems can be caused by the brain's not getting enough, or getting too much, of its essential macronutrients (carbohydrates, proteins, and fat) and micronutrients (vitamins and minerals).

In my early childhood, I was a fan of the television show Gilligan's Island. (I may as well admit that I occasionally watch reruns of the show once in a great while still.) A ship's captain, his first mate, an actress, a professor, a farm girl, a millionaire and his wife, all stranded on an uncharted desert island in the South Pacific, are the central characters of this once-popular sitcom.

In one of my favorite episodes, the castaways become convinced that their lives depend on the vitamin C in Gilligan's last orange and argue over how to divide it among them, as they ignore the bowl of vitamin C-rich pineapples on the table in front of them.

From a nutritional perspective, the irony of the comedy is that if the castaways had just divided the orange into seven slices and eaten, maybe the temporary boost to their brainpower would have helped them to recognize the value of the pineapples sitting in front of them. Fruits and vegetables, the professor did not know, protect against hysteria and aggressive behavior. Here's how:

Everyone has periods of stress that are outside his or her control. Uncontrollable stress commonly results in increased feelings of depression, anger, tension, and fatigue.

Most of us can control our impulses, but recent science suggests that people who "lose it" but who otherwise do not suffer a mental illness have a shortage of the brain chemical tryptophan. In a clinical experiment conducted at Oxford University, eighteen mentally healthy volunteers consumed an amino-acid drink containing tryptophan. An equal number of mentally healthy volunteers consumed an amino-acid drink without tryptophan.

Participants in the study were then presented with choices between simultaneously presented gambles. The bets differed in the magnitude of expected gains (that is, the reward), the magnitude of expected losses (that is, punishment), and the probabilities with which these outcomes were delivered. In other words, the purpose of the test was to determine whether tryptophan in the brain somehow provides the ability to make choices that are mindful of consequences. When volunteers were "depleted" of tryptophan, they tended to make wild choices without regard to outcomes.

When volunteers were "repleted" of tryptophan (when their tryptophan levels were restored), they still tended to show emotions, but they avoided "flying off the handle" when the consequences were large.

The reason the researchers tested the amino-acid drink is that the brain turns tryptophan into the mood regulator serotonin. The Oxford researchers believe that serotonin mediates decision-making in healthy volunteers by modulating the processing of estimates of outcomes of reward and punishment, perhaps within the part of the brain known as the orbitofrontal cortex.

Tryptophan connects aggression to diet. Eating large quantities of refined carbohydrates produces a "sugar surge." When the sugar concentration of the bloodstream increases, the amino acid tryptophan more readily enters the brain. The brain converts tryptophan into serotonin, which overstimulates the orbitofrontal cortex. This is why eating enough-but not binging on-carbohydrate is essential to keeping your cool.

Chocolate cravings, especially in women and more particularly in overweight women, are strongly correlated to the need to establish emotional control. Eating enough fat, measured as the proportion of fat in your diet, is also essential to maintaining emotional control. Clinical study has found, as many dieters will attest, that reducing the percentage of calories from fat from 40 percent to 25 percent is associated with elevated anger and hostility.

Controlling tryptophan is not the entire answer to controlling your emotions. People who never exercise at all are given to emotional extremes. The key to using food to control your temper is to combine eating with exercise. Vigorous exercise is not necessary for regaining emotional control. Weight loss is not necessary for regaining emotional control.

Even regular exercise is not needed to emotional control. Clinical study finds the exercise you need to help you keep from "losing it" is a few (2-3) minutes of the most minimal exercise, just enough that your primary mental focus in on physical activity-but you do need that much. Losing weight by eating less food, rather than by taking in a smaller proportion of calories in the form of fat, however, helps with emotional control. Dieting will make you more irritable-but it will also give you greater self-control. Research even shows that the more irritable and nervous you are when you diet, provided you maintain an internal locus of emotional control, the more weight you will lose!

So the general nutritional advice for controlling bad temper is exercise a little, eat just a little. Don't omit carbohydrates and fat (that is, stay away from Atkins and "Paleolithic" diets), but make a point of eating less. And don't forget your veggies.

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