If you’ve have been reading my blogs for the last year, you may have noticed that I’m fascinated with neuroscience—the multi-disciplinary study of the structure, development, function and pathology of the brain and nervous system.

Since I often write about murder, my fascination with neuroscience initiated from my research into a basic question: “Why do people kill?” In order to develop the characters in my novels and understand their motivation to commit murder, I needed to know if there was a chemical link to the psychology of killing.

What I found was a biological and chemical explanation for behavioral neuroscience, and that became the subject of one blog. Then I delved deeper into the study of the biological basis for murder and that evolved into another blog. Meanwhile, ideas for deviant characters evolved in my mind and some have already been incorporated into my stories.

More recently, however, I’ve discovered that the foods we eat can play a key role in how we behave. This new field of study is called nutritional neuroscience—the study of the role of diet in neurochemistry and subsequently on behavior.

A review of the effects of macronutrients is basic to this understanding. A diet rich in saturated fats, for instance, increases cholesterol and triglycerides, and scientists have documented that high triglyceride levels are strongly linked to depression, hostility and aggression.

We’ve known for a long time that carbohydrates affect blood sugar levels and can create positive or negative mood swings. Ask any parent about the aggression that results from their children consuming sugary foods, with the follow-up lethargy as the “sugar-high” subsides. The consumption of complex carbohydrates, however, evens out blood sugar levels and prevents such mood changes.

The most exciting area of nutritional neuroscience, however, involves proteins. Proteins are broken down into their amino acid components in our digestive tracts and utilized for muscle repair, enzyme and hormone production, and development and repair of the brain’s neurotransmitters. Much research has been done on the effects of specific proteins on the body’s neurochemistry because our brains consume up to one-fifth of our daily intake of protein and other macronutrients, and up to one-half of our daily intake of micronutrients (like vitamins and electrolytes).

The specific amino acids arginine, tyrosine, phenylalanine and tryptophan have been found to normalize stress levels and prevent mood swings.

Arginine supplementation has been shown in studies to dramatically reduce stress-related anxiety in humans. Food rich in arginine include pine nuts, peanut butter sesame seeds, eggs, cheese and white meats.

Tyrosine is the precursor to the neurotransmitters dopamine and norepinephrine and is essential to preventing stress during fatigue and sleep deprivation. One study found that tyrosine improved cognitive and dexterity performance in fatigued individuals. Food rich in tyrosine include soy, egg whites, cottage cheese, salmon, turkey and chicken.

Phenylalanine has been shown to have both analgesic and antidepressant effects by stimulating the area of the brain responsible for the emotional sensation of pleasure. Excellent food sources of phenylalanine are red and white meats, and legumes.

Tryptophan is a precursor to a number of brain chemicals, specifically serotonin and melatonin, and is therefore considered to have antidepressant properties. Foods rich in tryptophan include chocolate, oats, dried dates, milk, yogurt, many nuts and seeds, and both red and white meat.

So my initial question of “Why do people kill?” might need to be expanded to include “What do murderers eat?” as I profile my next sinister character.

Could diet, or lack of the appropriate nutrients in a killer’s diet, alter brain chemistry enough to turn on a killer gene? Will we come to realize at some point that eating high quality proteins can calm the killer instinct and lack of good nutrition could become a predictor of criminal intent?

Time will tell and the answers to these complex questions will not be easy to prove, but it appears that nutritional neuroscience is in its infancy. There is much more to learn and implement on this subject as we nourish both our minds and bodies to become the best we can be.

Thoughts? Comments? I’d love to hear them!