Can Taking Supplements Help Curb Prison Violence?

Could something as simple as a vitamin-mineral-essential fatty acid supplement reduce violence among prisoners? A study published in the July British Journal of Psychiatry says it can.

However, an American prison psychiatrist who reviewed the study for Psychiatric News, questioned the study’s results.

Previous research has linked certain nutrients with brain chemistry and also with specific mental states. Also, omega-6 and omega-3 essential fatty acids, which influence levels of the neurotransmitters serotonin and dopamine, have been found to be deficient among violent offenders. Thus, C. Bernard Gesch, a senior research scientist in the Laboratory of Physiology at Oxford University in England, and colleagues hypothesized that certain prisoners might be lacking in certain nutrients and that correcting this deficiency might help counter their antisocial behavior.

They recruited 231 young-adult prisoners aged 18 and over for their study. Half the subjects were randomized to receive one vitamin-mineral supplement and four essential fatty acid supplements daily for an average of four or five months. The others were given placebos. Neither group knew what it was getting. The placebos looked like the supplements—opaque gelatin capsules—but contained vegetable oil instead.

The researchers tracked the number of disciplinary offenses that the subjects committed throughout the study period to determine whether the nutritional supplements had any effect on them. And the supplements indeed had an impact, Gesch and co-workers reported. The number of disciplinary offenses committed by the supplement group at the end of the study was reduced 35 percent compared with the number it had committed by the start of the study—a highly statistically significant difference. In contrast, the placebo-group’s number of disciplinary offenses was reduced only 7 percent during the study period, which was not a statistically significant difference. With regard to reduction in violent incidents from the start to the end of the study, the supplement group experienced a 37 percent decrease, which was highly statistically significant. In contrast, the placebo group experienced a 10 percent reduction, which was not statistically significant. When the number of disciplinary infractions of the supplement group at the end of the study was compared with that of the placebo group, there were 26 percent fewer in the former, a statistically significant difference

Gesch and his colleagues concluded that the supplements reduced disciplinary offenses, especially those involving violence, among their subjects to a “remarkable degree,” and their results suggest that “the effect of diet on antisocial behavior has been underestimated, and more attention should be paid to offenders’ diets.”

Did Deficiencies Exist?

J.S. Zil, M.D., J.D., chief forensic psychiatrist of the State of California Department of Corrections, is skeptical of these results. The reason, he told Psychiatric News, is that the researchers purportedly tested the effects of correcting nutritional deficiencies in prisoners’ diets, yet there was no concrete evidence that the prisoners, who were receiving prison food, had any such deficiencies in the first place. Had the study design been based on parolees or probationers, who may well have had nutrient-deficient diets, then the study might have been worth undertaking, he noted.

In an interview with Psychiatric News, Gesch said that he and his colleagues had only tentative evidence that their subjects had any nutritional deficiencies. It came from food diaries the subjects had filled out and suggested that they were consuming less-than-optimal amounts of minerals such as selenium, magnesium, potassium, iodine, and zinc. Vitamin assessments from the food diaries were less reliable than the mineral assessments, and the food diaries did not divulge the levels of essential fatty acids that subjects were getting.

Better Study to Come

Gesch noted, however, that their study is only a first step in exploring a possible link between nutritional deficiencies in prisoners and their infractions. He and his colleagues, along with researchers from Britain’s Institute of Psychiatry and Medical Research Council, will attempt to replicate these findings with a better-designed study. For instance, in the next investigation, they will be analyzing subjects’ blood levels of specific nutrients to determine whether they are deficient or not.

The study was supported by donations from various foundations to the charity Natural Justice.

An abstract of the study, “Influence of Supplementary Vitamins, Minerals, and Essential Fatty Acids on the Antisocial Behavior of Young Adult Prisoners,” is posted on the Web at http://bjp.rcpsych.org/cgi/content/abstract/181/1/22. ▪