If you are what you eat, then, apparently, trans fatty acids are aggressive and prone to depression. A new observational study links dietary trans fat intake to adverse behaviors that affect others.

Between 1999 and 2004, researchers evaluated the diets of nearly 1000 men and women. Their average age was 57 years, more than two-thirds of the group was male, and more than three-quarters was Caucasian. None of the participants had cholesterol extremes, diabetes, heart disease, or cancer at the time of enrollment. The average daily consumption of trans fatty acids reported by the participants was 3.49 grams.  Validated behavioral questionnaires were used to collect information regarding impatience, irritability, and aggression toward self, others, and objects. The study is available online at PLoS One.

Overall, participants who consumed more trans fats had higher scores on each adverse behavior measured. The association was true for both genders, all age groups, and all ethnic groups. The associations were stronger between trans fats and adverse behaviors than any other factor, including lifestyle and alcohol intake.

Trans fatty acids are also known as unsaturated fatty acids. They occur rarely in nature, though certain kinds are found in milk and meat from cows. In general, trans fats are the result of food production and are prevalent in snack foods, fast foods, fried foods, and commercially-prepared baked goods. Trans fatty acids, whether naturally or artificially produced, have essentially no nutritional value and are not necessary for human health. In the commercial food industry, trans fats provide a longer shelf-life for products.

Currently, most fast food sandwiches contain less than 2 grams of trans fat, but increasing regulation and public attention has significantly decreased the amount of trans fat used in the food industry. Prior to 2006, a fast food sandwich likely contained up to 10 grams of trans fat. According to labeling requirements, a product can be listed as containing “0” trans fats if its content is less than 0.5 g per serving; foods labeled as trans-fat free may still contain 0.49 grams per serving.

Trans fats have long been associated with cardiovascular disease, high cholesterol, metabolic dysfunction, insulin resistance, inflammation, obesity, and decreased general health. A link between trans fats and depression has also been reported, as well as decreased learning and memory.

The current study was observational and used only subjective dietary and behavioral recall to assess associations between the two, rather than objective data. It is unclear if there is a cause-and-effect relationship between trans fat and behavior, or if trans fat consumption is simply a marker for an unhealthy lifestyle that predisposes and individual to making adverse behavioral choices.

Also, the study was conducted prior to changes in regulation and public awareness regarding trans fats in the food industry. The individuals may not have the same dietary intake of fat today. However, the study serves as one more reminder of the dangers of processed foods. Attempts to limit trans fatty acid intake — either through regulation or personal choice — have far-reaching personal and public health benefits.

References

Collison KS, Makhoul NJ, Inglis A, Al-Johi M, Zaidi MZ, Maqbool Z, Saleh SM, Bakheet R, Mondreal R, Al-Rabiah R, Shoukri M, Milgram NW, & Al-Mohanna FA (2010). Dietary trans-fat combined with monosodium glutamate induces dyslipidemia and impairs spatial memory. Physiology & behavior, 99 (3), 334-42 PMID: 19945473

Golomb BA, Evans MA, White HL, & Dimsdale JE (2012). Trans fat consumption and aggression. PloS one, 7 (3) PMID: 22403632

Mozaffarian D, Aro A, & Willett WC (2009). Health effects of trans-fatty acids: experimental and observational evidence. European journal of clinical nutrition, 63 Suppl 2 PMID: 19424218

Mozaffarian D, Jacobson MF, & Greenstein JS (2010). Food reformulations to reduce trans fatty acids. The New England journal of medicine, 362 (21), 2037-9 PMID: 20505187

Teegala SM, Willett WC, & Mozaffarian D (2009). Consumption and health effects of trans fatty acids: a review. Journal of AOAC International, 92 (5), 1250-7 PMID: 19916363

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