Trans Fat's Role in Infertility

The Trans fat, found in processed foods, may play a role in infertility. Implicated in prostate cancer, heart disease, and diabetes, and long thought to be a significant hindrance to good health, trans fat has been associated with ovulation disorders, according to a new publication¹², each 2% increase in trans fat calories doubles the risk of coronary artery disease. Since trans fats carry no health benefits and are potentially risky, experts have recommended reducing trans fats to trace amounts in the diet. Infertility has been associated with trans fat intake. A study published in the January issue of American Journal of Clinical Nutrition from a group of researchers at Harvard University found that women with ovulation-related fertility problems tended to eat more trans fats than fertile women. Obtaining just 2 percent of total calories from trans fats was associated with a doubled risk for this type of infertility. The study showed that each 2% increase in dietary trans fat calories was associated with a 73% increased risk of ovulatory infertility³. It has been difficult to separate out the effects of total fat and trans fat, since a diet high in trans fat diet is often high in total fats. In contrast to trans, higher total fat is known to decrease the risk of ovulation problems, improving ovulation, whereas women with a diet high in trans fat have an increased risk of ovulation disorders. Dietary fats have been linked to markers of inflammation, a possible mechanism of trans fat effects⁴. In a randomized crossover study, 50 men consumed diets for five weeks that varied in trans fat content. Inflammatory protein markers were higher in men after the trans fat diet, showing that dietary fatty acids can modulate markers of inflammation. The data is preliminary, but concerning. Since trans fats have no benefit and carry potential risks, they are best limited in the diet. Labeling requirements now include listing of trans fat content for foods. Lawmakers in several major US locales have passed regulations banning trans fats. Tiburon, California, on a voluntary basis was the first city to have trans fat free restaurants. Restaurants in New York City and Philadelphia are barred from using trans fat containing frying oils and spreads. The ban will be expanded to all restaurant foods next year. California is considering a statewide ban on trans fats. Reducing processed foods and avoiding trans fats in your diet is an excellent goal for all, but patients with infertility may have special concerns. While more research is required regarding infertility and diet, there is no question a healthy diet is important. A diet of diverse and balanced carbohydrates, proteins, and fats, including omega-3 fats, will provide personal and possibly reproductive benefits for years to come. Philip Chenette, MD References: 1. Chavarro JE et al., May 2007, A prospective study of dairy foods intake and anovulatory infertility, Human Reproduction, 22 (5): 1340-1347. 2. Hu, FB et al. 1997 "Dietary fat intake and the risk of coronary heart disease in women". New England Journal of Medicine, 337 (21): 1491-1499. 3. Chavarro JE et al., January 2007, Dietary fatty acid intakes and the risk of ovulatory infertility. American Journal of Clinical Nutrition, 85 (1), 231-237. 4. Baer DJ et al., June 2004, Dietary fatty acids affect plasma markers of inflammation in healthy men fed controlled diets: a randomized crossover study. American Journal of Clinical Nutrition, Vol. 79, No. 6, 969-973.

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