Trans Fats and Infertility: Could Cookies and Crackers Hurt Your Ability to Conceive?

2007 was a bad year for trans fats—the type of fat that is formed when liquid oils are processed into solid fats like shortening and hard margarine or commercial frying fats that can be used repeatedly without breaking down. First, several states have proposed bills banning all artificial trans fats from restaurants. Then, a Harvard School of Public Health study was published showing that trans fats may prevent women from conceiving.

What's Wrong with Trans Fats?

Trans fats are no-goodniks in general: They increase levels of "bad" cholesterol (LDL) and decrease relative levels of "good" cholesterol (HDL). They also promote inflammation and the formation of blood clots within blood vessels. The eight-year study measured the impact of a diet high in trans fats on more than 18,000 otherwise healthy women who were trying to get pregnant. Researchers found that, along with other health concerns associated with trans fats (high blood pressure, heart disease, and obesity), decreased fertility appeared to be directly linked to trans fat consumption.

Trans fats can impede fertility in a few ways. First, a diet high in trans fats is a diet likely to lead to obesity. Being significantly overweight is not good for regular ovulation. Second, overweight or not, trans fats interfere with body chemistry such that the body becomes more resistant to insulin. This makes levels of both sugar and insulin in the bloodstream go up, another strike against full fertility. Lastly, the inflammatory effect of trans fats can interfere with ovulation, conception, and even early embryo development.