Trans-fats linked to increased risk of endometriosis

24 march 2010

New research, published today in Human Reproduction, suggests that women whose diets are rich in foods containing Omega-3 oils might be less likely to develop endometriosis, whilst those whose diets are heavily laden with trans fats might be more likely to develop the disease.

Picture of Stacey Missimer

Lead author, Professor Stacey Missmer
Harvard Medical School

The study – which is the largest to have investigated the link between diet and endometriosis risk and the first prospective study to identify a modifiable risk factor for the condition – found that while the total amount of fat in the diet did not matter, the type of fat did [1]. Says Dr Missmer:

Women with the highest consumption of omega-3 fatty acids had 0.78 times the risk of endometriosis diagnosis compared to those who had the lowest consumption.

Women with the highest consumption of trans fats had 1.44 times the risk of endometriosis diagnosis compared to those who had the lowest consumption.

This provides more evidence that a healthy diet is not necessarily low in fat overall but rather is low in unhealthy fats and higher in healthy fats.

This study included nearly 120,000 US nurses who were aged 25-42 and who had not been diagnosed (neither clinically nor surgically) with endometriosis at the start of the study.

The investigators collected detailed information about their diets over 12 years and identified those who were and were not diagnosed with endometriosis. Based upon animal studies and the investigators’ understanding of the influence that fatty acids have on prostaglandin production and inflammatory responses, it was hypothesised that healthy fats known as Omega-3 fatty acids (the fats in fatty fish such as salmon and mackerel and in olive oil) would be more prevalent in the diets of women who remained free of endometriosis.

Conversely, it was hypothesised that the women with diets highest in the most unhealthy form of fat — trans fats (which are hydrogenated oils found in many fried and processed foods) — would have a greater risk of being diagnosed with endometriosis. This is indeed what was observed.

The authors stress that this is the first large, prospective study of the relation between fat in the diet and that these associations need to be replicated in additional populations.

Hopefully this is evidence that large scale study of risk factors for endometriosis is possible and critical to understanding this enigmatic disease. Epidemiologic studies have been instrumental in identifying lifestyle factors that are now well substantiated recommendations from doctors to patients to prevent cardiovascular disease and several types of cancer. It is reasonable to believe that such modifiable factors are waiting to be identified for reproductive health as well

says Missmer, who added that

a next step could be to investigate whether dietary intervention that reduces trans fats and increases Omega-3 oils can alleviate symptoms in women who already have endometriosis.

The study has been funded by the US National Institutes of Health.

  1. Missmer SA, Chavarro JE, Malspeis S, Bertone-Johnson ER, Hornstein MD, Spiegelman D, Barbieri RL, Willet WC, Hankinson SE. A prospective study of dietary fat consumption and endometriosis risk. Hum Reprod 2010;25(6):1528-35.

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