Higher Intakes of DHA/EPA and Supplement Use and Lower Risk of Endometrial Cancer
Arem, H. et al., European Journal of Nutrition, in press, 2012
Yale School of Public Health, School of Medicine, New Haven, CT, USA
Endometrial cancer is the fourth most common cancer amongst women with various lifestyle factors (diet, exercise, others) now being recognized as risk factors. The present study evaluated the association between endometrial cancer risk and the intake of DHA/EPA omega-3 fatty acids and fish. For this purpose, 556 women with confirmed endometrial cancer (ages 35-81 years, average age being 61 years) and 533 controls (disease-free) were recruited (similar ages). Dietary and nutrient intakes were assessed by a food frequency questionnaire (FFQ) and a nutrient database with specific information being gathered on the consumption of various fish/ seafood as well as the use of fish oil supplementation as a source of DHA/EPA. The FFQ was directed to estimating food/nutrient consumption during the 1-5 year period before diagnosis among the cancer cases.
No relationship between dietary omega-6 fatty acid intakes and cancer risk was found. However, those women with cancer reported significantly lower intakes of DHA and EPA as compared to the healthy controls. While the average daily intake of DHA and EPA for all the women was 135 mg and 65 mg, respectively, higher intakes of DHA/EPA were associated with a reduced risk for endometrial cancer. When adjusting for various other factors , the overall risk for cancer was 43 % lower for those with the highest intakes of EPA (top 25 % versus the bottom 25 %) and 36 % lower in the case of the highest intakes of DHA (versus the lowest). Also, the healthy controls reported a significantly higher frequency of fish oil supplement use (24 %) as compared to those with cancer (only 15 %). Furthermore, whether the dietary intakes of DHA or EPA (mostly from fish/seafood) were higher or lower, fish oil supplement usage was associated with significantly lower risks of endometrial cancer ranging from 26-48 % lower.
Dr. Holub's Comments:
The present results from this US study indicates that higher intakes of DHA plus EPA from fish/seafood and fish oil supplements may offer important protective effects against the development of endometrial cancer. The various possible mechanisms for such effects are diverse ranging from a reduced production of pro-inflammatory ‘eicosanoids’ from the cellular omega-6 fatty acid in the form of AA (arachidonic acid) , a reduced synthesis of 2-series prostaglandin (from AA) with a lessening of estrogen formation and cell growth, and other processes which help protect against carcinogenesis. The present study supports the concept that much higher intakes of DHA plus EPA per person than the average intake of approximately 120 to 200 mg/day in North America may be expected to provide a lesser risk for developing endometrial cancer.