Increased Total Survival among Women with Breast Cancer having Higher Intakes of Fish Omega-3 Fatty Acids
Khankari, N. K. et al., Cancer, in press, 2015
Dept. of Epidemiology, Univ. of North Carolina, Chapel Hill , NC, USA
Since long-chain omega-3 fatty acids from fish/fish oil have been reported to reduce cell growth in malignant breast cancer cells, it was of interest to determine if their intake over an extended time period might benefit the survival of women with breast cancer. For this purpose, 1463 women (ages 20-98 years, 67 % being postmenopausal) newly-diagnosed with first primary breast cancer were interviewed shortly thereafter to determine their food intakes (food-frequency questionnaire). Governmental databases providing the nutrient contents of the foods consumed were used to assess the daily intakes of the long-chain omega-3 fatty acids (mainly from fish/seafood) as EPA (eicosapentaenoic acid) plus DHA (docosahexaenoic acid) plus DPA (docosapentaenoic acid). The average daily intake of these per person were found to be 50, 90, and 10 mgs, respectively, such that 93 % of the combined intake of the three fatty acids was represented by EPA plus DHA. The median follow-up time was 14.7 years during which 485 women died of which 210 were breast cancer-specific.
The researchers observed reductions of 16 - 34 % for all-cause mortality after 15 years of follow-up for those women with the higher intakes of the long-chain omega-3 as compared to those with the lowest intakes of EPA/DHA/DPA. It is noted that the strongest statistical evidence (linear trend) for a protective effect was exhibited for DHA consumption. Those in the top 25 % grouping with respect to intakes consumed more than 120 mgs of DHA, 60 mgs of EPA, and 20 mgs of DPA daily. The authors also indicated that higher long-chain omega-3 fatty acid intakes were associated with lessened all-cause and breast cancer-specific mortality within the first five years after diagnosis and that the omega-3 have the potential to reduce the 15-year mortality from other causes including cardiovascular disease. The authors concluded that dietary intakes of fish and other sources of long-chain omega-3 fatty acids ‘may provide an additional strategy with which to improve survival after breast cancer’.
Dr. Holub's Comments:
The combined intake of EPA plus DHA in those women in the top 25 % with the highest intakes (over 180 mgs daily/person) was well above the average intakes for all the women and approximately 5 times higher those with the lowest intakes (bottom 25 %). It is noted that the intake of the short-chain omega-3 as LNA (alpha-linolenic acid) , mainly from plant food sources and their oils, was considerably higher (averaging 850 mgs/day/person) than for EPA/DHA/DPA combined . Higher intakes of LNA were not found to be significantly associated with all-cause or breast cancer-specific mortality.