More Evidence of Cardiovascular Benefits of Omega-3 Fatty Acids
Hey guys! Listen up! US men are 3 times more likely to have calcified coronary arteries than Japanese men, even after adjusting for known cardiovascular risk factors (cigarette smoking, alcohol consumption, high blood pressure, diabetes and blood cholesterol levels). Why? Sekikawa and colleagues attribute this observation to low omega-3 long-chain polyunsaturated fatty acid (LCPUFA) intakes.
Japanese men consume ~3 times more omega-3 fatty acids [eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA)] than US men. In Japanese men, 2.36% and 5.88% of the blood (serum) LCPUFA were EPA and DHA vs 0.79% and 2.38% of the US men, respectively. The authors write that it takes about 1g daily to achieve the beneficial actions of omega-3 LCPUFA.
According to “What We Eat in America, NHANES 2009-2010”, the average US male > 20y typically consumes 160 mg marine omega-3 LCPUFA (EPA+DPA+DHA) with only 80 mg EPA and 40 mg DHA. It is lower for women. This is abysmal. The key message is: many men (and women) need to increase their consumption of EPA and DHA.
A limitation of interpreting serum omega-3 LCPUFA concentrations is that they reflect short term dietary fat intake and not reflect long-term status. This may explain inconsistent findings from findings from randomized control trials (RCTs). Or as suggested by Sekikawa and colleagues, intakes in some RCTs may have been too low to have observed a beneficial effect, e.g. SU.FOL.OM3.
Stratifying by a single baseline blood sample, Brasky et al (2013) published that men with high plasma phospholipids fatty acid concentrations of omega-3 LCPUFA had increased risk of prostate cancer. Total serum fatty acid percentages (EPA+DPA+DHA) ranged between 4.1 to 4.9%. The quartiles were <3.68, 3.68-4.41, 4.42-5.31, and > 5.31% fatty acids (Table 3). Although fatty acid percentages tend to be higher in plasma phospholipids than blood, it is important to put the paper by Brasky and colleagues in perspective.
Brasky et al (2013) report on men who volunteered for a prostate cancer RCT. Experience from the Physicians’ Health Study shows that RCT volunteers have different lifestyles and disease risks. The analysis by Brasky and colleagues shows a study population with a narrow range of serum fatty acid concentrations at baseline yet the average (~4.5%) is higher than those of the US men (3.84%) and much lower than the Japanese men (8.5%) studied by Sekikawa and colleagues. There isn’t any evidence that having high omega-3 fatty acid status increases risk of prostate cancer in Japanese men. In fact, American men are twice as likely to die from prostate cancer than Japanese men. Yet Sekikawa et al (2014) report does find a vast difference in heart disease risk factors according to serum concentrations of long chain omega-3 fatty acids.
Bottom line. Outside of regions where people eat lots of fish, men, women and children have low intakes of DHA and EPA. People should be encouraged to consume more DHA and EPA. The benefits outweigh any apparent risks.
Sekikawa A, Miura K, Lee S, Fujiyoshi A, Edmundowicz D, Kadowaki T, Evans RW, Kadowaki S, Suttion-Tyrrell, Okamura T, Bertolet M, Masaki KH, Nakamura Y, Barinas-Mitchell EJ, Willcox BJ, Kadota A, Seto TB, Maegawa H, Kuller LH, Ueshima H for the ERA JUMP Study Group. Long chain n-3 polyunsaturated fatty acids and incidence rate of coronary artery calcification in Japanese men in Japan and white men in the USA: population based prospective cohort study. 2014 Heart doi:10.1136/heartjnl-2013-304421
Galan P, Kesse-Guyot E, Czernichow S, Briancon S, Blacher J, Hercberg S for the SU.FOL.OM3 Collaborative Group. Effects of B vitamins and omega 3 fatty acids on cardiovascular diseases: a randomized placebo controlled trial. 2010 Br Med J doi:10.1136/bmj.c6273
Brasky TM, Darke AK, Song X, Tangen CM, Goodman PJ, Thompson IM, Meyskens Jr FL, Goodman GE, Minasian LM, Parnes HL, Klein EA, Kristal AR. Plasma phospholipid fatty acids and prostate cancer risk in the SELECT Trial. JNCI doi:10.1093/jnci/djt174
Harris WS. The omega-3 index as a risk factor for coronary heart disease. 2008 Am J Clin Nutr 87:1997S-2002S
Sesso HD, Gaziano JM, VanDenburgh M, Hennekens CH, Glynn RJ, Buring JE. Comparison of baseline characteristics and mortality experience of participants and nonparticipants in a randomized clinical trial: the Physicians’ Health Study. 2002 Control Clin Trials doi:10.1016/S0197-2456(o2)00235-0
Center MM, Jemal A, Lortet-Tieulent J, Ward E, Ferlay J, Brawley O, Bray F. International variation in prostate cancer incidence and mortality rates. 2012 Eur Urol doi:10.1016/j.eururo.2012.02.054