Alpha-linolenic acid as effective as long chain omega 3 fatty acids in reducing coronary death

By Kelley Fitzpatrick

Posted on

Evidence continues to support an equivalent role of omega-3 alpha-linolenic acid (ALA; 18:3n-3) and the long chain omega-3 fatty acids (LCn3PUFA) found in marine products, eicosapentaenoic acid (EPA; 20:5n-3), docosapentaenoic acid (DPA; 22:5n-3), and docosahexaenoic acid (DHA; 22:6n-3) in the reduction of coronary heart disease (CHD). In the latest paper posted to Flaxresearch.com, the JAMA Internal Medicine reports the first output from the Fatty Acids and Outcomes Research Consortium (FORCE), a collaboration of scientists who individually have conducted 19 different observational studies on omega 3 fats (1). The meta-analysis included data from 45,637 participants throughout 16 countries.

The study showed that individuals with the highest omega 3 fatty acids in the blood level had about a 25% lower risk of dying from a heart attack compared to those with the lowest levels. Overall, omega 3s from both plant and seafood sources were associated with a 10% lower risk of a fatal cardiac event. Measuring omega-3 levels in the blood is important since most previous studies relied on participants reporting their intake. The self-reporting of dietary intake is generally not viewed as the most accurate form of data accumulation. This extensive analysis also supported omega-3 status as an important biomarker of coronary heart disease.

This latest publication supports a number of large population studies that have demonstrated an inverse relationship between ALA levels and cardiovascular events (2). Another meta-analysis reported that each 1 g/day increment of ALA intake was associated with a 10% lower risk of death from CHD (3). This evidence has led to the recommendation that ALA intake be increased to 2–3 g/d to reduce the risk of CHD (4).

There have been decades of unrecognized work which has shown the cardiovascular benefits of ALA.  In 2008, an inverse relationship between 0.7% adipose tissue ALA and dietary ALA intake (ca. 1.8 g/day) and the risk of nonfatal myocardial infarction (MI) in 1819 patients who survived an MI and 1817 matching controls was reported (5). The relationship between ALA and MI was nonlinear; risk did not decrease with intakes above 0.65% energy (1.8 g/d). These observations are significant in that ALA as assessed both by questionnaire and in adipose tissue was associated with reduced risk of MI in a large population. The maximum benefit of ALA was obtained within a realistic and achievable range of intake, and the association between ALA and MI was independent of fish intake.

Of note, research suggests that ALA plays an important role among populations with either high or low fish intake. The PREDIMED trial included 4139 women and 3063 men between 55-80 years of age. For each additional daily gram intake of ALA, the research found a 23% lower risk of total mortality (6). Close to eighty percent of the study population met the American Heart Association’s recommendation of ≥500 mg/d of LCn3PUFA. These results suggest that ALA contributes to a reduction of total mortality even when the background diet is high in marine-derived LCn3PUFA.

In low fish-consuming populations, an intake of 1 g/day ALA was associated with a 50% lower risk of nonfatal myocardial infarction among men consuming <100 mg/d LCn3PUFA from fish (7). The data assessed was from the Health Professional Follow-up Study, which began in 1986 with a cohort of 45,772 health professionals. The observations strongly support a role of ALA consumption in decreasing CHD risk and further indicates that ALA may be of particular importance in sectors of the population that do not eat fatty fish.

ALA from flaxseed provides numerous health benefits as well as some unique advantages over marine omega-3 fatty acid sources, the latter of which include limited global availability, high cost, allergenicity, and toxins that have been reported with some seafood products (8). For consumers trying to eat healthier, sustainable, plant-based diets, flaxseed and its oil are beneficial additions.

References

  1. Del Gobbo LC, Imamura F, Aslibekyan S, et al. 2016. Omega-3 Polyunsaturated Fatty Acid Biomarkers and Coronary Heart Disease: Pooling Project of 19 Cohort Studies. JAMA Internal Medicine. June 27. doi:10.1001/jamainternmed.2016.2925
  2. Rodriguez-Leyva, D, Bassett, CMC, Richelle McCullough, R, Pierce, GN. 2010. The cardiovascular effects of flaxseed and its omega-3 fatty acid, alpha-linolenic acid. Can J Cardiol. 26(9):489-96.
  3. Pan, A, Chen, M, Chowdhury, R, Wu, JHY, et al. 2012. Alpha-Linolenic acid and risk of cardiovascular disease: a systematic review and meta-analysis. Am J Clin Nutr. 96(6):1262-73. doi: 10.3945/ajcn.112.044040.
  4. Fleming JA, Kris-Etherton PM. 2014. The evidence for α-linolenic acid and cardiovascular disease benefits: Comparisons with eicosapentaenoic acid and docosahexaenoic acid. Adv Nutr. 14;5(6):863S-76S.
  5. Campos, H, Baylin, A, Willett, WC. 2008. α -Linolenic Acid and Risk of Nonfatal Acute Myocardial Infarction, Circulation. 118:339-345.
  6. Sala-Vila, A, Guasch-Ferre, M, Hu, FB, et al. 2016. Dietary α-Linolenic Acid, Marine ω-3 Fatty Acids, and Mortality in a Population With High Fish Consumption: Findings From the PREvención con DIeta MEDiterránea (PREDIMED) Study. J Am Heart Assoc. 2:5(2). pii: e002077. doi: 10.1161/JAHA.116.002077.
  7. Mozaffarian, D, Ascherio, A, Hu, FB, et al. 2005. Interplay between different polyunsaturated fatty acids and risk of coronary heart Disease in men. Circulation. 111: 157-164.
  8. Foran, SE, Flood, JG, Lewandrowski. KB. 2003. Measurement of Mercury Levels in Concentrated Over-the-Counter Fish Oil Preparations: Is Fish Oil Healthier Than Fish? Arch Path Lab Med. 127(12):1603-1605. This content is copyright protected