Consumption of α-Linolenic Acid Linked to Lower CVD Risk & May Play a Role in Reduced Rates of Cognitive Decline

by | Jun 22, 2022 | 2022, Brain Health, Cardiovascular Health, Cognitive Health

Written by Taylor Woosley, Staff Writer. Analyses of observational studies show that increasing ALA intake is associated with a 10% lower risk of total CVD, while a prospective cohort study reported that higher ALA consumption was associated with slower decline in global cognitive functioning.  

heart healthPolyunsaturated fatty acids (PUFAs) are fatty acids that feature more than one double bond along the hydrocarbon chain, which have a high nutritional content and some of these fatty acids, such as omega-3 and omega-6, are essential 1. Long chain PUFAs are key components of membrane phospholipids and are one of the main cellular building blocks of the body 2. Among the n-3 PUFAs, alpha-linoleic acid (ALA; 18:3n3) cannot be synthesized in humans and must be obtained through diet 3. Main sources of ALA include flaxseeds, soybeans, pumpkin seeds, walnuts, and tofu 4.

In clinical studies, the consumption of ꙍ-3 PUFAs has exhibited pleiotropic benefits in the control of chronic diseases, stemming from its use as a systemic anti-inflammatory approach in metabolic diseases 5. ꙍ-3 PUFA deficiency impairs learning and memory and is associated with age-related neurodegenerative disorders 6. In addition, ALA acts as a precursor for the long-chain n-3 PUFAs, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) which may help reduce the risk of cardiovascular disease 7. One reason for omega-3 fatty acid’s positive effect on cardiovascular disease may be due to its ability to significantly reduce inflammation in patients with cardiovascular disease 8.

Sala-Vila et al. assessed meta-analyses of observational studies to better understand the association between ALA consumption and risk of total cardiovascular disease and its role in cognitive functioning. Significant findings of the meta-analyses are as follows:

  • One meta-analysis which examined associations between dietary ALA and ischemic heart disease (IHD) risk found that higher compared with lower ALA intake was associated with reduced risk of fatal IHD (RR: 0.80; 95% CI: 0.65, 0.98). In dose-response analyses, each additional 1 g/d of ALA intake was associated with a 10% reduction in risk of fatal IHD (RR: 0.90; 95% CI: 0.83, 0.99).
  • A 2018 meta-analysis of 26 RCTs examining the effects on lipids of walnuts, a high source of ALA, concluded that significant reductions of total cholesterol, LDL cholesterol, and triglycerides were observed through walnut consumption compared to control diets.
  • Results of the WAHA trial (60% of subjects with mild hypertension) comparing subjects in a walnut supplementation group compared to control observed with 24-h ambulatory BP monitoring, reported that mean office systolic BP decreased by 4.6 mm Hg (95% CI: -7.4, -1.8 mm Hg) in the walnut group.
  • A cross-sectional study of patients with CVD assessed the importance of dietary n-3 PUFA intake and its inverse association with markers of inflammation. An increase in n-3 PUFA of 1 g/1000 k cal was associated with a 33% reduction in CRP and a 48% reduction in IL-1β.
  • One study focused on structural brain alterations related to stroke risk concluded that subjects with higher dietary ALA intake had decreased odds of cerebral macroinfarcts and microinfarcts.
  • A prospective cohort study observing possible associations between ALA intake and cognition reported that higher n-3 PUFA (especially ALA) consumption was associated with slower decline in global cognitive function and memory.

In conclusion, the benefits of ALA on CVD risk and cognition is an increasing area of interest in research. Although the study findings can be inconclusive regarding the benefits of ALA in certain settings, epidemiologic studies and RCTs have proven the benefit of ALA intake on reducing blood pressure and markers of inflammation which both help reduce risk of CVD. Although more research needs to be examined to understand the association between ALA consumption and cognition, past studies show that ALA may play a role in reducing the decline in cognitive functioning which should be further explored in future studies.

Source: Sala-Vila, Aleix, Jennifer Fleming, Penny Kris-Etherton, and Emilio Ros. “Impact of α-Linolenic Acid, the Vegetable ω-3 Fatty Acid, on Cardiovascular Disease and Cognition.” Advances in Nutrition (2022).

© The Author(s) 2022. Published by Oxford University Press on behalf of the American Society for Nutrition. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. Adv Nutr 2022;00:1–19; doi: https://doi.org/10.1093/advances/nmac016.

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Posted June 22, 2022.

Taylor Woosley studied biology at Purdue University before becoming a 2016 graduate of Columbia College Chicago with a major in Writing. She currently resides in Glen Ellyn, IL.

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