Key Findings:
In agreement with recent reviews on ALA, this analysis concludes that ALA offers modest protection against coronary heart disease and notes an increase in the number of studies over the last 10 years that support a beneficial role. The author suggests a need for prospective studies focusing on various cardiovascular outcomes. The review reports research that supports benefits of ALA in reducing bone fracture risk and type 2 diabetes. Clinical trials at the primary and secondary levels are recommended to determine mechanisms of ALA effects. The author also acknowledges the sustainability issues related to marine sources is a concern and recommends that ALA foods should be included in the diet, irrespective of the consumption of marine omega 3s, especially for those whose consumption of EPA and DHA is low. Also emphasized was that whole foods containing ALA, such as flaxseed, provide other bioactive constituents that act synergistically with ALA to produce favorable modification of disease risk factors.
ABSTRACT:
Alpha-Linolenic acid (ALA) is an n–3 (omega-3) fatty acid found mostly in plant foods such as flaxseed, walnuts, and vegetable oils, including canola and soybean oils. Most of the health benefits observed for n–3 fatty acids have been attributed to the marine-derived long-chain n–3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid, because of the strength of evidence from both epidemiologic studies and randomized controlled trials. Furthermore, the observed cardioprotective and other health effects of ALA have been credited to its precursor role in converting to EPA in the body. The promotion of fatty fish consumption for its documented health benefits may not be practical for those who are concerned with the unsustainability of marine sources or who avoid eating fish for a variety of reasons. ALA-rich plant sources are more abundant and may serve as a suitable alternate. It is therefore worthwhile to consider the evidence for the health benefits of ALA. The purpose of this review is to present the evidence from recent studies on the association between ALA and cardiovascular disease, type 2 diabetes, and fracture risk. The potential mechanisms that explain these associations will also be briefly discussed. (Authors Abstract)