The essential
fatty acid alpha-linolenic acid (ALA) is present in high amounts in
oils such as flaxseed, soy, hemp, rapeseed, chia, and perilla, while
stearidonic acid is abundant in echium oil. ALA is metabolized to
eicosapentaenoic acid (EPA) and
docosahexaenoic acid (DHA) by desaturases and elongases in humans. The conversion of ALA to EPA and DHA is limited, and these long-chain n-3
polyunsaturated fatty acids (PUFAs) are mainly provided from dietary sources (fish and seafood). This review provides an overview of studies that explored the effects of dietary supplementation with ALA in
obesity and related diseases. The
obesity-associated changes of desaturase and elongase activities are summarized, as they could influence the metabolic conversion of ALA. Generally, supplementation with ALA or ALA-rich
oils leads to an increase in EPA levels and has no effect on DHA or omega-3 index. According to the literature data,
stearidonic acid could enhance conversion of ALA to long-chain
n-3 PUFA in
obesity. Recent studies confirm that EPA and DHA intake should be considered as a primary dietary treatment strategy for improving the omega-3 index in
obesity and related diseases.