Omega-3 fatty acids intake in vegetarian diets

Vegetarian diets have an important role in reducing body mass index, ischemic heart disease mortality, lower prevalence of hypertension, type 2 diabetes, colon, and prostate cancer [1]. Vegetal food sources of omega 3 fatty acids (n-3PUFA) contain α-linolenic acid (C18: 3n-3) (ALA). The conversion of ALA to the active compounds, eicosapentaenoic acid (C20: 5n-3) (EPA) and docosahexaenoic acid (C22: 6n-3) (DHA) in the body involves desaturation and elongation. Food sources of n-3PUFA in an omnivorous diet are either ALA or by the direct consumption of fish or animal products, while in an ovo-lacto-vegetarian or vegan diet intake of n-3PUFA is limited to the bioconversion of ALA to EPA and DHA. The conversion of ALA to EPA and DHA has a low efficiency as an important part of ALA is used in mitochondrial β-oxidation. Another problem of ALA conversion is the competition between ALA and linoleic acid (C18: 2n-6) (LA), the precursor of omega 6 fatty acids (n-6PUFA), for Δ6 desaturase, a key enzyme in the PUFA metabolism, converting LA and ALA into γ-linolenic acid (C18:3n-6) (GLA) and (C18:4n-3), respectively, with a higher affinity for LA [2]. Following a vegetarian or vegan diet raises the issue of adequate supplementation with EPA and DHA, as important precursors of extremely active compounds obtained via cyclooxygenase or lipoxygenase pathway, or from the class of resolvins or neuroprotectins with complex physio pathological implications ([Fig. 1]).

Fig. 1 Biosynthesis of EPA, DHA and AA (arachidonic acid) from precursors ALA and LA.

Publication History

Article published online:
16 November 2023

• References

• 1 Tero-Vescan A. et al. Farmacia 2015; 63 (04) 504-509
• 2 Saunders AV. et al. Med J Aust 2013; 199 (S4): S22-26