How important are fatty acids in human health and can they be used in treating diseases?

Abstract

Most of the short-chain fatty acids (SCFAs) are produced by <i>Bifidobacterium</i>, <i>Lactobacillus</i>, Lachnospiraceae, <i>Blautia</i>, <i>Coprococcus</i>, <i>Roseburia</i>, <i>Facealibacterium</i> and <i>Oscillospira</i>. Butyrate (C₄H₇O₂^-) supplies 70% of energy to intestinal epithelial cells (IECs), supports tight-junction protein formation, induces the production of inflammatory cytokines, and inhibits histone deacetylase (HDAC). Butyrate is also associated with the recovery of brain trauma, improvement of dementia, the alleviation of autoimmune encephalitis, and several intestinal disorders. Low levels of SCFAs are associated with hypertension, cardiovascular disease (CVD), strokes, obesity, and diabetes mellitus. <i>Cis-</i>palmitoleic acid (C₁₆H₃₀O₂), a mono-unsaturated fatty acid (MUFA), increases insulin sensitivity and reduces the risk of developing CVD. Lipokine palmitoleic acid reduces the expression of pro-inflammatory cytokines IL-1β (pro-IL1β), tumor necrosis factor α (TNF-α), and isoleucine 6 (IL-6). Polyunsaturated fatty acids (PUFAs), such as omega-3 and omega-6, are supplied through the diet. The conversion of PUFAs by cyclooxygenases (COX) and lipoxygenases (LOX) leads to the production of anti-inflammatory prostaglandins and leukotrienes. Oxidation of linoleic acid (LA, C₁₈H₃₂O₂), an omega-6 essential fatty acid, leads to the formation of 13-hydroperoxy octadecadienoic acid (13-HPODE, C₁₈H₃₂O₄), which induces pro-inflammatory cytokines. Omega-3 PUFAs, such as eicosapentaenoic acid (EPA, C₂₀H₃₀O₂) and docosahexaenoic acid (DHA, C₂₂H₃₂O₂), lower triglyceride levels, lower the risk of developing some sort of cancers, Alzheimer's disease and dementia. In this review, the importance of SCFAs, MUFAs, PUFAs, and saturated fatty acids (SFAs) on human health is discussed. The use of fatty acids in the treatment of diseases is investigated.