Mead acid: honorary PUFA and its role in an EFAD
"What is the 'problem' in the case of omega-9? I think the 'problem' is simply that they allow us to live at a higher energy level, with greater resistance to stress and quicker healing." - Ray Peat
I get the impression that mead acid, also known as omega-9, has been intentionally memory-holed in modern scientific literature, partly because it’s produced endogenously during an essential fatty acid deficiency. The ratio of mead acid to arachidonic acid (trienoic:tetraenoic) is used as a “marker” to diagnose an EFAD, and so its increased levels in serum are frowned upon because it indicates that “your diet lacks the essentiality of the unstable fats”. The various symptoms induced by an EFAD are usually resolved by addressing the nutritional deficiencies created by the increase in metabolism. Because of the rarity of an EFAD outside of a laboratory setting, the biological effects of mead acid are seldom studied in the general population. Mead acid is synthesized either from the elongation of oleic acid or from sugars. It is present at relatively low concentrations in the body but is widely distributed throughout all tissues. The highest concentrations are found in young cartilage (2% in humans, 3% in sheep, 5% in calves, 8% in pigs, and 17% in chicks) (Kawashima et al., 2023). This presence in young animals is explained by their fairly saturated tissues, which shift towards being more unsaturated in old age. When the diet lacks the supposed essential fatty acids, serum levels of mead acid rise by as much as 1263% (Siguel et al., 1987). Newborns with naturally high omega-9 levels stop producing it completely by day 10, as dietary linoleic acid increases (Farrell et al., 1988).
Unlike the anti-inflammatory properties of omega-3 fatty acids through immunosuppression, omega-9 exhibits a wide range of true anti-inflammatory properties. In mice fed coconut oil, there is a significant increase in mead acid levels that lower inflammation on the skin by lowering neutrophil count (Tiwari et al., 2019).
Mead acid suppresses the development and growth of mammary cancers by lowering breast cancer cell proliferation, but not accelerating cell death. Authors conclude that MA may be used as a chemopreventive and chemotherapeutic agent. (Kinoshita et al., 2015). One reason for its therapeutic action on the various tissues is its ability to displace ARA, EPA, and DHA by competing in PUFA metabolism. MA has therapeutic effects on experimentally produced bowel lesions (Soh et al., 2003).
I think mead acid is the only polyunsaturated fat that acts like a saturated one, and its tightly regulated endogenous production and enzymatic oxidation are far safer than the erratically unstable oxidation of ingested PUFAs. I’d imagine the therapeutic effect of chicken soup, especially when it contains cartilage/bone is not only due to the high gelatin content, but the MA present in it.
References
Kawashima, H., & Yoshizawa, K. (2023). The physiological and pathological properties of Mead acid, an endogenous multifunctional n-9 polyunsaturated fatty acid. Lipids in Health and Disease, 22(1). doi.org/10.1186/s12944-023-01937-6
Farrell, P. M., Gutcher, G. R., Palta, M., & DeMets, D. (1988). Essential fatty acid deficiency in premature infants. The American Journal of Clinical Nutrition, 48(2), 220–229. doi:10.1093/ajcn/48.2.220
Siguel, E. N., Chee, K. M., Gong, J. X., & Schaefer, E. J. (1987). Criteria for essential fatty acid deficiency in plasma as assessed by capillary column gas-liquid chromatography. Clinical Chemistry, 33(10), 1869–1873. doi:10.1093/clinchem/33.10.1869
Tiwari, P., Nagatake, T., Hirata, S., Sawane, K., Saika, A., Shibata, Y., … Kunisawa, J. (2019). Dietary coconut oil ameliorates skin contact hypersensitivity through mead acid production in mice. Allergy. doi:10.1111/all.13762
Kinoshita, Y., Yoshizawa, K., Hamazaki, K., Emoto, Y., Yuri, T., Yuki, M., … Tsubura, A. (2015). Dietary effects of mead acid on N-methyl-N-nitrosourea-induced mammary cancers in female Sprague-Dawley rats. Biomedical Reports, 4(1), 33–39. doi:10.3892/br.2015.530
Soh, H., Sando, K., Wasa, M., Takagi, Y., Okada, A., & Yoshida, H. (2003). Beneficial Effects of n -9 Eicosatrienoic Acid on Experimental Bowel Lesions. Surgery Today, 33(8), 600–605. doi:10.1007/s00595-003-2572-9