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What Are n-7 Fatty Acids and Are There Health Benefits Associated with Them?

Published:January 27, 2015DOI:https://doi.org/10.1016/j.jand.2014.11.021
      Dietary fatty acids are often characterized by their saturation status. Of all the fatty acid categories, monounsaturated fatty acids (MUFAs) are consumed the most, comprising 36% of total fat intake, and the majority of MUFA consumption is oleic acid at 27 g/day. Second to oleic acid is palmitoleic acid at 1.2 g/day. Palmitoleic acid is an n-7 fatty acid, which is a small family of unsaturated fatty acids in which the site of unsaturation is seven carbon atoms from the end of the carbon chain. Palmitoleic acid is not commonly found in food but is a product of palmitic acid metabolism in the body. Food sources that naturally contain palmitoleic acid are limited and include certain blue-green algae, macadamia nuts (3.7g/oz; 17% of fat content), and sea buckthorn oil extracted from the seed or berries of the plant.
      Academy of Nutrition and Dietetics
      Position of the Academy of Nutrition and Dietetics: Dietary fatty acids for healthy adults.
      Considering the small contribution that palmitoleic acid makes to fatty acid intake in the American diet, it is not surprising that there is not a large body of research on palmitoleic acid. There are other fatty acids in this group, but palmitoleic acid has garnered the attention of researchers. Palmitoleic acid comes in two forms: a cis isomer when a source like macadamia nuts are consumed or produced endogenously in the body, and a trans isomer that is naturally present in full-fat dairy products and meat fat.
      • Weisenberger J.
      The omega fats.
      Because previous studies in animals suggested that the cis form of this fatty acid may have beneficial effects, researchers wanted to see whether blood levels of the trans isomer, which is derived from diet only (no endogenous production), would be similarly associated with health benefits. Researchers found an association with lower insulin resistance, atherogenic dyslipidemia, and incident diabetes in study participants with higher levels of circulating trans palmitoleate. Their observational findings were striking, but the need for detailed further clinical and experimental investigation was stressed.
      • Mozaffarian D.
      • Cao H.
      • King I.B.
      • et al.
      Trans-palmitoleic acid, metabolic risk factors, and new-onset diabetes in US adults: A cohort study.
      A Google search of the Internet brings up 848,000 results indicating that palmitoleic acid is currently being widely marketed as a supplement with claims of preventing or reducing heart disease. However, in an April 2014 interview, Irena B. King, PhD, one of the authors of the study on trans-palmitoleic acid, stated, “There are both positive and negative associations with omega-7 intakes. It’s not so clear-cut.”
      • Weisenberger J.
      The omega fats.
      The Natural Medicines Comprehensive Database states that sea buckthorn oil from the seed is used for heart disorders including angina and high cholesterol.

      Sea buckthorn. Natural Medicines Comprehensive Database. http://naturaldatabase.therapeuticresearch.com/nd/Search.aspx?cs=&s=ND&pt=100&id=765&ds. Accessed November 21, 2014.

      This publication cites emerging research in China suggesting that taking 10 mg of a particular sea buckthorn extract three times daily for 6 weeks lowers cholesterol, reduces angina, and improves heart function in people with heart disease. Overall, however, the evidence is insufficient to rate the effectiveness for cardiovascular disease and more research is needed.

      Sea buckthorn. Natural Medicines Comprehensive Database. http://naturaldatabase.therapeuticresearch.com/nd/Search.aspx?cs=&s=ND&pt=100&id=765&ds. Accessed November 21, 2014.

      The Academy recommends a food-based approach through a diet that includes the regular consumption of fatty fish, a variety of nuts (including macadamia nuts) and seeds, and lean meats and poultry. Nutrition and dietetics practitioners can help clients set and maintain realistic goals for the intake of total fat and fatty acids by encouraging food-based consumption first and supplements second when the science supports it.

      References

        • Academy of Nutrition and Dietetics
        Position of the Academy of Nutrition and Dietetics: Dietary fatty acids for healthy adults.
        J Acad Nutr Diet. 2014; 114: 136-153
        • Weisenberger J.
        The omega fats.
        Today’s Dietitian. 2014; 16: 20
        • Mozaffarian D.
        • Cao H.
        • King I.B.
        • et al.
        Trans-palmitoleic acid, metabolic risk factors, and new-onset diabetes in US adults: A cohort study.
        Ann Intern Med. 2010; 153: 790-799
      1. Sea buckthorn. Natural Medicines Comprehensive Database. http://naturaldatabase.therapeuticresearch.com/nd/Search.aspx?cs=&s=ND&pt=100&id=765&ds. Accessed November 21, 2014.