Associação do ácido graxo poli-insaturado ômega-3 com a massa e a força muscular

Abstract

Aging is related to the decrease in strength and muscle mass, which can cause several health problems to the individual. Thus, nutritional strategies that can positively impact this situation are of great importance. In this sense, omega-3 (ω-3) is included, which is a polyunsaturated fat that has numerous health benefits, and which has recently been identified as a potential nutrient to impact muscle strength and mass. Thus, the objective of the present thesis was to evaluate the association between ω-3 and muscle strength. Three articles were developed, one being a narrative review (article 1) and the others with a cross-sectional design (articles 2 and 3). The narrative review showed that ω-3 does not seem to promote increases in muscle mass in sedentary young and elderly people, there are conflicting results between studies when there is an association between physical training and there is no consensus regarding the effects on muscle function in the elderly. Therefore, the scientific evidence is still limited. In this context, we conducted two cross-sectional studies involving data from the National Health and Nutrition Examination Survey (NHANES). In the first cross-sectional study (NHANES 1999-2002), involving individuals aged 50-85 years, the association between ω-3 food intake and isokinetic strength of the knee extensors (peak strength) was evaluated. It was observed that the consumption of ω-3 was positively associated with muscle strength in men, but not in women. In addition, after performing an isocaloric substitution analysis of other types of fat with ω-3, no significant differences were observed. In the second cross-sectional article (NHANES 2011-2012), we investigated the association of plasma levels of ω-3 and the food intake of this fat with muscle handgrip strength in adult individuals (over 20 years old). A positive association between handgrip strength and plasma DHA (younger men) and total blood ω-3 was observed for older men. Regarding dietary ω-3, a positive association was observed between DHA consumption and muscle strength in older men. For women, no significant association was observed after the insertion of adjustments in both plasma assessment and dietary analysis. In conclusion, significant associations were found only for the male group, but not for women. Thus, it is suggested that the next studies evaluate these groups separately, since the associations were sex-dependent. Thus, further studies are needed involving this topic, in order to better elucidate the relationship between ω-3 and muscle health.