Omega-3 polyunsaturated fatty acids augment the muscle protein anabolic response to hyperinsulinaemia–hyperaminoacidaemia in healthy young and middle-aged men and women

Abstract

Increased dietary long-chain n-3 polyunsaturated fatty acid (LCn-3PUFA) intake stimulates muscle protein anabolism in individuals who experience muscle loss due to aging or cancer cachexia. However, it is not known whether LCn-3PUFA elicit similar anabolic effects in healthy individuals. To answer this question we evaluated the effect of 8 weeks of LCn-3PUFA supplementation (4 g·d−1 of Lovaza®) in nine 25–45 y old healthy subjects on the rate of muscle protein synthesis (by using stable isotope labelled tracer techniques) and the activation (phosphorylation) of elements of the mTOR-p70s6k pathway during basal, postabsorptive conditions and during a hyperinsulinemic-hyperaminoacidemic clamp. We also measured the concentrations of protein, RNA, and DNA in muscle to obtain indices of the protein synthetic capacity, translational efficiency and cell size. Neither the basal muscle protein fractional synthesis rate nor basal signalling element phosphorylation changed in response to LCn-3PUFA supplementation but the anabolic response to insulin and amino acid infusion was greater after LCn-3PUFA (i.e., the muscle protein fractional synthesis rate during insulin and amino acid infusion increased from 0.062 ± 0.004 to 0.083 ± 0.007 %·h−1 and the phospho mTORSer2448 and p70s6kThr389 concentrations increased by ~50%; all P < 0.05). In addition, the muscle protein concentration and the protein-to-DNA ratio (i.e., muscle cell size) were both greater (P < 0.05) after LCn-3PUFA supplementation. We conclude that LCn-3PUFA have anabolic properties in healthy young and middle aged adults.

Marine omega-3 fatty acids prevent myocardial insulin resistance and metabolic remodeling as induced experimentally by high insulin exposure

“…Aas et al (1) also observed an increase in basal glucose and fatty acid uptake after treatment with EPA in human skeletal muscle cells. This observation could probably be explained in terms of a general anabolic effect of -3 PUFAs, in line with results reported by Smith et al (43) showing increased muscle protein concentration in response to dietary intake of -3 PUFAs. However, in light of the observation that EPA or DHA did not increase p70 S6K phosphorylation, the activity of the anabolic master regulator mTOR appears not to be altered by these -3 PUFAs.…”

Omega-3 polyunsaturated fatty acids protect against ischemia-reperfusion renal injury through AMPK-mediated autophagy

“…In our data, it is confusing that mTOR is more elevated in fat-1 sham mice that wt sham mice, unlike being decreased in fat-1 IRI mice than wt IRI mice. However, omega 3 intake increased mTOR-p70s6k signaling which control muscle protein anabolism and muscle protein growth in human [41]. It may be possible that omega 3 elevate mTOR in basal status kidney, like muscle.…”

High Dose Omega-3 Fatty Acid Administration and Skeletal Muscle Protein Turnover in Maintenance Hemodialysis Patients

“…During physiologic assessment, protein synthesis is not expected to increase in a fasting state. Studies have shown that v-3 supplementation improves skeletal muscle protein synthesis during a hyperinsulinemic-hyperaminoacidemic clamp where patients are in an anabolic state as opposed to under fasting conditions (4,5). Since there is a physiologic balance between protein synthesis and protein breakdown designed to compensate for each other to maintain a net nitrogen balance, our results are physiologically appropriate in that fish oil did decrease steady-state protein breakdown, which was in turn compensated for by a decrease in protein synthesis resulting in no appreciable change in net balance.…”