New article in Diabetologia
/Findings after 12 weeks of combined strength and endurance exercise suggest enhanced muscle and adipose tissue branched-chain amino acid metabolism as mediators of improved insulin sensitivity.
Accumulation of the branched-chain amino acids (BCAAs) valine, leucine and isoleucine in blood were already linked to obesity and insulin resistance in the 1960s. However, these results were largely overlooked, and intake of BCAAs as dietary supplements have become a multi-million industry.
More recently, large prospective epidemiological studies applying metabolomic profiling of blood have shown that plasma BCAAs could predict future type 2 diabetes and insulin resistance, again indicating that BCAAs may have a detrimental effect on metabolic health.
We have now shown that even though levels of BCAAs in blood may be increased in insulin resistance and correlate with liver fat content, they did not respond to 12 weeks of exercise despite substantially enhanced insulin sensitivity. Instead, we observed signs of suppressed BCAA catabolism in muscle and adipose tissue with insulin resistance, and that enhanced BCAA catabolism in these tissues were highly related to the increased insulin sensitivity after 12 weeks of exercise. Hence, we propose that levels of BCAAs in blood are only markers of insulin resistance, and that tissue capacity to oxidise BCAAs is the important factor for insulin sensitivity.
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Sindre Lee-Ødegård
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