SUN-P237: Leucine Supplementation Enhances Integrated Myofibrillar Protein Synthesis in Older Men Consuming Lower and Higher Protein Diets

Αcute effects of essential amino acid gel-based and whey protein supplements on appetite and energy intake in older women

“…Both WP and GEL supplements had a high EAA content (7.5 g); a prerequisite for optimisation of muscle protein synthesis (Phillips et al 2009;Breen et al 2011;Churchward-Venne et al 2014;Xu et al 2015;Murphy et al 2016;Phillips 2016;Hamarsland et al 2017). Increased muscle protein synthesis rates are credited to a large extent to the higher leucine content in high quality proteins, which contributes to the regulation of muscle protein synthesis (Hamarsland et al 2017).…”

“…Furthermore, the ratio of EAAs in the GEL was specifically optimised (i.e. higher leucine content) for older people (Katsanos et al 2006;Xu et al 2015;Murphy et al 2016;Phillips 2016).…”

“…Consumption of at least 0.4 g•kg -1 •BM of high quality protein per meal (Moore et al 2014;Phillips 2015;Lancha Jr et al 2016) is also recommended. This is primarily due to their high essential amino acid (EAA) content which optimises muscle protein synthesis (Breen et al 2011;Churchward-Venne et al 2014;Paddon-Jones et al 2014;Xu et al 2015;Murphy et al 2016;Phillips 2016;Hamarsland et al 2017). However, current evidence is limited regarding the beneficial impact of protein or EAA supplementation alone on the muscle mass and strength of predominantly healthy (Tieland et al 2017) or clinical older populations (Ferrando et al 2010;Cramer et al 2016).…”

Recent developments in deuterium oxide tracer approaches to measure rates of substrate turnover

“…Although the application of D 2 O to the measurement of protein turnover dates back to the work of Hans Ussing in 1941, it is only in the past decade that its validity for measuring muscle protein turnover has been established and subsequently applied in humans [3][4][5][6][7]. Given the importance of skeletal muscle as a metabolic tissue in health and disease, it is unsurprising the application of these techniques has initially been focused on the measurement of muscle protein synthesis (MPS).…”

“…deuterated alanine into protein, glucose into glycogen, fatty acids into triglycerides and ribose moieties into nucleic acids (RNA/DNA) (Table 1) [2]. D 2 O has a slow elimination rate from human body water (t½ 9-11 days) and so steady or pseudo-steady state enrichments can be easily maintained by regular daily or weekly top-ups, providing the unique potential for measurements of metabolism to be performed over hours, days, weeks or even months [3][4][5][6]. Further, by collection of regular saliva (or urine) samples, body water enrichment can be easily monitored throughout, tracking with precursor labeling, enabling subjects to undertake their usual habitual activity and dietary regimes.…”