Whey protein supplementation for the preservation of mass and muscular strength of patients with heart failure: study protocol for a randomized controlled trial

The contradictory role of branched-chain amino acids in lifespan and insulin resistance

Branched-chain amino acids (BCAAs; a mixture of leucine, valine and isoleucine) have important regulatory effects on glucose and lipid metabolism, protein synthesis and longevity. Many studies have reported that circulating BCAA levels or dietary intake of BCAAs is associated with longevity, sarcopenia, obesity, and diabetes. Among them, the influence of BCAAs on aging and insulin resistance often present different benefits or harmful effects in the elderly and in animals. Considering the nonobvious correlation between circulating BCAA levels and BCAA uptake, as well as the influence of diseases, diet and aging on the body, some of the contradictory conclusions have been drawn. The regulatory mechanism of the remaining contradictory role may be related to endogenous branched-chain amino acid levels, branched-chain amino acid metabolism and mTOR-related autophagy. Furthermore, the recent discovery that insulin resistance may be independent of longevity has expanded the research thinking related to the regulatory mechanism among the three. However, the negative effects of BCAAs on longevity and insulin resistance were mostly observed in high-fat diet-fed subjects or obese individuals, while the effects in other diseases still need to be studied further. In conclusion, there is still no definite conclusion on the specific conditions under which BCAAs and insulin resistance extend life, shorten life, or do not change lifespan, and there is still no credible and comprehensive explanation for the different effects of BCAAs and insulin resistance on lifespan.

Dietary supplementation with whey protein improves systemic microvascular function in heart failure patients: a pilot study

Endothelial dysfunction is a well-known component of the pathophysiology of heart failure (HF), with proven prognostic value. Dietary supplementation with whey protein (WP) has been widely used to increase skeletal muscle mass, but it also has vascular effects, which are less understood. This study aimed to evaluate the effects of WP supplementation on the systemic microvascular function of HF patients. This was a blinded, randomized, placebo-controlled clinical trial that evaluated the effects of 12-week WP dietary supplementation on systemic microvascular function, in patients with HF New York Heart Association (NYHA) classes I/II. Cutaneous microvascular flow and reactivity were assessed using laser speckle contrast imaging, coupled with pharmacological local vasodilator stimuli. Fifteen patients (aged 64.5±6.2 years, 11 males) received WP supplementation and ten patients (aged 68.2±8.8 years, 8 males) received placebo (maltodextrin). The increase in endothelial-dependent microvascular vasodilation, induced by skin iontophoresis of acetylcholine, was improved after WP (P=0.03) but not placebo (P=0.37) supplementation. Moreover, endothelial-independent microvascular vasodilation induced by skin iontophoresis of sodium nitroprusside, was also enhanced after WP (P=0.04) but not placebo (P=0.42) supplementation. The results suggested that dietary supplementation with WP improved systemic microvascular function in patients with HF.

The role of diet and nutrition in heart failure: A state-of-the-art narrative review

Heart Failure (HF) incidence is increasing steadily worldwide, while prognosis remains poor. Though nutrition is a lifestyle factor implicated in prevention of HF, little is known about the effects of macro- and micronutrients as well as dietary patterns on the progression and treatment of HF. This is reflected in a lack of nutrition recommendations in all major HF scientific guidelines. In this state-of-the-art review, we examine and discuss the implications of evidence contained in existing randomized control trials as well as observational studies covering the topics of sodium restriction, dietary patterns and caloric restriction as well as supplementation of dietary fats and fatty acids, protein and amino acids and micronutrients in the setting of pre-existing HF. Finally, we explore future directions and discuss knowledge gaps regarding nutrition therapies for the treatment of HF.