β-alanine Supplementation in Adults With Overweight/Obesity

Overweight and obesity are major public health problems. Recent estimates show that 64.3% of people in the UK are living with overweight or obesity; this is projected to increase to 71% by 2040, which equates to approx. 42.2 million people (Cancer Research UK, 2022). Overweight and obesity are characterised by excess amounts of adiposity and systemic, chronic, low-grade inflammation, which is associated with a range of metabolic disorders including dyslipidaemia, hypertension, and hyperglycaemia (Calder et al., 2011). This confers an increased risk of developing prediabetes, type-2 diabetes, and cardiovascular disease, as well as associated microvascular complications such as retinopathy, neuropathy, and nephropathy (Brannick et al., 2016). Lifestyle interventions can help delay or prevent the progression of overweight or obesity, thereby reducing morbidity (Lin et al., 2017; Wing et al., 2021). Such interventions, however, can be challenging to implement and a lack of long-term adherence can limit their effectiveness (Fappa et al., 2008). It is therefore important to develop low-cost, novel adjunct therapies to improve cardiometabolic health and help delay or prevent disease progression.

The multifunctional dipeptide carnosine has emerged as a candidate for improving glycaemic control and cardiometabolic health. A recent meta-analysis showed that supplementation with carnosine, or its rate-limiting precursor β-alanine, reduces fasting glucose and HbA1c in humans and rodents. Work from our Research Group shows that treatment with carnosine decreases highly toxic lipid peroxidation products in skeletal muscle cells, leading to an increase in insulin-stimulated glucose uptake under glucolipotoxic conditions. A similar role occurs in vivo, where supplementation with β-alanine leads to greater formation of carnosine-adducts in post-exercise skeletal muscle samples. Given that skeletal muscle insulin resistance is a key component of prediabetes and type 2 diabetes, and reactive aldehydes can directly interfere with insulin signalling, carnosine may exert its therapeutic actions in skeletal muscle. There is also emerging evidence that carnosine, and other histidine-containing dipeptides (HCDs), play an important role in Ca2+ handling and excitation-contraction coupling in cardiac muscle, which may have implications for cardiovascular health. A limitation of existing studies is that the low carnosine dose used is likely to have only a modest effect on tissue carnosine content. Supplementation with β-alanine, however, can increase skeletal muscle carnosine content by 60-80% in 4-10 weeks, but it has not yet been trialled in adults with overweight or obesity.

Please note: a change was made to the study eligibility criteria, which was approved by the UK Health Research Authority Research Ethics Committee on 01/09/2022.