Creatine, Carnitine and Carnosine in Vegetarians

Balanced vegetarian diets are popular and contain health-promoting characteristics. A balanced lacto-ovo-vegetarian diet differs in nutrient intake from an omnivorous diet, e.g. by increased intake of fibre, magnesium and antioxidants, but lower intake of omega-3 fatty acids and vitamin B12. However, the impact of reduced to near absent intake of carnitine, carnosine and creatine in a vegetarian diet is less well established and could be relevant in relation to muscle function, exercise capacity and sports performance. Few longitudinal intervention studies investigating the effect of a vegetarian diet on the availability of these compounds currently exist. This study aimed therefore to investigate the effect of of transiently switching omnivores onto a vegetarian diet for 6 months on muscle and plasma creatine, carnitine and carnosine homeostasis. We hypothesized that homeostasis of creatine and carnosine would be disrupted when their dietary intake was missing. For carnitine, however, we hypothesized that homeostasis can be maintained given its slow turnover rate and its presence in some non-meat nutrients. A second aim was to investigate whether supplementation of creatine and beta-alanine (the rate-limiting precursor of carnosine synthesis), concurrently with a lacto-ovo-vegetarian diet, was able to correct for potentially emerging deficiencies.