Vegetarians are more responsive to the effects of creatine supplementation on exercise performance than their carnivorous counterparts. That was the clear conclusion of a Canadian study on creatine-supplemented recreational athletes following an eight-week resistance training programme.

Of the 42 subjects, who were aged 19-55, 18 were vegetarian (either lacto-ovo or vegan) and the remainder were non-vegetarian. All were measured at the beginning and end of the study period for muscle fibre morphology and metabolite concentrations, body composition, hydration status, exercise performance and strength (assessed by 1-RM bench press and leg press).

The subjects were split into four groups for the duration of the study, as follows:

• vegetarian with creatine (0.25g per kg lean tissue mass for a seven-day loading phase, followed by 0.0625g/kg LTM for another seven weeks, mixed with fruit juice);
• vegetarian with placebo (the same amount of maltodextrin mixed with fruit juice);
• non-vegetarian with creatine;
• non-vegetarian with placebo.

All subjects then followed the same high- volume, heavy-load (>70% 1-RM) whole-body resistance training programme designed to increase lean tissue mass and strength for eight weeks.

The main findings emerging from comparisons between the groups were as follows:

• at baseline, there were significant differences between the vegetarians and the non-vegetarians, with the former consuming lower total calories and lower calories as protein than the latter, as well as demonstrating lower total muscle creatine concentrations, but with no significant differences in 1-RM bench press and leg press;
• creatine subjects showed greater increases in phosphocreatine, total creatine, bench-press strength, isokinetic work, type 2 muscle fibre area and whole-body lean tissue than those on placebo;
• vegetarians who took creatine showed greater increases in total creatine, phosphocreatine, lean tissue and total work performance than their non-vegetarian counterparts.

The researchers comment: ‘This is the first study to demonstrate that habitual vegetarians (lacto-ovo or vegan) have lower resting intramuscular concentrations of total creatine (TCr) as compared with omnivorous peers.’

Their findings are also significant in being the first to demonstrate ‘that individuals with low initial intramuscular TCr have heightened response to creatine supplementation during resistance training’.

Med Sci Sports Exerc 2003; 35:11:1946-1955