Drinking fat-free milk after resistance exercise has a greater effect on helping to increase lean body mass compared to soy or carbohydrates in young male weightlifters, a study has concluded.
Researchers from McMaster University, Canada, found taking milk after a work-out promotes a greater protein balance than consuming a soy protein drink.
The work, published in the American Journal of Clinical Nutrition, adds to an increasing body of evidence to the positive health benefits of milk in the sports nutrition market, which is currently dominated by isotonic drinks.
Earlier this month researchers from the UK's Loughborough University's School of Sports and Exercise Sciences found that drinking skimmed milk after exercise may promote recovery and rehydration better than water or an isotonic sports drink.
Their work, published in the British Journal of Nutrition, found a group of volunteers remained hydrated after drinking milk, but remained dehydrated after drinking the other drinks.
According to market analyst Mintel, the sports drink market in the UK was worth £137m ($252m, €200m) in 2003, and is dominated by isotonic drinks like Lucozade Sport, Powerade and Gatorade.
In the US, the sports drinks market is reported to have generated almost $3bn (£1.6bn, €2.4bn) with Gatorade dominating the market with 82 per cent of the market. Powerade is a distant second with a reported 13 per cent of the market.
In the past five years there have been 128 launches of milk based sports drinks launched globally, according to Mintel's Global New Product Database.
This study aimed to determine the long-term consequences of milk or soy protein or equivalent energy consumption on training-induced lean mass accretion.
Fifty-six healthy young men were recruited, split into three groups, and asked to train five days a week for 12 weeks on a rotating split-body resistance exercise program.
They were then randomly assigned to consume drinks immediately and again after one hour exercise. The groups were given fat-free milk, fat-free soy protein that was isoenergetic, isonitrogenous, and with macronutrient ratio matched to milk. The third group had maltodextrin that was isoenergetic with milk and soy.
Muscle fibre size, maximal strength, and body composition by dual-energy X-ray absorptiometry (DXA) were measured before and after training. The researchers found that no between-group differences were seen in strength and that type II muscle fibre area increased in all groups with training, but with greater increases in the milk group than in both the soy and control groups.
Type I muscle fibre area increased after training only in the milk and soy groups, with the increase in the milk group being greater than that in the control group. DXA-measured fat- and bone-free mass increased in all groups, with a greater increase in the milk group than in both the soy and control groups.
NutraIngredients.com has not seen the full results prior to publication.
The researchers concluded that chronic postexercise consumption of milk promotes greater hypertrophy during the early stages of resistance training in novice weightlifters when compared with isoenergetic soy or carbohydrate consumption.
Source: American Journal of Clinical Nutrition
Vol. 86, No. 2, 373-381, August 2007
Title: "Consumption of fat-free fluid milk after resistance exercise promotes greater lean mass accretion than does consumption of soy or carbohydrate in young, novice, male weightlifters."
Authors: Joseph Hartman, Jason Tang, Sarah Wilkinson, Mark Tarnopolsky, Randa Lawrence, Amy Fullerton and Stuart Phillips.