Fortified Milk and Exercise

February 10/Melbourne, Australia/Aging & Elder Health Week -- Data detailed in"Effects of Resistance Exercise and Fortified Milk on Skeletal Muscle Mass, Muscle Size, and Functional Performance in Middle-aged and Older Men: an 18-mo randomized controlled trial" have been presented. "Limited data have suggested that the consumption of fluid milk after resistance training (RT) may promote skeletal muscle hypertrophy. The aim of this study was to assess whether a milk-based nutritional supplement could enhance the effects of RT on muscle mass, size, strength and function in middle-aged and older men," investigators in Australia report.

"This was an 18-mo factorial design (randomized control trial) in which 180 healthy men aged 50-79 were allocated to the following groups: 1) exercise + fortified milk, 2) exercise, 3) fortified milk or 4) control. Exercise consisted of progressive RT with weight-bearing impact exercise. Men assigned to the fortified milk consumed 400mL/day of low-fat milk, providing an additional 836kJ, 1000mg calcium, 800IU vitamin D(3), and 13.2g protein per day. Total body lean mass (LM) and fat mass (FM) (dual-energy X-ray absorptiometry), midfemur muscle cross-sectional area (CSA) (quantitative computed tomography), muscle strength, and physical function were assessed. After 18 months, there was no significant exercise by fortified milk interaction for total body LM, muscle CSA, or any functional measure. However, main effect analyses revealed that exercise significantly improved muscle strength (approximately 20-52%, p<0.001), LM (0.6 kg, p<0.05), FM (-1.1 kg, p<0.001), muscle CSA (1.8%, p<0.001), and gait speed (11%, p<0.05) relative to no exercise. There were no effects of the fortified milk on muscle size, strength, or function," wrote S. Kukuljan and colleagues, Deakin University.

The researchers concluded, "The daily consumption of low-fat fortified milk does not enhance the effects of RT on skeletal muscle size, strength, or function in healthy middle-aged and older men with adequate energy and nutrient intakes."

Kukuljan and colleagues published their study in the Journal of Applied Physiology ("Effects of Resistance Exercise and Fortified Milk on Skeletal Muscle Mass, Muscle Size and Functional Performance in Niddle-aged and Older Men: An 18-mo Randomized Controlled Trial." Journal of Applied Physiology, 2009;107(6):1864-73).

For additional information, contact S. Kukuljan, 1Centre for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University, Melbourne, Australia.

From the February 15, 2010, Prepared Foods E-dition