Ads for Ensure Muscle Health claim that this new nutrition beverage helps counter the natural muscle loss that occurs with aging. Its trademark "Revigor" ingredient is hydroxymethylbutyrate (HMB), derived from the amino acid leucine. An 8-ounce bottle also contains 13 grams of protein, along with 24 vitamins and minerals. For best results, you're supposed to drink two bottles a day, in combination with exercise.
A few studies have shown that HMB increases lean muscle mass in healthy adultsboth young and oldwhen they strength train, with those who are less fit seeming to do best. Some research also suggests that HMB may reduce exercise-induced muscle soreness and muscle damage.
In theory at least, it may help for conditions where there is muscle wasting, such as in AIDS, cancer or long bed rest. There's much conflicting evidence, however, and a number of studies show little or no benefit from HMB. A review of data from nine studies, in the Journal of Strength and Conditioning Research in 2009, found that HMB increased lower-body strength slightly in young men who lifted weights for five weeks. But it didn't have a significant effect on upper-body strength or in trained weight lifters.
Most studies on HMB have been small and short and have used different methodologies, so it's hard to determine who would benefit and whether any effects last. Moreover, the studies are often done by researchers with financial interest in the product.
Keep in mind, too, that to get the amount of HMB used in studies, you'd have to drink two bottles of Muscle Health a day, which would give you a total of 500 calories, 44 grams of sugar (11 teaspoons) and 480 milligrams of sodium (about a third of the sodium limit for most adults). That's a pretty high calorie way to get protein.
Bottom line: Though HMB appears to be safe, we don't recommend Ensure Muscle Health as a way to tone up. Instead, go with what's known to increase muscle mass: regular strength training and a diet with adequate calories and protein. You can easily get the amount of protein in a serving of Muscle Healthwith far fewer caloriesby drinking 1 1/2 cups of nonfat milk (165 calories) or eating a cup of nonfat or low-fat yogurt (130 to 140 calories) or two large eggs (145 calories). And if you eat a balanced diet, you don't need a nutrient-fortified beverage.
Adapted from The University of California, Berkeley Wellness Letter (February 2012)