Wheying In

Many dietitians claim that protein supplements are a waste of money. Various nutrition texts suggest that getting 15 percent of daily calories from protein easily meets the requirements for athletics. It’s not that difficult to eat foods high in protein—meat, eggs, fish, poultry and dairy—they say. What’s often overlooked, however, is that concentrated protein  supplements have specific absorption characteristics, as well as ingredient “accessories” that are highly beneficial to health.

An example of how a combination of protein supplements can promote muscle gains is evident in a recent study that gave subjects various combinations of milk protein with colostrum and creatine.¹ Before we get to the details, you may need some background on colostrum, which is milk that cows produce for a few days after calving. It’s touted for athletic purposes because it’s rich in immune and growth factors—100 times greater than ordinary milk. A key element is the high concentration of insulinlike growth factor 1, which is considered the anabolic effector of growth hormone.

One form of IGF-1 is a primary regulator of the anabolic response in muscle to weight training. The question is, Does the IGF-1 in the supplement affect humans?

Newborns, both human and bovine, have relatively permeable digestive tracts that permit many proteins to pass into the body intact. After infancy, that permeability disappears. Since IGF-1 is a peptide hormone—that is, a large string of bonded amino acids—taking it in orally would normally result in its degradation into amino acids before its hormonal function kicks in.

Some studies suggest that other substances in colostrum ferry intact IGF-1 into the body, where it exerts its anabolic effects. Other studies have concluded that IGF-1 in colostrum doesn’t survive the digestive barrier.

On to the new study. Forty-nine resistance-trained subjects participated in a 12-week total-body-workout regimen. They were divided into groups according to the following supplements:

1) Protein alone

2) Protein and colostrum

3) Protein and creatine

4) Colostrum and creatine

The supplements all contained the same number of calories and provided the same amount of protein: 60 grams daily. The protein was casein and whey and/or colostrum. At the start, midpoint and end of the 12 weeks the subjects underwent tests for body composition, strength and anaerobic-exercise capacity, as judged by 30-second sprints.

After 12 weeks all the subjects increased strength and muscle endurance equally. Sprint performance gains were also similar. The primary difference was that those in every group except the protein-only group had greater gains in body mass, with the protein-and-creatine and colostrum-and-creatine subjects showing the greatest gains in fat-free mass.

Another new study had some surprising results in relation to how much protein produces an increase in muscle protein synthesis after a weight workout.² Eight young men, average age 21, trained only one leg with leg extensions and leg presses at two separate workouts. After the first workout they received one of two drinks that contained the same number of calories. The first drink contained 10 grams of whey protein and 21 grams of fructose, a sugar that doesn’t elicit an immediate insulin release. The second drink consisted of fructose and maltodextrin, a carbohydrate. The workouts were separated by two weeks to determine the effects of each of the drinks in isolation.

Measurements of muscle protein synthesis revealed that the whey-and-fructose combo led to a twofold increase in muscle protein synthesis after exercise. What’s interesting about the study was the minimal amount of protein in the drinks—only 10 grams, about what you get in one egg. It doesn’t take a lot of high-quality protein to start the muscle-building process following training.

Two recent studies that used rats as subjects illustrated the fat-reducing properties of whey. In the first experiment rats were fed different protein combinations over 25 days.³ Ten diets were created, the control diet being normal protein and the others variously formulated with whey and milk proteins. The primary finding was that a part of whey called beta-lactalbumin seemed to be highly effective in triggering bodyfat loss, along with retention of lean body mass. Researchers suggested that to maximize the appetite-reducing effects of a high protein intake, you also need to go either low carb or high fat; in short, the effects of a high-protein diet in reducing food cravings are strongest when it’s a low-carb, high-protein, high-fat plan.

Another rat study found that when rodents were fed whey, they experienced far less weight and bodyfat gain.⁴ One theory is that glycomacropeptide, a peptide contained in whey isolate, lowers appetite by spurring the release of a gut hormone called cholecystokinin. The rats were fed either whey isolate or casein. The ones getting the whey had 30 percent less weight gain than the ones fed casein. One possible reason is that the glycomacropeptide led to a 64 percent lower resting insulin condition, which favors both increased bodyfat loss and decreased fat synthesis.

A separate study examined the effects of whey taken orally before and after a weight workout on myostatin, a protein that inhibits muscle growth.⁵ Middle-aged and older men engaged in weight training got either 15 grams of whey or a placebo before and after working out. Only in the placebo group did myostatin RNA decrease, confirming that weight training alone lowers myostatin. That didn’t happen to those in the whey group, although whey has other anticatabolic properties with respect to myostatin: Tests demonstrated an increase in myostatin-binding proteins, which inactivate myostatin, in the whey group. The researchers concluded that whey plus weight training blunts myostatin through a different mechanism from the exercise itself, thus compounding the beneficial effects of weights in relation to myostatin control. IM

References

¹ Kerksick, C.M., et al. (2007). Impact of differing protein sources and a creatine containing nutritional formula after 12 weeks of resistance training. Nutrition. 23:647-56.

² Tang, J.E., et al. (2007). Minimal whey protein with carbohydrate stimulates muscle protein synthesis following resistance exercise in trained young men. Appl Physiol Nutr Metab. 32:1132-1138.

³ Pichon, L., et al. (2007). High protein diets containing different milk protein fractions differently influence energy intake and adiposity in the rat. Brt J Nutr. In press.

⁴ Royle, P.J., et al. (2007). Whey protein isolate and glycomacropeptide decrease weight gain and alter body composition in Wistar rats. Br J Nutr. In press.

⁵ Hulmi, J.J., et al. (2008). The effects of whey protein on myostatin and cell cycle-related gene expression responses to a single heavy resistance exercise bout in older men. Eur J Applied Physiol. In press.