The local park is no longer the place where people just go for a gentle stroll or to feed the ducks. For many today, it’s the place where they go for their regular workout. Those who have completed a marathon are increasingly commonplace.
The trend has made sports nutrition a growing market. Particularly among the performance addicts who are most committed to their physical fitness, protein-rich supplements are a necessity to build muscle mass and speed up muscle recovery after strenuous exercise.
Against this background, a series of studies have investigated which protein sources are most efficient – soy, whey or caseinate. Recent findings suggest that the best results are achieved using a combination of all three.
Protein blend versus single source
In a clinical study conducted by the University of Texas Medical Branch in collaboration with DuPont Nutrition & Health, 16 healthy subjects aged 19 to 30 were given protein beverages to consume one hour after exercise. The beverages contained either a soy-dairy blend, comprising 25% soy protein isolate, 25% whey protein isolate and 50% caseinate, or whey protein isolate as the single protein source.
Results from the leg muscle biopsies taken at baseline and five hours after exercise indicate that the soy-dairy blend prolonged the delivery of select amino acids to muscle for an hour longer than whey protein alone. A longer-lasting increase in the muscle’s net amino acid balance was also evident in subjects who had consumed the blend. This points to sustained muscle building and recovery.
More muscle gain with soy-dairy protein
Another clinical study of 68 active young men made similar findings. Here, the subjects were assigned to one of three supplements, which they consumed in combination with resistance exercise over three months. The supplements contained a soy-dairy protein blend, whey protein isolate or a carbohydrate placebo in the form of maltodextrin.
Compared to the carbohydrate, both protein supplements supported similar and significant muscle gains. However, only subjects who consumed the soy-dairy blend continued to gain arm, trunk and whole body mass during the last six weeks of training. The overall result was that 87% of the soy-dairy blend group gained on average more than 1.5kg of lean body mass, against 77% in the whey protein group and 50% in the maltodextrin group.
Further research is ongoing to identify the long-term effects of soy and dairy proteins on muscle mass and strength. That’s important knowledge for sports nutrition manufacturers and for consumers – especially when exercise is not just a walk in the park.