Diet & Fitness

Whey protein, like other supplemental proteins, may aid people on a low-calorie weight-loss diets by suppressing appetite and preserving muscle.² Protein from whey and other sources also increase heat production and energy expenditure.³ Furthermore, whey protein has been shown to have positive effects on cardiovascular and metabolic health generally, with effects such as enhancing blood glucose control, lowering blood pressure, and improving lipid levels.⁴ In one clinical trial, 56 participants with type 2 diabetes and overweight or obesity ate similar lunches and dinners along with either a high-protein breakfast with 28 grams of whey protein, a high-protein breakfast with mixed protein, or a high-carbohydrate (control) breakfast for 12 weeks; at the end of the trial, those in the whey protein group lost an average of 7.6 kg (16.7 pounds), those in the mixed protein group lost 6.1 kg (13.4 pounds) and those in control group lost 3.5 kg (7.7 pounds). In addition, whey protein had greater benefits on blood glucose control than mixed protein.⁵ In a meta-analysis that included nine controlled trials in subjects with overweight and obesity, whey protein supplement use was found to slightly reduce body weight and body fat and improve markers of cardiovascular health.⁶

Animal studies suggest that whey protein can increase gains in lean body mass resulting from exercise.⁷ A controlled trial found that six weeks of strength training while taking 1.2 grams of whey protein per 2.2 of pounds body weight per day resulted in greater gains in lean body mass, but improved only one out of four strength tests.⁸ Another controlled study found that people taking 20 grams per day of whey protein for three months performed better on a test of short-term intense cycling exercise than people taking a similar amount of milk protein (casein).⁹ However, a double-blind trial found that men taking 1.5 grams per 2.2 lbs of body weight per day of predigested whey protein for 12 weeks along with a strength training exercise program gained only half as much lean body mass and had significantly smaller increases in strength compared with men using a similar amount of predigested casein along with strength training.¹⁰ A controlled study of HIV-infected women found that adding whey protein to strength training exercise was no more effective than exercise alone for increasing strength or improving body composition.¹¹

A double-blind trial showed that 45 grams per day of whey protein increased blood glutathione levels in a group of HIV-infected people.¹² Test tube^13,14 and animal¹⁵ studies suggest that whey protein may improve some aspects of immune function.

 

Whey protein is rich in the amino acid cysteine, which the body uses to make glutathione, an important antioxidant. A double-blind trial showed that 45 grams per day of whey protein increased blood glutathione levels in a group of HIV-infected people.¹⁶ Test tube¹⁷ and animal¹⁸ studies suggest that whey protein may improve some aspects of immune function.

Some whey proteins may reduce bone loss.¹⁹ Milk basic protein (MBP) is a mixture of some of the proteins found in whey protein. A preliminary trial found that 300 mg per day of MBP improved blood measures of bone metabolism in men, suggesting more bone formation was occurring than bone loss.²⁰ A double-blind trial found that women taking 40 mg per day of MBP for six months had greater gains in bone density compared with those taking a placebo.²¹ No osteoporosis-related research has been done using complete whey protein mixtures.