The minor constituent responsible for the ability of whey protein concentrate to prevent the oxidation of LDL appears to be the lactoferrin fraction of the protein.
When the lactoferrin was removed from the protein, the ability of whey to prevent LDL oxidation was greatly reduced, leading the researchers to speculate, “lactoferrin is the main factor responsible for the inhibitory effect of whey protein (on LDL) and it may function synergistically with other factors in the whey protein, for example, alpha-lactalbumin.” Therefore, it's a good idea to use a whey protein with high levels of lactoferrin.
Another study with rats examined the effects of whey protein on cholesterol and the risk factors of heart disease. The researchers found at the high dietary protein level (300 grams per kilogram of feed), whey protein significantly lowered plasma and liver cholesterol and also plasma triacylglycerols. This would translate into approximately 30% of the animals’ food intake.
In this study, the cholesterol-lowering effect of whey protein was also associated with a reduction in LDL cholesterol. This effect was not seen when the animals were fed amino acid mixtures that simulated whey protein, so it is clear that there are properties within the whey that have cholesterol lowering properties beyond that of its amino acid profile.
Whey and Bone Growth
Finally, whey protein appears to play a direct role in bone growth. Researchers found that feeding rats whey protein concentrate resulted in increased bone strength and bone protein, such as collagen. This discovery led researchers to test if whey protein directly stimulated osteoblast (bone cell) growth in vitro.
Whey protein was found to stimulate, dose dependently, total protein synthesis, DNA content, and increased hydroxyproline contents of bone cells. This means the factors within bone that make up its structural matrix were increased, thus making the bones stronger.
It should be noted that not all whey proteins are created equal. Processing whey protein to remove the lactose and fats without losing its biological activity takes special care by the manufacturer. The protein must be processed under low temperature and low acid conditions so as not to “denature” the protein. Maintaining the natural state of the protein is essential to its biological activity.
These research findings, combined with the previous decade of study on whey protein, should convince anyone that whey protein is truly a staple supplement for athletes and health and fitness enthusiasts alike. The following summary of research with whey will further illustrate that fact.
Previous Studies of Interest
Whey protein concentrate dramatically raises glutathione levels. Glutathione is an essential water-soluble antioxidant in the body that protects cells and serves as a primary detoxifier of harmful compounds such as peroxides, heavy metals, carcinogens and other toxins.
Glutathione is also intimately tied to immunity, and reduced glutathione levels have been associated with diseases such as AIDS, atherosclerosis, Alzheimer's disease and Parkinson's disease. In fact, glutathione levels appear to be one way of modulating immunity. As a rule, increasing glutathione improves immunity and resistance to life’s many assaults. Whey protein concentrate was found to consistently raise this extremely important immune stimulating antioxidant beyond that of any protein studied (including soy) to higher than normal levels in multiple animal studies.
A small pilot study with HIV-positive men who were fed 20 grams of whey protein per day reported dramatic increases in glutathione levels of all the study participants, with two out of three men reaching their ideal body weight. In fact, there have been several U.S. and international patents granted for the treatment of AIDS and improving immunity with whey protein concentrates.
Whey protein improves immune function and fights infections. Animals fed whey protein consistently showed dramatic enhancement of both the humoral and cellular immune response to a variety of immune challenges, such as salmonella, streptococcus pneumonia and extreme cancer-causing chemicals. This effect on immunity was not seen with other proteins.