Whey Protein
Description
Whey proteins are one of the two major protein groups in cow’s
milk; the other group is the caseins.
Caseins account for about 80% of the protein; whey for 20%. Whey is a byproduct of cheese making. Whey proteins, like caseins, are high-quality proteins. The main whey proteins, beta-lactoglobulin and alpha-
lactoglobulin, account for 70% to 80% of total whey protein.
Proteins present in lesser amounts include immunoglobulins IgG,
IgA and IgM; glycomacropeptides; bovine albumin; lactoferrin; lactoperoxidase; and lysozyme. Whey
also contains smaller peptides.
Raw whey also contains fat and lactose. It is processed to
produce whey protein concentrates and whey protein isolates.
Whey protein concentrates are rich in proteins; they also contain
fat and lactose. Whey protein isolates are low in fat and lactose.
Function
Whey proteins may have antimicrobial, immunomodulatory,
anticancer, and antioxidant activity. Such effects are not well-established and are based mainly on animal research.
There is no credible evidence that whey proteins build muscle
faster than other protein sources. Infants
Whey proteins are used as the sole proteins in some infant
formulas, and this may result in fewer allergies in these infants.
Soy Protein
The US FDA allows food labels to claim that soy can help reduce
the risk of heart disease on low-fat foods containing at least 6.25 grams of soy protein.
Theory or modest research sugg
ests that soy-based foods chill hot
flashes, prevent breast and prostate cancer, aid weight loss, and prevent osteoporosis. These effects may be due to their high concentrations of isoflavones—
phytoestrogens or plant-made
estrogens.
As is often the case, marketing claims go beyond the available
evidence. Heart Disease
Soy lowers cholesterol levels. A 1995 meta-analysis of 38 studies showed about 50 grams of
soy protein daily in place of animal protein reduces total cholesterol by 9.3%, LDL cholesterol by 12.9%, and triglycerides by 10.5%.
50 grams of soy protein is the equivalent of 1½ pounds of tofu or
eight 8-ounce glasses of soymilk.
The American Heart Association recommends including soy-
based foods as part of a heart-healthy diet. Hot Flashes
Soybeans are rich in phytoestr
ogens that could theoretically
reduce menopausal symptoms including hot flashes.
Research has not found this benefit.
Breast Cancer
Studies are mixed.
Nutrition for Sports, Essentials of 65
