Whey is left over when milk is coagulated during the process of cheese production, and contains everything that is soluble from milk.
Whey protein is considered a complete protein and contains all 9 essential amino acids and is low in lactose content.
Whey protein is the collection of globular proteins isolated from whey, a by-product of cheese manufactured from cow’s milk. The protein in cow’s milk is 20% whey protein and 80% casein protein, whereas the protein in human milk is 60% whey and 40% casein. The protein fraction in whey constitutes approximately 10% of the total dry solids in whey. This protein is typically a mixture of beta-lactoglobulin (65%), alpha-lactalbumin (25%), bovine serum albumin (8%), and immunoglobulins. These are soluble in their native forms, independent of pH.
Being a by-product of the cheese making process, and likelihood of animal rennet use, whey protein as well as casein products may not be suitable for consumption by lacto-vegetarians or observers of kosher dietary laws. There are, however, specialty producers of vegetarian-approved whey protein products produced using non-animal “rennet” (enzymes). These products are often also labeled as kosher and halal approved.
Whey protein typically comes in three major forms:
- Concentrates have typically a low (but still significant) level of fat and cholesterol but, in general, compared to the other forms of whey protein, have higher levels of bioactive compounds, and carbohydrates in the form of lactose — they are 29%–89% protein by weight.
- Isolates are processed to remove the fat, and lactose, but are usually lower in bioactivated compounds as well — they are 90%+ protein by weight. Like whey protein concentrates, whey protein isolates are mild to slightly milky in taste.
- Hydrolysates are whey proteins that are predigested and partially hydrolyzed for the purpose of easier metabolizing, but their cost is generally higher. Highly hydrolysed whey may be less allergenic than other forms of whey.
Whey protein and muscle building
Whey protein supplementation along with resistance exercise can help improve muscle protein synthesis and promote the growth of lean tissue mass.
Much better gains in strength are associated with whey isolate supplementation compared to casein.
This was demonstrated in another study published in theInternational Journal of Sport Nutrition and Exercise Metabolism, which concluded that in “two groups of matched, resistance-trained males whey isolate provided significantly greater gains in strength, lean body mass, and a decrease in fat mass compared to supplementation with casein during an intense 10-week resistance-training program.”
There are many benefits associated with the consumption of whey protein, and researchers are constantly finding new possible therapeutic properties.
The possible health benefits of consuming whey protein include:
- Losing weight – according to one study, published in Nutrition & Metabolism, people who took a specialized whey fraction (Prolibra™, high in leucine, bioactive peptides and milk calcium) “lost significantly more body fat and showed a greater preservation of lean muscle compared to subjects consuming the control beverage.”
- Anti-cancer properties – Promising results were published in the journal Anticancer Research for the use of whey protein concentrate (WPC) and glutathione modulation in cancer treatment.
- High cholesterol – according to a study published in The British Journal of Nutrition, “there was a significant decrease in total cholesterol and LDL cholesterol at week 12 in the whey group compared with the casein (group)”.
- Asthma – whey protein could improve immune response in children with asthma. One study, published in the International Journal of Food Science and Nutrition, found that children with asthma who were supplemented with whey for one month had an improved cytokine response.
- Lowering blood pressure and reducing risk of cardiovascular disease – research published in theInternational Dairy Journal found that beverages that were supplemented with whey protein significantly reduced blood pressure in patients with hypertension, their risk of developing heart disease or strokewas also lower.
Some people who are allergic to milk may be specifically allergic to whey.
In moderate doses whey protein doesn’t generally cause any adverse events.
However, consuming severely high doses can cause:
- Stomach pains
- Reduced appetite