Whey Protein Composition
- Bovine serum albumin (BSA)
- Immunoglobulins (IgG1, IgG2, secretory IgA and IgM)
- Smaller components: iron binding proteins (lactoferrin, lactoferricin),
calcium, potassium, sodium, phosphorous, Vitamins A, C, B1, B2, B3, B5, B12,
folic acid and biotin.
- Balanced source of essential amino acids and peptides
- High protein efficiency ratio
- One study showed that milk protein elicits greater increase in
branched chain amino acid concentrations in peripheral tissues as
compared to soy. 1
- Excellent source of sulfur amino acids (methionine and cysteine)
- Cysteine is the rate limiting amino acid for the synthesis of the
- Excellent source of
acids (leucine, isoleucine, valine)
- Leucine is a both a key signal molecule for initiation and an
important substrate for new protein synthesis. 2
- Excellent source of
- Crosses stomach quickly and rapidly absorbed in the intestine (vs.
casein which exits the stomach much slower). 3
Whey & Fat
Calcium (a minimal
component of whey protein) decreases accumulation of body fat and accelerates
weight and fat loss. The proposed mechanism is thought to be that parathyroid
hormone and 1,25-(OH)2-D respond to low calcium diets and promote fat storage.
High calcium diets inhibit these hormones and thus inhibit fat storage and
promote increased fat breakdown and energy partitioning from fat to lean.
Whey & The Digestive Tract
Lactose (found in whey but not whey concentrate)
is broken down into galacto-oligosaccharides that are used by intestinal
bacteria leading to better functioning of the digestive tract. 6
Whey & Free Radical Production
Glutathione: Powerful antioxidant used in
detoxification. Glutathione levels have been shown to decrease with exercise.
7 The rate limiting amino acid for the synthesis of glutathione is
- Whey protein increases glutathione levels far more than casein,
specifically in heart and liver tissues. 8
- Kent and colleagues looked at whether enzymatically hydrolyzed whey
protein isolate (WPI) could increase intracellular GSH concentrations and
protect against cell death secondary to free radicals in a human prostate
epithelial cell line. They found that treating these cells with WPI
increased intracellular GSH by 64% and protected the cells against
oxidant-induced cell death compared with control cells receiving no
hydrolyzed WPI ( P <0.05).
Interestingly, they found a similar increase in GSH with N -acetylcysteine,
which donates cysteine and thereby raises intracellular GSH levels. In
contrast, treating the cell line with hydrolyzed sodium caseinate, a
cysteine-poor protein source, did not significantly elevate intracellular
- BOTTOM LINE: Whey protein can increase GSH synthesis and protect against
oxidant-induced cell death. Lactoferrin and lactoferricin (two minor whey
proteins) function as antioxidants via their iron binding capacity, which
inhibits bacterial growth and oxidative reactions. 10
The body is highly sensitive to insulin after exercise and shuttles
carbohydrates and proteins into muscle cells instead of fat cells. This
sensitivity declines post-workout until ~2 hours at which point it reaches
Furthermore, the anabolic effects of insulin are
synergistic with amino acids.11 Given the rapid absorption of
whey, it is the ideal
choice for post-workout to take advantage of the insulin-amino acid synergistic
- Minimal risk of food allergies (same risk as with soy, casein, or
- Questionable risk Insulin-dependent diabetes mellitus (IDDM) in
children: BSA (bovine serum albumin) thought to be a possible trigger for
IDDM. Some studies have found increased levels of anti-BSA antibodies in
sera from children developing IDDM.12 However, other studies have
shown no increases in anti-BSA in IDDM children. 13 Thus the
exact role of BSA in IDDM development remains unclear.
- Kidney damage. Research does not support the idea of kidney damage.
14 However, some researchers warn against excessive protein intake
(>2g/kg of body weight per day).
- Increased risk of dehydration with excess protein intake. 15
- Possible risk for calcium loss. Very large amounts of protein intake
results in increased acid production. Calcium is released from bone as a
buffer for the increased acid load.16