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Table 3. Meal Plan with Supplements Using Whey Protein

Meals/Foods	Kcal/protein (g)
Breakfast
Cereal (1 bowl)	80/3
Whole milk (1 cup)	160/8
Orange juice with 13 g whey protein ( 1 cup)	120/10
Toast (1 slice)	15/3
Butter (1 pat)	45/0
	420/24
Lunch
Tuna sandwich (1/2)	182/14
Tossed salad with dressing	70/4
Chocolate cake (1 piece)	223/3
Soda (1 can)	200/0
	675/21
Snack
Fortified nutritional drink with 13 g whey protein	290/18
Dinner
Chicken (3 ounces)	165/21
Mashed potato (1/2 cup)	80/3
Carrots (1/2 cup)	25/2
Chocolate chip cookies (2 small)	96/1
Juice with 13 g whey protein (1/2 cup)	60/10
Total	426/37

quantities of antibodies naturally in their milk to be clinically effective (on file, Optim Nutrition, 1995).

HOW THE WHEY PROTEIN WORKS

The whey protein Promune, developed from the colostrum substitute product, contains a number of substances which are of potential benefit to patients with a number of conditions. It also is a high-quality protein source for healthy individuals.

Immunoglobulins

One benefit of Promune to a critically ill immuno-compromised patient is that it contains immunoglobulins from a cow, which are effective in humans. This is because the structure of these immunoglobulins is nearly the same as that in other mammalian species, including man (Figure 1).
Most immunoglobulins are composed of four polypeptide chains consisting of two identical heavy chains linked by covalent and

noncovalent disulfide bridges. Both light chains and heavy chains of the immunoglobulin contain regions with constant amino acids and with a variable region. That region is the site where the antibody molecule reacts with the antigen i.e., the foreign body.3 Cow milk antibodies are highly resistant to peptic digestion, which is desirable when humans are using the whey enriched with immunoglobulins.4 The antibodies derived from cow's milk are active in protecting a human against certain bacteria, viruses, and parasites.

These antibodies are referred to as the humoral portion of the immune system. The other arm of the immune system is referred to as "cell-mediated". Each of the antibodies contained in the whey protein has a specific role in the immune function.3 Promune contains the following immunoglobulins: IgG1, IgG2, IgM, and IgA. The IgM is an early responder to an antigen and is specific to bacteria and viruses. In contrast, immunoglobulins G1 and G2 attack viruses and other toxins after IgM. IgA can block bacterial adherence and is pivotal in viral defense.

In conditions where gastrointestinal dysfunction occurs (e.g., AIDS), the benefit of the passive provision of these antibodies becomes apparent. The intestinal epithelium is the interface between the external world and the internal parts of the body.5 The epithelium coats the intestine with a lipid layer that is an excellent barrier to most chemicals, but a poor physical barrier to the penetration of foreign materials. The body has both nonimmunologic defenses, such as gastric acid and digestive enzymes, and the immune defense system, referred to as gut-associated lymphoid tissue (GALT). The GALT contains both cell-mediated and humoral immunity. In the intestinal lumen, antigens (foreign bodies) are bound in the presence of secretory immunoglobulins. This binding prevents adherence to or penetration through the epithelial layer of the intestine; without it, the antigen would cross the intestinal barrier and imbed in the enterocyte, potentially causing illness.

Amino Acids

In Table 2, some amino acid profiles and the biological value of whey (e.g., Promune) are compared with other high-quality proteins. Whey protein has the highest biological value, which is an estimate of the amount of nitrogen replaceable by 100 g of protein in the adult diet. Selected amino acids are discussed below.

Branched-Chain Amino Acids

The branched-chain amino acids (BCAAs) are readily oxidized by the skeletal muscle for energy during stress. Some have postulated that stressed patients may be able to ingest lesser amounts of dietary pro

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