Proteins in our bodies are made from amino acids that we acquire from digestion of food or supplements or protein rich drinks. Proteins from food are usually broken down by the digestive system into amino acids before absorption through the gut wall. The body requires only 8 essential amino acids but other amino acids are also absorbed. They may compete with each other for absorption and for actions in the intestines. High loading of protein at one meal or one consumption may not be all absorbed - i.e. absorption is limited by capacity of digestive enzymes and by body intake.
Proteins from meat, fish, eggs, dairy or plants vary considerably in their amino acid profile, and different modes of protein powder processing from the whey of dairy, soya or vegetarian sources can also vary the product characteristics and quality.
The broad spectrum protein supplements or powders are taken usually for three reasons:-
To enhance muscle and body tissues mainly for sport performance or athleticism;
To increase muscle proportion in the body because of illness or older age when muscle has wasted away or not restored.
Meal replacements in a high protein weight management diet
To achieve fitness and strength and repair to collagen, then the body’s usage of protein must be efficient. Protein synthesis is usually most efficient after resistant exercise. This benefits muscle and bone condition. The requirement ranges between 0.8 to 2g of protein per kg of body weight/day dependent on age and typical physical activity. The biological value (BV) of protein sources varies and generally vegetarian sources do not always have all the essential amino acids required in one plant and are not as well absorbed – partly because of some inhibitors. However vegetarian or vegan sources of protein can contain higher quantities of other nutrients (e.g. fibre or antioxidants). Protein from dairy whey is readily absorbed and is high in all amino acids including Leucine which is considered valuable for muscle anabolism.
Some foods, e.g. quinoa or millet, have a higher content of protein than meats as well as high mineral contents. These seem excellent gluten free sources for young children or infants.
Most dairy whey sources of protein powders or shakes are virtually lactose free but can contain casein. We would advocate selecting protein powders that do not contain aspartame as sweeteners.
At whatever age if the use of protein does not provide sufficient muscle mass, or condition then use digestive enzymes or a digestive supplement along with the protein to ensure proper break down into the amino- acid components.