Protein is essential for life. It is an integral part of every cell in the body and is needed to build and maintain skin, muscle, bones and organs. Proteins are also used to make hormones, transports nutrients, act as enzymes, maintain water balance and support immune function through antibodies. In order for your body to build or maintain tissue your food choices must contain essential amino acids, in sufficient amounts. Animal proteins contain all the essential amino acids in proportions needed. Sources of animal proteins are: meat, fish, poultry, eggs, cheese & milk. Animal protein is of higher quality than vegetable protein meaning, it is more easily digested.
Animal protein has the following effects on blood parameters:
- Raises artery-clearing HDL cholesterol
- Lowers triglycerides
- Balances blood sugar and insulin levels
Lean animal protein does not cause bone loss, kidney damage or any disease in healthy individuals. As with any calorie containing nutrient, consuming an excess of the body’s needs will result in a repackaging process that will become stored fat. Likewise, the body cannot store extra protein or amino acids for a later use.
Protein from vegetables sources include: lentils, nuts, soy and in grains, but soy protein , or any of these sources alone, do not have the protein efficiency ratio (i.e. the protein quality) that animal protein does. The benefit of soy on blood lipids comes from its isoflavones which are a class of phytochemicals, (compounds found only in plants) that protect against hormone-related disorders. However, soy protein is low in methionine (one of the essential amino acids) and not allowed as a sole source of protein for infant formulas because of its low protein efficiency.
The ideal protein consumption ranges between for 55-125 grams per day, or about 30% of total calories in healthy adults. Those with more muscle mass need more protein to maintain their lean muscle tissue. Additionally, anyone restricting calories, under stress or healing from an injury may require more protein. There is at present no adequate way to determine the ideal protein intake in humans. The best is to experiment and look for functional parameters, including lean muscle mass, energy levels, blood sugar balance and overall well-being. However, be aware that it is exercise, not dietary protein intake, that increases/maintains muscle tissue, and the body can only rebuild muscle during time of rest, from the available amino acid pool.