The digestive system breaks all food proteins down into their component amino acids so that they can enter the bloodstream.

Protein in the human diet may come from animal and vegetable sources. Most animal sources (meat, milk, eggs) provide complete protein. These sources contain all of the essential amino acids.

On the other hand, vegetable sources are usually missing or low in certain essential amino acids. Rice is low in isoleucine and lysine. Since different vegetable sources are deficient in different amino acids, we can combine different foods to provide all of the essential amino acids throughout the course of the day. Nuts and legumes are high in protein. By combining them with whole grains, you can get complete coverage of all essential amino acids.

A glass of milk contains about 8 grams of protein. A slice of whole grain bread might contain 2 or 3 grams of protein. A serving of high protein whole grain cereal contains 8 grams. Clearly, it is not that hard to meet the RDA for protein with a balanced natural food diet.

Even so, according to noted holistic physician and author Dr. Alan Gaby, the American diet tends to contain too much protein. And Dr. Susan Brown’s China Health Project suggests that we eat too much protein, which can function as a noted anti-nutrient. As a group, we consume two and three times the ideal. Studies have indicated that excessive protein in the diet may encourage bone loss. When you eat more protein, the urinary excretion of calcium rises. The digestion of protein liberates acidic breakdown products. As we know, calcium is mobilized to buffer these chemicals. Dr. Gaby maintains that science has shown that people who eat a vegetarian diet have stronger bones later in life than those who eat meat.

The amino acid methionine, which is abundant in animal protein, is converted in the body to homocysteine. It now looks like this chemical, which has become known as a cardiovascular disease risk factor marker, is also capable of causing bone loss.

Animal flesh contains phosphorous, a necessary nutrient. But Dr. Gaby says that excessive consumption contributes to osteoporosis. One of the breakdown products, phosphoric acid, must be buffered by calcium. This probably explains in part why excessive protein has an adverse effect on bone.

Beans, peasand other legumes, including lentils, are an excellent source of protein. If you include these in your diet, and also eat whole grains such as whole wheat, oats, corn, barley, millet, buckwheat and, rice, these two food groups together will provide the entire assortment of essential amino acids you need for protein. Legumes are high in the alkaline minerals calcium, magnesium, potassium, iron, copper, zinc and vitamin B-complex, all nutrients that benefit strong bones. As an added benefit, legumes are high in soluble fiber, the kind that lowers cholesterol.

Having said this, remember- it’s still necessary to consume enough protein. Several studies correlate dietary protein and bone density. Decreased density of the femur density is associated with the amount of protein in the diet. The bone is composed of a very important protein matrix, in which minerals are deposited. Unless there is sufficient dietary protein, the body cannot preserve its protein matrix. So, as with most things, balance is the key- we need neither too much nor too little protein.

If you are eating meat for protein, it just has to be balanced by more potassium, found in vegetables, at least two servings each at lunch and dinner, so that the pH balance is maintained. The average American can process about 50-60 grams per day of protein, in terms of maintaining acid and mineral balance. Most are eating well over that, and 100 grams per day is common.