The following article is from The Health Crusader.
“Pro-tein: any of numerous naturally-occurring extremely complex combinations of amino acids that contain the elements carbon, hydrogen, nitrogen, oxygen, usually sulfur and occasionally other elements (such as phosphorus or iron); an essential constituent of all living cells; is synthesized from raw materials by plants but assimilated as separate amino acids by animals.”
Most of what was in the past believed to be true about the body’s need for protein has, in recent years, been shown to be false. This is true particularly in regard to the amount of protein the body requires.
The first well-publicized study of protein needs was done by the German physiologist Voit at around 1890. Voit studied healthy, young, physically active German men who were eating their conventional diet. He found that they maintained “nitrogen balance” on a diet containing 120 grams of protein daily. For years this was accepted as the standard.
Urinary nitrogen (in the form of urea, uric acid, creatinine and other substances) is derived almost wholly from protein metabolism. Voit assumed that the amount of urinary nitrogen excreted reflected the body’s needs. He observed that when the German males reduced their protein intake significantly, they initially excreted more nitrogen than they consumed, a state he referred to as “negative nitrogen balance.” Had he continued his experiments longer, he would have discovered that these same subjects would have re-established a nitrogen balance at the lowered intake level.
Today we know that it is not valid to determine needs on the basis of excretory levels. The body excretes the residues from materials it has merely disposed of. Whatever amount of nitrogen we consume in the form of protein must ultimately be eliminated. When an enormous excess of nitrogen enters the system, the body merely deaminizes the amino acids, converting the amino radicals into ammonia, urea and other by-products of protein breakdown. The remaining ketogenic or glucogenic acids then undergo combustion in the same manner as the fats and carbohydrates, rendering calories.
High-protein diets actually accelerate the turnover of proteins in the body, causing a metabolic bonfire that may mistakenly be regarded as a state of well-being. When one reduces the amount of protein consumed, it takes time for the body to re-adjust its metabolism, to reset its thermostat, so to speak. This is why a state of negative nitrogen balance may temporarily ensue.
During World War I the Danish government hired a physiologist by the name of M. Hindhede to study protein needs. The hardships of the war had made animal foods scarce and prohibitively expensive. A people who had been accustomed to eating lots of meats, eggs and milk were forced to rely upon grains and vegetables, especially potatoes, to sustain themselves.
Hindhede’s task was to determine how little protein people could consume and still maintain health. He did extensive studies on young and old alike over a period of several years and concluded that 60 grams of protein a day was more than adequate to meet the body’s needs. Even the lowly potato, Hindhede said, contained enough high-grade protein to supply body needs (assuming that total caloric intake was adequate).
The orthodox scientific community vilified Hindhede. (He is even left out of the 1963 Encyclopaedia Britannica, while Voit is in it and his discoveries praised.) Imagine, cutting the Voit standard for protein need in half! More recent studies, however, based upon verified patterns of enzyme synthesis, collagen turnover and muscle metabolism have drastically reduced the Hindhede figure. Guyton’s Physiology (considered the standard in the field) maintains today that 30 grams of protein a day is fully adequate.
Other respectable sources cite figures in the 20s, but even Guyton figure of 30 grams is significantly lower than the daily allowance of 70 grams recommended for active adult males by the Food and Nutrition Board of the National Research Council. This 70 grams includes a considerable “safety factor” (to allow for some degree of malabsorption).
Many if not most Americans are consuming in excess of 100 grams of protein a day despite the much lower recommendation. Eliminating the by-products of this protein overload places great stress upon the body. The liver and kidneys bear the brunt of the punishment. Fats and carbohydrates burn clean, leaving a residue of only carbon dioxide (which is relatively innocuous and is readily excreted by the lungs) and water (which is hardly a waste product).
Protein metabolism, on the other hand, leaves non-oxidizable waste products such as urea, uric acids, etc. It is a much greater burden for the body to process great surpluses of protein than to process excesses of fat or carbohydrate. It behooves all of us to consume no more protein than we need so as to prevent premature aging and the deterioration that comes from organ abuse.
Another mistaken concept regarding protein needs has to do with protein quality. For decades it was held that only animal proteins contained a full complement of all eight essential amino acids (those we cannot synthesize from other amino acids) to meet the body’s needs. Although most natural foods do contain all eight essential amino acids, the claim was that the proportion of one amino acid to the others was not right. It was observed that animals grew and matured more rapidly on animal proteins than on vegetable proteins, so vegetable proteins were declared to be inadequate. Speed of development and size were considered to be a direct reflection of nutritional thoroughness.
Today we know that weight and size are not necessarily the best indicators of health and well-being, that gigantism is just as pathological when spread throughout a population as it is when it occurs in an isolated individual. We know that an individual’s body is not immediately dependent upon the content of his meals in order to maintain nutrition.
Referring again to Guyton’s Physiology, radioisotopic studies have shown that at any given time protein synthesis utilizes two-thirds endogenous amino acids (from the blood circulatory pool) and one-third exogenous amino acids (as derived from meals). In other words, in regard to protein, the body is always living upon its reserves and the purpose of eating is to replenish those reserves. It matters not whether a given meal provides the exact proportion of amino acids because the body is fully capable of withdrawing from reserve sources whatever amino acids are needed to balance out the dietary supply.
Frances Moore Lappe stated in Diet For a Small Planet that one must combine different proteins at the same meal or otherwise preclude the possibility of utilization. Ms. Lappe said that consuming single vegetable proteins would not provide adequate nutrition. This idea, however, has been shown to be false, not only by physiological calculations, but also by the empirical evidence gained from observations of countless numbers of people around the world who live and thrive on simple vegetable diets. The experience of Hygienists in this country also provides proof of the sufficiency of simple combinations of non-animal foods.
Many common foods that we don’t generally regard as sources of protein actually supply substantial amounts. The case of the potato has already been cited. Even more impressive are green leafy vegetables, which supply 3-6% protein of high-biological value, on the average slightly more than cow’s milk and several times more than mother’s milk. Eating a large raw vegetable salad every day can alone supply most of the protein the body needs.
Eating a variety of whole natural foods that supply an adequate number of calories would, by necessity, supply an adequate amount of protein. The problem isn’t how to get enough protein, but how to avoid getting too much.
Another widely-accepted but incorrect idea is that athletes and hard physical workers require more protein than less active people. Actually muscular activity entails no increase in the rate of protein catabolism (breakdown). Urinary creatinine is considered a reliable indicator of muscle breakdown, and it has been found that physical activity does not significantly increase creatinine excretion. Nor does it significantly increase the excretion of urea. What physical activity does entail, however, is a rapid utilization of muscular glycogen. It is carbohydrate replenishment that vigorous activity calls for, not protein.
Learn more about proteins
The average American consumes two to four times as much protein as he needs, and cancer (which is characterized by runaway protein synthesis) is killing one person in four. Cutting down total protein in general and animal protein in particular is a desperate need.
It is important to realize that all of the marvelous amino acids contained within flesh foods were derived from the animals diet. Other animals are just as powerless to synthesize the essential amino acids as we are; and we are just as capable as they of deriving our amino acids directly from the only producing source: plants.