The protein myth: when too much of a good thing is a bad thing.

The Protein Myth

It all started in the middle of the nineteenth century. The seeds were sown by Dr. Justus von Liebig, one of the most famous German chemists of the time. His renown stemmed from having developed a method of determining the amount of protein in plant and animal tissue. Though somewhat refined, his method is still used today.

But Liebig made a big mistake.

Observing that muscles are made up largely of protein, he assumed that protein must be their primary fuel. Thus he proclaimed, "Muscle strength depends on the amount of protein eaten."

Sometime later, one of his proteges, Dr. Karl Voit, noted that the daily diet of laborers and soldiers contained on average 118 grams, or four ounces, of protein. He reasoned that since these men were big, strong, and muscular, they must be eating the ideal amount of protein. One hundred eighteen grams of protein per day became Voit's standard requirement for protein, a standard that quickly gained international acceptance.

But across the Atlantic, at Yale University, Dr. Russell Chittenden wasn't convinced. He wondered, "Should the amount of protein be more? or should it be less?"

In other words, was 118 grams what the body required -- or simply what these hardworking men happened to be eating? To find out, he studied soldiers and athletes under a variety of situations.

After years of careful research he found that 40 to 60 grams of protein, or less than half the amount recommended by Voit, was more than adequate, even for hardworking men. But by this time Voit's standard was so well established that little attention was paid to Chittenden's findings.

In fact, many people still believe that a high-protein diet is the healthiest way to eat. Take, for example, my uncle Larry. During my early teen years, I usually spent my summer vacations at his house in Michigan. The thing that impressed me most was how tall, muscular, and strong Uncle Larry was.

Each summer he would have a message for his skinny, "100-pound-weakling" nephew. "Billy," he would thunder, "you've got to eat more protein to put some muscle on those shoulders and arms. Let me cook you up a good beefsteak."

Who could blame him, though? I had pipe stems for arms and anemic-looking shoulders, while Uncle Larry could pick up my 200-pound father and spin him around above his head.

Now, don't get me wrong. Protein is a vital component of everyone's diet. That cannot be disputed. The myth isn't about the need for protein, but rather over the touting of protein as the most essential dietary item, especially in terms of strength and endurance.

In order to dispel this error, it is helpful to know the proper role of protein in the body. Next to water, protein is the main substance in plant and animal cells (with the exception of fat cells).

In young animals, growth is a result of the increase in the number of cells. The faster an animal grows, the more rapidly cells must be manufactured, and thus more protein must be available to support this rapid growth.

Take a look at Table 1. It shows the growth rate of a human from birth to maturity. Notice that growth is not always constant. During the first year of life, growth is faster than it is during the second, which is faster than during the third, and so on. Growth rate levels off during the early school years, then during adolescence there is another growth spurt.

The body's need for protein varies in conjunction with these changes in growth rate. When growth is rapid and vast numbers of new cells are being formed, the demand for protein is high. But when maturity is reached, protein needs lessen. This is because adults don't need protein for growth. They need protein only for maintenance and, in the case of injury, for repair of damaged tissues. Thus, to a large extent, the amount of protein needed depends on how rapidly growth is taking place.

Table 2 shows a list of common domestic animals, arranged according to the time it takes for the newborn of each species to double its birth weight.

Humans grow slower than any other animal. A newborn baby takes 180 days to double its birth weight. In comparison, a horse grows three times as fast, doubling its birth weight in just 60 days. And the cat is faster still, doubling its birth weight in just seven days. This is 26 times faster than the growth of the human baby.

Nature has accounted for these varying growth rates in a most interesting way. On a percentage basis, human milk contains the lowest amount of protein, averaging just 1.4 percent during the early weeks of infancy. On the other hand, the milk the mare feeds her colt contains 2 percent protein. The mother cat provides her kittens a much higher level of protein--9.5 percent. So if anyone would like a protein jag, just drink a glass of cat's milk.

But remember, the 1.4 percent protein in the woman's breast milk is an average. Research has shown that the protein content of human milk lessens week by week to accommodate the slowing growth rate of the infant. Beginning with a high of 2 percent during the first week after birth, the protein drops to 1.2 percent at the end of 8 weeks and then later levels off at around 1 percent.

Yet, what do we do? As soon as baby Wally is weaned we place him on the higher-protein cow's milk and feed it to him for the rest of his life. Since an eight-ounce glass of milk contains eight grams of protein, it's easy to see how in the course of a day milk can be a major source of protein.

Over the past 70 years, more and more research has shown the fallacy of the high-protein standard that Voit advocated. Currently the Nutrition Board of the National Research Council of the United States recommends 56 grams of protein per day for the average man, and 44 grams for women. For many years the World Health Organization of the United Nations has advocated 50 grams of protein per day, recognizing that even this amount provides a generous margin of safety. An unrefined diet easily provides this amount or more, even when no animal products are eaten.

I once had a cocky graduate student who failed to take a particular class seriously. He made it a habit to come late to class, and even began to skip classes. One day I called him into my office. I reminded him of my policy that if a student missed class sessions he would have to make them up by completing a project that dealt with the material covered in the missed sessions.

I then proceeded to give him an assignment of designing a low-protein diet (30 grams or less) that would meet the nutrient requirements for the average 30-year-old male who ate 2,500 calories.

"A piece of cake," laughed the rebelious student as he left my office.

One week later he returned griping about the unfairness and the impossibility of the assignment I had given him. You see, protein is one of the easiest nutrients to get in the diet. When enough calories are available from unrefined foods, it is almost impossible to create a protein deficiency.

In fact, the typical American diet, which is too high in protein (the average is more than 100 grams a day, and many get much more than this), may actually do more harm than good.

Dr. Chittenden said it well: "Any excess over and beyond what is really needed is not only uneconomical, but may be directly injurious. This is especially true of the protein foods."

More recently, Dr. Barry Brenner from Harvard University says, "There is a fundamental mismatch between the design of the human kidney and the burden imposed on it by the high-protein diet of the average American or Westerner."

He is referring to the fact that excess dietary protein places added burdens on the kidneys, thereby contributing to premature loss of kidney function even in otherwise healthy people.

Studies have shown that high-protein diets cause animals to grow faster and mature earlier. Unfortunately, those animals also die sooner.

A final argument against a high-protein diet lies in the very design of the human body. Humans were not designed anatomically nor physiologically to eat high-protein diets. Our digestive system most nearly resembles that of animals that are primarily fruit eaters. The original diet provided by the Creator for the occupants of the Garden of Eden is still the best today and therefore recommended by VIBRANT LIFE. It is a high-complex-carbohydrate, low-protein, low-fat regimen.

Liebig and Voit were great scientists, but as Dr. Hindhede from the Hindhede Laboratory of Nutrition Research said, "The errors of great men are a hundred times more dangerous than the nonsense of the multitude."

The errors of these men have not died easily. But over the years the cracks have been exposed. With the weight of current scientific evidence the protein myth is being crumbled.

Dr. Mervyn G. Hardinge, founder and dean emeritus of the School of Public Health at Loma Linda University, is now director of Health Productions, a department in the university that produces slide/tape and video transfer programs on health topics. William Andress, D.H.Sc., M.P.H., is production manager for Health Productions.