Shattering the myth of protein

Vegetarian Times, March, 1995 by Debra Blake Weisenthal

Ever since Francis Moore Lappe wrote her 1971 manifesto Diet for a Small Planet (Ballantine Books), in which she warned that vegetarians need to eat plant-based foods in certain combinations, vegetarians have worried needlessly about getting "complete" protein. But Lappe' doesn't deserve all the blame for our apprehension, and vegetarians certainly aren't the only group concerned about protein.

Since its discovery in the late 19th century, protein has had a stronghold on American culture and cuisine. Parents worry that their children may not be getting enough, as do many teenage boys and body-builders who are interested in "beefing up." Getting enough protein is still the main worry new vegetarians have. It's even a concern of longtime, relatively knowledgeable vegetarians like me.

Twenty years ago, I diligently combined beans with grains to make sure I was getting enough protein. When study after study finally convinced me that obsessing over protein was unwarranted, I stopped being such a kitchen chemist. Still, from time to time I had misgivings. I was healthy, but sometimes I felt I wasn't as energetic as I ought to be. Other vegetarians I knew also feared they weren't getting enough protein. Some even went back to eating meat on occasion to boost their protein intake and up their energy levels.

But protein wasn't what any of us needed. "Loss of energy isn't a symptom of protein deficiency," says Anne Shaw, Ph.D., a nutritionist with the U.S. Department of Agriculture's Agricultural Research Service. In fact, protein deficiency is so rare in this country that Shaw says she'd have to look up its symptoms because it's been so long since she's had to think about them. She reminds me that all of the recent research on the topic of protein indicates that if you're getting enough calories - just about no matter what you're eating - you're also getting sufficient protein. It's not just a claim made by defensive vegetarians; it's a subject of broad scientific agreement.

Still, there's a lot of confusion about protein - or to be more precise, the tiny amino acids that make up the long strands of protein - especially as it pertains to vegetarians. In fact, Lappe was right about protein combining to a certain extent. All plant-based foods are low in at least one of the nine amino acids our bodies need to get from foods. But the only foods that are truly protein-deficient are fruits, fats and sugars. And you need to obtain all nine amino acids over the course of a day or two, not within an hour of each other.

Even if you ate nothing but rice, which is low in the amino acid lysine, you'd still get enough of all the essential amino acids; if you ate nothing but beans, which are low in methionine, you wouldn't be courting a protein deficiency. But since you do not (and should not) eat just one food all day, every day, the foods that are relatively low in an amino acid are naturally complemented by those that are abundant in that amino acid. It's simply not necessary to think about what combines with what, especially if you naturally eat a variety of foods within a 24- to 48-hour time span.

Moreover, in the mid- 1980s, researchers discovered that what had been considered the ideal balance of essential amino adds was not correct. Until then, all proteins were assessed according to a system called the protein efficiency ratio (PER). On the PER scale, the egg was considered the "perfect" protein source, an assumption based on tests done with rats. Beef and milk also rated very high, while vegetables were low, in part because they are low in the sulfur-containing amino acids that animal foods tend to have, and which rats need more of than do humans. Rats, which differ from humans in many ways, also have different nutritional needs. The egg's amino acid pattern happens to suit them perfectly.

Protein research conducted on people resulted in a change in the way proteins are rated. The current standard for humans is known as the protein digestibility corrected amino acid score (PDCAAS). The system still involve a food's amino acid pattern and its digestibility, but it also throws in the amino acid requirements of human beings.

Using the PDCAAS scale, soy protein receives a top rating, along with eggs, dairy products and meats. But since no one-vegetarian or non-vegetarian needs to optimize the quality of their protein in order to get enough of it, it's unnecessary to consider such ratings in deciding what foods to eat.

The fact is, protein deficiency simply is not a concern for anyone in the developed world. "We never talk about protein anymore, because it's absolutely not an issue, even among children," says Marion Nestle, Ph.D., chair of the Department of Nutrition, Food and Hotel Management at New York University. "If anything, we talk about the dangers of high-protein diets. Getting enough is simply a matter of getting enough calories."

WHAT IS PROTEIN FOR?

Try to answer this question: What does protein do for you? Did you say it gives you energy? Sorry; carbohydrates do that. Builds muscles? Nope, that's what exercise is for. Protein does have a variety of very important functions, just not the ones most people associate with it. Protein helps you think and see, makes up and repairs muscle and bone tissue, regulates hormones and enzymes, helps fight infections and heal wounds, affects the way you digest foods and affects your genes and chromosomes.