Protein: More Is Not Better

Think of proteins as the Swiss Army knives of nutrients. They're major players in all sorts of bodily processes, including growth, maintenance, healing, and repair. Without them, the very process of Renewal couldn't take place.

Proteins serve as the primary building blocks of connective tissues such as ligaments and tendons. They shuttle oxygen, nutrients, and other vital substances to wherever they're needed in the body. Many proteins function as hormones, which regulate cellular activity; as antibodies, which defend the body against disease; and as enzymes, which digest food and facilitate all of the body's chemical reactions.

Since proteins do so much for us, the more protein-rich foods we consume, the better off we'll be . . . right? Well, it's a logical assumption. But unfortunately, it's wrong.

Yes, we do need modest amounts of proteins in our diets. But more definitely is not better. In fact, most of us eat too much rather than too little. And our health is suffering as a result.

Built from Scratch

Proteins consist of various configurations of substances called amino acids. The task of assembling the correct combination of amino acids in the proper sequence falls to cell structures known as ribosomes. The process works something like this: The DNA in a cell's nucleus issues a blueprint that shows how a particular protein should look. A ribosome reads this blueprint, then amasses the appropriate amino acids and links them in the proper order to form a complete protein molecule.

Each type of protein has a unique amino acid sequence, or chain. Amazingly, the body needs just 20 amino acids to manufacture the thousands of different proteins it needs. Even more amazing, the body can make 12 of these amino acids on its own (with the assistance of enzymes made from--you guessed it--proteins). The remaining 8 amino acids must come directly from foods and therefore are essential nutrients in the adult diet.

Any diet consistently lacking in one or more of the eight essential amino acids will cause protein deficiency malnutrition, a condition that affects many people worldwide but is extremely rare in the United States. In this country, our problem is protein overconsumption. The average American eats roughly twice as much protein as he needs.

The Ideal Intake

So how much protein do you need? In general, the average adult male or female should consume about 0.3 gram of protein per pound of body weight per day. For a person who weighs 150 pounds, this translates to 45 grams, a bit less than 2 ounces, per day.

Certain segments of the population have slightly higher requirements. Pregnant and lactating women, for instance, need more protein because they are literally eating for two. Athletes in training need more protein because their bodies must work harder to repair damaged tissues (protein, you'll recall, is the basic structural component of muscle and connective tissue). For similar reasons, people recovering from surgery, injury, or illness need more protein while their bodies are on the mend.

In addition, some people have difficulty breaking down proteins into their component amino acids. Their bodies no longer produce enough hydrochloric acid and proteolytic enzymes, the substances responsible for digesting proteins. (Hydrochloric acid is secreted by the stomach, and proteolytic enzymes, by the pancreas.) This condition is quite common, especially in older people, and can cause digestive symptoms as well as food allergies.

For people with this condition, eating extra protein can actually make matters worse. You're better off trying supplements to correct any deficiencies. I recommend hydrochloric acid capsules (in the form of betaine hydrochloride) and a plant-based digestive enzyme product. You'll find both supplements in health food stores. If you're not sure which brands to choose, ask the salesclerk for assistance. Follow the dosage recommendations on the labels.

Enough Is Enough

If you follow the standard American diet, complete with generous amounts of meats and dairy products, chances are that you're taking in a lot more protein than you need. Consider that a single six-ounce serving of steak, hamburger, chicken, or fish supplies more than 100 grams of protein--more than double your protein quota for an entire day. That doesn't even account for the cheese, eggs, milk, and other protein-rich foods you may also be consuming.

Overdoing protein in this way, as so many of us do, robs us of good health and long life. Population studies have established an indisputable link between protein consumption and longevity. Quite simply, people who follow high-protein diets have shorter average life expectancies than people who follow low-protein diets. Animal studies produce similar results: Comparing groups fed the same number of calories, those on high-protein diets die younger than those on low-protein diets.

Problems with Protein Overload

Remember, your body needs some protein to function. It's the excess that gums up the works. How?

For starters, too much protein depletes your body's calcium supply, causing loss of bone mass and eventually osteoporosis. Here's what happens: Breaking down large quantities of protein produces a virtual deluge of amino acids. Your body can't possibly use all of the available amino acids. So to neutralize the excess, it enlists the assistance of calcium, pulling the mineral from your bones. (Antacids such as Tums work on the same principle, except that they use their own calcium supply to neutralize stomach acid.) The "spent" calcium is then excreted in the urine.

When this process repeats itself over and over again, as is necessary for a protein-laden diet, the resulting calcium shortage causes bones to become brittle and gradually disintegrate. This leads to osteoporosis, a condition characterized by bones that break easily and vertebrae that collapse under the weight of the body they were intended to support.

Of course, there are other risk factors for osteoporosis--some that you can't control (gender, age, genetic predisposition), others that you can (low calcium intake, lack of regular exercise, drug and alcohol use). Add a high-protein diet to the mix, and you make yourself an odds-on favorite for an osteoporosis-related fracture.

If you want to increase your calcium intake, by the way, forget about milk, cheese, yogurt, and other dairy products. These foods have high protein contents. So any calcium they provide, plus a bit more, gets eaten up by the amino acidneutralizing process described above.

A high-protein diet stresses not only your skeleton but also your kidneys. When you consume too much protein, your kidneys have to put in lots of overtime to flush the excess out of your system. As a result, they wear out sooner than they should--a condition called renal failure.

We're Number One

We Americans have earned the dubious distinction of eating more protein--especially animal protein--than any other population in the world. Not so coincidentally, we also have the highest rate of osteoporosis-related hip fractures. Here's how we measure up.

---

COUNTRY	HIP FRACTURES (PER 100,000 PEOPLE)	PROTEIN INTAKE (G./DAY)
		Total	Animal
United States	98	106	72
Sweden	59	105	57
Finland	44	93	61
United Kingdom	43	90	54
Hong Kong	32	82	50
Singapore	20	82	39
South Africa	6	55	11

The Meat Myth

Meats have long had a reputation as the best protein sources around. This is because they're rich in complete proteins--in other words, they supply all of the amino acids that the body can't make on its own.

Unfortunately, when you eat meats, you're getting not only complete proteins but also saturated fat, cholesterol, and pesticides--substances that aren't quite so kind to the body. Saturated fat and cholesterol clog and harden arteries, paving the way for heart disease. And pesticides and other toxins weaken the immune system and stress the organs of elimination.

Plus, meats are completely devoid of the all-important essential fatty acids and fiber. In chapter 8, we saw how essential fatty acid deficiencies can cause or aggravate scores of health problems. When fiber is in short supply, toxins aren't being swept out of the digestive tract efficiently. This increases the workload for the liver, kidneys, and colon, the three organs responsible for cleansing.

The bottom line is that meats frustrate the Renewal process in a variety of ways. You can get all the protein you need from other, healthier sources--sources that won't overburden your body and undermine your health.

Plant Proteins: Better for Your Body

Grains, beans, fruits, and vegetables--the four main "ingredients" in the Anti-Aging Diet--are naturally low in protein. By eating them in a variety of combinations, you get a balanced supply of all the amino acids that your body needs, without risking protein overload.

Plant proteins treat your body much more kindly than animal proteins do. While animal proteins raise cholesterol, vegetable proteins--meat mt especially soy protein--have been shown to lower cholesterol. In fact, the Italian national health service provides free soy protein to physicians for the treatment of patients with high cholesterol.

What's more, the ratio of calcium to protein is much higher in plant-derived foods than in animal-derived foods. The "extra" calcium gets shipped to your bones for storage rather than being spent to neutralize amino acids. So plant proteins support skeletal health--unlike animal proteins, which contribute to osteoporosis.

Complete without Meat

With the exception of soy, no single plant-derived food supplies a complete protein. In other words, no plant-derived food provides all eight essential amino acids. A deficiency of even one amino acid is enough to prevent cells from assembling the proteins your body needs to heal and grow. (You'll recall that cells build proteins by joining amino acids to form chains.)

To avoid a deficiency, you'll need to consume plant-derived foods in combinations that supply all the necessary amino acids. Such foods are often referred to as complementary plant proteins. For example, grains and beans function as complementary plant proteins. Grains in general are rich in the amino acids tryptophan and methionine but come up short in the amino acids lysine and isoleucine. For beans, the opposite is true: They generally contain little tryptophan and methionine but plenty of lysine and isoleucine. (A notable exception is soybeans, in which all four amino acids are abundant.) So by combining any grain and any bean, you get your full complement of these essential amino acids. Your body then has all the raw materials it needs to manufacture complete proteins.

And contrary to popular belief, you don't need to eat complementary plant proteins at the same meal. Research has shown that the body recycles amino acids quite efficiently. So as long as you feed your body a variety of complementary plant proteins on a regular basis, it will have optimum quantities of all the amino acids it needs.

*

Plant-derived foods are shaping up to be Renewal's greatest allies. As we've seen so far, they're not only low in fat and protein but also high in vitamins, minerals, phytochemicals, and fiber. But even plant-derived foods aren't immune to the corrupting effects of pesticides, additives, and other chemicals. The next chapter explains how you can safeguard your food supply against these manmade toxins.