The word protein comes from the Greek word protos, which means "first." When I was growing up I remember being taught that protein was of first importance.  Any serious discussion of optimum nutrition has to begin with a discussion of protein.  Its a big topic so Ive decided to present the information in stages. Part I presents technical information about protein.

Protein Chemistry

Protein is made from molecules of:

	Carbon
	Hydrogen
	Oxygen
	Nitrogen
	and Sulfur (sometimes)

Point of interest ... Nitrogen is the component of protein that makes it a protein. Without nitrogen it would be a carbohydrate or a fat.

Individual proteins are made up of amino acids joined together in chains of various lengths. There are 20 naturally occurring amino acids.

	Monopeptides are proteins made from single amino acids. (Example: Some neurotransmitters such as epinephrine and serotonin - are made from a single amino acid.)
	Dipeptides are proteins made from two amino acids.
	Tripeptides are composed of three amino acids.
	Polypeptides are proteins made from many amino acids. (Example: Myosin - which is muscle protein - is composed of 4500 amino acids. Hence, its a polypeptide.)

At least nine of the amino acids cannot be manufactured by the body and must be supplied by diet. These are called essentialamino acids. The essential amino acids are leucine, isoleucine, lysine, phenylalanine, threonine, tryptophan, valine, methionine, and histidine.

The remaining amino acids are called non-essential because they can be manufactured in the body as long as there is available nitrogen. The non-essential amino acids are alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, and glutamine, glycine, proline, serine, and tyrosine.

Functions of Protein in the body:

Protein is used for energy but this is not its primary role. The primary role of protein is to provide the building materials for body tissue. It is an essential structural component of all living matter. It is involved in almost every biological process in the human body.

Types of muscle & connective tissue proteins:

	myosin
	actin
	collagen
	elastin
	keratin

Other body proteins:

	hemoglobin (red *lo** cells)
	enzymes (speed up chemical reactions)
	hormones (chemical messengers carried by *lo**)
	neurotransmitters (brain chemicals)
	antibodies (part of the immune system)
	protein carriers in the *lo** (carry cholesterol and fats)

Did you know that you have 35 neurotransmitters?

Perhaps the most famous is serotonin, which is made from tryptophane. Serotonin is known for its calming and anti-depressant effect. Also well known are dopamine and norepinephrine, which are made from tyrosine. Dopamine and norepinephrine help to keep us alert.  Neurotransmitters effect memory, mood, appetite & muscular coordination.

Body proteins are sometimes classified by shape:

	Fibrous proteins are long and stringy. Examples: myosin and actin (muscle proteins.) Also, collagen, elastin, and fibrin.
	Globular proteins are round. Examples: albumin (found in *lo**) and globulin (also found in *lo**) Globulin helps to protect the body from infectious diseases.

Dietary proteins are sometimes classified by quality:

	Complete proteins contain all of the essential amino acids.
	Incomplete proteins are deficient in one or more essential amino acids.

Proteins containing all of the essential amino acids are considered superior in quality because of their ability to support the growth of baby animals. This superior nature is referred to as high biological value. In general, proteins from animal sources - such as milk, eggs, fish, chicken, beef - have a higher biological value than proteins from vegetable sources, such as nuts, seeds, cereal grains, and legumes (beans.)

When certain food sources of protein are consumed together they may compliment each other. The protein quality of the two foods c****ined may be superior to the quality of the protein in either individual food.

Example: Grains are low in the amino acid lysine but high in methionine. Beans (legumes) are low in methionine, but high in lysine. In c****ination they compliment each other and provide protein of higher biological value.

How much protein does the body need each day?

The RDA for protein is set at a mere 44 grams for women and 56 grams for men. The formula used to estimate protein need is .8 grams per kg (2.2 lb.) of body weight. A number of factors increase protein requirement. These factors include exercise, age, illness, injury, pregnancy, and caloric intake. Approximately 70% of protein intake is used for tissue maintenance. The remaining 30% is used for energy.

Are these recommendations adequate? Or do you need more protein than this?

Protein (Part II)

Are you getting enough protein?

Do you suffer from fatigue? Depression? A failing memory? Do you catch colds a lot? Does it take you a long time to heal from a wound or injury? Are you hungry all day long? Do you overeat on carbohydrates? Do you have problems with hypoglycemia (low *lo** sugar)? Low *lo** pressure? Is your hair falling out? Are you anemic? If you answer yes to any of these questions there is a possibility you may not be getting enough protein.

During the 1960s and early 1970s protein was America's favorite diet food and a lot of people tried to live on high protein, very low carbohydrate diets in an effort to lose weight. By the 1980s carbohydrates were back in style, fats were out, and many people started avoiding proteins - like meats and cheeses - because of the fat content. Today, it is quite common for me to counsel someone who is overtly protein deficient. So let me begin by reminding you that protein is of first importance, and while it is not possible to live on any single food group to the exclusion of others, you cannot survive without adequate protein.

As I mentioned before, the RDA for protein is set at a measly 44 grams per day for women, and 56 grams for men. Mind you, those numbers are averages or reference points. The formula for estimating your individual requirement is .8 grams of protein per kg. of body weight. Of that amount, 70% goes to tissue maintenance, and 30% is used for energy production.

Unfortunately, those numbers don't consider protein quality, nor do they allow for special needs. My personal recomendation would be to aim for at least 60 grams of protein if you're a woman, and 75 grams of protein if you're a man.

Who needs more protein?

	athletes For athletes protein need may be 125% greater than average. Those involved in strength, power, or speed activities may benefit from 1.8 grams per kg. of body weight per day. This is considerably higher than the .8 gram per kg. suggested for more sedentary individuals.
	children (for growth)
	pregnant women (for the growth of the fetus, and because of increased metabolism)
	Other factors which increase protein requirement include: injury, surgery, burns, and illness.
	You may also need more protein if you are on a low-calorie diet.

The reason? As you decrease your calorie intake your body may convert the protein you eat into glucose and use it for energy. Protein being used as fuel cannot be used for tissue replacement, or for the product of hormones, enzymes, etc. Thus it is possible to be deficient in protein even when consuming a seemingly adequate number of protein grams.

Some people I speak to are trying to survive on a diet of bagels and pasta. And most of them are not only gaining weight, some are going bald from malnutrition.

Case studies in protein deficiency.

Case # 1.

At the age of 29 Janet's hair was falling out in fistfuls, and it was actually her concern about going bald that brought her to my office. The problem? Janet had switched to a vegetarian diet, which was extremely low in protein and low in iron and zinc.

Note: Hair loss is a typical symptom of iron and zinc deficiency. And red meat is a major source of both of these minerals.

Janet had eliminated meats because she was trying to avoid fats believing this was the best way to stay slim and healthy. She was essentially living on lettuce leaves (salads) which could not possibly provide her with the protein and nutrition she required.

Is it possible to get adequate protein on a vegetarian diet? Yes! But you need to include high-protein foods, such as nuts, legumes, soy products, eggs, and perhaps low-fat dairy products.

Case #2

Henry was referred to me by his cardiologist. "There's something wrong," he told me. "I'm very tired. My energy is way down. I get breathless, and I'm depressed. And I'm losing my memory. I can't remember things like I used to. I know you probably can't help me, but I just don't feel right." He didn't say it, but I knew from the look on his face that Henry thought he was dying.

It would have been easy to dismiss Henry's complaints as being age-related. After all, he was 77 years old. His breathlessness and lack of stamina could have been from lack of exercise. And his depression could have been from social isolation. After all, he lived alone.

I asked Henry to tell me what he was eating for breakfast, lunch dinner, and snacks, and it was immediately clear that his diet deficient in protein.

He had toast for breakfast. A frozen entree of rice and vegetables for lunch. Most of his calories were coming from carbohydrates. He didn't have enough protein for energy, or to make the neurotransmitters required for memory and well-being.

Part of the problem, it turned out was financial. Henry was on a tight budget with only his social security to cover his expenses. And starches are cheaper than proteins.

We discussed some high-protein foods for him to include as part of breakfast: eggs, cottage cheese, peanut butter. He would also get some small cans of tuna and salmon, and some fat free American cheese, to make sandwiches for supper. And for his main meal of the day, at noon, we decided that Henry would walk to the local senior center for a hot, balanced meal that included protein.

"Do you really think this can help?" Henry asked me.

"I know it can help. Have faith."

"How long will it take before I notice a difference?"

"You should notice a difference immediately, a day or two at the most. Your energy should improve. Your memory should improve. You should have more stamina, and be less breathless. And, you'll be less depressed."

Just as I had promised, Henry's health did a complete about face.

Case # 3

Marilyn was a mature woman in her early sixties. She appeared frail and fatigued, and by her own description she was severely depressed, and as far as she could remember she had been depressed ever since her husband died. These days, she rarely left her house. At her friends urging she joined a health club, but to date had never used it. It was through the health club that she found her way to my office. The visit was included with her membership.

There is little doubt that the death of one's spouse can have a prolonged impact on one's life. And it would not have been a stretch to blame Marilyn's depression on stress. But the fact is that her husband had been dead for almost two years. There was a good chance that the origin of her depression was physical.

As it turned out, Marilyn's diet -- like Henry's -- was low in protein. After her husband died Marilyn stopped preparing balanced meals. After all, since it was just for herself, why bother?

This is actually a fairly common phenomenon. Women are notorious for going out of their way to serve other people, but they frequently won't go out of their way for themselves.

After only one week of higher protein intake, Marilyn fairly flew into my office. She was excited, bubbly, energetic, and far from depressed. She was so bowled over by the power of protein to improve mood and well being, she was ready to get on a soap box and start preaching about nutritional salvation!

Ask 10 different health professionals how much protein we need every day, and you'll likely get 10 different answers. I can think of several well-known health experts who preach the virtues of high carbohydrate, low-protein consumption. Proponents of food-c****ining seem to think we can get enough protein eating nothing but fruit. (Don't you believe it!) At the other extreme are some of the weight-loss Gurus who suggest we eat nothing but protein, if we want to be lean and mean. (Don't believe that one either!)

Reality check: an all-protein diet is actually only about 30% protein. The rest of the calories come from fat.

For the record, I don't recommend either low-protein or all-protein diets. For most of us the optimum amount of protein lies somewhere on the continuum between these two extremes.

Advocates of low-protein regimes tell us that too much protein stresses the liver and kidneys. They fail to mention that too little protein will compromise every system of the body, including the immune system. For the record, I encounter many more people who eat too little protein, than who eat too much.

We often hear from the food police that a high protein diet will leach calcium from our bones and put us at risk for osteoporosis. But the people I see with osteoporosis are all on low-protein diets. They are typically vegetarian, and typically extremely thin. And did you know that one of the nutrients you must have in adequate amounts in order to build bone is protein? Now, think about the diet of most body-builders. They tend to consume large amounts of protein. And did you ever see a body-builder with osteoporosis? I never have.

Reality check: The factor which most closely correlates with bone density is body weight. As weight goes up, so does bone density. As weight goes down, so does bone density. The reason is simple: The heavier you are the stronger your bones have to be in order to support you.

Important note: I am not saying that you can't overdo protein. You can, and many people do. If you eat out a lot, and order meat or poultry dishes, the serving size of the protein entree may be 2-6 times the amount you actually require. The Palm restaurant in New York City serves a pound and a half of sirloin steak. At the Carnegie Deli a roast beef sandwich may have 12 ounces of roast beef. The corner coffee shop may serve you half a chicken, when the maximum amount any of us should have at one sitting is a quarter.

As is often the case with nutrition, protein consumption is not an all or nothing issue. Too much protein does indeed put a strain on our liver and kidneys. Too little brings a different set of health problems. What we are seeking is a certain optimum amount of protein, some where between the two extremes.

As a guideline, aim for 3 high protein foods per day, and space them out over the course of the day.

How to estimate your protein intake:

Remember the following numbers.... 7 and 2.

There are approximately 7 grams of protein in an egg, an ounce of fish, chicken, meat, and cheese, a cup of milk, 1/4 cup cottage cheese, 1/2 cup legumes, 1/2 cup tofu, 2 T. of nut butter or 1 oz. of nuts.

There are approximately 2 grams of protein in a slice of bread, 1/2 cup potato, rice pasta, oatmeal, cereal, or 1/2 cup cooked vegetables.

Step # 1: Write down everything you've eaten in the past 24 hours.

Step # 2: Add up the number of ounces of protein, glasses of milk, eggs, etc. and multiply by 7.

Step # 3: Add up the number of slices of bread, plus the 1/2 cup portions of starch and vegetables and multiply by 2.

Step # 4: Add the totals together for an estimation of the total number of grams of protein you've consumed.

Example

Food                     high protein foods         vegetables/starches

Breakfast

1/2 cup oatmeal                                         2

1 cup skim milk               7

1 boiled egg                    7

1/2 banana

Lunch

turkey sandwich            21                          4

(3 oz turkey; 2 bread)

mixed green salad                                        2

Snack

apple

Supper

1/2 cup rice                                                 2

1/2 cup baked beans          7

1/2 cup broccoli                                           2

1/2 cup carrots                                               2

1 peach

Snack

1/2 cup flavored yogurt     4

_____________________________________________

Totals:                            46             +           14              = 60 grams

Reminder: For the perfectionists among us, this is an estimate. No, it is not as exact as it might be if we weighed and measured everything, and then subjected it to a computerized analysis. But it is accurate enough to serve as a guideline to help you determine if you are consuming enough protein for optimum health.