Protein: Keeps the Body Running
Protein is made from different combinations of amino acids and is good for keeping the body running.
High Protein Diets
High protein diets have made a name for themselves when it comes to weight loss. But even for those with no need to lose weight, the issue of protein is critical. Although protein is the essence of life itself (our muscles, skin and bones contain it and every cell of our body utilizes it), recent research suggests the current recommended daily allowance (RDA) for healthy adults over 50 may not be adequate.
Your body relies on protein to build and repair body organs, muscles and bones and to make enzymes, antibodies and hormones, all of which are needed to keep your body running smoothly. Protein is made up of amino acids. Of the 20 amino acids that your body needs, eight must be obtained from the food you eat and are considered essential, while the remaining 12 are made by your body and are "nonessential".
About 75-percent of the protein you eat should be high quality, as determined by its amino acid makeup. "Complete" or high quality proteins contain all eight essential amino acids and come from animal sources (milk, eggs, meat, poultry and fish) and foods made from soy (tofu and tempeh). Most plant proteins (legumes, nuts, rice and other grains) are "incomplete" because they do not contain all the essential amino acids. But by combining incomplete proteins in a meal, you can amass protein of sufficient quality to be considered complete (beans and rice, peanut butter on whole grain bread, milk with cereal).
Protein requirements may increase with age. That is because changes in the function and capacity of all body systems occur with aging, including a gradual loss of lean body mass, like muscle. Although this loss means your body needs fewer calories, your protein needs are unchanged or perhaps increased. This challenges older individuals to consume enough protein without consuming extra calories.
So, How Much Protein is Enough?
The RDA for protein is based on body weight. Recent research indicates that the current recommendation (0.36 grams per pound of body weight) may not be sufficient to maintain muscle mass in healthy people over 50, and that an increase (to 0.45 grams per pound of body weight) may be recommended. A 125-pound woman would need approximately 56 grams of protein daily to maintain her muscle mass. Unless you are ill or recovering from surgery or injury, you do not need a high-protein diet. But it would be wise to discuss your protein needs with your doctor or dietitian.
Getting the right amount of protein plays a vital role in your health. Do you know what your protein needs are? Calculate them with the equation and peruse the following table for suggested foods for protein consumption. Calculate your daily requirement, keeping in mind 75-percent must be high quality protein.
Multiply your weight in pounds by 0.36 grams. Example: 125 x 0.36 grams of protein equals 45 grams of protein per day.
Commonly Eaten Foods and their protein content in grams
|3 ounces chicken breast (no skin): 26g||1 ounce cheddar cheese: 7g|
|3 ounces beef, veal or pork: 25g||1 medium-sized egg: 7g|
|3 ounces white fish: 18g||1/2 cup cooked pinto beans: 7g|
|1/2 cup cottage cheese: 13g||1 ounce nuts: 6g|
|8 ounces 1-percent milk: 9g||1 slice wheat bread: 4g|
|2 tablespoons peanut butter: 8g||1/2 cup white rice: 2g|
When you have an infection, you should eat more protein because it helps create the antibodies your immune system needs to fight disease. If you are injured, you may need more, as well, to help your blood clot and make repairs.
Your body can use protein for energy, if necessary, but it is best to eat plenty of carbohydrates for that purpose and save your protein for the important jobs other nutrients cannot do.
Protein malnutrition leads to the condition known as kwashiorkor. Lack of protein can cause growth failure, loss of muscle mass, decreased immunity, weakening of the heart and respiratory system, and death.
Eating lots of protein, such as the amounts recommended in the low-carb or no-carb diets, takes up lots of calcium from the body. Some of this may be pulled from bone. Following a high-protein diet for a few weeks probably won't have much effect on bone strength. Doing it for a long time, however, could weaken bone. Although more research is clearly needed to define the optimal amount of daily protein, long-term high-protein diets should be practiced with adequate knowledge of the effects and amounts of protein ingested.
Some of the protein you eat contains all the amino acids needed to build new proteins. This kind is called complete protein. Animal sources of protein tend to be complete. Other protein sources lack one or more amino acids that the body can't make from scratch or create by modifying another amino acid. Called incomplete proteins, these usually come from fruits, vegetables, grains, and nuts.
Adults should get 45 percent to 65 percent of their calories from carbohydrates, 20 percent to 35 percent from fat, and 10 to 35 percent from protein. Acceptable ranges for children are similar to those for adults, except that infants and younger children need a slightly higher proportion of fat (25 to 40 percent).
Pick Your Protein Carefully
Your body needs many different proteins for various purposes. It makes them from about 20 "building blocks" called amino acids. Nine of these are essential amino acid, which means you must get them from food. The others are nonessential. This does not mean you do not need them. You just do not have to eat them because your body can produce them.
It is easiest to get protein from meat, chicken, turkey, fish and dairy foods. Cooked meat is about 15 to 40 percent protein. Foods from animal sources provide complete protein, which means they contain all the essential amino acids.
Next to meat, legumes -- beans, peas and peanuts -- have the most protein. But they are called incomplete proteins because they are lacking some essential amino acids. You can get complete protein if you combine them with plant foods from one of these categories -- grains, seeds and nuts, and vegetables. Eat any two or more of these plant foods, with or without beans, and you get complete protein.
You do not have to eat these foods in the same dish, or even in the same meal. But many cultures have created combinations that work well -- like corn and beans in Mexico, or rice and split peas in India. Many Americans enjoy legumes and grains in a peanut butter sandwich.
Make Digestion Easier
Your body can digest and use animal protein more easily than plant protein. But be sure to avoid excess fat by choosing lean meats and low-fat dairy products. Legumes are next easiest to digest, followed by grains and other plant sources.
Cooking protein foods with moist rather than dry heat, perhaps boiled in a stew rather than fried, or soaking meat in a marinade using wine, lemon juice, or vinegar makes it easier to digest.
Set Healthy Limits
Since protein is so important to your body's survival, you may think you need to eat a lot of it. Fortunately, your body actually recycles protein from tissues that break down and uses it to make new ones. So you do not need more than 10 to 15 percent of your total calories from protein.
Protein deficiencies are common in poor, undeveloped countries. Even in modern nations, they sometimes occur in certain groups. In fact, vegetarians need to be very careful about eating the right combinations of plant foods to get enough complete protein.
The chances are far greater that you eat too much protein, especially from meat sources. The typical Western diet includes about 100 grams of protein, while 50 grams is closer to what your body needs.
If you are healthy, with no liver or kidney problems, you can get rid of any excess with little trouble. Yet, meat protein can be expensive and high in fat, two good reasons not to eat more than your body can use.
Beware the Dangers of a High-Protein Diet
If you are looking for a quick way to lose weight, it is easy to get fired up about a high-protein diet. Unfortunately, the American Heart Association, the American Dietetic Association and other health organizations advise against it.
An initial drop in weight is common with a high-protein diet, but it is due primarily to water loss. These diets do not work very well in the long run -- nor do they build muscles as they claim. Most important, they can be dangerous, increasing your risk of heart disease, kidney disease and artery damage, and bone loss.
While most high-protein foods contain plenty of vitamin B12 and iron, they are low in other vitamins and minerals. Only a diet with lots of fruits, vegetables, and grains supplies the other nutrients that keep you healthy.
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