Proteins, today's topic, are another of the major nutrients our body absorbs. While there are not many protein diets, like there are with carbohydrates and lipids, proteins are consumed in many different ways by people everyday. Before I briefly touch on fad protein consumption, I want to discuss what proteins are, where they come from, what they do in the body, and the dangers of protein malnutrition.
Protein makes up about 50% of the content of our muscles, 23% of our bones, 10% of our skin, 8% of our blood and liver, and about 1.5% of our brain. Each of us has about 10 kg (which is about 22 lbs) of protein in the body; the distribution of which depending greatly on gender, training, and bones.
Proteins have a very similar chemical organization as both carbohydrates and lipids, except they contain Nitrogen. In fact, 16% of the protein molecule is nitrogen. Additionally, proteins are polymers of their subparts called Amino Acids (or AA). A polymer is a compound that is made by combining many smaller molecules (in this case, amino acids). In fact, proteins are made up from the combination of any two of 23 amino acids.
So what are amino acids? Amino acids are made up of two parts: an amino group (NH2) and a carboxyl, or acid, group (COOH). Then proteins are further distinguished by the addition of a R, or variable, group called a side chain. These R groups are the only place amino acids differ from each other. Each different side chain causes the amino acid to take on a different function in the body. Since there are 23 different amino acids and so many ways these amino acids can link together, there are almost an infinite number of proteins. However, there are two important classifications of amino acids for our diets: Essential and Non-Essential amino acids.
Essential amino acids cannot be synthesized in the body, such as tryptophan and lysine. Therefore, we must consume and absorb them from our foods. In adult, there exist eight essential amino acids that must come from food, and in children there are nine. Non-essential amino acids, on the other hand, are already synthesized in the body. Therefore, any that we consume will be added to the number that already exist in our body, such as glutamine or tyrosine.
So where to we get our protein from? As most of you already know, a large portion of our proteins are absorbed from meat and dairy products. However, we can also obtain protein from grain products, eggs, nuts, soybeans, and more! Some foods; like eggs, fish, poultry, and some meats are considered to have complete proteins. This means that they contain all of the essential amino acids in the correct ratio, unlike incomplete proteins that lack one or more essential amino acids. Additionally, different kinds of foods contain different percentages of proteins. Meats, fish, poultry, and eggs contain the most: 44%. Dairy contains 24%, cereals 19%, and fruits and veggies contain about 7% protein.
With protein coming from so many different sources (essentially all sources), it is interesting to know that the way we combine our foods greatly affects the quality of the proteins we obtain. For example, you can improve the quality of your protein if you combine legumes; such as black-eyed peas, chick peas, peanuts, lentils, sprouts, or beans with grains; such as rice, wheat, corn, rye, oats, or barley.
The amount of protein that we each require depends on both age and physical activity, but generally we need about .8 or .9 grams of protein per kilogram of body weight. Keep in mind that one kilogram equals out to about 2.2 lbs. So if a person weights 110 lbs, then they require about 40g of protein per day. An older teen requires about .9g/kg body weight, a normal adult requires .8g/kg body weight, and an adult athlete requires 1.1 to 1.6 g/kg body weight. This is the only nutrient among all nutrients that we have an exact number we know the body needs for proper functioning.
Proteins are needed for many different functions; including anabolism, as enzymes, as a vitamin precursor, and for use as energy. 1 gram of protein in the body amounts to about 4 calories. When consumed, proteins are absorbed, causing a few different reactions in the body; such as the excretion of nitrogen, Gluconeogenesis (or synthesis of glucose), oxidation of proteins for energy, and fat synthesis.
While our nation is filled with more overweight people than ever before, we are faced with more malnutrition than we ever have before as well. One type of malnutrition that is occurring is protein malnutrition, of which there are a few types. In pure protein deficiency, people are getting enough food, but they are not getting enough of the proper amino acids needed. In protein-energy malnutrition (PEM), people are not getting enough food, and thus not enough amino acids. Long-term protein deficiency is often associated with sever energy deficiency, mostly affecting children. Maramus is a sever form of PEM where the individual becomes thinner and thinner from progressive loss of fat and muscle. These individuals become weak and listless, often suffering from infections. Finally, Kwashiorkor is a condition when the body becomes swollen with fluid because there is less protein than is normal in the blood and the blood migrates to tissues, causing liver disease.
While there are definite consequences to protein malnutrition, there are also consequences with over-indulgence of protein as well; such as heart disease, obesity, osteoporosis, and cancer. This is usually the case when most protein is absorbed from animal products because animal products also contain a high number of saturated fats. Thus, many individuals decide to avoid such products high in saturated fats, aka animal products, to pursue a diet of mostly plants; such as vegetarian and vegan diets. It is especially important if you are undertaking any of these diets, to check the different fruits, vegetables, and nuts for protein amounts (and types) in order to insure you are obtaining enough protein in your diet!
There is a special case where individuals actually do require a higher than normal amount of protein: endurance athletes. Endurance athletes actually burn a lot more fat and thus need more protein than the average individual in order to stay in protein balance. So instead of consuming the normal .8-.9 g/kg body weight, endurance athletes need more like 1.4-1.7 g/kg body weight. Other athletes like body builders should actually continue to consume the regular amount of protein in order to stay in protein balance.
Many workout enthusiasts have begun to consume different types of supplemental protein. In the body, there are specific carriers for amino acids to be absorbed and transported into the blood. If we are flooding these absorptive carries with one type of amino acid contained in the supplemental protein, then other similar amino acids will go by the site without having a chance to be absorbed. This will then cause competition for amino acid transport and often the dietary proteins, or amino acids, consumed will be lost through excretion even if it was present in your diet. Therefore, the best guarantee of having a good balance of amino acids in your body is to supply the dietary needs of protein from food, rather than from supplements.
Today's Workout: Today I was still not feeling well enough to actually go and work out. So if you ever are like me and are sick multiple day's in a row, my suggestion is just to get out and move a bit. It is really good to get some fresh air, so I suggest taking a walk outside, even if it is only for a few minutes. Today I got up and outside for about that long. I feel a lot better just because I moved a bit.
Today's Food Tip: If you are ever sick, another good thing to make for yourself is some hot tea. Not only does the warmness help soothe a sore throat, it also helps keep you hydrated. When feeling ill, the body often becomes incredibly dehydrated so it is very important to keep drinking up some fluids all day long.
Today's Relaxation Activity: Today I suggest to relax on a comfortable piece of furniture, like a fluffy couch, and cover up with a warm blanket while watching a feel good TV show with your family. I caught the ABC show "The Bachelor" with my family tonight and felt good being around my family.
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