Protein and Carbohydrates
Nutrients are substances necessary for proper bodily function. Some are required in large quantities (macronutrients) and some are required is small quantities (micronutrients). There are 4 types of macronutrients: Proteins, Carbohydrates, Fats and Water and two types of micronutrients: Vitamins and Minerals.
Proteins are the basic structure of all living cells. Proteins are used in making hormones, blood plasma transport systems, and enzymes. The basic building blocks of proteins are called amino acids. There are two types of proteins complete and incomplete. Amino acids are categorized as essential and non-essential. Of the twenty amino acids that have been identified, nine are considered essential amino acids those that are not manufactured by the body, these must come from dietary intake. The body can manufacture the non-essential amino acids from the by-products of carbohydrate metabolism. Amino Acids are crucial for proper Central Nervous System (CNS) function.
Non-Essential Amino Acids
- Alanine - provides energy for muscle tissue, brain and CNS; aids antibody production to enhance the immune system; helps metabolize sugars and organic acids.
- Arginine - improves immune response to bacteria, viruses and tumor cells; promotes healing and liver regeneration; aids the release of growth hormones for muscle growth and tissue repair.
- Aspartic Acid (Asparagine) - aids in the excretion of ammonia, which is toxic to the CNS; may increase resistance to fatigue and increase endurance.
- Cysteine - antioxidant protection against radiation and pollution; slows the aging process; deactivates free radicals; neutralizes toxins; aids in protein synthesis. Crucial for the skin development aiding in the recovery from burns and surgical procedures. Hair and skin are comprised of 10-14% Cysteine.
- Glycine - aids in the release of oxygen during the cell-making process. Important for hormone production in strengthening the immune system.
- Glutamic Acid (Glutamine) - improves mental capabilities; helps healing of ulcers; reduces fatigue; helps control alcoholism, schizophrenia and sugar cravings.
- Taurine - stabilizes membranes excitability in the control of epileptic seizures. Controls biochemical changes responsible for the aging process; aids in the excretion of free radicals.
- Proline - promotes proper joint and tendon function; strengthens heart muscles.
- Serine - storage source of glucose for the liver and muscles, antibody production enhances the immune system, synthesizes fatty acid covering around nerve fibers (insulator).
- Tyrosine - transmission of nerve impulses to the brain; fights depression; improves memory and mental alertness; promotes the proper function of the adrenal, thyroid and pituitary glands.
Essential Amino Acids
- Histidine - hemoglobin component; used in the treatment of rheumatoid arthritis, allergic diseases, ulcers & anemia. A deficiency may cause hearing problems.
- Isoleucine and Leucine - mental alertness, also provides manufacturing components for other essential biochemical components in the body, which are utilized for the production of energy and upper brain stimulants.
- Lysine - Insures adequate absorption of calcium; helps form collagen (component of bone, cartilage and connective tissues); aids in the production of antibodies, hormones & enzymes. Lysine may be effective against herpes by improving the balance of nutrients that reduce viral growth. A deficiency may result in tiredness, inability to concentrate, irritability, bloodshot eyes, retarded growth, hair loss, anemia & reproductive problems.
- Methionine - a sulfur source which prevents disorders of the hair, skin and nails. Lowers cholesterol by increasing the liver's production of lecithin and reduces liver fat build-up. Protects the kidneys; a natural chelating agent for heavy metals; regulates the formation of ammonia and creates ammonia-free urine thereby reducing bladder irritation; promotes healthy hair growth.
- Phenylalanine - allows brain to produce Norepinephrine used for the transmission of signals between nerve cells and the brain; regulates hunger, antidepressant; improves memory and mental alertness.
- Threonine - a component of collagen, Elastin, and enamel protein; reduces liver fat build-up; promotes proper digestive system function and metabolism.
- Tryptophan - a relaxant, alleviates insomnia, prevents migraine; reduces anxiety and depression; promotes proper immune system function. It reduces the risk of cardiovascular spasms. Works in conjunction with Lysine to lower cholesterol levels.
- Valine - Promotes mental health, muscle coordination and tempers emotions.
Other protein comes from the recycling of enzymes and other proteins. Protein is synthesized in all tissues in the body; however, the liver and muscles are the most active. The body synthesizes about 300 grams of protein per day even though average intake is only 70 grams.
Proteins that contain all nine essential amino acids in sufficient quantity to sustain life are called complete proteins. The protein efficiency ratio (PER) is a measurement of protein's completeness. Protein is rated according to various indices. The most common measurement being the Biological Value or BV of the protein. The higher the BV value the more readily the protein is absorbed by the body. Eggs have the highest BV value (100). Whey protein's value is close to 100 while beans have a BV of 49. Ratings of greater than 100 refer to the chemical score of an amino acid pattern in a reference protein to a test protein and not the BV.
Meat, fish, milk, cheese and eggs contain complete proteins. Incomplete proteins such as vegetables, grains, seeds, and nuts are those which do not contain all nine essential amino acids by themselves. However, combinations of incomplete protein foods or mutual supplementation can supply all nine essential amino acids such as beans with rice or peanut butter on wheat bread. Therefore vegetarians can get all the amino acids required by combining incomplete protein foods. It is not necessary to combine proteins at the same meal as many people believe. Therefore a breakfast of one incomplete protein and a dinner of another incomplete protein will provide the benefits of eating a complete protein.
Examples of Protein rich foods:
- High Fat - Meat, salmon, eggs, peanut butter, milk, cheese
- Low Fat - Tuna, egg whites, red beans, skim milk, non-fat cheese
Proteins begin digestion in the stomach but are primarily digested in the small intestine and metabolized by the liver for the building of tissue. Proteins that are not required for building can be utilized as an energy source and provide 4 calories per gram. About 98% of the protein from animal sources and about 80% of the protein from vegetable sources is absorbed by the body.
Fasting causes the body to use protein as an energy source even to the point of breaking down vital tissues such as organs and muscles to use as an energy source. Excess protein, not utilized for tissue repair or growth or as an energy source is converted by the body to fat and stored.
Protein requirements depend on the individual and daily activity. Tissue growth, whether due to growth, injury, weight training, or pregnancy effect protein requirements. During illness, protein is not only required for repair but is generally used as an energy source. According to RDA requirements, an adult should consume approximately 0.36 grams of protein per pound of body weight on a daily basis (0.8 grams of protein per kg of body weight) as a minimum requirement. As an example, a 150-pound person should consume approximately 50 grams of protein daily. This translates to 200 calories of protein daily. As a general rule, for intense weight training, up to 1 gram per pound of body weight may be consumed.
Since protein metabolism produces nitrogen in the body this creates an extra workload for the kidneys and liver to eliminate the excess. Dehydration can occur because the kidneys require increased amounts of water to dilute the nitrogen. Dehydration can impede workout performance. It's therefore important to adequately hydrate when consuming increased levels of protein.
Hair-loss and thinning, as well as, brittle and discolored fingernails can be external manifestations of protein deficiencies. Internal ramifications can be muscle wasting, weak ligaments and cellular dysfunction since amino acids will be in short supply. Muscle growth will also be limited or unavailable due to an insufficient amount of protein.
Carbohydrates are utilized for energy, both instant and sustained. When insufficient carbohydrates are taken in, the body must utilize proteins for energy even to the point of catabolizing muscle tissue for energy.
Digestive enzymes in the small intestines break down the carbohydrates into glucose. The glucose can be immediately utilized by the body or stored as glycogen in the muscles and liver. The muscles can store about 20 minutes of glycogen for energy. The bloodstream can hold about an hour of glucose for energy. If glucose levels are maximized and all glycogen storage locations are full then the excess glucose is converted to fat by the liver and stored in adipose tissue or fat cells. There is really no limit to the amount of fat that a body can store. According to studies at the University of Massachusetts, carbohydrates are generally converted to fat at the rate of 75% where 25% of the carbohydrates are used in the conversion process.
There are three types of carbohydrates Monosaccharides, Disaccharides and Polysaccharides. Monosaccharides are simple sugars and are the basic unit of carbohydrate. Examples of monosaccharides are glucose and fructose. Disaccharides are composed of two monosaccharides. Examples of disaccharides are table sugar (sucrose) which is composed of fructose and glucose also milk sugar (lactose) which is composed of glucose and galactose.
Polysaccharides are composed of multiple monosaccharides. Examples of Polysaccharides are starches (bread, fruit, grain, pasta, rice). These are also called complex carbohydrates.
Carbohydrates should comprise approximately 60% of the daily caloric intake. Therefore, for a 3000 calorie total daily intake, 1800 of those calories should be carbohydrates.
Fiber is a form of carbohydrate. Approximately 20 grams of dietary fiber is required in our diets. Fiber facilitates elimination and decreases appetite as a bulking agent. Fiber also inhibits the absorption of cholesterol into the blood stream. It has also been shown that fiber slows the absorption of sucrose into the bloodstream. This can be important in the treatment of type II diabetes. Too much fiber in the diet can restrict the absorption of necessary vitamins and minerals. Excess carbohydrates are converted into fat by the liver and stored in adipose tissue.
Sugar is absorbed into the bloodstream within minutes. Consuming large amounts of sugar prior to exercise can actually inhibit performance. This produces a drastic increase in blood sugar. This causes the pancreas to secrete large amounts of insulin to metabolize the sugar. All this insulin inhibits the metabolization of fat by the muscles. Therefore, the muscles rely more on glycogen which is in limited supply. The insulin reduces blood sugar level which is already being reduced by the muscles utilization of glycogen stores for energy production. The blood sugar level reduces to a level which may not only cause fatigue but dizziness as well. Therefore consumption of excess sugar prior to exercise reduces performance and endurance.
Carbohydrate loading is when an athlete depletes and then force-feeds carbohydrates over a period of several days. Carbohydrates are first depleted, for example on a long fast run, then large amounts of carbohydrates eaten. The theory is that the body will overcompensate and store extra glycogen.
This technique requires the consumption of several different kinds of carbohydrates each assimilated by the body at different rates based on their gylcemic value. Eating a high glycemic food provides immediate energy while a low glycemic food provides energy at a slower controlled rate. This technique provides greater endurance for athletes.