Proteins

• Proteins are the basic material of every body cell.
• By the age of 4 years, body protein content reaches the adult level of about 18% of body weight.
• Both conditions can result in impaired physical and mental development.
• An adequate supply of proteins in the daily diet is essential for normal growth and development and for the maintenance of health.
• Proteins are appropriately named, as the word protein is of Greek derivation and means “of first importance.”
• The primary function of proteins is to build and repair body tissues, made possible by the provision of the correct type and number of amino acids in the diet.
• As cells are broken down during metabolism (catabolism), some amino acids released into the blood are recycled to build new and repair other tissue (anabolism).
• The body uses the recycled amino acids as efficiently as those obtained from the diet.
• Proteins are important components of hormones and enzymes that are essential for the regulation of metabolism and digestion.
• Proteins help maintain fluid and electrolyte balances in the body and thus prevent edema.
• Proteins are essential for the development of antibodies and, consequently, for a healthy immune system.
• Proteins can provide energy if and when the supply of carbohydrates and fats in the diet is insufficient.
• Each gram of protein provides 4 calories, which is not a good use of proteins, however.
• Proteins are found in both animal and plant foods, with the animal food sources providing the highest quality of complete proteins.
• The animal food sources of complete proteins include meats, fish, poultry, eggs, milk, and cheese.
• Despite the high biologic value of proteins from animal food sources, they also provide saturated fats and cholesterol.
• The American Heart Association does not recommend diets high in protein.
• Extra protein is stored as fat.
• Excessive protein intake may contribute to heart disease and provide more calories than are desirable.
• The National Academies Press published Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids in 2005.
• If carbohydrates are lowered with the increased protein, the body will not be able to completely burn fat.
• To determine your requirement, divide body weight by 2.2 (the number of pounds per kilogram) and multiply the answer obtained in step 1 by 0.8 (gram of protein per kilogram of body weight).
• The National Research Council recommends that protein intake represent no more than 15% to 20% of one’s daily calorie intake and not exceed double the amount given in the table of DRIs.
• Chymotrypsin is a pancreatic enzyme necessary for the digestion of proteins.
• Animal protein also contains saturated fat, which can lead to coronary heart disease, stroke, and several kinds of cancer.
• In 2002, the Dietary Reference Intakes (DRIs) for protein were published by the National Academy of Sciences.
• An Adequate Intake (AI) was established for infants 0 to 6 months, with all other recommendations based on 0.8 g/kg of body weight.
• Pancreatic enzyme helps digest proteins.
• Eating too much protein restricts healthful foods that provide essential nutrients.
• The National Research Council of the National Academy of Sciences considers the average adult’s daily requirement to be 0.8 gram of protein for each kilogram of body weight.
• Carboxypeptidase is a pancreatic enzyme necessary for protein digestion.
• Complete proteins should be carefully selected from low-fat animal foods such as fish, lean meats, and low-fat dairy products.
• Whole eggs should be limited to two or three a week if hyperlipidemia is a problem.
• Proteins found in plant foods are incomplete proteins and are of a lower biologic quality than those found in animal foods.
• Even so, plant foods are important sources of protein.
• Examples of plant foods containing protein are beans, peas, lentils, nuts, seeds, and soybeans.
• Complete proteins are proteins that contain all the essential amino acids.
• Textured soy protein and tofu are both economical and nutritious meat replacements.
• Amino acids are nitrogen-containing chemical compounds of which protein is composed.
• Nitrogen is a chemical element found in protein and is essential to life.