Proteins are high molecular weight polyamides, consisting of one or more chains of amino acids, which then fold into a form that gives that protein a particular function.
Proteins are present in all living tissues and are the principal material of skin, muscle, tendons, nerves, and blood; they form enzymes and antibodies and have a supporting role in molecular biology.
NUTRITIONAL REQUIREMENTS OF AMINO ACIDS AND PROTEINS:
Protein intake is relatively constant at 10-12% of energy intake and diminishes in parallel with the fall in energy that accompanies aging. This may be a factor in muscle loss with age. A safe protein intake should not be lower than 0.75 g/kg /day (WHO/FAO/UNO, 1985). Dietary protein provides nitrogen in an organic form for the renewal of amino acids for their various functions including Proteins in the cell walls, plasma proteins, muscles, enzymes, and college. The amino acids of protein can be determined and may act as an energy source in their own right.
DIETARY AMINO ACID AND PROTEIN REQUIREMENTS:
Proteins are different in their biological quality, depending on the amounts and proportions of essential amino acids. A protein that is rich in all the amino acids would source higher on the scale of biological quality than a protein that is deficient in one or more essential amino acids.
It is necessary to define protein and specific amino acid needs in diets with both abundant and deficient amounts of nutrients, including protein and specific amino acids. The protein requirements of all age groups should be based on the recommendations in the report of FAO/WHO/UNO Expert Consultation, where the values were based on estimates and the amounts of high-quality egg or milk protein required for nitrogen (N) equilibrium. The estimated average intake of protein increases from 10.6 g/day at 4-6 months to 14.8g/day at 4-6 years and 22.8g/day at 7-10 years. In males, the prone requirement increases from 33.8g/day in 11-14-year-Olds to 42.6g/day in the over 50s. In the female, corresponding values are 33 and 37g/day. Athletes may require more dietary protein depending on the muscle power required in the sport. Additions were made for growth, in infants and children, pregnancy, and lactation, additions were made to account for the growth of the fetus and to allow for adequate breast milk production. An addition should be made of 6g/day in pregnancy and 11g/day in lactation during the first 6 months, then 8g/day after 6 months as the protein content of the breast milk begins to fall. There is relatively little change with age in the requirement for protein for maintenance, values falling from 120 mg Nitrogen (N)/kg/day at 1 year and 96 mg (N) for adults. This assumed efficiency of dietary utilization of 70% during growth.
In the case of the elderly, the recommended nitrogen intake is the same as for younger adults, '0.75'-grams of protein/kg/day. Daily protein intake in the UK has tended to increase, to a figure of 84 g for men and 64 for women. There have been concerns that excessive intake of protein may be associated with health risks.
Dietary allowances have been defined as operational or factorial. Operational allowance defines the amount of each amino acid that has to be eaten to keep body functions within normal or identified limits, "e.g" maintenance of weight, amino acid concentrations, and excretion of nitrogen in the urine. These are practical day-to-day nutritional issues. In human nutrition, the outcome may be described, rather than defined, as normal, optimal, maximal, and engendering well-being.
You must be logged in to post a comment.