Human body nutritional needs

The human body contains only about 1.5 mg of cobalt, almost all of it is in the form of cobalamin, vitamin B12. Ruminant animals, such as cattle and sheep, have a relatively high nutritional need for cobalt and in regions with a low soil cobalt content, such as Australia, cobalt deficiency in these animals is a serious problem. This need for cobalt largely reflects the high requirement of the microorganisms of the rumen (paunch) for vitamin B12. All bacteria require vitamin B12 but not all are able to synthesize it. For example, E. coli lacks one enzyme in the biosynthetic... 

Understanding the total nutritional needs of the human body requires a more detailed consideration of the chemical composition of different nutrients. As we have seen in Chapter 22, the body cannot synthesize many of the amino acids needed to build proteins. For this reason, the body requires proteins that contain the essential amino acids in sufficient quantities. Too little animal protein will lead to nutritional deficiencies because plant proteins do not contain an adequate supply of all the amino acids that active humans must receive from their diets. 

Every human body requires certain amounts of various macro- and micronutrients, water, and fiber to function properly, objective 1 (Section 12.1), Exercise 12.2. The amounts needed vary with a number of factors such as body size, age, and sex. Various countries have established nutritional guidelines in attempts to maintain good health for their citizens. In the United States, the Reference Daily Intake (RDI) and Daily Reference Values (DRV) are designed to represent appropriate nutrient intake for 95% of the population. 

Molybdenum is considered an ultra-trace element with an approximate amount of 5 mg in the adult human body. It is a cofactor for at least three enzymes in humans (sulfite oxidase, xanthine oxidase, and aldehyde oxidase) and is involved in the catabolism of sulfur-containing amino acids, purine, and pyrimidine. A better understanding of human molybdenum metabolism is needed in order to give evidence-based recommendations regarding optimal nutrition, although molybdenum deficiency and associated pathological symptoms have not yet been observed in humans [74]. 

Derived plant and animal products make better use or upgrade the nutritional quaHty of already existing materials or products. Synthetic and manufactured products arose from knowledge of the functional properties of food ingredients and of human and animal nutrition that involved more precise definition of nutrient requirements for growth, reproduction, lactation, and body maintenance in both humans and domestic Hvestock. Pood products have been developed to meet human needs under abnormal environments, eg, military rations for arctic, tropical, or desert environments, and special products for astronauts ia space flights. 

Nutritional Value of Milk Products. Milk is considered one of the principal sources of nutrition for humans. Some people are intolerant to one or more components of milk so must avoid the product or consume a treated product. One example is intolerance to lactose in milk. Fluid milk is available in which the lactose has been treated to make it more digestible. The consumption of milk fat, either in fluid milk or in products derived from milk, has decreased markedly in the 1990s. Whole milk sales decreased 12% between 1985 and 1988, whereas the sales of low fat milk increased 165%, and skimmed milk sales increased 48% (35). Nutritionists have recommended that fat consumed provide no more than 30 calories, and that consumption of calories be reduced. Generally, a daily diet of 2000—3000 cal/d is needed depending on many variables, such as gender, type of work, age, body responses, exercise, etc. Further, there is concern about cholesterol [57-88-5] and density of fat consumed. Complete information on the nutritive value of milk and milk products is provided on product labels (36) (see also Table 4). 

Estimation of the vitamm Be requirements of infants presents a problem, and there is a clear need for further research. Human mUk, which must be assumed to be adequate for infant nutrition, provides only 2.5 to 3.5 //g of vitamin Be per g of protein-lower than the requirement for adults. Although their requirement for catabolism of amino acids may be lower than in adults (because they have net new protein synthesis), they must also increase their body content of the vitamin as they grow. Coburn (1994) noted that the requirement for growth in a number of animal species was less than that to maintain saturation of transaminases or rniriimum excretion of tryptophan metabolites after a test dose and was about 15 nmol per g of body weight gain across a range of species. 

These are synthetic versions of compounds the body makes to stimulate the growth of cartilage. The theory is that these compounds rebuild cartilage and reduce the symptoms of arthritis. It is an acceptable treatment in veterinary medicine, but the Arthritis Foundation and the American College of Rheumatology have not recommended it for humans. The Food and Drug Administration has not approved it to treat arthritis. At this time, they are sold as nutritional supplements, and therefore do not need evidence that they are safe and effective. 

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