Vitamins requirements, list

Intestinal bacteria contribute considerably toward fulfilling the vitamin requirements listed in Table XIX. This can be considered an example of symbiosis. Man s requirement of vitamin K, for example, is filled almost entirely by the bacteria. Cows which received no thiamine or riboflavin still produced milk with a normal content of vitamins. And on the other hand, high doses of sulfonamides or antibiotics can liquidate the intestinal flora to such an extent that the source of vitamins stops suddenly and serious avitaminoses may develop unless the diet is corrected. 

An example of the use of photodiode array detectors for determining peak homogeneity is in the analysis of /3-carotene,8 where an impurity in the all-trans isomer was positively identified as the cis isomer.9 Since the U.S. Federal Register began to require listing of the presence and concentration of various vitamins on the labels of foods, there has been increased activity in the measurement of these vitamins. /3-Carotene is one such vitamin, and research links the presence of /3-carotene to a reduction in the occurrence of some degenerative deseases such as cardiovascular diseases and cancer. 

A variety of ot janic molecules act as ooenzymes Many, thnugh not all, coenzymes are vitamins, amall organic molecules that must be obtained in the diet and are required in trace amounts for proper growth. Table 26.3 lists the 13 known vitamins required in the human diet and tlieir enzyme functions. 

Beneath the heavy line on every nutrition facts label are mandatory listings for vitamin A, vitamin G, calcium, and iron. Here also, these required listings are for those vitamins and minerals deemed to he of greatest public health concern. The major deficiency diseases of today are anemia, associated with iron deficiency, and osteoporosis, associated with calcium deficiency. The two vitamins in the mandatory list are those that decrease cancer risk. 

Animals exposed to sunlight for extended lengths of time do not require substantial dietary vitamin D. Current livestock management practices place an emphasis on high productivity, and most feed manufacturers recommend vitamin D supplementation of diets. Recommendations for practical levels of vitamin D in feeds for various animals, as recommended by feed manufacturers, are listed in Table 10. 

The antiscurvy (antiscorbutic) activity was called vitamin C, and when its structure became known it was called ascorbic acid. The fat-soluble factor preventing rickets was designated vitamin D. By 1922, it was recognized that another fat-soluble factor, vitamin E, is essential for full-term pregnancy in the rat. In the early 1930s vitamin K and the essential fatty acids were added to the list of fat-soluble vitamins. Study of the human blood disorders "tropical macrocytic anemia" and "pernicious anemia" led to recognition of two more water-soluble vitamins, folic acid and vitamin B12. The latter is required in minute amounts and was not isolated until 1948. Have all the vitamins been discovered Rats can be reared on an almost completely synthetic diet. However, there is the possibility that for good health humans require some as yet undiscovered compounds in our diet. Furthermore, it is quite likely that we receive some essential nutrients that we cannot synthesize from bacteria in our intestinal tracts. An example may be the pyrroloquinoline quinone (PQQ).e... 

Vitamins are divided into water-soluble and lipid-soluble groups. In addition to vitamins, vitaminlike nutrients are required in small amounts by the organism and frequently function in similar capacities to vitamins. These vitaminlike compounds are not classified as vitamins because rats and humans have a limited capacity to synthesize them, provided that the diet contains the essential precursors. Table 10.1 lists both vitamins and vitaminlike nutrients. 

Japaa In Japanese Food Law, synthetic and naturally occurring additives are treated differently. The latter, in particular naturally occurring flavors and vitamins, do not require any special permission for use. The Japanese Ministry of Health and Welfare (MHW) is responsible for the approval of color additives which are outlined in a positive list of approved colors. MHW allows petitions for the addition of a new colorant to the list. Synthetic dyes permitted for food coloring in Japan include food dyes approved in the EU or/and in the USA (Table 5.7). 

Humans and guinea pigs are the only primates unable to synthesize vitamin C. The human requirement of vitamin C is not well defined. Figures ranging from 45 to 75 mg/ day have been listed as daily needs. Continued stress and drug therapy may increase the need for this vitamin. 

To evaluate nutrition requirements, the reader needs a basic understanding of nutrients and the parameters that affect their needs. Nutrients are chemical substances needed to maintain life which are supplied to the body in food or drinks. The nutrients include vitamins, minerals, carbohydrates, fats, proteins, and water. These classifications of nutrients encompass approximately 45 different chemicals that are involved in every function or structure of the body. Wiile some of these functions that are directly influenced by exercise will be discussed in the subsequent chapters, a complete listing of these functions is beyond the scope of this book. For a more thorouc(i review of nutrient functions, the reader is referred to any one of a number of excellent nutrition references (5-6,15-16). 

Equally, demonstrating that a compound has a physiological function as a coenzyme or hormone does not classify that compound as a vitamin. It is necessary to demonstrate that endogenous synthesis of the compound is inadequate to meet physiological requirements in the absence of a dietary source of the compound. Table 1.3 lists compounds that have clearly defined functions, but are not considered vitamins because they are not dietary essentials endogenous synthesis normally meets requirements. However, there is some evidence that premature infants and patients maintained on long-term total parenteral nutrition may be unable to meet their requirements for carnitine (Section 14.1.2), choline (Section 14.2.2), and taurine (Section 14.5.3) unless they are provided in the diet, and these are sometimes regarded as... 

The rigorous criteria oudined here would exclude niacin (Chapter 8) and vitamin D (Chapter 3) from the list of vitamins, because under normal conditions endogenous synthesis does indeed meet requirements. Nevertheless, they are considered to be vitamins, even if only on the grounds that each was discovered as the result of investigations into once common deficiency diseases, pellagra and rickets. 

As noted above, all vitamin B 2 is produced by microbial fermentation. A partial list of microoiganisms that synthesize vitamin B 2 under appropriate conditions follows. Most strains, in their wild state, produce less than 10 mg/L vitamin B 2 although a few approach 40 mg/L. The oiganisms are both aerobes and anaerobes. The carbon requirements in the fermentations are satisfied from sources as wide ranging as hydrocarbons, methanol, and glucose. 

As stated earlier, only classical amino acids are built into polypeptides during amino acid polymerization, Howe er, other amino adds, classical amino acids that have been modified after incorporation into the chain, are found in proteins. >ome of the modified amino acids found in proteins are listed in Table 1.4. Vitamins ate required for the synthesis of some of the modified amino acids. For example, vitamin C is required for conversion of proiine to hydroxyproline. This and other vitamin cofactors are listed in Table T4. 

Intrepreting Scientifc Illustrations Human cells require vitamin C to properly synthesize materials that make up connective tissue such as that found in ligaments. List the functional groups present in the Vitamin C molecule. 

The coagulation proteins that are synthesized in the liver are listed in Table 47-1. These proteins interact to produce a fibrin clot. Inhibitors of the coagulation system, including antithrombin, protein C, and protein S, are also synthesized in the fiver. Some of the coagulation factors (II, VII, IX, and X) require vitamin K for posttranslational carboxylation within the hepatocyte. Protein C and S are also carboxylated by a vitamin K-dependent enzyme. Activated protein C in plasma inhibits coagulation by inactivating factors V and... 

---