Vitamin research with

The first commercial synthesis of a vitamin occurred ia 1933 when the Reichsteia approach was employed to manufacture vitamin C (6). AH 13 vitamins ate available ia commercial quantities, and their biological functions have largely been estabUshed (7). A Hst of Nobel prize winners associated with vitamin research is given ia Table 2. 

Prevention of vascular disease is one of the goals of a study in progress in Sweden, in which newly diagnosed diabetic children have been randomized in a doubleblind study where one group receives placebo and the other a preparation containing ascorbic acid, )3-carotene, nicotinamide, selenium and vitamin E (Ludvigsson, 1992). Future research with antioxidants may attempt to prevent the onset of pancreatic beta-cell destruction in the prediabetic phase of susceptible individuals. 

Earlier, I mentioned that Casimir Funk had raised the issue of priority in the discovery of the vitamins. Hopkins did not enter into the debate at the time but he did devote a significant part of his Nobel Address to Funk and his contributions to the vitamin hypothesis. With respect to the other principals involved in the early episodes of vitamin research, it is appropriate to see what Hopkins said about them in Stockholm on that December day in 1929- His comments afford one more illustration of both the clarity and confusion that dominated his 1912 paper. 

E. P. Ralli, "Recent Advances in Nutrition Research with Emphasis on the Newer B Vitamins," Nutrition Symposium Series, The National Vitamin Foundation, Inc., New York, N.Y., 1952, Vol. 5, pp. 78103. 

Wick, A. E. Felix, D. Steen, K. Eschenmoser, A. Helv. Chim. Acta 1964, 47, 2425. Albert Eschenmoser (Switzerland, 1925-) is best known for his work on, among many others, the monumental total synthesis of Vitamin B12 with R. B. Woodward in 1973. He now holds appointments at ETH Zurich and Scripps Research Institute, La Jolla. Felix, D. Gschwend-Steen, K. Wick, A. E. Eschenmoser, A. Helv. Chim. Acta 1969, 52, 1030. 

In 1920, Coward entered University College, London (UCL), to study biochemistry. Awarded a Beit Fellowship, she undertook research on vitamin A with Jack Drummond,50 a total of 22 publications being authored or co-authored from her work. She was elected Fellow of the Chemical Society in 1923, one of her nominators being Katherine Burke (see Chap. 3). Receiving her D.Sc. in biochemistry in 1924, she travelled to the United States on a Rockefeller Travelling Scholarship to continue her studies on vitamin A at the Department of Agricultural Chemistry of the University of Wisconsin at Madison. 

Folic acid is one of the B vitamins. Research has established that consuming about 800 micrograms by way of foods and supplements, along with vitamins B6 and B12, reduces levels of the amino acid homocysteine, another risk factor for heart disease. Now recent... 

Nutrition. Fats and oils are recognized as important nutrients for both humans and animals because they provide a concentrated source of energy, contain essential fatty acids, and serve as carriers for fat-soluble vitamins. Research studies have also indicated a relationship between saturated fats, cholesterol, and trans-isomers and the incidence of coronary heart disease. In many cases, shortening functionality can be maintained with formulations limiting cholesterol, the identified saturated fatty acids, and tran -isomers. Shortening formulation can also aid in reductions of fat consumption by development of more effective products to reduce the levels required to produce the desired functionality and finished product quality. 

The unique interactions of vitamin D with the VDRs have been a focus of research and have led to the development of vitamin D analogs, which vary in their affinity for this receptor and thus may result in less hypercalcemia, while retaining the positive physiologic actions on bone and parathyroid tissue. Paricalcitol and doxercal-ciferol are D2 compounds which effectively lower PTH in dialysis patients. Paricalcitol differs from calcitriol by the absence of the exocyclic carbon 19 and the fact that it is a vitamin D2 derivative. Currently this analog is available only for IV administration however, an oral formulation is in development. Doxercalciferol, in contrast to calcitriol and paricalcitol, is a prohormone that needs to be hydrox-ylated in the liver to its active 1,25-dihydroxyvitamin D2 product. Doxercalciferol is available for both IV and oral administration. 

Recent research has shown that the interaction of vitamin E with membranes enhances its effectiveness as an antioxidant. Another function of antioxidants such as vitamin E is to react with, and thus to remove, the very reactive and highly dangerous substances known as free radicals. A free radical has at least one unpaired electron, which accounts for its high degree of reactivity. Free radicals may play a part in the development of cancer and in the aging process. 

Vitamins are essential lead compounds for the development of novel radiopharmaceuticals. Many vitamin receptors such as the folate receptor are overexpressed on different tumor cell lines (Parker et al. 2005). Biotin labeled with Tc is under investigation since many years in different settings. A vitamin that has not found as much interest as hiotin is vitamin B12. Since it is a relatively large molecule, it has heen proposed to use B12 as a Trojan horse since rapidly proliferating cells and some bacterial stems show a high demand for this growth essential vitamin. While research toward labeled folate and B12 has intensified over the past couple of years, research with biotin rather slowed down. The biochemical pathways of folate and B12 are interlinked since folate delivers the -CH3 group to the apoenzyme in order to activate it toward its function in the methionine synthase cycle. 

The largest prospective dietary intake study to date is the Nurses Health Study (NHS), examining the relationship of vitamins to CVD (Manson et ai, 1992a,b, 1993 Stampfer et al., 1993). Researchers with the NHS have followed a cohort of 121,000 female nurses ages 30-55 at the beginning of the study since 1976. Biennial questionnaires elicited information about a wide variety of demographic, behavioral, and medical risk factors for CVD. In 1980 and 1984 semiquantitative food frequency questionnaires also asked for data on food intake pattern and supplemental vitamin use. 

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