Taking baseline data on the first day of a Washington State University study, researchers found that four of six young, healthy moderate smokers -- men and women who smoked less than a pack a day -- had unacceptably low blood levels of Vitamin B-6, a vitamin believed to be protective against the DNA damage that can lead to cancers. Only one of the otherwise comparable non-smokers had unacceptable Vitamin B-6 status. After three months of consuming increasingly high levels of dietary and/or supplemental Vitamin B-6, the smokers eventually reached acceptable levels. But they never caught up with their non-smoking counterparts. Considering Vitamin B-6's role in DNA synthesis and repair, these results further convinced the researchers that the current RDA for this critical vitamin is too low for even moderate smokers and could be too low for the population as a whole.
Dr. Terry Shultz presented the study at the Experimental Biology 2003 meeting in San Diego, as part of the American Society for Nutritional Sciences program.
In several large population studies, people with a higher intake of Vitamin B-6 were found to have a lower risk of colon, prostate, lung, gastric and pancreatic cancers. The good news from this study, says Dr. Shultz, is that adding Vitamin B-6 to the diet rapidly improved both smokers' and non-smokers' Vitamin B-6 status and, equally rapidly, decreased the number of DNA strand breaks in both groups.
That makes sense biochemically, he says. The body uses Vitamin B-6 to convert the vitamin folate to a form that can produce thymine, a component of DNA. If the body doesn't have enough Vitamin B-6, it doesn't make enough thymine and it tries to make do by substituting uracil. Uracil is not a normal component of DNA, and the normal DNA repair mechanisms of the cell become stressed. This inefficiency in the normal repair mechanisms leads to breaks in DNA strands and instability of chromosomes -- possible first steps in thPage: 1 2 3 Related biology news :1
Contact: Sarah Goodwin
Federation of American Societies for Experimental Biology
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