Two new studies shed light on how vitamin D and vitamin B6 may or may not affect cancer risk. The first study debunks the long-held belief that vitamin D can help stave off cancer. The second indicates that vitamin B6 may help reduce the risk of lung cancer.
For the study that involves vitamin D, researchers at the Prevention and Research Center at Mercy Medical Center looked at whether or not increased levels of vitamin D affected cancer diagnosis rates of seven different cancers. These cancers included non-Hodgkin lymphoma, endometrium, esophageal, stomach, kidney, ovarian and pancreatic cancer.
Over a course of three decades, the research team followed 12,000 men and women. By taking vitamin D levels at the beginning of the study, the team was able to compare differences in participants who were eventually diagnosed with cancer and those who were not.
According to the study’s co-investigator, Dr. Demetrius Albanes of the National Cancer Institute, “We did not see lower cancer risk in persons with high vitamin D blood concentrations compared to normal concentrations for any of these cancers.” Similarly, “at the other end of the vitamin D spectrum, we did not see higher cancer risk for participants with low levels.”
Even more confusing, researchers determined that high levels of vitamin D might actually increase the risk of pancreatic cancer. Additional studies are needed to clarify this portion of the research.
The National Institutes of Health and National Cancer Institute both assisted in the study.
Things seem more promising for vitamin B6. A study performed at the International Agency for Research on Cancer in Lyon, France found that high blood levels of vitamin B6, as well as an amino acid called methionine, seem to lower the risk of lung cancer. This linkage remains true regardless of whether or not a person smokes cigarettes.
The conclusion is based off of blood samples culled from more than 519,000 participants who enrolled in the study between 1992 and 2000. Over the years, 899 participants were eventually diagnosed with lung cancer. These patients were compared against a group of 1,770 healthy participants, who were matched to the lung cancer group based on country of origin, sex, age and date of blood sample.
After factoring in smoking, the team concluded that individuals with the highest levels of vitamin B had a reduced risk of lung cancer of 56 percent (when compared to those with the lowest levels of vitamin B).
The team also looked at methionine levels, which assist in the process of vitamin B metabolism. Similarly, participants with the highest levels of methionine had a 48 percent reduced risk for lung cancer.
While the linkage between vitamin B6 and lung cancer is still unknown, one theory suggests that deficiencies of the vitamin may accelerate DNA damage and mutation of genes – two factors that can spur growth of cancer cells.
Though the study shows promise, experts are quick to point out that further research is necessary before an endorsement of vitamin B supplements for those at risk for lung cancer can be made. Additionally, experts such as Michael J. Thun, MD, of the American Cancer Society stress that, “These findings should not be interpreted as evidence that smokers can substitute taking vitamin B6 for stopping smoking, nor as encouragement to take very high doses of vitamin B6, since this can have toxic effects on the skin and nervous system.”
For those interested in maintaining good levels of vitamin B6, the recommended dietary allowance for adults under the age of 50 is 1.3 milligrams. Two bananas a day is a good way to meet this allowance. Other good sources of vitamin B6 include beans, poultry and fish.
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