People with colorectal cancer (CRC) lived longer when vitamin D levels were higher and those with higher levels of quercetin or vitamin B6 were less likely to have CRC, according to three new studies.
Doctors in a vitamin D study said that earlier findings showed people with low vitamin D levels were more likely to have CRC and wanted to see if vitamin D levels could predict survival after diagnosis. Researchers estimated vitamin D levels—from sun exposure, diet, supplements, skin type and body mass index—in more than 1,000 people at the time they were diagnosed with CRC. After over 18 years of follow-up, those with higher vitamin D scores were half as likely to die from the disease as were those with lower vitamin D scores.
Doctors in a CRC study believe that flavonoids—the antioxidants in plants, fruits, vegetables and tea—reduce the chances of CRC. Researchers explained that CRC rates are high in England and set out to measure flavonoids in the English diet. Englishmen and women get most of their flavonoids from drinking tea, so scientists measured non-tea flavonoids in the diets of 264 people with CRC plus 408 healthy participants. Those whose diets had the highest levels of the flavonoid quercetin from non-tea sources were 40 percent less likely to have CRC than those with the lowest quercetin levels.
In a vitamin B study, scientists measured blood levels of B vitamins in over 200 people with CRC and also in more than 400 healthy people of similar age, sex and ethnicity. As blood levels of the active form of vitamin B6 fell, chances of CRC rose. Those with the lowest levels of vitamin B6 were 51 percent more likely to have CRC than were those with the highest vitamin B6 levels.