Vitamin D :: Vitamin D intake halves cancer risk
Vitamin D – known to maintain normal blood levels of calcium and phosphorus – may also help in reducing cancer risk, a new study has found.
According to cancer prevention specialists at the Moores Cancer Center at the University of California, San Diego (UCSD) Medical Center, taking 1,000 international units (IU) of vitamin D3 daily appears to lower an individual’s risk of developing certain cancers, including colon, breast, and ovarian cancer, by up to 50 percent.
While previous studies by these researchers showed the link between vitamin D deficiency and higher rates of colon cancer, the new study associates the same risks to breast and ovarian cancers.
“For example, breast cancer will strike one in eight American women in their lifetime. Early detection using mammography reduces mortality rates by approximately 20 percent. But use of vitamin D might prevent this cancer in the first place,” said co-author Cedric F. Garland.
The researchers said that the high prevalence of vitamin D deficiency, combined with the discovery of increased risks of certain types of cancer in those who are deficient, suggest that vitamin D deficiency may account for several thousand premature deaths from colon, breast, ovarian and other cancers annually.
The study also found that residents of the northeastern United States, and individuals with higher skin pigmentation were at an increased risk of vitamin D deficiency. This is because solar UVB is needed for the human body to make vitamin D. The increased skin pigmentation of African-Americans reduces their ability to synthesize vitamin D.
“Primary prevention of these cancers has largely been neglected, but we now have proof that the incidence of colon, breast, and ovarian cancer can be reduced dramatically by increasing the public’s intake of vitamin D,” said Garland.
Since the safety of daily intake of vitamin D3 in the recommended range has been thoroughly assessed and confirmed by the National Academy of Sciences, and the benefits found so far in observational studies are considerable, expanded use of vitamin D as a public health measure should not be delayed, according to the authors.
They recommend intake of 1,000 IU/day of vitamin D, half the safe upper intake established by the National Academy of Sciences. Garland said that while this study looked at all forms of vitamin D ‘intake through diet or supplements, and photosynthesis through modest sun exposure’ as a practical matter, the majority of people will most easily achieve the target levels by eating foods containing vitamin D and taking supplements, which the authors estimated would cost about five cents per day.
“Many people are deficient in vitamin D. A glass of milk, for example, has only 100 IU. Other foods, such as orange juice, yogurt and cheese, are now beginning to be fortified, but you have to work fairly hard to reach 1,000 IU a day,” said Garland.
“Sun exposure has its own concerns and limitations. We recommend no more than 15 minutes of exposure daily over 40 percent of the body, other than the face, which should be protected from the sun. Dark-skinned people, however, may need more exposure to produce adequate amounts of vitamin D, and some fair-skinned people shouldn’t try to get any vitamin D from the sun. The easiest and most reliable way of getting the appropriate amount is from food and a daily supplement,” he added.