Flying Lessons
Flying Lessons
The term “flying off the shelves” always struck me as funny. For instance, according to a Canadian newspaper, “Vitamin D pills are apparently flying off the shelves in Montreal.”
Wouldn’t you prefer non-flying supplements?
It seems vitamin D pills are suddenly airborne because of a new study that shows the vitamin is linked to cancer prevention. Of course, that’s a broad simplification of the results. But there’s no doubt that something good is going on here, as long as you’re informed about the different types of vitamin D and how best to supplement with them.
Doubled defense
The new vitamin D study comes from a team at the Osteoporosis Research Center at Creighton University in Omaha, Nebraska. But it isn’t JUST a vitamin D study. In fact, it’s actually more of a calcium study that included vitamin D.
In the June 2007 issue of the American Journal of Clinical Nutrition, the researchers note that observational studies have suggested that supplements of calcium and vitamin D are linked with a reduced risk of some common cancers. Their objective with this study: “to determine the efficacy of calcium alone and calcium plus vitamin D in reducing incident cancer risk of all types.”
STUDY PROFILE Researchers recruited nearly 1,180 healthy post-menopausal women over the age of 55
Subjects were divided into three groups: One group received a supplement of 1,400-1,500 mg of calcium daily, one group received the same calcium supplements in addition to 1,100 IU of vitamin D daily, and one group received placebos
Over the four-year intervention period, cancer rates were about the same in the calcium group compared to the placebo group
Subjects in the calcium-plus-D group had a 60 percent reduced risk of cancer compared to the other two groups
When researchers isolated cancer rates during the last three years of the study, results were even more impressive: Subjects in the calcium-plus-D group had a 77 percent reduced risk of cancer compared to the other groups
The write-ups about this study all highlighted vitamin D as a remarkable cancer preventive. And that’s not surprising. Nutritional researchers are well aware of D’s reputation as an anti-cancer vitamin. But calcium may have boosted the cancer-fighting effect of vitamin D. After all, these two nutrients are known to have complementary effects in promoting bone health. Perhaps they did the same in preventing cancer.
Beyond the sun
The D supplement used in the Creighton University study was vitamin D3, the same form of the vitamin that’s produced in the skin after exposure to sunlight. As most HSI members are aware by now, moderate daily exposure to sunlight is the most effective way to boost blood serum concentrations of vitamin D.
But not everyone lives in Cancun and other spots near the equator where UVB radiation (the component of sunlight that prompts the manufacture of D) remains high all year round. So how large a daily dose should the average person who lives north of the tropics shoot for? As you might suspect, this is a point of disagreement.
An Associated Press article about this study quotes Dr. Michael Holick, who was a member of the panel that set the 1997 guidelines for vitamin D. Those guidelines call for 200 to 600 units per day, depending on age. Based on the new evidence, Dr. Holick told the AP that he now believes the daily recommended dose should be 1,000 IU of vitamin D3. But Dr. Michael Thun of the American Cancer Society told the AP that we should stick with the lower recommended dosage for now. He also noted that in the 1997 guidelines, 2,000 IU per day is considered dangerous.
Okay. Now let’s get real.
When the topic of D3 came up in a previous e-Alert, HSI Panelist Allan Spreen, M.D., stated that he would have no fear of taking 2,000 IU of D3 daily. And in the e-Alert “Sunny Side of the Street” (12/22/03), I told you about this recommendation from Jonathan V. Wright, M.D.: Between 1,600 and 2,000 IUs daily, as as much as 4,000 IUs for those over the age of 40.
Dr. Wright notes that it’s not possible for most people to get enough vitamin D from the sun alone, and he discourages the intake of dairy products because of the health concerns they raise. Instead he suggests other food sources like salmon and sardines, or cod liver oil, which provides more than 1,300 IUs of vitamin D per tablespoon.
