Vitamin D Q&A from my Readers:
I did get a few questions about the Vitamin D recommendations after last week’s article.
Q: Is it ok to give kids supplements of Vitamin D?
A: Of course, always check with your child’s doctor before starting supplementation. They know the child’s medical history and lab work to make sure there aren’t any contraindications. In terms of the recommendations for Vitamin D and kids, the review article that I talked about last time (Click here to read Part I) states recommended daily intake and maximum amounts by age. For most children the recommended intake is 600 IU and after the age of 9, the upper limit is 4000 IU.
Q: My brother had a lot of back pain and they found out he was deficient in Vitamin D. He took 50,000 IU of Vitamin D for deficiency, and that after taking it he felt much better. Does this article suggest that maybe he wasn’t deficient?
A: There definitely are people who are deficient in Vitamin D, many who may not be diagnosed. Therefore it’s important to talk with your doctor if you think you might be deficient and have a blood test done. Also, you want to make sure that you understand how they will determine if you are deficient, since there isn’t agreement on what level is recommended. For many people who are deficient, a prescription level of Vitamin D is needed, which is typically found in a once a week, 50,000 IU form. Almost as important is to make sure that you have follow up labs done to determine when your levels have come back to normal.
I also had another reader share a really easy recipe that I will post in my next article, so you can look forward to that!
The Evidence for Vitamin D and Cancer Prevention
I wanted to make sure that I addressed the most current information regarding Vitamin D and cancer prevention as there have been claims that low levels of Vitamin D can increase risk for cancer. There are also some reports that cancer survivors have a higher incidence of deficiency than the average public.
The report that I reviewed in my last post, New Vitamin D and Calcium Recommendations Part I reports that there was not evidence to support the role of Vitamin D and reducing risk of any disease except for bone health. There was also a great review done by the National Cancer Institute in June 2010 regarding Vitamin D and cancer prevention.
Basically, their summary agrees with the Institute of Medicine review that there isn’t enough evidence right now to confirm a link between low vitamin D levels and increased cancer risk. However, they do report that laboratory studies (which are studies not done on humans) have shown that vitamin D promotes
healthy cell growth, decreases cancer cell growth, and stimulates cell death in unhealthy cells. And, of course, they also report that there are other ways by which vitamin D could affect cancer risk that is not fully
understood.
National Cancer Institute Conclusions:
Here are the main conclusions that they reported:
- Vitamin D is essential for the formation, growth, and repair of bones
and for normal calcium absorption and immune function. It is obtained
primarily through exposure of the skin to ultraviolet radiation in
sunlight, but it can also be obtained from some foods and dietary
supplements. - Some studies suggest that
higher intakes of vitamin D from food and/or supplements and higher
levels of vitamin D in the blood are associated with reduced risks of
colorectal cancer; however, the research results overall have been
inconsistent. - Whether vitamin D is associated with
reduced risks of other cancers, including breast, prostate, and
pancreatic cancers, remains unclear. - The National Cancer Institute (NCI) does not recommend for or against
the use of vitamin D supplements to reduce the risk of colorectal or any
other type of cancer.
Another point I thought was interesting is that they report blood levels of Vitamin D vary by race, with the season,
and possibly with gene activity. These variations complicate the
interpretation of studies that measure the concentration of vitamin D at a single point in time.
I think this drives home the point that it is important to actually monitor your vitamin D levels if you are going to be taking high doses as a supplement or for treatment for deficiency. Who knows if your levels might be changing and you would want to decrease the amount you are taking!
If you want to read more on this, check out this fact sheet: http://www.cancer.gov/cancertopics/factsheet/prevention/vitamin-D
The Bottom Line:
Unfortunately, there is not a clear right and wrong here. That often seems to be the case, doesn’t it??! Basically, we need more evidence to be able to judge what levels of vitamin D are adequate, what portion of the population is deficient and how a low or deficient level of vitamin D affects risk for cancer.
Reading through an email discussion about this topic among other oncology dietitians also makes it clear that there isn’t one obvious answer to this issue. There was much discussion among everyone on both sides of the issue of supplementation. And a response posted by the vitamin D council sites many studies showing the benefit of higher doses of vitamin D.
Until we have more consistent data, we’ll just have to make due with the information we have! I guess we should make sure to get in the sun in the middle of the day for vitamin D production. But don’t stay too long to increase risk for skin cancer. Supplement, if you think you need it and make sure to be in touch with your doctor about it. Life is such a juggling act!
– Julie
