Vitamin D intake not one-size-fits all, especially for Chicagoans

We have actually found local researchers who see the vitamin D issue the same way we do: vitamin D supplementation should not be one-size-fits-all.

Vitamin D recommendations should vary because risk for vitamin D deficiency varies widely. A study conducted in Chicago looked at 25 hydroxyvitamin D levels in 492 men age 40 to 79 who lived in Chicago, Illinois. They found that 93% of African-American men and 69.7% of European-American men were vitamin D-deficient, with 25(OH)D levels of less than 30 ng/mL. "This study shows that across the board, vitamin D recommendations just won’t work for everybody," according to Adam B. Murphy, MD, MBA, clinical instructor in the Department of Urology at Northwestern University Feinberg School of Medicine, Chicago, said in a statement. He reported on the study at the Fourth American Association for Cancer Research (AACR) Conference on the Science of Cancer Health Disparities (SCHD).

"I think the IOM's [Institute of Medicine's] recent recommendation is a complete farce," exclaimed one researcher, Rick Kittles, PhD, associate professor of medicine and epidemiology and biostatistics at the University of Illinois at Chicago. The IOM recommended raising the recommended dietary allowance from 400 to 600 IU of vitamin D for people aged 1 to 70. But many more criteria need to be taken into account when devising vitamin D recommendations, he said, including skin tone, occupation, geographic location, and weight. Having a blanket recommendation of 600 IU doesn’t make sense, he stated.

Here are several new studies having to do with vitamin D:

ACL Knee Surgery
A Journal of Evidence-Based Complementary & Alternative Medicine study identified that low vitamin D (below 30 ng/ml) appears to hinder strength recovery after anterior cruciate ligament surgery and during inflammatory insult.

Asthma
Children with severe therapy-resistant asthma (STRA) may have poorer lung function and worse symptoms compared to children with moderate asthma, due to lower levels of vitamin D in their blood, according to researchers in American Journal of Respiratory and Critical Care Medicine. Lower levels may cause structural changes in the airway muscles, making breathing more difficult.

Athletics
Vitamin-D deficiency increases risk of muscle injuries in athletes. Researchers looked at 89 football players from a single NFL team and conducted lab tests of vitamin D levels in the spring of 2010. The mean age of the players was 25. The team gave the researchers data to allow them to determine which players had lost time because of muscle injuries. The results showed that 27 players had deficient levels, and 45 more had levels consistent with insufficiency. Only 17 players had levels within normal limits. Sixteen players had suffered a muscle injury—and the mean vitamin-D level of the injured players was 19.9 nh/mL, a deficient value.

Breast Cancer
A recent study in Breast Cancer Research and Treatment has found that taking high doses of vitamin D can help relieve the joint and muscle pain caused by taking aromatase inhibitor drugs for breast cancer. Compared to women taking a placebo, those given the 50,000 IU weekly dose of vitamin D2 experienced less overall pain and discomfort.

Colon Cancer
A lack of vitamin D increases the aggressiveness of colon cancer. Researchers in journal PLOS One have confirmed the pivotal role of vitamin D, specifically its receptor (VDR), in slowing down the action of a key protein in the carcinogenic transformation process of colon cancer cells. Beta-catenin, which is normally found in intestinal epithelial cells where it facilitates their cohesion, builds up in large quantities in other areas of the cells when the tumor transformation begins. As a result of these changes, the protein is retained in the cell nucleus, where it facilitates the carcinogenic process, and this is the point at which vitamin D intervenes.

Lupus
Vitamin D deficiency was significantly more frequent among patients with ANA-positive systemic lupus erythematosus (SLE) compared with those with ANA-negative SLE. Hence, vitamin D deficiency is associated with certain immune abnormalities in SLE, suggesting that vitamin D plays an important role in autoantibody production and SLE pathogenesis. Annals of Rheumatic Diseases, September 2011

Pregnancy
Researchers writing in the Journal of Bone and Mineral Research report that even a high supplementation amount in healthy pregnant women was safe and effective in raising circulating vitamin D to a level thought to be optimal. The study also found no adverse effects of vitamin D supplementation, in women or their newborns. The research team, studied healthy expectant mothers between 12 and 16 weeks into gestation to discover how varying dosages of daily supplements could safely sustain a circulating vitamin D level of at least 32 nanograms per milliliter. One group received 400 IU of vitamin D3 per day, the second group received 2,000 IU per day and the third received 4,000 IU daily. The team found that women who received the highest level of supplementation were more likely to achieve and sustain the desired level of circulating levels of vitamin D throughout their pregnancy. Moreover, the researchers found that pregnant women who received lower levels of vitamin D supplementation did not attain the threshold circulating level of the vitamin.