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Tuesday, April 18, 2017

Point-Counter point on Vitamin D and cancer

And then there’s budget politics
By Will Collette

Image result for vitamin d rich foodsI closely follow developments in science, especially those that may affect those near and dear to me (including myself). 

So I was surprised to see to two articles released the same day on the same study in Science Daily that discussed the value of using Vitamin D supplements to reduce cancer risk.

The Creighton University article, immediately below, found a 30% lesser risk among patients taking Vitamin D supplements.

However, JAMA – the Journal of the American Medical Association – article on the Creighton University study takes a very different spin, concluding that use of Vitamin D and calcium supplements produced no significant decrease in cancer risk among menopausal women.

So you can read and judge for yourself, I have reprinted both Science Daily articles on this subject. 

There was one point of consensus between the two articles and that is more research is needed.

Whether that research actually happens may depend in large part on how deeply Trump and the Republican-controlled Congress cut the budget for medical research. Just days ago, Trump suggested a 20% cut - $1.2 billion – to the research budget for the National Institutes of Health.

He needs the money for military spending and to build his Border Wall.

Here are the two contending articles:



Vitamin D decreases risk of cancer, new study suggests

Creighton University

Increasing vitamin D levels may lower risk for developing cancer, according to a study conducted by Creighton University with cooperation from the University of California San Diego. The results of the study were released today in the Journal of the American Medical Association

The study, funded by the National Institutes of Health, is a randomized clinical trial of the effects of vitamin D supplementation on all types of cancer combined.

The four-year study included 2,303 healthy postmenopausal women 55 years and older from 31 counties in Nebraska. Participants were randomly assigned to take either 2000 international units (IU) of vitamin D3 and 1500 mg. of calcium or identical placebos daily for 4 years. 

The vitamin D3 dose was about three times the US government's Recommended Dietary Allowance (RDA) of 600 IU for adults through age 70, and 800 IU for those 71 and older.

Women who were given vitamin D3 and calcium supplements had 30% lower risk of cancer. This difference in cancer incidence rates between groups did not quite reach statistical significance. 

However, in further analyses, blood levels of vitamin D, specifically 25-hydroxyvitamin D (25(OH)D), were significantly lower in women who developed cancer during the study than in those who remained healthy.

The average 25(OH)D level in the women's blood at the beginning of the study (33 nanograms/milliliter, ng/mL) was higher than the usual target levels that currently range from 20-32 ng/ml, according to different sources. This suggests that higher vitamin D levels than are currently recommended are needed for substantially decreasing risk of cancer.

"This study suggests that higher levels of 25(OH)D in the blood are associated with lower cancer risk," said principal investigator Joan Lappe, PhD, RN, Creighton University Criss/Beirne Professor of Nursing and Professor of Medicine. 

"The study provides evidence that higher concentrations of 25(OH)D in the blood, in the context of vitamin D3 and calcium supplementation, decrease risk of cancer" she said. These results contribute to a growing body of scientific findings, including results of a similar randomized controlled clinical trial preceding this one in Nebraska women, that indicate that vitamin D is a critical tool in fighting cancer" she said. 

"It is also of value in preventing other diseases, according to previous research," Lappe said.

Other Creighton researchers involved in the study included Robert Recker, M.D., Dianne Travers-Gustafson, Ph.D., R.N., and Patrice Watson, Ph.D. University of California San Diego Professors Cedric F. Garland, Dr.P.H., F.A.C.E. and Edward D. Gorham, Ph.D., were co-investigators. 

Professor Robert P. Heaney of Creighton University, who died August 6, 2016, played a key role in inspiring and planning this study. Heaney was the acknowledged world expert on the physiology of vitamin D and calcium and their relationship to several major diseases.

According to Lappe, most cells in the body need vitamin D to function properly. "Without adequate vitamin D, normally functioning cells can convert to malignant cells." Lappe said.

Cedric Garland, a co-investigator at the University of California San Diego said "This is the most important scientific study of this century to date." The study was open to all ethnic groups, but most of the participants were Caucasian, which Lappe said matched the population in the rural counties in Nebraska. 

Lappe said further studies are needed to determine if these research results apply equally to men and to other ethnic groups.

"While people can make their own vitamin D3 when they are in the sun near mid-day, sunscreen blocks most vitamin D production. Also, due to more time spent indoors, many individuals are lacking adequate levels of vitamin D compounds in their blood," Lappe said. 

"The results of this study lend credence to a call for more attention to the importance of vitamin D in human health and specifically in preventing cancer" Lappe said.

Vitamin D, calcium supplementation among older women does not significantly reduce risk of cancer
The JAMA Network Journals

Among healthy postmenopausal women, supplementation with vitamin D3 and calcium compared with placebo did not result in a significantly lower risk of cancer after four years, according to a study published by JAMA.

About 40 percent of the U.S. population will have a cancer diagnosis at some point during their lives. 

Evidence suggests that low vitamin D status may increase the risk of cancer, and considerable interest exists in the potential role of vitamin D for prevention of cancer. 

Joan Lappe, Ph.D., R.N., of the Creighton University Schools of Nursing and Medicine, Omaha, and colleagues randomly assigned 2,303 healthy postmenopausal women 55 years or older (average age, 65 years) to the treatment group (n=1,156; 2,000 IU/d of vitamin D3 and 1,500 mg/d of calcium) or to the placebo group (n=1,147). Duration of treatment was four years. 

The researchers examined the incidence of all-type cancer (excluding nonmelanoma skin cancers).

A new diagnosis of cancer was confirmed in 109 participants, 45 (3.89 percent) in the vitamin D3 + calcium group and 64 (5.58 percent) in the placebo group (difference, 1.69 percent). 

Incidence over four years was 0.042 in the treatment group and 0.060 in the placebo group. There was no statistically significant difference between the treatment groups in incidence of breast cancer.

Adverse events potentially related to the study included kidney stones (16 participants in the treatment group and 10 in the placebo group) and elevated serum calcium levels (six in the treatment group and two in the placebo group).

The authors write that one explanation for lack of statistically significant differences between the treatment groups in all-type cancer incidence is that the study group had higher baseline vitamin D (serum 25-hydroxyvitamin D) levels compared with the U.S. population.


"Further research is necessary to assess the possible role of vitamin D in cancer prevention."