Vitamin D | Fanatic Cook

The VITAL Study began in July, 2010 and should wrap up by October, 2017.

“VITAL is an ongoing research study in 25,875 men and women across the U.S. investigating whether taking daily dietary supplements of vitamin D3 (2000 IU) or omega-3 fatty acids (Omacor® fish oil, 1 gram) reduces the risk for developing cancer, heart disease, and stroke in people who do not have a prior history of these illnesses.”

This is a large, long (five-year), randomized, double-blind, placebo-controlled study. It’s going to be telling. They’ll also be recording negative effects of the supplements. Participants are men aged 50 or older, and women aged 55 or older. So results won’t be generalizable to a younger population, not technically.

One of the lead investigators, Dr. Manson, said:

“Many people had high hopes for vitamin E, vitamin C, beta-carotene, folic acid, selenium and other supplements as preventive tools for many diseases, but large-scale trials didn’t confirm the hoped-for benefits and even found some risks when consumed at higher levels. Let’s not jump on the bandwagon to take mega-doses of these supplements before clinical trials help to clarify their role.”

The Institute of Medicine (IOM) which sets the nation’s RDAs recently (in 2010) upped their recommended daily intake for vitamin D to 600 IUs for people aged 1 to 70, and 800 IUs for 71 and older. It used to be 400-600 IUs for these groups. This assumes little to no sun exposure. They said more research is needed to determine if higher doses are useful or pose health risks, questions this study was designed to answer.

They also may be able to weigh in on the link between omega-3 and prostate cancer, at least what 5 years can tell you. Recall there was a study last year which found that men with high blood levels of omega-3 fatty acids were more likely to develop prostate cancer:

Plasma Phospholipid Fatty Acids and Prostate Cancer Risk in the SELECT Trial, Journal of the National Cancer Institute, July 2013

“Conclusions: This study confirms previous reports of increased prostate cancer risk among men with high blood concentrations of [long-chain omega-3]-PUFA. The consistency of these findings suggests that these fatty acids are involved in prostate tumorigenesis. Recommendations to increase LCω-3PUFA intake should consider its potential risks.”

Something to look forward to.

Here’s the study as filed in ClinicalTrials.gov.

Population studies describe an association between levels of vitamin D and disease … low vitamin D seems to increase risk for heart disease, diabetes, some cancers, and other chronic illnesses. But does it? Supplementation with vitamin D, in intervention studies, does not improve health. What’s going on? Autier et al. in this recent analysis say that low vitamin D may merely be a marker for ill health:

Vitamin D Status And Ill Health: A Systematic Review, The Lancet Diabetes and Endocrinology, Online 6 December 2013

“We did a systematic search of prospective and intervention studies that assessed the effect of 25(OH)D concentrations on non-skeletal health outcomes in individuals aged 18 years or older. We identified 290 prospective cohort studies (279 on disease occurrence or mortality, and 11 on cancer characteristics or survival), and 172 randomised trials of major health outcomes and of physiological parameters related to disease risk or inflammatory status.

Investigators of most prospective studies reported moderate to strong inverse associations between 25(OH)D concentrations and cardiovascular diseases, serum lipid concentrations, inflammation, glucose metabolism disorders, weight gain, infectious diseases, multiple sclerosis, mood disorders, declining cognitive function, impaired physical functioning, and all-cause mortality. High 25(OH)D concentrations were not associated with a lower risk of cancer, except colorectal cancer.

Results from intervention studies did not show an effect of vitamin D supplementation on disease occurrence, including colorectal cancer. In 34 intervention studies including 2805 individuals with mean 25(OH)D concentration lower than 50 nmol/L at baseline supplementation with 50 μg* per day or more did not show better results. Supplementation in elderly people (mainly women) with 20 μg vitamin D per day seemed to slightly reduce all-cause mortality.

The discrepancy between observational and intervention studies suggests that low 25(OH)D is a marker of ill health. Inflammatory processes involved in disease occurrence and clinical course would reduce 25(OH)D, which would explain why low vitamin D status is reported in a wide range of disorders.”

* 50 μg is 50 micrograms or about 2000 IUs

Vitamin D has become a darling in the supplement world. That reputation may not be founded. What’s more likely is that low vitamin D levels, rather than being a cause of poor health, are a consequence.

Lead author of the study, Dr. Autier:¹

“Ageing and inflammatory processes involved in disease occurrence… reduce vitamin D concentrations, which would explain why vitamin D deficiency is reported in a wide range of disorders.”

¹ Doubt Cast On Vitamin D’s Role Against Disease, BBC, 5 December 2013