An analysis of research on vitamin D published in the British Medical Journal in
2014 included 107 systemic reviews, 74 meta-analyses, and looked at 137 conditions
or other outcomes. The study concluded that nearly all of the proposed
benefits of vitamin D supplementation remain uncertain, primarily because of a lack
of large, well-designed clinical trials. A 2016 review article considered, “Should
adults take vitamin D supplements to prevent disease?” It concluded that based on
randomized controlled trials, there is no consistent evidence that vitamin D supplementation
improves bone density, nor any consistent effects on falls, total fracture,
or hip fracture risk other than in severely vitamin D deficient frail, elderly women
in residential care, but not in seven trials of community-dwelling older people. The
article’s summary statement is that low dose vitamin D supplements (400-800 IU/
day) can be considered on an individual basis. Otherwise, current evidence does not
support the use of vitamin D supplementation to prevent disease.

Excellent data is coming from VITAL, a long-awaited well-designed NIH sponsored
placebo-controlled clinical trial that is testing supplemental vitamin D and omega-3
for their effects on a wide array of diseases. Its first results were published in
the New England Journal of Medicine in November 2018. After an average of 5.3
years, study subjects taking a high dose of vitamin D (2,000 IU) were compared to
those taking a placebo. Vitamin D did not bring about a reduced overall incidence
of major cardiovascular events (a composite of heart attacks, strokes, and cardiovascular
deaths) or invasive cancer. VITAL included baseline blood levels of vitamin
D and found that most participants (12 out of 13) enrolled in the study started
with adequate D levels—20 ng/mL or higher. And people with initially low levels
did not benefit from supplementation with regard to CVDs or cancer.

In a secondary analysis of subgroups, (considered less reliable and harder to interpret),
normal-weight and Black subjects, (but not overweight and obese study
subjects) given extra vitamin D had about a 25% lower rate of total cancer deaths
compared to the placebo—but only starting after the first two years among those of
normal weight. The VITAL researchers noted that the subgroup findings could be
due to just to chance, considering that the findings of the primary outcome measures
showed no benefit.

This blog presents opinions and ideas and is intended to provide helpful general information. I am not engaged in rendering advice or services to the individual reader. The ideas, procedures and suggestions in that are presented are not in any way a substitute for the advice and care of the reader’s own physician or other medical professional based on the reader’s own individual conditions, symptoms or concerns. If the reader needs personal medical, health, dietary, exercise or other assistance or advice the reader should consult a physician and/or other qualified health professionals. The author specifically disclaims all responsibility for any injury, damage or loss that the reader may incur as a direct or indirect consequence of following any directions or suggestions given in this blog or participating in any programs described in this blog or in the book, The Building Blocks of Health––How to Optimize Your Health with a Lifestyle Checklist (available in print or downloaded at Amazon, Apple, Barnes and Noble and elsewhere). Copyright 2021 by J. Joseph Speidel