Top Vitamin D Research of 2014

Top Vitamin D Research of 2014

by William B. Grant, PhD

(OMNS Feb 3, 2015) Higher vitamin D blood levels may reduce the risk of many types of disease including autoimmune diseases, cancers, cardiovascular disease, dementia, diabetes mellitus and falls and fractures.

Research into the health effects associated with vitamin D continued to be strong in 2014. The number of publications with vitamin D in the title or abstract listed at pubmed.gov increased from 3,119 in 2011 to 3,919 in 2014. Seven vitamin D researchers (listed after this report) worked together to pick the 20 papers in 2014 that made the most contribution to understanding the health effects of vitamin D in 2014.

Papers are not in priority order, but instead grouped by type of study. For the purpose of this article "vitamin D" in the blood is a measurement of 25-hydroxyvitamin D or 25(OH)D.

Do randomized controlled trials work for vitamin D?

No one refutes the fact that vitamin D is beneficial to the skeletal system. There are many studies (randomized controlled trials [RCT] and also epidemiological) that support this hypothesis. What is at odds is whether or not vitamin D is beneficial to the non-skeletal system. There are many observational (epidemiological, or association) studies that show vitamin D is beneficial, and many RCTs that show it isn't. Does that mean that vitamin D does not aid in disease prevention? Or does it mean that the RCT model does not work for nutrients?

Randomized Control Trials in 2014

Vitamin D3 supplementation in patients with chronic obstructive pulmonary disease [Martineau, 2014]

A vitamin D trial in the UK in which patients with chronic obstructive pulmonary disease (COPD) were given 120,000 IU vitamin D3 every two months for a year found that vitamin D3 supplementation was protective against moderate or severe exacerbation in those with baseline 25(OH)D concentrations < 50 nmol/L (20 ng/mL) but not for those with concentrations > 50 nmol/L. Vitamin D3 supplementation had no effect on upper respiratory infections. This is consistent with previous RCTs that used high doses at infrequent intervals, every 2 months in this case; however other trials that used an adequate dose given daily have shown reduction in upper respiratory tract infections.

Vitamin D promotes vascular regeneration [Wong, 2014]

This study demonstrated that vitamin D improved cardiovascular disease. The German team investigated this effect several ways. They showed that supplementation with 4000 IU/day of vitamin D3 increased the number of circulating angiogenic myeloid cells, which promote growth and vascular regeneration necessary for a healthy cardiovascular system. A similar result was found in a mouse model, which also demonstrated restoration of impaired angiogenesis (new vessel formation) function. They also examined the mechanisms by which vitamin D acted.

Vitamin D and depression: a systematic review and meta-analysis comparing studies with and without biological flaws. [Spedding, 2014]

This paper reported on a statistical average of many studies of vitamin D RCTs without methodological flaws and found that vitamin D supplementation resulted in a statistically significant improvement in clinical depression. However, the same analysis of vitamin D RCTs with methodological flaws found a statistically significant worsening of depression. The major flaws identified included not increasing 25(OH)D concentrations and not measuring baseline or final 25(OH)D concentrations. Vitamin D supplementation of > 800 IU/d was somewhat favorable in the management of depression. Read more