Research on vitamin D3 continues to pour in. The best sites on the net for information on vitamin D3 are Vitamin D Council, Grassroots Health, Vitamin D Society, and Vitamin D Wiki. The role, or impact, of vitamin D3 status on health, both in terms of prevention and treatment, is yet to be seen but as more and more good quality research is done using physiological doses of vitamin D3 [hint, not 1000-2000 IUs but in the neighbourhood of 4000-8000 IUs per day], we’ll have a better sense of just what vitamin D3 can do.
Some of the top vitamin D research of 2014
According to the top vitamin D researchers, some of the best studies on vitamin D in 2014 are:
Randomized Control Trials
In this study researchers gave patients with COPD large doses of vitamin D3, 120,000 IU every two months for one year to see if vitamin D could protect against moderate or severe exacerbation in those with low blood levels of vitamin D, defined as < 50 nmol/L [but did not look at the impact on those with vitamin D > 50 nmol/L]. The vitamin D3 supplements did not reduce the number of respiratory infections. This is consistent with other studies that gave large single doses with large intervals between dose. 120,000 IU every 2 months is only 2000 IU/day on average. This contradicts other studies that found a benefit when vitamin D3 is given daily; dosing that mimics the natural production of vitamin D from the sun versus how vitamin D3 was used in this study: supra-physiological doses with prolonged delays between doses.
Note, studies that give large doses [120,000, 300,000 or even 500,000 IU] with long time intervals have never produced the same benefits as those studies that give consistent, smaller, physiological doses. A better study would be to give patients a daily dose of 4000 – 6000 IU per day and then track infections [my emphasis].
Healthy volunteers where given 4000 IU of vitamin D3 per day to see if it could promote vascular regeneration, a.k.a. repair of blood vessels. In a nut shell, in both healthy volunteers and animal models, vitamin D3 increased vascular repair mediators and tissue repair while lowering inflammation too. This may have application for damaged blood vessels from disease, poor lifestyle and natural ‘wear and tear’ [my emphasis].
This study looked at the averages of several vitamin D3 studies that were well-designed (without methodological flaws) and found that supplementing vitamin D3 resulted in statistically significant improvement in clinical depression [meaning, clinically relevant and something that can be used while other supportive measures are used, and while more research is done on this topic] . Supplementing with > 800 IU of vitamin D per day was favourable in the management of depression.
It’s important to note that 800 IU is painfully low considering that the human body can produce between 6000 to 20,ooo IU daily under ideal conditions [this amount depends on complexion, time of year and day, use of sunscreens etc].
Several other studies using higher amounts of supplemental vitamin D3, > 3000 IU per day have found improvements in depression [my emphasis].
Clostridium difficle [C. diff] is life-threatening infection of the gastrointestinal tract and the incidence, recurrence and deaths resulting from this infection has been increasing over the past 10 years despite treatment [antibiotics]. Vitamin D3 is thought to play a role given vitamin D3’s role in supporting the immune system; low levels of vitamin D3 in the blood are known to impair the immune system’s response to infection. This study patients with C diff received standard antibiotic treatment and C diff-associated diarrhea was assessed at the 30-day follow up point; after controlling for other variables. Two variables were found to predict whether or not the diarrhea had resolved: age and vitamin D levels. Those with low levels of vitamin D, < 53 nmol/L were 4.75 times more likely to fail to resolve their diarrhea than those subjects with vitamin D > 75 nmol/L.
Grassroots Health is a non-profit group that initiated a voluntary reporting project called D*action. To date, there are over 7,000 participants in the study group, of which 2,012 have reported their data for a median of 19 months. In this group, there has been no evidence of an association of blood levels of vitamin D and kidney stones. This study found that a high body mass index is a significant risk factor; the more overweight and/or obese a person is, the greater the likelihood of developing kidney stones.. This study counters the Women’s Health Initiative study that reported an elevated risk of kidney stones for women taking as little as 400 IU/d vitamin D3 and 1500 mg/d calcium.
The average daily intake of vitamin D3 in the Grassroots Health group is 4000 IU per day; it makes sense that this amount shouldn’t lead to kidney stone formation since the body is designed to easily make between 6000 to 20,000 IU if needed under ideal conditions [my emphasis].
A study in Ireland and Scotland involving 1,598 patients with stage I to III colorectal cancer, found that 25(OH)D concentrations (measured approximately 15 weeks after diagnosis of colorectal cancer) were associated with survival rates. Those in the highest third of 25(OH)D concentrations with a median concentration of 51 nmol/L (20 ng/mL) compared to the lowest third with a median concentration of 10 nmol/L (4 ng/mL) had a 32% lower risk of cancer-specific mortality rate and a 30% lower risk of all-cause mortality rate over a ten-year follow-up period. This study provides support for the idea that people diagnosed with cancer should raise their 25(OH)D concentration to above a minimum of 50 nmol/L (20 ng/mL),
In this second paper on dementia and Alzheimer disease, a study in the United States involving 1,658 participants followed for 5.6 years found a 125% increased risk of Alzheimer’s disease for those with severely deficient 25(OH)D levels (< 25 nmol/L (10 ng/mL)), and a 53% increased risk for those with deficient levels ( ≥ 25 to < 50 nmol/L) compared to participants with sufficient concentrations ( ≥ 50 nmol/L (20 ng/mL)).