December 14, 2015

349 Three Vitamin D Studies [14 Dec 2015]

The Vitamin D Council recently reported on three important studies on Vitamin D published in 2015.

Alzheimer’s: An 8 year study of 382 elderly participants was published in JAMA in September. It found that low D levels in older adults was associated with accelerated declines in cognitive ability of up to three times faster.

Autism: A meta-analysis of 11 studies from the Netherlands was published in October in Eur. Child Adolesc. Psychiatry. The researchers reported that 8 of the 11 studies found lower D levels in children with Autism Spectrum Disorder (ADS) than other children. The report reviewed the many ways that vitamin D is involved in brain development and function, and showed that low D levels causes brain malfunctions similar to those occurring with autism. The researchers concluded that lower vitamin D levels might be a risk factor for ASD.

A case study of a 32 month old boy with ASD and vitamin D deficiency published in January 2015 in Pediatrics reported that his “core symptoms of autism improved significantly after vitamin D supplementation”. So it appears that vitamin D may also play an important role in the treatment of ASD.

Breast cancer survival
: A four-year study looked at women diagnosed with breast cancer and found that higher D levels significantly increased their survival time. A previous study from 2011 by the same researcher found that vitamin D levels of 125 nmol/L (50 ng/ml in the USA), which required supplementation of 4,000 IU per day to achieve, nearly doubled survival times. An earlier study by Lappe et al, 2007, in Am J Clin Nutr found a 77% reduction in risk of all cancers for the group taking 1100 IU D3 and 1500 mg calcium.

While the best way to increase our vitamin D is from safe sun exposure, that doesn’t work in Canada from September to April leaving supplementation as our only option. Dr. Cannell of the Vitamin D Council recommends supplementing with 5,000 IU daily (which is what I take) to maintain natural levels of 100-125 nmol/L. Even this is considered conservative by some. Dr. Joseph Mercola, who has studied vitamin D extensively, considers anything below 125 to be deficient and recommends 125-175 for optimum health and up to 250 for fighting cancer or heart disease. To achieve these levels, however, requires much higher supplementation – due to the law of diminishing returns – so is impractical for most of us. Winter supplementation of vitamin D of 4,000-5,000 IU seems optimal.

For more information on this or other natural health topics, stop in and talk to Stan; for medical advice consult your licensed health practitioner.


  1. For serum D levels in the USA divide nmol/L by 2.5 to get ng/ml. Mercola’s recommended levels in ng/ml are: deficiency < 50; optimum 50-70; treatment 70-100; excess > 100.

  2. See the first video in Mercola’s post (link in last paragraph) for interview with Prof. Garland debunking the recent studies which found vitamin D worthless for cancer and possibly dangerous.