Vitamin D May Protect Nervous System & Brain

In July, two unrelated studies found that vitamin D levels may play a role in two major health problems that affect millions of people around the world: Parkinson's Disease and cognitive decline. While both of these health problems primarily affect older people, they can affect young people as well.

Finnish researchers have published findings from a new study that has found that high blood levels of vitamin D may reduce the risk of Parkinson's disease.¹ Parkinson's Disease is a degenerative disorder of the central nervous system that may lead to loss of motor function, including limb control, and the abilities to walk and speak.

The researchers from the National Institute for Health and Welfare in Helsinki analyzed data collected on 3,173 Finnish men and women between the ages of 50 and 79 who were followed for up to 29 years. Over the course of the study, 50 participants developed Parkinson's disease. Analyzing the chemistry of blood samples that had been taken in 1979 (and subsequently frozen and stored) allowed researchers to compare baseline blood samples to more recent samples and the likelihood of developing Parkinson's Disease.

The researchers found that individuals with serum (blood level) vitamin D above 50 nanomol per liter (nmol/L) had a 65% lower risk of developing Parkinson’s Disease than those participants who had serum Vitamin D levels below 25 nmol/L. Researchers adjusted for confounding factors such as sex, education, smoking and body mass index.

This is not the first such study on Vitamin D and Parkinson's. In fact there is a sizable body of evidence suggesting the vitamin D may play an important role in Parkinson's prevention. However, at this time the exact role and mechanism of action are not known.

An unrelated study published within days of the Parkinson's study, found that having low serum Vitamin D may increase the risk of cognitive decline.² Cognitive decline is the age-related decline of a person's mental capacity that often leads to dementia and Alzheimer's Disease.

In this study, British researchers analyzed data from 858 adults that had participated in the InCHIANTI population-based study conducted in Italy between 1998 and 2006. All the participants where 65 years of age or older at the onset of the study and completed follow-up assessments every 3 years. Mental acuity was determined using standard mental exams: the Mini-Mental State Examination and the Trail-Making Tests A and B.

These researchers found that participants who where severely vitamin D deficient (defined as those with vitamin D level below 25 nmol/L) were 60% more likely to develop cognitive decline than those with vitamin D level above 25 nmol/L.

Recently, a number of studies have found that a large segment of the population is vitamin D deficient. Currently, optimal serum vitamin D level is defined as 20 to 60 nmol/L, with many studies suggesting the greatest benefit may be in the 40 to 60 nmol/L range. However, it is important to note that as with all fat-soluble vitamins, it is possible to get too much vitamin D. Levels greater than 90 nmol/L are considered toxic. Therefore, many experts now recommend having your vitamin D levels tested whenever you have your cholesterol checked. Talk to you doctor about having your vitamin D level tested and whether you should take a vitamin D supplement.

Vitamin D comes in several forms. The two forms of vitamin D that come from diet and supplements are cholecalciferol (vitamin D3) and ergocalciferol (vitamin D2). They are both converted within the body into 25-hydroxyvitamin D, the "storage form" of vitamin D, and 1,25-hydroxyvitamin D, the "active form."

Cholecalciferol (vitamin D3) is considered to have greater bioavailability. This is the same form produced in the skin when exposed to ultraviolet light.

Whole Health only sells the vitamin D3 form. Learn more about vitamin D here.

1. Evatt, M. L. (2010). "Beyond vitamin status: is there a role for vitamin d in Parkinson disease?" Arch Neurol 67(7): 795-7.

2. Llewellyn, D. J., I. A. Lang, et al. (2010). "Vitamin D and risk of cognitive decline in elderly persons." Arch Intern Med 170(13): 1135-41.