Vitamin D

Vitamin D is a fat-soluble steroid hormone responsible for the intestinal absorption of calcium, iron, magnesium, phosphate and zinc. In humans, dietary Vitamin D is negligible; most comes from exposure of skin to sunlight or from supplementation. Vitamin D is fat-soluble, regulates calcium levels and is vital to good bone health.

Vitamin D2
Vitamin D2 (ergocalciferol) is a vitamin D found in plants, mushrooms, and yeasts, and sometimes in foods fortified with vitamin D.

Vitamin D3
Vitamin D3 (cholecalciferol) is synthesized in the human skin from the UVB radiation in sunlight. D3 can also be obtained from supplements.

Immune function
Vitamin D improves regulatory T cell function in healthy adults and in patients with relapsing remitting multiple sclerosis, suggesting that it may play a role in both preventing and ameliorating autoimmune disease.

Infectious disease
Vitamin D deficiency increases the risk of viral infections.

Epstein-Barr virus
An Epstein-Barr virus protein EBNA-3 has an affinity for the Vitamin D receptor and may actually block the activation of VDR-dependent genes by Vitamin D.

Optimal levels
The recommended blood level of Vitamin D varies considerably by government body and health society.

The US Institute of Medicine suggests levels between 20 ng/ml and 50ng/ml.

The Vitamin D Council suggests a level of 50 ng/ml or 125 nmol/l as "ideal."

In the United States, 41.6% have serum levels below 20 ng/ml, the threshold for deficiency or 82.1% of African-Americans and 69.2% of Hispanics.

Toxicity
Vitamin D toxicity as a result of supplementation is rare and requires extremely high doses.

Chronic Fatigue Syndrome
A retrospective study found patients with CFS have lower levels of Vitamin D than the general population. However, it was uncertain whether this is correlated with the amount of time CFS patients spend indoors or with some other factor.

Raising Vitamin D levels has reportedly resulted in remission for some CFS patients.

Recent research has found no toxicity at 10,000 IU per day and levels as high as 15,000 IU/day are probably tolerated. At this dosage it will take 75-90 before symptom improvement is expected to be seen. Some people have seen some symptoms improved within days, but those are likely a small minority.

In 2015, Witham, et al, found that high-dose oral vitamin D3 did not improve markers of vascular health or fatigue in patients with chronic fatigue syndrome. The study consisted of patients with chronic fatigue syndrome according to the Fukuda (1994) and Canadian (2003) criteria who were either given 100,000 units oral vitamin D3 or a matching placebo every 2 months for 6 months.

In 2017, a study by Earl, et al, concluded that low serum concentrations of total 25(OH)D do not appear to be a contributing factor to the level of fatigue of CFS/ME.

Fibromyalgia
A cohort of Saudi women with fibromyalgia was found to be Vitamin D deficient. Vitamin D status was inversely correlated with pain. High dose Vitamin D supplementation resulted in improvement or resolution of symptoms. A second study also found improvement of symptoms with Vitamin D supplementation.

Autoimmune disease
Low Vitamin D is a possible risk factor for asthma, SLE, multiple sclerosis, rheumatoid arthritis, type 1 diabetes, inflammatory bowel disease and autoimmune thyroid disease. Active Crohn's disease was associated with lower Vitamin D levels.

Multiple sclerosis
Among people with early stage MS, those with higher Vitamin D levels had better outcomes five years after follow up.

It is theorized that there may be a link between low Vitamin D, Epstein-Barr virus and MS.

2011 UK and Canadian scientists, comparing DNA changes found against existing databases, identified the mutated gene, CYP27B1, in 35 parents of children with MS and, in every case, the child inherited this gene. Researchers say this adds weight to suggestions of a link between vitamin D deficiency and MS. When people inherit two copies of this gene they develop a genetic form of rickets - a disease caused by vitamin D deficiency which is the major cause of infantile rickets. Just one copy of the mutated CYP27B1 gene affects a key enzyme which leads people with this gene to have lower levels of vitamin D.There are high levels of both vitamin D deficiency and MS among Scotland's 10,500 MS sufferers, the highest incidence of MS anywhere in the world. This is copied and pasted - find original paper and edit --JenB (talk) 23:54, 28 March 2016 (PDT)

Notable studies relating to ME/CFS

 * 2014, Association between vitamin D status and markers of vascular health in patients with chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME)
 * 2015, Effect of intermittent vitamin D3 on vascular function and symptoms in chronic fatigue syndrome – A randomised controlled trial
 * 2017, Vitamin D status in chronic fatigue syndrome/myalgic encephalomyelitis: a cohort study from the North-West of England (Full Text)
 * 2018, Exogenous VD3 alleviates chronic fatigue syndrome by activating MEKs/ERKs-SIRT1 signaling pathway in skeletal muscle (Abstract)

Learn more

 * Linus Pauling Institute Micronutrient Information Center - Vitamin D
 * Vitamin D and the Microbiome