A recent paper published in the American Journal of Clinical Nutrition says that an adequate supply of vitamin D is vital for the health of 36 organs, including the bone marrow, colon, kidney, lung, prostate, retina, and skin.

Vitamin D & Immune Function/Overall Health

Study author Anthony Norman, professor emeritus of biochemistry and of biomedical sciences at the University of California at Riverside, says that studies have shown that vitamin D plays an important role in the adaptive and innate immune systems, the secretion and regulation of insulin by the pancreas, heart and blood pressure regulation, muscle strength, and brain activity, as well as being vital for bone health. The vitamin is also thought to reduce the risk of cancer.

"It is becoming increasingly clear to researchers in the field that vitamin D is strongly linked to several diseases," said Norman, in a news release issued by the University of California at Riverside. He recommends that “the nutritional guidelines for vitamin D intake must be carefully reevaluated to determine the adequate intake, balancing sunlight exposure with dietary intake, to achieve good health.”

The current recommended daily intake (RDI) of vitamin D for adults is 200 IU for people aged 18-50, 400IU for those aged 51 to 70, and 600 IU for those aged 70 and over. Norman believes that the RDI should be raised to 2,000 IU for all adults. Just this week, the American Academy of Pediatrics doubled the RDI for children from 200 IU to 400 IU.

Vitamin D & Parkinson's Disease

Researchers from Emory University have found that vitamin D deficiency is far more common in people with Parkinson’s disease than it is in healthy people.

Study results revealed that 55% of participants with Parkinson’s disease had insufficient levels of vitamin D, compared to 36% of healthy age-matched controls. Whilst 23% of Parkinson’s sufferers had vitamin D levels low enough to be classed as deficient, compared to just 10% of controls.

The researchers are uncertain as to whether the vitamin deficiency is a cause or a result of Parkinson’s disease, however they note that previous research has suggested that an inadequate amount of vitamin D may have a detrimental effect upon areas of the brain that are affected by the disease. Indeed, neurons in the substantia nigra, the part of the brain mainly affected by Parkinson’s, have a large number of vitamin D receptors, thus suggesting that the vitamin is somehow important for the normal functioning of the cells.

The researchers are currently conducting a pilot study where Parkinson’s disease patients are being treated with vitamin D to determine whether it is able to reduce the symptoms of the disease.

Sources
Norman AW. From vitamin D to hormone D: fundamentals of the vitamin D endocrine system essential for good health. American Journal of Clinical Nutrition. 2008;88:491s-499s.

Evatt ML, DeLong MR, Khazai N, Rosen A, Triche S, Tangpricha V. Prevalence of Vitamin D Insufficiency in Patients With Parkinson Disease and Alzheimer Disease. Arch Neurol. 2008;65:1348-1352.