Vitamin D is under intense scrutiny…and for all the right reasons. The 20,500 research papers published in the last 13 years have found vitamin D to be essential in disease prevention and many metabolic processes. Studies report that conditions such as cardiovascular disease, autism, cancer, poor immunity, dementia and pregnancy are improved when adequate levels of vitamin D are present. Research continues at a rapid rate into this handy little vitamin, as it has a myriad of health benefits spread throughout almost every system in the body.
How the body uses vitamin D…
Vitamin D aids development and protection of the nervous system. It up-regulates antioxidant action to prevent neuron death and protects the brain and nerve tissue against conditions such as Alzheimer’s and Parkinson’s disease. An adequate supply of vitamin D is thought to protect against multiple sclerosis, epilepsy and depression.
Vitamin D is also necessary in the regulation of our immune responses. It enhances our innate immune responses to bacteria, viruses and reduces inflammation, while suppressing the adaptive side of our immune system which, when overactive, can result in autoimmune diseases such as Celiac’s and Crohn’s disease.
How much vitamin D do we need?
Strictly speaking, vitamin D is not a vitamin at all, but a hormone. It can be synthesized by the body once the skin is exposed to UV radiation from the sun. However, many people are vitamin D deficient, mainly due to lack of exposure to the sun (particularly during the winter months), so it is also readily available in supplement form. Our requirement for vitamin D changes throughout the lifespan, and children need less than adults. According the National Health and Medical Research Council, from birth to the age of 5, both men and women require 5 micrograms of vitamin D per day, whether it be in supplement form or from direct sunlight. Between the ages of 50-70, the recommendation is increased to 10 micrograms, and increased further to 15 micrograms for anyone over the age of 70. For blood testing, the target range for vitamin D serum levels are between 60-160 nmol/L, with optimum levels thought to be 80 nmol/L. However, these amounts are being revised as more information is being collected on the wide range of processes that involve vitamin D and the higher therapeutic levels thought to be involved.
Research on the uses and effectiveness of vitamin D.
To date, there have been studies supporting the role of vitamin D in 15 types of cancer, and an increase in the survival rate of 7 types of cancer. One paper noted that there was a reduction in the risk of cancer death by up to 66% with adequate vitamin D supplementation. The authors of the paper write, “In conclusion, the present study demonstrates positive associations between Vitamin D measured at the time of diagnosis, and length of survival for patients with cancer of breast, colon, lung, and lymphoma. These ﬁndings conﬁrm previous ecologic data on vitamin D and cancer survival and add to a growing body of literature, indicating that serum levels of vitamin D are positively associated with cancer survival.” 
One of the best known roles of vitamin D is to facilitate the uptake of calcium and phosphorous into the body following digestion. This role is vital, because it maintains strong, healthy bones, muscles and nerves. A study found that with supplementation of 800IU daily, hip and non-vertebral fractures decreased by 30% and 14% respectively.
Interestingly, a recent population study was undertaken to observe the reduction in mortality rates that would occur if levels of vitamin D in the blood were doubled. The estimated reductions were up to 17% in the cases of mortality rates from diseases such as cancer, Alzheimers, cardiovascular disease, respiratory disease, Parkinson’s disease, and multiple scelerosis . Life expectancies varied by region, but the estimated average increase in life expectancy was around 2 years with increased blood serum levels of vitamin D.
There are several foods that contain vitamin D: egg yolks, salt water fish, liver and some dairy foods are often fortified with vitamin D. As winter is upon us, it becomes increasingly difficult to get out in the sun. Grey days, mixed with less hours of sunlight means that our level of exposure to UV rays makes it difficult for our bodies to produce enough vitamin D to fulfil our needs. This is when supplementation becomes important. It’s a very inexpensive and effective way to produce enormous health benefits.
 Wrzosek, M et al. Vitamin D and the Central Nervous System. 2013
Grant, W. Top Vitamin D Papers of 2011: Dosage Recommendations and Clinical Applications.
Orthomolecular News Service. April 10, 2012
Tretli et al. Serum levels of 25-hydroxyvitamin D and survival in Norwegian patients with cancer of breast, colon, lung, and lymphoma:a population-based study.
Cancer Causes and Control. February 1, 2012
 Biscoff,-Ferrari, et al. A pooled analysis of vitamin D dose requirements for fracture prevention. New England Journal of Medicine. July 5, 2012.
Grant, W.B. An estimate of the global reduction in mortality rates through doubling vitamin D levels.
European Journal of Clinical Nutrition. July 6, 2011