Vitamin D

There is an ongoing debate in medical science about the importance and usefulness of supplementation. No one doubts that we all need vitamins, minerals and trace metals and specific deficiencies are well described. With a modern, healthy diet, the vast majority of people derive all the micro nutrients needed to prevent a major deficiency disease.

But, there is no doubt that in modern society less than 10% of people consume the suggested 2–3 pieces of fruit per day along with 3–5 servings of vegetables per day (a serving being around ½ a carrot as an example). Fruit & vegetables are the most important source of micronutrients. One area of research that is gaining a very strong evidence base is Vitamin D.

Initially it was thought that low Vitamin D levels may predispose to osteoporosis but research over the past decade has found a more far reaching role for adequate Vitamin D levels. Unfortunately, around one third of the Australian population has Vitamin D levels less than 50 nmoles per litre. Despite the fact that Australia is a sun drenched country, we have embraced the ‘slip slop slap’ message and also with increasing sedentary jobs and lifestyles are spending more time in doors. Thus we are often not receiving adequate doses of Vitamin D.

Four new studies have highlighted the diverse and important nature of maintaining normal Vitamin D levels. The first, published in the BMJ, comes from Japan where 33,763 Japanese between the ages of 40–70 were followed up for a 16 year period. During this time, there were 3300 new cancer diagnoses. Those who had the highest blood levels of Vitamin D had a 20% lower cancer risk. Because of the nature of the study, it was difficult to relate this to specific cancers although there appeared to be somewhere between a 30–50% reduction in risk for liver cancer and no obvious link for lung and prostate cancer.

Vitamin D

There is an ongoing debate in medical science about the importance and usefulness of supplementation. No one doubts that we all need vitamins, minerals and trace metals and specific deficiencies are well described. With a modern, healthy diet, the vast majority of people derive all the micro nutrients needed to prevent a major deficiency disease.

But, there is no doubt that in modern society less than 10% of people consume the suggested 2–3 pieces of fruit per day along with 3–5 servings of vegetables per day (a serving being around ½ a carrot as an example). Fruit & vegetables are the most important source of micronutrients. One area of research that is gaining a very strong evidence base is vitamin D.

Initially it was thought that low vitamin D levels may predispose to osteoporosis but research over the past decade has found a more far reaching role for adequate vitamin D levels. Unfortunately, around one third of the Australian population has vitamin D levels less than 50. nmoles per litre. Despite the fact that Australia is a sun drenched country, we have embraced the slip slop slap message and also with increasing sedentary jobs and lifestyles are spending more time in doors. Thus we are often not receiving adequate doses of Vitamin D.

Four new studies have highlighted the diverse and important nature of maintaining normal vitamin D levels. The first, published in the BMJ, comes from Japan where 33, 763 Japanese between the ages of 40–70 were followed up for a 16 year period. During this time, there were 3300 new cancer diagnoses. Those who had the highest blood levels of vitamin D had a 20% lower cancer risk. Because of the nature of the study, it was difficult to relate this to specific cancers although there appeared to be somewhere between a 30–50% reduction in risk for liver cancer and no obvious link for lung and prostate cancer.

The second study, published in the Journal of Clinical Endocrinology and Metabolism, looked at the association between vitamin D and cardiovascular risk. This study from Norway looked at just over 4100 adults, average age 62, with a diagnosis of angina pectoris, who were followed up for 12 years. There were 895 deaths including 407 deaths from cardiovascular disease. Those with a normal vitamin D level compared with those with a vitamin D deficiency had a 30% reduction in cardiovascular death.

The third study, published in Heart, Lung and Circulation, looked at the link between vitamin D and heart failure. This was a study in mice looking at particular cells known as cardiac colony-forming unit fibroblasts (cCFU-Fs) which promote the formation of scar after the induction of a heart attack. The study clearly showed that vitamin D blocked the action of cCFU-Fs leading to reduced scar formation and therefore better cardiac function.

The final study, published in the Journal Neurology, looked at the link between vitamin D and multiple sclerosis. This examined lifelong sun exposure in 151 women with multiple sclerosis average age 40 and compared this with 235 age-matched controls. They then examined altitude, latitude and cloud cover and found that those who came from sunny climates with the highest UV-B exposure had a 45% reduction in risk for multiple sclerosis. In particular, those who lived in a sunny climate between the ages of 5–15 had a 51% reduction in risk for multiple sclerosis. Those who spent a lot of time outdoors from the same demographic, a 55% reduction in multiple sclerosis.

The research over the past decade has clearly demonstrated a link between low vitamin D levels and osteoporosis, cardiovascular disease, cancer, multiple sclerosis, type II diabetes, asthma and depression. Vitamin D plays a clear role in cholesterol metabolism, many facets of immune function and certainly appears important in brain function.

It is not as yet established as to whether you should obtain vitamin D from careful sun exposure, food sources or supplementation but with the evidence we have to date it is clear that low levels of vitamin D are associated with poor health outcomes.

The second study, published in the Journal of Clinical Endocrinology and Metabolism, looked at the association between Vitamin D and cardiovascular risk. This study from Norway looked at just over 4100 adults, average age 62, with a diagnosis of angina pectoris, who were followed up for 12 years. There were 895 deaths including 407 deaths from cardiovascular disease. Those with a normal Vitamin D level compared with those with a Vitamin D deficiency had a 30% reduction in cardiovascular death.

The third study, published in Heart, Lung and Circulation, looked at the link between Vitamin D and heart failure. This was a study in mice looking at particular cells known as cardiac colony-forming unit fibroblasts (cCFU-Fs) which promote the formation of scar after the induction of a heart attack. The study clearly showed that Vitamin D blocked the action of cCFU-Fs leading to reduced scar formation and therefore better cardiac function.

The final study, published in the Journal of Neurology, looked at the link between Vitamin D and multiple sclerosis. This examined lifelong sun exposure in 151 women with multiple sclerosis average age 40 and compared this with 235 age-matched controls. They then examined altitude, latitude and cloud cover and found that those who came from sunny climates with the highest UV-B exposure had a 45% reduction in risk for multiple sclerosis. In particular, those who lived in a sunny climate between the ages of 5–15 had a 51% reduction in risk for multiple sclerosis. Those who spent a lot of time outdoors from the same demographic, a 55% reduction in multiple sclerosis.

The research over the past decade has clearly demonstrated a link between low Vitamin D levels and osteoporosis, cardiovascular disease, cancer, multiple sclerosis, type II diabetes, asthma and depression. Vitamin D plays a clear role in cholesterol metabolism, many facets of immune function and certainly appears important in brain function.

It is not as yet established whether you should obtain Vitamin D from careful sun exposure, food sources or supplementation but with the evidence we have to date it is clear that low levels of vitamin D are associated with poor health outcomes.

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