In the absence of Vitamin D from sunlight, disease increases more than 1000 percent. Experts suggest that the chances of getting vitamin D from your diet are very low. And if you are a vegetarian, it is all the more difficult to gain vitamin D. What they repeatedly suggest is exposure to sunlight is the best source of vitamin D. Humans spend less time in the sun today than at any point in human history -- which is why more than 1 billion people worldwide are vitamin D deficient.
Humans make 90 percent of our vitamin D naturally from sunlight exposure to our skin -- specifically, from ultraviolet B exposure to the skin, which naturally initiates the conversion of cholesterol in the skin to vitamin D3.
Researchers have also discovered specific molecular signaling events by which vitamin D prevents inflammation. In their experiments, they showed that low levels of Vitamin D, comparable to levels found in millions of people, failed to inhibit the inflammatory cascade--a series of rapid biochemical events which propagates and matures the inflammatory response. However, levels considered adequate did inhibit inflammatory signaling.
The risk of heart failure (HF) was more than 12 times higher in elderly vitamin D-deficient subjects than in those with adequate status, reported the researchers from the Federal University of Pernambuco, Brazil.
Vitamin D deficiency presented a higher risk factor for HF than obesity or heart arrhythmia in a study of 137 elderly Brazilian cardiac outpatients.
"The risk of HF was present in more than half of the elderly and was strongly associated with vitamin D deficiency," concluded first author Catarina Magalhaes Porto, writing in ESC Heart Failure.
Vitamin D deficiency threshold in this study was defined as <30 nanogrammes/millilitre (ng/ml) (75 nanomoles/ litre (nmol/l)). (This contrasts with a more widely recognised deficiency definition of 20 ng/ml (50 nmol/l) with the range between these two levels classed as 'insufficency').
The findings present more evidence of the importance of adequate vitamin D status in the elderly for cardiovascular benefits as well as bone health.
"Based on the evidence presented in this study, which is supported by the literature, the high percentage of elderly individuals with vitamin D deficiency and its consequences for increased risk of HF suggest a need of dosage recommendations for this vitamin, especially in primary healthcare services," recommended Porto.
As the study was observational (cross-sectional design), the researchers could not establish a causal effect of vitamin D deficiency on HF. Nevertheless, they suggested that lower HF risk might arise from vitamin D's ability to suppress the inflammatory response, an established factor in heart failure pathogenesis.
The size of this observational study was relatively small and the researchers proposed that further work was needed to strengthen the evidence base with a view to eventual clinical trials.
"The low cost of its supplementation and the possibility of preventing and treating cardiovascular diseases point to the need for more studies on the supplementation with vitamin D in prospective cohort, so that the conduct of supplementation is implanted with a solid base of evidence," they wrote.