[pronut-hiv] BBC: Low vitamin D heart health risk

["ProNut-HIV" <pronut-hiv@healthnet.org>]

Having too little vitamin D has been linked to an increased risk of
heart disease, a US study has found. 

http://news.bbc.co.uk/2/hi/health/7175400.stm 

The Harvard Medical School team said the risk was particularly high for
those who also had high blood pressure. 
Writing in the journal Circulation, they said correcting vitamin D
deficiency could be beneficial. 
A British Heart Foundation spokeswoman said more information was needed
on how the vitamin affected heart health. 
Blood pressure link 
Vitamin D is mainly obtained from exposure to the sun, as well as from
certain foods such as oily fish and eggs. 
There are concerns that many people, including the elderly, pregnant
women and those who wear all-concealing clothing do not get enough of
the vitamin. 
A lack of the nutrient, already known to cause weakened bones, has also
been linked to multiple sclerosis and rheumatoid arthritis. 
The US study, which began in 1996, looked at over 1,700 people with an
average age of 59. 
Their vitamin D levels were tested and they were then monitored for up
to seven years. 
Those with low levels of vitamin D in their blood, below 15 nanograms
per millilitre (ng/ml), had twice the risk of a heart attack, heart
failure or a stroke compared to those with higher levels (above
15ng/ml). 
The highest incidence of cardiovascular disease was seen in those with
high blood pressure and low vitamin D levels. 
Overall, 28% of individuals had levels of vitamin D below 15 ng/ml.
Only 10% had levels above 30 ng/ml - considered ideal for bone health. 
The researchers say that because receptors for vitamin D are found in
heart muscle and blood vessel lining, low levels could be a contributing
factor in heart disease. 
Uncertainty 
But Dr Thomas Wang, who led the research, added: "What hasn't been
proven yet is that vitamin D deficiency actually causes increased risk
of cardiovascular disease. 
"This would require a large randomised trial to show whether correcting
the vitamin D deficiency would result in a reduction in cardiovascular
risk." 
Other studies looking at using different vitamins to benefit heart
health have not shown positive results. 
But Dr Wang said: "Just because other vitamins haven't succeeded
doesn't preclude the possibility of finding vitamins that might prevent
cardiovascular disease. 
"Vitamins are easy to administer and in general have few toxic
effects." 
June Davison, cardiac nurse at the British Heart Foundation said: "This
study suggests an association with Vitamin D deficiency and an increased
risk of heart and circulatory disease. 
"However, the reasons as to why this happens are uncertain and further
research is needed to understand the mechanisms behind this."