People with lower blood levels of sunshine vitamin D in their blood appear to have an increased risk of death from all causes and from cardiovascular diseases, according to an Austrian study in the June 23 issue of the Archives of Internal Medicine.The study found that people with the lowest level of vitamin D in their blood were twice as likely to die from any cause including death from heart disease during an eight-year period as those who had a high level.
Vitamin D is naturally produced in the body when the skin is exposed to sunshine. Exposure of the face and both hands for 20 minutes to strong sunshine is believed to generate enough vitamin D, while a dietary regimen is needed to have a preventative effect against certain diseases or death, particularly in dark-skinned individuals and the elderly who produce less vitamin D.
An estimated 50 to 60 percent of older people in North America and the rest of the world do not have sufficient vitamin D levels, and a similar percentage of young people have the same problem, according to the background information in the report.
Previous studies have linked blood levels of 25-hydroxyvitamin D in the blood lower than 20 to 30 nanograms per milliliter with risk of falls, fractures, cancer, immune dysfunction, cardiovascular disease and hypertension.
In the study, Harald Dobnig, M.D., an internist and endocrinologist at the Medical University of Graz, Austria, and colleagues measured 25-hydroxyvitamin D and 1, 25-dihydroxyvitamin D levels in 3,258 patients of an average age of 62 years who underwent coronary angiography testing between 1997 and 2000.
During the 7.7-year follow-up, 22.6 percent of participants died and among the dead, 62.8 percent were from cardiovascular causes.
Death rates from any cause and from the cardiovascular causes were higher in those with their blood 25-hydroxyvitamin D levels in the lower 50 percent and in the lowest one-fourth of 1, 25-dihydroxyvitamin D levels, the study found.
Low 25-hydroxyvitamin D levels were also linked with markers of inflammation such as c-reactive protein, as well as signs of oxidative damage to cells, the study found.
"Apart from the proved effects that vitamin D has on bone metabolism and neuromuscular function, appropriate serum levels (that may also be higher than in the present investigation) are associated with a decrease in mortality," the researchers concluded.
"Although not proved, it seems possible that at least part of this effect may be due to lowering of a risk profile promoting atherosclerosis [narrowing of the arteries] and preventing cardiovascular end points," the researchers said.
"Based on the findings of this study, a serum 25-hydroxyvitamin D level of 20 nanograms per milliliter or higher may be advised for maintaining general health." (Editor’s note: many other studies have suggested that 30 nanograms per milliliter are needed.)
The current study merely established an association between the serum vitamin D level and death risk and it did not prove that taking vitamin D supplements to increase its level in the body would actually reduce the risk of death from all causes although the possibility cannot be excluded either.
However, many clinical trials have already demonstrated the preventative effect of vitamin D against premature deaths from all causes including cardiovascular causes.
One study meta-analyzed data from 18 separate trials of 57,000 participants who had a dietary supplement of vitamin D at a dose ranging from 300 to 2000 International Units and found that those who took vitamin D had a 7 percent lower risk of death than those who did not.
The study was conducted by Philippe Autier, M.D., of the International Agency for Research on Cancer, Lyon, France, and Sara Gandini, Ph.D., of the European Institute of Oncology in Milan, Italy, and published in the September 10, 2007 issue of the Archives of Internal Medicine.
Overall, earlier studies showed that deficiencies in vitamin D are associated with a higher risk of death from cancers (including breast, prostate, and colon cancer), heart disease, and diabetes-illnesses, which overall are responsible for 60 to 70 percent of deaths in developed countries.
Another study conducted by Edward Giovannucci, M.D., Sc.D., at the Harvard School of Public Health and colleagues revealed that it is 2.42 times more common to find people with 15 nanograms per milliliter of blood or less (deficiency) than it is to find those with a sufficient amount (30 nanograms per milliliter). The findings were published in the June 9, 2008 issue of Archives of Internal Medicine.
The researchers came to this conclusion after they compared 454 men ages 40 to 75 who had non-fatal heart attacks or fatal heart disease during the follow-up period with 900 men who did not have a history of cardiovascular disease.
Sunshine is the basic source of vitamin D. But readers should be careful about the advice they receive from news media, a health observer affiliated with foodconsumer.org suggested. Exposure to ultraviolet rays is widely viewed as a risk for developing skin cancer, and people are often urged to use screens to block exposure to sunshine. Be aware though that vitamin D deficiency can put an individual at a higher risk of dying from other more serious types of cancers and a variety of other chronic diseases.
Other sources include fortified foods such as fortified milk and cereals, natural foods such as cod liver oil, fatty fish such as cooked salmon, mackerel, tuna, and sardines, egg yolks, liver, and supplements.
The current recommended daily allowance for vitamin D is 200 IU per day for people under 50, 400 IUs for those between 50 and 70, and 600 IUs for those over 70. Older people need higher doses. Research has found that healthy people can tolerate intake of up to 10,000 IU per day. Vitamin D experts have already complained that the current RDA is too low to have a protective effect, and have recommended that the RDA should be increased to at least 1,000 IU per day.
source
No comments:
Post a Comment