***Beneficial Effects of Vitamin D on Immunity, Longevity, and Cardiovascular Health

Vitamin D, the Immune System, and Heart Attack and Atherosclerosis

The June 9, 2008 issue of Archives of Internal Medicine published by the American Medical Association presented the finding of Harvard researchers that men who have deficient vitamin D levels have a greater risk of myocardial infarction (heart ...

Vitamin D and Heart Attack and Atherosclerosis

The June 9, 2008 issue of Archives of Internal Medicine published by the American Medical Association presented the finding of Harvard researchers that men who have deficient vitamin D levels have a greater risk of myocardial infarction (heart attack) than men whose blood levels of the vitamin are sufficient.

Edward Giovannucci, MD of Harvard School of Public Health and his associates reviewed data from men aged 40 to 75 who participated in the Health Professionals Follow-up Study, a prospective cohort investigation designed to evaluate associations between the occurrence of chronic disease and diet among male health care professionals who now have been followed for many years. Blood samples collected from 1993 to 1995 were analyzed for plasma 25-hydroxyvitamin D (25-OHD), lipoprotein and triglyceride levels, and diet and lifestyle factors were determined though the use of questionnaires which were given to each of the participants on study entry. Nine hundred participants without heart disease were matched for age, smoking status, and time of blood collection with 454 men of similar age (age 40 to 75) who had fatal coronary heart disease or non-fatal heart attack which was diagnosed in the 9 to 11 year period between the time of blood sample collection through January, 2004.

Adjusted analysis of the data found a 2.42 times greater risk of heart attack among subjects with plasma vitamin D levels of 15 nanograms per milliliter or less compared with those whose levels were sufficient at 30 nanograms per milliliter or higher. Even those men whose vitamin D levels fell in an "intermediate range" had a 43 to 60 percent greater risk of heart attack compared to men with sufficient levels. Adjustment for a number of factors, such as family history of heart attack, failed to significantly reduce the association. Men with low levels of vitamin D were more likely to live in northern states (where there is less exposure to the sun, especially during winter months), and less likely to be white or to use a multivitamin supplement, among other characteristics revealed by the analysis.

In their commentary, the authors cite the known beneficial effect of Vitamin D on smooth muscle cell proliferation, inflammation, vascular calcification, and blood pressure via the renin-angiotensin system as possible protective mechanisms against myocardial infarction. Vitamin D as an anti-inflammatory agent showing benefit in cardiovascular disease is a possible mechanism of benefit, as cardiovascular disease has been linked in the past to inflammation and inflammatory markers such as C reactive protein, a protein often present when inflammation is present in the body. Other potential mechanisms include protection against type 2 diabetes, inflammation, and seasonal respiratory tract infections (especially influenza), all of which can impact cardiovascular disease mortality.

“These results further support an important role for vitamin D in myocardial infarction risk,” the authors stated. “If this association is causal, which remains to be established, the amount of vitamin D required for optimal benefit may be much higher than would be provided by current recommendations (200-600 IU per day), especially in those with minimal sun exposure. Thus, the present findings add further support that the current dietary requirements of vitamin D need to be increased to have an effect on circulating 25(OH)D levels substantially large enough for potential health benefits.”

Source: [ 25-Hydroxyvitamin D and Risk of Myocardial Infarction in Men. Giovannucci, et al. ]

Vitamin D and All-cause Mortality: This vitamin could help you live longer

Low vitamin D levels have been linked with cancer, diabetes, and high blood pressure. Using the National Health and Nutrition Examination Survey, a large population-based study, researchers at the Albert Einstein College of Medicine evaluated whether low serum vitamin D levels were associated with mortality in the general population. These researchers studied the association of low vitamin D levels with all-cause mortality, cancer, and cardiovascular disease (CVD) mortality among 13,331 American adults who were 20 years or older. Vitamin D levels of these study participants were collected over a 6-year period (from 1988 through 1994), and participants were followed for mortality through the year 2000 (12 years). The researchers found that being older, female, nonwhite, having diabetes, a current smoker, and having a higher body mass index were all independently associated with a greater risk of being vitamin D deficient, while greater physical activity, vitamin D supplementation, and evaluating subjects in a non-winter season (greater exposure to sunshine) were all associated with higher levels of vitamin D. During a median of 8.7 years of follow-up, there were 1806 deaths, including 777 (43%) from cardiovascular disease.

The authors divided the participants into 4 groups (called "quartiles") based on their blood levels of vitamin D, and adjusted for baseline demographics, season, and CVD risk factors (all of which can effect vitamin D levels). Being in the lowest quartile (defined as vitamin D levels less than 17.8 ng/mL) was associated with a 26% increased rate of death from any cause (mortality rate ratio, 1.26; 95% CI, 1.08-1.46). The adjusted models of CVD and cancer mortality revealed a higher risk, but it was not statistically significant. The authors concluded that having low blood levels of vitamin D was independently associated with an increase in all-cause mortality in the general population.

Source: [ Arch Intern Med. 2008 Aug 11;168(15):1629-37. ]

Vitamin D could add 5 years to your life span.

Among many factors that may be responsible for the apparent effect of vitamin Ds on all-cause mortality is the effect of this vitamin on telomeres (the terminal end of each gene) and its potential effect on slowing aging . Richards and coworkers examined whether vitamin D concentrations could slow the rate of shortening of telomeres on leukocytes (a marker of aging ). The authors stated that vitamin D is a potent inhibitor of the proinflammatory response and slows the turnover of leukocytes. Leukocyte telomere length (LTL) is predictive of the development of numerous aging -related disease, and length of leukocyte telomeres decreases with each cell division and with increased inflammation (more common in the elderly). Researchers measured the concentrations of vitamin D in the blood of 2160 women aged 18-79 years (the mean age of these women was about 49 years) from a large population-based study. This study divided the group into thirds [tertiles] based on vitamin D levels, and found that increased age was significantly associated with shorter LTL (r = -0.40, P < 0.0001). The higher the levels of serum vitamin, the longer the leukocyte telomeres. (r = 0.07, P = 0.0010), and this finding persisted even after adjustment for age (r = 0.09, P < 0.0001) and other variables that independently could effect leukocyte telomere length (age, season of vitamin D measurement, menopausal status, use of hormone replacement therapy, and physical activity). The difference in LTL between the highest and lowest tertiles of vitamin D was highly significant (P = 0.0009), and the authors stated that this was equivalent to 5.0 years of aging. The authors concluded that higher vitamin D levels, (these types of levels are easily modifiable through nutritional supplementation), were associated with longer LTL, which underscores the potentially beneficial effects of vitamin D on aging and age-related diseases.

Source: [ Am J Clin Nutr. 2007 Nov;86(5):1420-5. ]

This information was originally posted at: Beneficial Effects of Vitamin D