Vitamin D and endometrial cancer

New research indicates that low serum vitamin D may be associated with an increased incidence of endometrial cancer.

The November 16, 2007 issue of the journal Preventive Medicine reported an association between ultraviolet light exposure and a reduced risk of endometrial cancer. Two previous investigations have already linked a lower rate of kidney and ovarian cancer with greater UV exposure, which increases the formation of vitamin D3 in the body.

Researchers analyzed data made available through GLOBOCAN, a database of cancer incidence and mortality in 175 countries. In general, the incidence of endometrial cancer was highest at the highest latitudes in both hemispheres. The correlation between low UV exposure and low vitamin D levels and endometrial cancer incidence remained strong even after adjusting for variables such as fat intake, weight, cloud cover, skin pigmentation and others.

Most previous studies have focused on hormone levels and dietary fat intake and their role in the development of the disease. This is the first study linking low serum vitamin D levels to an increased risk of endometrial cancer. Along with other preventive measures, vitamin D adequacy should be considered as part of a comprehensive program for prevention of endometrial cancer.

Prev Med 2007 Nov;45(5):323-4.

Vitamin D supplementation lowers fracture risk

Researchers have found that doses of 700 to 800 IU of vitamin D3 per day may reduce the risk of hip fracture by 26 percent and nonvertebral fracture by 23 percent.

The May 11 2005 issue of the Journal of the American Medical Association published the results of a meta-analysis of 12 clinical trials involving vitamin D supplementation in the prevention of fracture. The analysis concluded that supplementation with higher than the commonly recommended 400 international unit (IU) doses of vitamin D reduces the risk of hip and nonvertebral fractures in older individuals.

The vitamin D studies included a total of 19,114 men and women aged 60 and older. The trials used the form of the vitamin known as cholecalciferol, or vitamin D3, which, according to studies cited in the current review, may be much more effective than the dietary form of the vitamin.

The researchers found that doses of 700 to 800 IU of vitamin D3 per day reduced the risk of hip fracture by 26 percent and nonvertebral fracture by 23 percent. Studies that used 400 IU vitamin D3 or less found no significant benefit for either type of fracture. The role of additional calcium supplementation could not clearly be defined from the studies, but it appears that at least 700 milligrams calcium per day may also be necessary for nonvertebral fracture prevention.

JAMA 2005 May 11;293(18):2257-64.

Supplemental vitamin D and calcium reduces risk of diabetes

The incidence of type-2 diabetes is lower among women who get adequate calcium and supplement with vitamin D. Researchers used data from the Nurses Health Study, which includes over 83,000 women, to study the relationship of calcium and vitamin D intake to type-2 diabetes.

After 20 years of follow-up, it was concluded that a combined daily intake of over 1,200 mg of calcium and more than 800 IU of vitamin D was associated with a 33 percent lower risk of type-2 diabetes. Interestingly, dietary vitamin D intake did not appear to provide any statistically significant benefit. But the women who supplemented with at least 400 IU of vitamin D had a 13% lower risk of diabetes when compared to those who took less than 100 IU per day. Both dietary and supplemental calcium resulted in decreased risk of type-2 diabetes, and those with overall intakes above 1,200 mg had a 21% lower risk than those who got less than 600 mg per day.

Elevated intakes of calcium and vitamin D, especially from supplements, are significantly associated with lower incidence of type-2 diabetes.

Diabetes Care 29:650-656, 2006

Vitamin D reduces the risk of certain cancers

A study published in the American Journal of Public Health, has found that vitamin D deficiency may account for several thousand premature deaths annually. The researchers reviewed 63 studies on the relationship between vitamin D and certain types of cancer worldwide between 1966 and 2004. The majority of studies found a protective relationship between sufficient vitamin D status and lower risk of cancer, especially in cancers of the colon, breast, prostate and ovary.

Vitamin D is acquired either through the diet or through exposure to sunlight. Food sources include milk, yogurt, cheese, and fortified orange juice. A typical serving provides approximately 100 international units (IU). Researchers suggested that people might want to consider a vitamin supplement to raise their overall intake to 1,000 IU's per day. Supplementing with additional vitamin D could be especially important for people living in northern areas, which receive less vitamin D from sunlight.

The evidence suggests that improving vitamin D status through diet and supplements could reduce cancer incidence and mortality at low cost, with few or no adverse effects.

American Journal of Public Health February 2006, Vol 96, No. 2:252-261.

Vitamin D deficiencies widespread among pregnant women and infants despite prenatal vitamin usage

Vitamin D deficiency early in life is associated with rickets, a disorder characterized by soft bones. New research has shown that despite taking a prenatal vitamin, vitamin D deficiency is very common in pregnant women and newborn infants. Higher-dose supplementation and increased sun exposure is needed to improve maternal and infant vitamin D status.

Even among those taking prenatal multivitamin supplements, vitamin D levels were found to be insufficient or deficient in pregnant women, particularly in African-American women and women living in northern regions, according to new research published in the Journal of Nutrition. Researchers took blood samples from 400 pregnant women - 200 black women and 200 white women - before 22 weeks gestation and again after delivery.

More than 80% of African American women and nearly half of white women tested at delivery had levels of vitamin D that were insufficient, even though more than 90% of them used prenatal vitamins during pregnancy.

In addition, umbilical cord blood from newborns showed 92.4% of African American babies and 66.1% of white infants had insufficient vitamin D levels at birth, leaving them at risk for rickets and other health problems. A newborn relies completely on its mother for its vitamin D stores.

These results suggest that black and white pregnant women and newborns residing in the northern US are at high risk of vitamin D insufficiency, even when mothers regularly take prenatal vitamins. Higher-dose supplementation is needed to improve maternal and infant vitamin D status.

J. Nutr. 137:447-452, February 2007

Calcium and vitamin D enhance heart health benefits of weight loss

Weight loss and reduced waist circumference are related to an improvement in heart health and factors related to metabolic syndrome. According to a new study, supplementing with calcium and vitamin D during weight loss enhances heart health benefits in women with typically low calcium intake.

Recent research has shown that overweight individuals with low calcium and dairy consumption are at increased risk of developing metabolic syndrome. The findings suggest that adequate calcium intake could create a healthier metabolic profile similar to a balanced diet and regular exercise.

In a new study, researchers investigated this issue by testing cardiovascular benefits of long-term calcium supplementation in women with usual low calcium intake. Healthy, overweight or obese women with a daily calcium intake of less than 800 mg/day were randomly assigned to 1 of 2 groups: the group consuming 2 tablets/day of a calcium + vitamin D supplement (600 mg elemental calcium and 200 IU vitamin D/tablet) or the group consuming placebo. Both groups completed a 15-week reduced calorie weight-loss program.

Significant decreases in LDL cholesterol levels, as well as the ratios of Total to LDL and LDL to HDL were seen the calcium +D group. These changes were independent of the changes due to fat loss and reduced waist circumference. A tendency for more beneficial changes in HDL cholesterol, triglycerides, and total cholesterol was also observed in the calcium +D group.

This was the first study to show that consumption of calcium +D during weight-loss enhances the beneficial effect of body weight loss on cardiovascular risk factors in overweight women with typically low calcium intake.

American Journal of Clinical Nutrition, Vol. 85, No. 1, 54-59, January 2007

Higher levels of vitamin D reduce the risk of multiple sclerosis

People with higher circulating vitamin D levels are significantly less likely to develop multiple sclerosis, according to a new study by Harvard researchers.

The RDA for vitamin D was recently increased in the elderly to 600 IU per day. Many reports and most experts suggest levels between 600-1,000 IU per day, especially for those in northern climates or with poor sunlight exposure. Typical dietary intake is between 100-200 IU per day.

A report published in the December 20, 2006 issue of the Journal of the American Medical Association concluded that having a higher serum level of vitamin D is associated with a lower risk of multiple sclerosis (MS) among men and women. The finding adds to those of previous studies that suggest that the vitamin may have a protective effect against the disease.

Harvard researchers studied more than 250 individuals diagnosed with multiple sclerosis between 1992 and 2004. The team determined that for every 50 nanomole per liter increase in serum vitamin D among white participants there was a 41 percent decrease in the risk of MS. Whites in the top one-fifth of serum vitamin D concentrations had the lowest risk of the disease, and those in the lowest fifth had the greatest risk. Those with the highest vitamin D levels experienced a 62 percent lower risk of MS compared to those in the group with the lowest levels.

The results of this study suggest that high circulating levels of vitamin D are associated with a lower risk of multiple sclerosis.

JAMA. 2006;296:2832-2838.