SBH Rep contact request

Four New Studies Underscore Vital Role of Vitamins & Minerals

Latest Findings are Encouraging

Four new studies reinforce previous findings for some essential nutrients, while suggesting potential new benefits for others. Calcium, vitamin D and three of the B-vitamins are featured in a quartet of studies published in the Archives of Internal Medicine.

The Calcium and Cancer Connection

Some previous population-health studies have found a link between calcium intake and cancer, but the evidence has been inconsistent. The calcium-cancer relationship appears to be affirmed in the large National Institutes of Health AARP Diet and Health Study which followed nearly 294,000 men and 199,000 women aged 50-71 for seven years (1).

Women consuming up to 1,300 mg of calcium daily from foods and supplements had a decreased risk of any type of cancer. A 23% lower risk for digestive types of cancer, particularly colorectal cancer, was seen for those women in the top 20% of calcium intake compared to those consuming the least. The highest consumers among men also had a 16% lower risk of cancer in the digestive cancer category.

Higher Vitamin D for Fewer Broken Bones

Though calcium may prove important in cancer prevention, the results of another study suggest that calcium may play second fiddle to higher levels of vitamin D when it comes to protecting bones. Harvard researchers performed a meta-analysis (review) of 12 clinical trials involving vitamin D supplements in over 42,000 adults aged 65 or older (2). They found that supplemental vitamin D was associated with a 14% decrease in the risk of non-vertebral fractures and a 9% decrease in the risk of hip fractures. More importantly, when they looked at 9 of the studies using doses over 400 IU per day, the supplements were associated with a 20% and 18% reduction in non-vertebral and hip fractures, respectively. The researchers noted that while calcium was protective, the mineral did not have an additional effect in individuals taking high doses of vitamin D.

Risk of Colds Influenced by Vitamin D?

vitamin D deficiency has resurfaced in recent years, resulting in diseases such as rickets in children. vitamin D research has also exploded, with better blood levels of vitamin D now linked to lower incidences of cancer, multiple sclerosis and heart disease. Another line of inquiry under hot pursuit is vitamin D's role in the immune system.

In an analysis of the 3rd National Health and Nutrition Examination Survey (3), researchers found that people with low blood levels of this vitamin were more likely to have an upper respiratory tract infection (URTI) which can include colds, sinusitis, pharyngitis and flu. Compared to people with higher vitamin D blood levels (30 ng/mL or more), those with lower values (under 10 ng/mL) were 36% more likely to have had a recent URTI. People with intermediate values (10-29 ng/mL) had 24% higher odds. Whether getting more vitamin D will actually help prevent URTIs needs to be confirmed in controlled trials.

B-Vitamins Lower AMD Risk in Women

Previous studies have suggested an association between age-related macular degeneration (AMD) and elevated blood levels of homocysteine - a compound that can be lowered by folic acid, B6 and B12. To determine whether B-vitamins might help prevent AMD, about 5,400 female health professionals who already had, or were at high risk for, heart disease were given very high doses of these 3 B's or a placebo (4).

After more than 7 years of follow-up, the women assigned to the supplemental B-vitamin group lowered their risk of developing any AMD by 34%. The risk for visually significant AMD was reduced by a solid 41%. These findings are exciting, and the next step is to test whether lower, more reasonable levels of the B's are just as effective when supplemented over time.

References

1. Park Y, et al. Dairy food, calcium and risk of cancer in the NIH-AARP Diet and Health Study. Arch Int Med 169:391-401, 2009.
2. Bischoff-Ferrari HA, et al. A meta-analysis of randomized controlled trials Prevention of non-vertebral fractures with vitamin D and dose dependency. Arch Int Med 169:551-61, 2009.
3. Ginde A, et al. Association between serum 25-hydroxyvitamin D level and upper respiratory tract infection the Third National Health and Nutrition Examination Survey. Arch Int Med 169:484-90, 2009.
4. Christen W, et al. Folic acid, pyridoxine, cyanocobalamin combination treatment and age-related macular degeneration in women. Arch Int Med 169:335-4, 2009.