Carotenoid supplements provide protection against DNA damage

New research published in the January 2006 issue of the American Journal of Clinical Nutrition shows that carotenoid supplementation is protective against DNA damage.

Researchers randomly assigned study subjects to one of three treatments: A daily dose of mixed carotenoids (beta-carotene, lutein, and lycopene: 4 mg each), a 12 mg single carotenoid (beta-carotene, lutein or lycopene) or a placebo. In addition, the subjects were instructed to limit carotenoid-rich fruit and vegetables from two weeks prior to the study until completion. Following the supplementation period, researchers analyzed plasma carotenoid concentrations and lymphocyte DNA damage. Each carotenoid group exhibited significantly reduced DNA damage compared to baseline, whereas the placebo group showed no such improvement. Both the mixed carotenoid and the beta-carotene groups further displayed significantly less oxidative DNA damage as early as 15 days into supplementation.

The results indicate that carotenoid supplementation, whether in combination at moderate doses or individually at higher doses, provides protection against DNA damage.

American Journal of Clinical Nutrition, Vol. 83, No. 1, 163-169, January 2006

Congestive Heart Failure and Vitamin B1 Deficiency

A study published in the January 17, 2006, issue of the Journal of the American College of Cardiology reported that approximately one out of three patients hospitalized with heart failure have deficient levels of thiamin, also known as vitamin B1. Thiamin deficiency manifests as symptoms of congestive heart failure and, therefore, may worsen existing heart failure. Congestive heart failure patients may be at increased risk for thiamin deficiency as a result of diuretic-induced urine thiamin excretion, disease severity, malnutrition, and advanced age.

Researchers measured thiamin levels among 100 heart failure patients and compared them with measurements of 50 healthy subjects. They found a deficiency of the vitamin in 33 percent of the heart failure patients compared to 12 percent of those without the disease.

It has been observed that heart failure may increase the body's need for certain nutrients, so that even individuals with healthful diets may still come up short on vitamin B1. Researchers noted that a relatively small dose of thiamin from a multivitamin was protective against developing thiamin deficiency and may decrease disease severity in those with congestive heart failure.

J Am Coll Cardiol, 2006; 47:354-361

Antioxidants lower macular degeneration risk

A report published in the December 28, 2005 issue of the Journal of the American Medical Association concluded that individuals whose diets contain high amounts of the antioxidants beta-carotene, vitamin C, vitamin E and zinc have a significantly lower risk of developing age-related macular degeneration (AMD) than people whose diets contain lower levels of the nutrients. Age-related macular degeneration is the most common cause of permanent blindness in the developed world.

The current study included 4,176 men at women at risk of AMD who were participants in the Rotterdam Study, which enrolled 7,983 men and women aged 55 or older. Five hundred-sixty subjects were diagnosed with new macular degeneration during the follow-up period. Participants with an above-median intake of all 4 nutrients, beta carotene, vitamin C, vitamin E, and zinc, had a 35% reduced risk of AMD compared to those whose intake of any of the nutrients was below average.

The results of this study suggest that high dietary intakes of antioxidants, in particular vitamin E and zinc, may reduce the risk of AMD and delay its development.

JAMA 2005;294:3101-3107

Vitamin D reduces the risk of certain cancers

A recent study has found that vitamin D deficiency may account for several thousand premature deaths annually. These findings were published last week online in the American Journal of Public Health.

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). 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.

AJPH First Look, published online ahead of print Dec 27, 2005