Multivitamins and Healthy Immune Function

Adequate intakes of micronutrients are required for the immune system to function efficiently. A good multivitamin/mineral can enhance the immune system by supporting the body's natural defenses on both structural and cellular levels.

A recent article published in the British Journal of Nutrition summarizes the roles of selected vitamins and trace elements in immune function.

Adequate intakes of micronutrients are required for the immune system to function efficiently. Micronutrient deficiency suppresses immunity by affecting antibody responses, leading to imbalances in the immune system. This situation increases susceptibility to infections, which increases disease and death risk. In addition, infections aggravate micronutrient deficiencies by reducing nutrient intake, increasing losses, and interfering with utilization by altering metabolic pathways. Inadequate intakes of micronutrients are common in people with eating disorders, smokers (active and passive), individuals with chronic alcohol abuse, certain diseases, during pregnancy and lactation, and in the elderly.

Micronutrients contribute to the body's natural defenses on three levels by supporting physical barriers (skin/mucosa), cellular immunity and antibody production. Vitamins A, C, E and the mineral zinc assist in enhancing the skin barrier function. The vitamins A, B6, B12, C, D, E and folic acid and the minerals iron, zinc, copper and selenium work in synergy to support the protective activities of the immune cells. Finally, all these micronutrients, with the exception of vitamin C and iron, are essential for the production of antibodies. Overall, inadequate intake and status of these vitamins and minerals may lead to a suppressed immune system, which increases the risk of infections and aggravates malnutrition. Therefore, supplementation with a multivitamin/mineral that includes these micronutrients can support the body's natural defense system by enhancing all three levels of immunity.

Br J Nutr. 2007 Oct;98 Suppl 1:S29-35.

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.

Zinc supplements decrease incidence of infections in the elderly

Elderly adults are increasingly susceptible to infections, oxidative stress and immune dysfunction. According to new research, supplementing with zinc for one year decreased the incidence of infections and lowered markers of oxidative stress in a group of adults aged 55-87 years.

Adults over the age of 55 years are more susceptible to infections, immune dysfunction, increased oxidative stress, and zinc deficiency. Since zinc has anti-inflammatory and antioxidant properties, new research sought to determine the effect of zinc on the incidence of total infections in the elderly.

Researchers also tested the effect of zinc on markers of oxidative stress. A randomized, double-blind, placebo-controlled trial of zinc supplementation was conducted in 50 healthy subjects of both sexes aged 55-87 years. The zinc- supplemented group received 45 mg of zinc orally for 12 months. Incidence of infections during the supplementation period was documented. Plasma zinc concentrations and markers of oxidative stress were measured at the beginning and after supplementation.

After zinc supplementation, the incidence of infections was significantly lower, plasma zinc was significantly higher, and generation of oxidative stress markers was significantly lower in the zinc-supplemented than in the placebo group.

American Journal of Clinical Nutrition, Vol. 85, No. 3, 837-844, March 2007

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

Folate intake still below recommendations despite fortification

Despite significant improvements in public health measures to increase folate intakes through fortification of grain products, dietary intakes still fall well below recommendations. Regular use of a multivitamin supplement containing folic acid is an easy way to ensure that you receive an adequate intake.

Folate is found in foods such as green leafy vegetables, chick peas and lentils, and it is increasingly accepted that folate deficiency in early pregnancy is linked to a risk of neural tube defects such as spina bifida and anencephaly in infants. This connection led to the introduction of public health measures in the US and Canada, whereby all grain products are fortified with folic acid " the synthetic, bioavailable form of folate.

A new study, published in October's American Journal of Public Health, concluded that since fortification was implemented folic acid intake has in fact increased, but not nearly enough to meet FDA goals and recommendations. Even with significant improvements and widespread fortification, only 39 percent of white women, 26 percent of black women, and 28 percent of Mexican American women attained the 400 microgram per day target for folate consumption. In addition, over half the subgroups showed a decrease in folic acid intake since fortification began in 1998.

The FDA recommends at least 400 micrograms of folate daily for nonpregnant women, and adult men, as well as children four and older. However, the daily recommendation for pregnant women increases to at least 800 micrograms per day. Despite the fact that recent surveys show that the majority of women know the importance of folic acid, daily folic acid supplementation appears to be critical since dietary intakes still fall well below recommendations.

Population-Level Changes in Folate Intake by Age, Gender, and Race/Ethnicity after Folic Acid Fortification. American Journal of Public Health. October, 2006.