News
Vitamin E may benefit lung health
7 February 2011
Regular vitamin E supplementation may reduce the risk of chronic lung disease in women, a new US analysis reports.
18 September 2014
According to a new US review big portions of the populations do not meet the estimated required intakes of vitamin E, which is particularly important for all children through about age two, for women who are pregnant and for the elderly.
The review evaluated the information available on the adverse consequences of inadequate vitamin E (alpha-tocopherol) supply status (1). More than 90% of Americans do not consume sufficient dietary vitamin E (2) to meet estimated average requirements (EARs). Many of the consequences of this inadequate intake are less obvious, such as its impact on things like nervous system and brain development, or general resistance to infection. However, current research has shown that plasma alpha-tocopherol concentrations below 12 mmol/L are associated with increased infection, anemia, stunting of growth, and poor outcomes during pregnancy for both the infant and the mother (3). Hypothetically, these low intakes of antioxidant alpha-tocopherol lead first to anemia because of a damage of erythrocytes by oxygen. Experimental data indicate that vitamin E is critically important to the early development of the nervous system in embryos, in part because it protects the function of omega-3 fatty acids, especially docosahexaenoic acid (DHA), which is important for brain health. In the elderly, severe or chronic vitamin E depletion may lead to cognitive impairment while increased intakes seem to slow the progression of Alzheimer's disease (4). The protection of DHA by vitamin E is thought to be important throughout life: a study showed that people with high plasma DHA concentrations had a 47% reduction in the risk of developing all-cause dementia (5).
Measures of circulating vitamin E levels in the blood often rise with age as lipid levels also increase, but do not prove an adequate delivery of vitamin E to tissues and organs. There seem to be efficient regulatory controls governing circulating vitamin E concentrations: an increase and normalization of blood vitamin E concentrations at the expense of depletion of (liver) tissue alpha-tocopherol. These processes serve to protect circulating lipids, which are readily oxidized and potentially exposed to higher concentrations of oxygen and reactive oxygen species. Here the case of nonalcoholic fatty liver disease, related to obesity and type 2 diabetes, is of interest because the progression of this disorder to more serious forms of the disease is dependent on oxidative damage to lipids, suggesting that inadequate vitamin E intakes may promote disease progression and a vitamin E supplementation may improve the disease (6). The researchers concluded that these data emphasize the importance of adequate vitamin E status in obese individuals to maintain healthy liver function and potentially prevent the progression of fatty liver to more serious forms of the disease.
Supplements providing vitamin E intakes in excess of 100-fold dietary intakes increase plasma concentra-tions only by about 2- to 4-fold above baseline values (7). The limitation on plasma concentrations and prevention of toxic tissue concentrations appear to be a result of increased hepatic vitamin E metabolism and excretion (8). Intakes of 12–15 mg alpha-tocopherol per day are sufficient in normal healthy individuals to provide adequate vitamin E status on the basis of the health benefits associated with these intakes (9).
7 February 2011
Regular vitamin E supplementation may reduce the risk of chronic lung disease in women, a new US analysis reports.
20 January 2009
According to a U.S. survey, individuals with low vitamin D blood levels have a higher risk of nose and throat infections. In a secondary analysis of the Third National Health and Nutrition Examination Survey (NHANES), a survey of the U.S. population, found that individuals with low blood levels of a vitamin D marker (25-hydroxyvitamin D) were also more likely to have an upper respiratory tract infection (URTI). Specifically, the analysis found that compared to those with levels greater than 30 nanograms/milliliter (ng/ml), individuals with less than 10 ng/mL had a 36% higher risk of having a recent URTI; those with 10–<30 ng/mL had a 24% higher risk (1). In recent years, vitamin D deficiency has reemerged, resulting in the resurfacing of diseases such as rickets in children. According to the Dietary Guidelines for Americans 2005, “Older adults, people with dark skin, and people exposed to insufficient ultraviolet band radiation (i.e., sunlight) should consume extra vitamin D from vitamin D-fortified foods and/or supplements.” The researchers commented that the evidence supporting the benefits of vitamin D continues to build. Given that vitamin D levels are relatively low in most foods and there are serious risks associated with excessive sun exposure, dietary supplements can be an effective alternative for achieving a sufficient intake. However, this study on its own does not mean that higher vitamin D intake will ensure prevention of upper respiratory tract infection. 1.Ginde A. et al. Association Between Serum 25-Hydroxyvitamin D Level and Upper Respiratory Tract Infection in the Third National Health and Nutrition Examination Survey. Archives of Internal Medicine, 2009; 169 (4):384–390.
1 May 2011
High concentrations of oxygen radicals in the body (oxidative stress) have been linked to the exacerbation of atherosclerosis and hence the onset of cardiovascular disease. At the same time, observation studies have consistently indicated that antioxidant micronutrients in the diet could have a protective effect in the context of cardiovascular disease.