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Biomedical subjects

A Bendich

Publications and source records attributed to A Bendich.

At least 37 records · Page 2Linked to original sources
PubMed1996

Essential nutrients and immunologic functions.

Several indexes of immune response, including responses on delayed-type hypersensitivity skin tests, antibody production, lymphocyte proliferation, cytokine production, and numbers of the specific subgroups of white blood cells, are influenced by essential nutrient intake and may serve as functional tests for evaluating nutritional status. In certain segments of the population, such as elderly persons and smokers, activity of the immune indexes can be increased through dietary supplementation with micronutrients, and there may be a rationale to increase selected recommended dietary allowances for the general population. The activity of the immune system may also be enhanced with decreases in total fat intake or lessened with increases in total fat intake, particularly of the n-3 type. Research to date, therefore, suggests that several dietary components, both essential and nonessential, can affect human immune response. The intake of these nutrients can be modulated to regulate the activity of the immune system.

Antibody Formation↗
PubMed1996

Folic acid and the prevention of birth defects.

Thirty years ago, it was suggested that maternal intake of certain vitamins during pregnancy affected the incidence of serious fetal malformations. Subsequent research has revealed that folate (folic acid), a B vitamin, plays a crucial role in the development of the central nervous system during the early weeks of gestation, which is generally before the pregnancy is confirmed. In a significant number of embryos, an inadequate supply of folate at this time leads to a failure of the primitive neural tube to close and differentiate normally and results in neural tube birth defects (NTD). Numerous studies have confirmed the importance of an adequate intake of folate during the weeks just before and after conception. Overall, the data predict that if women consume multivitamin supplements containing folic acid during the periconceptional period, the number of children born with serious malformations (such as spina bifida and anencephaly) could be reduced by half. Although programs to increase dietary folate intake of potential mothers may be effective in reducing NTD, the only proven and practical preventive measure currently available is to take oral multivitamin supplements containing folic acid. Multivitamin supplementation has also been associated with reduced incidence of other congenital malformations. Current research is focusing on the role of micronutrients in embryogenesis, and on methods to identify prospective mothers at increased risk for bearing a child with NTD or with other major malformations shown to occur at reduced frequency with multivitamin supplementation. Of equal importance is the development of methods to communicate current knowledge as a public health measure.

Congenital Abnormalities↗
PubMed1996

Vitamin C and human health--a review of recent data relevant to human requirements.

The recent scientific literature indicates that beyond merely protecting against scurvy vitamin C contributes to many aspects of human health. The main areas of research reviewed include: 1. Vitamin C requirements of smokers. The data indicate that the vitamin C requirement of smokers is higher by at least 60 mg per day (up to 140 mg per day) than that of nonsmokers. 2. Important functions of the body, such as immune response, pulmonary function, and iron absorption are related to vitamin C intakes. Daily vitamin C intake of at least 150-200 mg per day enhance these functions. 3. Vitamin C may play critical roles in the prevention of CHD, cancer and cataract. Based on the available data, vitamin C intakes of at least 80-120 mg per day are associated with lowering the risk of these chronic diseases. 4. The literature documents that these and much higher intake levels of vitamin C are safe.

Ascorbic Acid↗
PubMed1995

The health effects of vitamin C supplementation: a review.

A comprehensive review of the literature indicates that populations with long-term consumption of higher than RDA levels of vitamin C (> or = 60 mg/day) from foods and/or supplements have reduced risks of cancer at several sites, cardiovascular disease, and cataracts. The safety of higher than RDA intakes of vitamin C is confirmed in eight placebo-controlled, double-blind studies and six non-placebo clinical trials in which up to 10,000 mg of vitamin C was consumed daily for up to 3 years. There are no clinical data which suggest that vitamin C's enhancement of non-heme iron absorption in individuals with low iron status could be a critical factor in the possible increased risk of heterozygous hemochromatosis-related cardiovascular disease. In fact, the cumulative data do not confirm that iron status is related to risk of cardiovascular disease. Moreover, higher than RDA intakes of vitamin C have been associated with several indices of lowered cardiovascular disease risk including increases in HDL, and decreases in LDL oxidation, blood pressure and cardiovascular mortality.

Ascorbic Acid↗
PubMed1994

Daily micronutrient supplements enhance delayed-hypersensitivity skin test responses in older people.

A placebo-controlled double-blind trial of the effects of daily micronutrient supplements on circulating vitamin and trace metal concentrations and delayed-hypersensitivity skin test (DHST) responses was conducted. Subjects, aged 59-85 y, were randomly assigned to placebo (n = 27) or micronutrient (n = 29) treatment groups. DHST and circulating concentrations of nine micronutrients were measured before and after 6 and 12 mo of micronutrient ingestion. For the micronutrient group, there were statistically significant increases at 6 and/or 12 mo in the mean serum concentrations of ascorbate, beta-carotene, folate, vitamin B-6, and alpha-tocopherol. There was a significant increase at 12 mo in the number of subjects in the placebo group with one or more low concentrations. DHST responses to a panel of seven recall antigens were significantly increased at 12 mo in the micronutrient group but not the placebo group. This study demonstrates that daily supplementation with low-to-moderate doses of micronutrients can prevent low concentrations of some micronutrients and can improve DHST responses in healthy, independently living older adults.

Aged↗
PubMed1993

Physiological role of antioxidants in the immune system.

Diets contain naturally occurring antioxidant compounds that can stabilize highly reactive, potentially harmful molecules called free radicals. Free radicals are generated during normal cellular metabolism and result from the metabolism of certain drugs or xenobiotics. Exposure to UV light, cigarette smoke, and other environmental pollutants also increases the body's free radical burden. The harmful activities of free radicals are associated with damage to membranes, enzymes, and DNA. The ability of antioxidants to destroy free radicals protects the structural integrity of cells and tissues. This review focuses on data indicating that the functions of the human immune system depend on the intake of micronutrients, which can act as antioxidants. Recent clinical trials have found that antioxidant supplementation can significantly improve certain immune responses. Specifically, supplementation with vitamins C, E, and A or beta-carotene increased the activation of cells involved in tumor immunity in the elderly. Supplementation with the antioxidant vitamins also protected immune responses in individuals exposed to certain environmental sources of free radicals. Supplementation with vitamin A, a relatively weak antioxidant, decreases morbidity and mortality associated with measles infections in children.

Aging↗
PubMed1992

Vitamin E status of US children.

Data from several national surveys consistently show that American children have lower than recommended intakes of vitamin E, which is reflected in lower than average serum levels. Reduction in dietary fat can further exacerbate the low vitamin E status of children. The consequences of low vitamin E intake may include impaired immune responses, as seen in a study of over 500 Canadian children. Low vitamin E status has been correlated with increased risk of atherosclerosis and cardiovascular disease, cancer, cataract and impaired immune responses in adult populations. Since early signs of chronic degenerative diseases of aging have been seen in autopsies of children, efforts should be made to ensure that prolonged low intakes of vitamin E are avoided in children as well as adults.

Adolescent↗
PubMed1992

Effect of beta-carotene supplementation on photosuppression of delayed-type hypersensitivity in normal young men.

The aim of this study was to examine whether beta-carotene protects against the immunosuppression seen with long-wave ultraviolet-light (UV-A) exposure. Free-living, healthy men, aged 19-39 y received 30 mg beta-carotene/d or a placebo while on a single-menu, low-carotenoid diet. After 28 d all subjects received 12 exposures to a UV-A/B light source over a 16-d period. The total UV-A dose received ranged from 15.9 to 19.3 J/cm2. The total shorter-wave ultraviolet-light (UV-B) dose varied from 1.59 to 1.96 J/cm2. Follow-up continued for 21 d. Carotenoid assays and delayed-type hypersensitivity (DTH) tests were performed at baseline, pre-UV, post-UV, and after follow-up. The DTH-test responses were significantly suppressed in the placebo group after UV treatments. The suppression was inversely related to plasma beta-carotene concentrations in this group. There was no significant suppression of DTH test responses in the beta-carotene group. It is concluded that beta-carotene protects against photosuppression of immune function.

Adult↗
PubMed1992

Vitamins and immunity.

The effects of vitamin deficiencies on increased morbidity and mortality from infectious disease were noted very soon after the discoveries of the vitamins. Repletion and, in numerous instances, supplementation with the deficient vitamin resulted in clinically relevant immunoenhancement. However, communication of the importance of vitamin status, especially in children with measles complications, has not progressed to the point that micronutrient assessment and intervention, when appropriate, occurs on a routine basis.

Child↗
PubMed1990

Antioxidant nutrients and immune functions--introduction.

This short introduction encompasses only a small portion of the literature linking free radical production and consequent effects on immune functions. The role of essential dietary components in modulating these effects is an area of intense and expanding investigation. Each of the nutrients examined in the following chapters has distinct functions, but in this volume we concentrate on their shared capacity to act as antioxidants.

Animals↗