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Biomedical subjects

A Bendich

Publications and source records attributed to A Bendich.

At least 19 recordsLinked to original sources
PubMed1998

Effect of UV exposure and beta-carotene supplementation on delayed-type hypersensitivity response in healthy older men.

OBJECTIVES: The aims of this study were to determine if ultraviolet light (UV) is immunosuppressive in healthy older males, if beta-carotene (betaC) supplementation could prevent any observed UV-induced immunosuppression, and to compare these effects with those observed previously in younger men. METHODS: The study was a placebo-controlled, randomized trial that employed a 2 x 2 factorial design. Healthy older men (mean age 65.5 years) received 30 mg betaC or placebo daily throughout the 47-day trial, while on a low carotenoid diet. After 28 days, half of each group received 12 suberythemic exposures to UV over a 16-day period. Delayed-type hypersensitivity (DTH) tests and plasma carotenoid assays were performed at baseline, pre-UV and post-UV time points, with DTH testing performed on an area of skin protected from UV exposure. RESULTS: UV exposure resulted in significantly suppressed DTH response in the placebo group but not in the betaC-UV group. While there was no significant interaction between betaC supplementation and UV on DTH response, there was a significant inverse relationship between final plasma betaC concentration and extent of UV-induced suppression of DTH response. A similar correlation existed among subjects not exposed to UV. CONCLUSIONS: Suberythemic UV exposure was immunosuppressive, as measured by DTH response, in healthy older men as in younger men. Higher plasma betaC was significantly associated with maintenance of DTH response, although the extent of protective effect of betaC appeared less than previously observed in younger subjects. The attenuated effect of betaC in the older UV-exposed subjects may have resulted in part from muted plasma betaC responses to betaC supplementation and/or higher plasma vitamin E levels than those of younger men. The finding that stronger DTH responses were associated with higher plasma betaC concentrations in both UV and non-UV subjects further supports a role for this nutrient in immunomodulation.

Adult↗
PubMed1997

Use of multivitamin/mineral prenatal supplements: influence on the outcome of pregnancy.

The objective of this study was to examine the association of prenatal multivitamin/mineral supplement use during the first and second trimesters of pregnancy by low income, urban women in the Camden Study (1985-1995, n = 1,430) and preterm delivery (< 37 completed weeks) and infant low birth weight (< 2,500 g). Prenatal supplement use was corroborated by assay of circulating micronutrients at entry to care (no differences) and week 28 gestation (increased concentrations of folate and ferritin for supplement users). Compared with women who entered care during the first or second trimester but did not use prenatal supplements, supplement use starting in the first or second trimester was associated with approximately a twofold reduction in risk of preterm delivery. After controlling for potential confounding variables, risk of very preterm delivery (< 33 weeks' gestation) was reduced more than fourfold for first trimester users and approximately twofold when use dated from the second trimester. Infant low birth weight and very low birth weight (< 1,500 g) risks were also reduced. Risk of low birth weight was reduced approximately twofold with supplement use during the first and second trimester. Diminution in risk was greater for very low birth weight infants, amounting to a sevenfold reduction in risk of very low birth weight with first trimester supplementation and a greater than sixfold reduction when supplement use started in the second trimester. Thus, in low income, urban women, use of prenatal multivitamin/mineral supplements may have the potential to diminish infant morbidity and mortality.

Adolescent↗
PubMed1997

Vitamin E and human health: rationale for determining recommended intake levels.

The recent literature provides strong evidence that vitamin E intakes much higher than the current recommendations can contribute to and/or improve human health. In fact, the available data indicate that at higher-than-current recommended intake levels, vitamin E affects several functions related to human health. For example, Vitamin E is required to protect polyunsaturated fatty acids (PUFAs) against auto-oxidation. The amount of vitamin E needed to protect PUFAs against oxidative damage is at least 0.4-0.8 mg vitamin E per gram PUFAs and may be in excess of 1.5 mg/g when diets contain higher-than-average levels of long-chain PUFAs. Based upon studies of vitamin E kinetics and metabolism, a daily vitamin E intake of 135-150 IU is suggested. Important functions such as protection against oxidative damage, immune response, and the propensity of platelets to adhere to the vessel wall are related to vitamin E intakes. Vitamin E intake of 40 IU/d was the least amount demonstrated to inhibit low-density lipoprotein oxidation; a dose-dependent effect was seen up to 800 IU/d. Vitamin E intakes of at least 60 IU/d enhanced immune responses and intakes of 200 IU-400 IU/d decreased platelet adhesion to the vessel wall. Based upon the effects of modulating these functions, it is hypothesized that vitamin E plays a pivotal role in the prevention of cardiovascular diseases. Indeed, many observational studies have reported vitamin E to reduce the risk of cardiovascular disease. Recent intervention studies corroborate these findings. Of equal importance, there is a solid body of literature that demonstrates that these and much higher vitamin E intakes are safe.

Cardiovascular Diseases↗
PubMed1997

Serum concentrations of alpha tocopherol, beta carotene, and retinol preceding the diagnosis of rheumatoid arthritis and systemic lupus erythematosus.

OBJECTIVES: Because oxidative damage has been implicated in the pathogenesis of rheumatoid arthritis and systemic lupus erythematosus, this study was designed to see if serum concentrations of alpha tocopherol, beta carotene, and retinol, substances believed to be involved in the prevention or repair of oxidative damage, might be lower among persons who develop rheumatoid arthritis or systemic lupus erythematosus than among those who do not. METHODS: For this prospective case-control study, persons with rheumatoid arthritis and systemic lupus erythematosus that developed two to 15 years after donating blood for a serum bank in 1974 were designated as cases. For each case, four controls were selected from the serum bank donors, matched for race, sex, and age. Stored serum samples from cases and controls were assayed for alpha tocopherol, beta carotene, and retinol. RESULTS: Cases of both diseases had lower serum concentrations of alpha tocopherol, beta carotene, and retinol in 1974 than their matched controls. For rheumatoid arthritis, the difference for beta carotene (-29%) was statistically significant. CONCLUSIONS: These findings support those of a previous study that low antioxidant status is a risk factor for rheumatoid arthritis. They suggest a similar association for systemic lupus erythematosus.

Adult↗
PubMed1997

Potential health economic benefits of vitamin supplementation.

This study used published relative risk estimates for birth defects, premature birth, and coronary heart disease associated with vitamin intake to project potential annual cost reductions in U.S. hospitalization charges. Epidemiological and intervention studies with relative risk estimates were identified via MEDLINE. Preventable fraction estimates were derived from data on the percentage of at-risk Americans with daily vitamin intake levels lower than those associated with disease risk reduction. Hospitalization rates were obtained from the 1992 National Hospital Discharge Survey. Charge data from the 1993 California Hospital Discharge Survey were adjusted to 1995 national charges using the medical component of the Consumer Price Index. Based on published risk reductions, annual hospital charges for birth defects, low-birth-weight premature births, and coronary heart disease could be reduced by about 40, 60, and 38%, respectively. For the conditions studied, nearly $20 billion in hospital charges were potentially avoidable with daily use of folic acid and zinc-containing multivitamins by all women of childbearing age and daily vitamin E supplementation by those over 50.

Adult↗
PubMed1997

Rationale for the introduction of long chain polyunsaturated fatty acids and for concomitant increase in the level of vitamin E in infant formulas.

There is significant scientific agreement that human milk is the best source of nutrients for the human infant. In addition it is also agreed that the constituents of human milk and their concentrations should form the basis of infant formula compositions. The objectives of this review are two fold: to examine the data on the long chain polyunsaturated fatty acid levels (LC-PUFA) in human milk and the rationale for inclusion of these lipids in infant formulas; secondly, as a consequence of addition of highly unsaturated lipids to infant formulas, the antioxidant requirements are increased. Therefore the effect of the addition of LC-PUFA on infant vitamin E status is also examined.

Antioxidants↗
PubMed1996

High dose-B-vitamin treatment of hyperhomocysteinemia in dialysis patients.

Hyperhomocysteinemia, an arteriosclerotic risk factor, persists in 75% of dialysis patients despite routine low dose supplementation with the B-vitamin co-factors/substrates for homocysteine (Hcy) metabolism, and normal or supernormal plasma status of these vitamins (Atherosclerosis 114:93, 1995). We conducted a placebo-controlled eight-week trial of the effect on plasma homocysteine of adding supraphysiologic dose folic acid (15 mg/day), B-6 (100 mg/day), and B-12 (1 mg/day) to the usual daily dosing of 1 mg folic acid, 10 mg B-6, and 12 micrograms B-12, in 27 hyperhomocysteinemic dialysis patients. Total plasma homocysteine was measured at baseline, and after four and eight weeks. Blinded analyses revealed no evidence of toxicity in the group randomized to supraphysiologic dose B-vitamin supplementation. Plasma homocysteine was significantly reduced after both four weeks (-29.8% vs. -2.0%; P = 0.0024) and eight weeks (-25.8% vs. +0.6%; P = 0.0009) of active versus placebo treatment. Also, 5 of 15 treated versus 0 of 12 placebo group patients had their plasma Hcy reduced to within the normative range (< 15 mumol/liter). Supraphysiologic doses of B-vitamins may be required to correct hyperhomocysteinemia in dialysis patients.

Adult↗
PubMed1996

Dietary beta-carotene and ultraviolet-induced immunosuppression.

Ultraviolet (UV)-induced immunosuppression is a critical step in UV carcinogenesis, permitting tumour outgrowth. We investigated the effect of dietary beta-carotene on UV suppression of contact hypersensitivity (CHS) to trinitrochlorobenzene (TNCB) in BALB/c mice. Mice were fed for 10-16 weeks chow alone or supplemented with 1% beta-carotene or placebo as beadlets. Serum beta-carotene was detectable by high performance liquid chromatography (HPLC) analysis only in beta-carotene-fed mice (2.06 +/- 0.15 micrograms/ml). Serum retinol was 0.22-0.27 micrograms/ml in all three groups. Mice (n = 41/dietary group) were irradiated with 0, 4.5, 9 or 18 kJ/m2 of UVB and the CHS response was measured. Decreased CHS responses were observed in all UV-irradiated groups compared with unirradiated controls. UV dose-responses for suppression of CHS derived by first-order regression analyses of plots of percentage suppression of CHS as a function of log10UV dose showed significant slopes (P < 0.02) for all three dietary groups and similar residual variances between groups, P > 0.05. The UV dose for 50% suppression of CHS was 6.3 kJ/m2 for control, 6.4 kJ/m2 for placebo, and 5.5 kJ/m2 for beta-carotene-fed mice. No significant differences in slopes or elevations between UV dose-responses were observed, P > 0.05. Skin levels of the initiator of UV-induced immunosuppression, cis urocanic acid, were determined by HPLC in mice given 0 or 9 kJ/m2 of UV (n = 28/dietary group). No significant differences were observed between dietary groups (range 35.2-41.1 ng/mg skin, P > 0.15) We conclude feeding beta-carotene to BALB/c mice does not alter susceptibility to UV immune suppression, in contrast to human studies.

Animals↗
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↗