Antioxidant status and risk of cancer in the SU.VI.MAX study: is the effect of supplementation dependent on baseline levels?

The SUpplementation en VItamines et Mineraux AntioXydants (SU.VI.MAX) study, a randomised double-blind, primary-prevention trial showed that after 7.5 years, low-dose antioxidant supplementation lowered the total cancer incidence in men, but not in women. To explain this difference in the impact of antioxidant supplementation in men and women, we hypothesised that the effect of supplementation is dependent on initial antioxidant status; 12 741 French adults (7713 females aged 35--60 years; 5028 males aged 45--60 years) received daily antioxidant supplementation (120 mg vitamin C, 30 mg vitamin E, 6 mg beta-carotene, 100 microg Se, 20 mg Zn daily) or a matching placebo. Cut-off limits for baseline serum concentrations of the different antioxidant vitamins and minerals were defined as follows for both men and women: 0.3 micromol/l for beta-carotene, 11.4 micromol/l for vitamin C, 15 micromol/l for vitamin E, 0.75 micromol/l for Se and 10.7 micromol/l for Zn. The percentage of men with serum concentrations under cut-off limits was higher for vitamins C and E and beta-carotene in those who developed a cancer than in those who did not. The risk of cancer was higher in men with baseline concentrations of serum vitamin C or vitamin E under cut-off limits, but not in women. The effect of supplementation was greater in men with baseline serum concentrations of vitamin C, vitamin E and beta-carotene below the cut-off limits compared with those above it. This effect was maintained only for vitamin E after adjustment for age, tobacco, and alcohol consumption and BMI. No effect of supplementation could be seen in women. Baseline antioxidant status is related to the risk of cancer in men but not in women and therefore does not entirely explain the differences observed in the effect of antioxidant supplementation on cancer risk between sexes in the SU.VI.MAX study.     

Changes in serum retinol,alpha-tocopherol,vitamin C,carotenoids, xinc and selenium after micronutrient supplementation during alcohol rehabilitation

OBJECTIVE: To test the effect of a 21-day supplementation with moderate doses of antioxidant nutrients on biochemical indicators of vitamin, carotenoid and trace element levels in alcohol-dependent patients during a program of alcohol rehabilitation. DESIGN: A randomized double-blind trial was performed comparing two groups receiving daily either a combination of micronutrients (beta-carotene: 6 mg, vitamin C: 120 mg, vitamin E: 30 mg, zinc: 20 mg, selenium: 100 micro g) or a placebo. SUBJECTS: 106 alcohol-dependent patients 20 to 60 years of age without severe liver disease, hospitalized for a 21-day rehabilitation program. Measure of Outcome: Vitamin C, retinol, alpha-tocopherol, zeaxanthin/lutein, beta-cryptoxanthin, lycopene, alpha- and beta-carotene, zinc and selenium were measured in serum, initially and after supplementation. RESULTS: (1) In the placebo group, after 21 days of rehabilitation, serum concentrations of vitamin C and all five carotenoids significantly increased, whereas retinol and alpha-tocopherol concentrations decreased; zinc and selenium levels were unaffected. (2) At the end of the hospital stay, serum indicators were significantly improved in the supplement group as compared to the placebo group for vitamin C, alpha-tocopherol, beta-carotene, zinc and selenium; conversely, lycopene changes were higher in the placebo group than in supplement group. (3) Of the serum antioxidants measured at entrance, only vitamin C was significantly depleted in heavy smokers, and, after the supplementation period, vitamin C was efficiently repleted in this later group. CONCLUSION: Our results indicate that a short-term supplementation with physiological doses of antioxidant vitamins, carotenoids and trace elements during alcohol rehabilitation clearly improves micronutrient status indicators. Heavy smokers in particular seem to respond to vitamin C supplementation.     

维生素E、C和β-胡萝卜素对DNA损伤的影响

目的通过较高剂量补充维生素Ｅ、Ｃ和β－胡萝卜素,观察三种维生素对淋巴细胞损伤的影响。方法选取５０～５９岁健康男性随机分为实验组和对照组,每组５０人,实验组每人每天服用β－胡萝卜素２５ｍｇ、维生素Ｃ１００ｍｇ,维生素Ｅ２８０ｍｇ,实验期为２０周,采集实验组和对照组的全血分离淋巴细胞。ＤＮＡ损伤程度的分析采用“彗星”电泳技术分析;血清中维生素Ｃ、α－生育酚和β－胡萝卜素的测定均采用高效液相色谱法分析。结果外周血淋巴细胞ＤＮＡ的损伤程度分析发现ＤＮＡ自发损伤率在实验组和对照组人群中均较低,ＤＮＡ损伤率分别为６．１％和６．８％,两组间差异无明显性;但是当实验组和对照组人群外周血淋巴细胞经Ｈ２Ｏ２处理后,对照组人群在３０μｍｏｌ／Ｌ、１００μｍｏｌ／Ｌ、３００μｍｏｌ／ＬＨ２Ｏ２剂量组细胞ＤＮＡ损伤率逐渐升高,分别达到３６．１４％、５９．４５％和６９．６２％,并明显高于实验组Ｈ２Ｏ２相应处理剂量细胞ＤＮＡ损伤率。结论通过补充维生素Ｅ、Ｃ和β－胡萝卜素,可以有效地降低Ｈ２Ｏ２所致的ＤＮＡ损伤     

Beta-carotene supplementation increases antioxidant capacity of plasma in older women

The antioxidant effect of dietary beta-carotene supplementation on the peroxidation potential of plasma was investigated in a randomized double-blind, placebo-controlled study. Twelve healthy women (62-80 y) supplemented their usual daily diet with 90 mg of beta-carotene (n = 6) or placebo (n = 6) capsules for 3 wk. Plasma concentrations of beta-carotene, alpha- and gamma-tocopherol, ascorbate, urate, bilirubin and in vitro production of phosphatidylcholine hydroperoxides (PC-OOH) and utilization of plasma antioxidants in the presence of 50 mmol/L 2,2'-azobis (2-aminopropane) hydrochloride (AAPH), a free radical generator, at 37 degrees C were measured before and after dietary treatment. Plasma beta-carotene increased from 0.76 +/- 0.16 to 6.45 +/- 1.16 micromol/L (P < 0.05) in supplemented but not placebo-treated subjects. The plasma concentrations of other antioxidants did not change significantly in either group. beta-Carotene supplementation did not affect basal levels of plasma PC-OOH as measured by HPLC post-column chemiluminescence but did affect AAPH-induced production of PC-OOH. Before supplementation, the induction period of plasma PC-OOH production was 2.4 +/- 0.4 h, with levels reaching 5.39 +/- 1.50 micromol/L after 6 h of incubation. After supplementation, the induction period increased significantly to 4.2 +/- 0.4 h (P < 0.01), with a lower PC-OOH production of 2.16 +/- 0.90 micromol/L after 6 h (P < 0.05). In this system, plasma ascorbate concentrations were depleted first, followed by loss of bilirubin and alpha-tocopherol and then by the sequential loss of gamma-tocopherol, urate and beta-carotene. These results indicate that beta-carotene supplementation increases the plasma antioxidant capacity of older women.     

Zinc supplementation might potentiate the effect of vitamin A in restoring night vision in pregnant Nepalese women

BACKGROUND: Zinc deficiency may result in abnormal dark adaptation or night blindness, a symptom primarily of vitamin A deficiency. During a placebo-controlled trial in Nepal, weekly vitamin A supplementation of women reduced but failed to eliminate the incidence of night blindness during pregnancy, suggesting a role for zinc. OBJECTIVE: The study examined the efficacy of daily zinc supplementation in restoring night vision of pregnant women who developed night blindness while routinely receiving either vitamin A, beta-carotene, or placebo in a field trial. DESIGN: Women (n = 202) who reported to be night blind during pregnancy were randomly assigned in a double-blind manner, stratified on vitamin A, beta-carotene, or placebo receipt, to receive 25 mg Zn or placebo daily for 3 wk. Thus, the 6 groups studied were as follows: beta-carotene + zinc, beta-carotene alone, vitamin A + zinc, vitamin A alone (vitamin A + placebo), zinc alone (zinc + placebo), and placebo (2 placebos: one for the vitamin A or beta-carotene study and one for the zinc study). Women underwent a clinic-based assessment that included pupillary threshold testing and phlebotomy before and after supplementation. Supplement use and daily history of night blindness were obtained at home twice every week. RESULTS: Zinc treatment increased serum zinc concentrations, but alone (zinc alone group), failed to restore night vision or to improve dark adaptation. However, women in the vitamin A + zinc group who had baseline serum zinc concentrations <9.9 micromol/L were 4 times more likely to have their night vision restored (95% CI: 1.1, 17.3) than were women in the placebo group and tended to have a small improvement in pupillary threshold scores (by 0.21 log candela/m2; P = 0.09). CONCLUSION: These data suggest that zinc potentiated the effect of vitamin A in restoring night vision among night-blind pregnant women with low initial serum zinc concentrations.     

Maternal vitamin A or beta-carotene supplementation in lactating bangladeshi women benefits mothers and infants but does not prevent subclinical deficiency

The effects of maternal postpartum vitamin A or beta-carotene supplementation on maternal and infant serum retinol concentrations, modified relative dose-response (MRDR) ratios and breast milk vitamin A concentrations were assessed during a community-based trial in Matlab, Bangladesh. At 1-3 wk postpartum, women were randomly assigned to receive either (1) a single dose of 200,000 international units [60,000 retinol equivalents (RE)] vitamin A followed by daily placebos (n = 74), (2) daily doses of beta-carotene [7.8 mg (1300 RE)] (n = 73) or (3) daily placebos (n = 73) until 9 mo postpartum. Compared to placebos, vitamin A supplementation resulted in lower maternal MRDR ratios (i.e., increased liver stores) and higher milk vitamin A concentrations at 3 mo, but these improvements were not sustained. The beta-carotene supplementation acted more slowly, resulting in milk vitamin A concentrations higher than the placebo group only at 9 mo. Irrespective of treatment group, over 50% of women produced milk with low vitamin A concentrations (/=0. 06. We conclude that while both interventions were beneficial, neither was sufficient to correct the underlying subclinical vitamin A deficiency in these women nor to bring their infants into adequate vitamin A status.     

Circulating levels of retinol, tocopherol and carotenoid in Nepali pregnant and postpartum women following long-term beta-carotene and vitamin A supplementation

OBJECTIVE: To characterize circulating carotenoid and tocopherol levels in Nepali women during pregnancy and post-partum and to determine the effects of beta-carotene and vitamin A supplementation on their concentration in serum. DESIGN: Randomized community supplementation trial. SETTING: The study was carried out from 1994 to 1997 in the Southern, rural plains District of Sarlahi, Nepal. SUBJECTS: A total of 1431 married women had an ascertained pregnancy, of whom 1186 (83%) provided an analyzable serum sample during pregnancy; 1098 (77%) provided an analyzable 3-4 months post-partum serum sample. INTERVENTIONS: Women received a weekly dose of vitamin A (7000 microg RE), beta-carotene (42 mg) or placebo before, during and after pregnancy. Serum was analyzed for retinol, alpha-tocopherol, gamma-tocopherol, beta-carotene, alpha-carotene, lycopene, lutein + zeaxanthin, and beta-cryptoxanthin concentrations during mid-pregnancy and at approximately 3 months post-partum. RESULTS: Compared to placebo, serum retinol, beta-carotene, gamma-tocopherol, beta-cryptoxanthin and lutein + zeaxanthin concentrations were higher among beta-carotene recipients during pregnancy and, except for beta-cryptoxanthin, at postpartum. In the vitamin A group, serum retinol and beta-cryptoxanthin were higher during pregnancy, and retinol and gamma-tocopherol higher at postpartum. Lutein + zeaxanthin was the dominant carotenoid, regardless of treatment group, followed by serum beta-carotene. Serum lycopene level was lowest, and very low compared to the US population. Serum retinol was higher, and carotenoid and alpha-tocopherol lower, at postpartum than during pregnancy in all groups. CONCLUSIONS: Pregnant and lactating Nepali women have lower serum carotenoid and tocopherol levels than well-nourished populations. beta-carotene supplementation appeared to increase levels of tocopherol and other carotenoids in this population.     

Serum concentrations of beta-carotene, vitamins C and E, zinc and selenium are influenced by sex, age, diet, smoking status, alcohol consumption and corpulence in a general French adult population

OBJECTIVE: To assess relationships between energy, nutrient and food intakes, alcohol consumption, smoking status and body mass index (BMI), and serum concentrations of beta-carotene, alpha-tocopherol, vitamin C, selenium and zinc. METHODS: Data on health status, alcohol consumption, smoking habits, anthropometric data and biochemical measurements were obtained in 1821 women aged 35-60 y and 1307 men aged 45-60 y, participant to the SU.VI.MAX Study. Data on dietary intake were available on a subsample who reported six 24-h dietary records during the first 18 months of the study. RESULTS: Women had higher baseline serum beta-carotene and vitamin C concentrations and lower concentration for serum vitamin E, zinc and selenium than men. In women, younger age was associated with lowered mean concentration of serum beta-carotene, vitamin E and selenium. In men, only differences were observed for serum zinc, which was lower in older men. Current smokers of both sexes had significantly lower concentrations of serum beta-carotene, vitamin C and selenium, and, only in women, of vitamin E, than nonsmokers. Alcohol consumers had lower concentrations of serum beta-carotene and higher selenium concentrations. Serum beta-carotene and vitamin C concentrations were lower in obese subjects. There were positive associations of dietary beta-carotene, vitamin C and E with their serum concentrations. Age, nutrient and alcohol intakes, serum cholesterol, BMI and smoking status explained 15.2% of the variance of serum beta-carotene in men and 13.9% in women, and 10.8 and 10.0% for serum vitamin C, and 26.3 and 28.6% for serum vitamin E, respectively. CONCLUSION: Serum antioxidant nutrient concentrations are primarily influenced by sex, age, obesity, tobacco smoking, alcohol consumption and especially dietary intake of those antioxidant nutrients.     

Daily intake of multivitamins during long-term intake of olestra in men prevents declines in serum vitamins A and E but not carotenoids

The objective of this study was to determine whether vitamin supplementation during long-term (36 wk) ingestion of olestra supplemented with vitamin E could prevent decreases in vitamin E, vitamin A, and carotenoids. This was a 36-wk study of 37 healthy males randomly assigned to consume a control diet composed of 33% energy from fat, a similar diet in which one third of the energy from fat had been replaced with olestra, or a fat-reduced (25% of energy from fat) diet. Subjects also ingested a daily multivitamin (Centrum). Serum concentrations of alpha-tocopherol, retinol, beta-carotene, lycopene, and lutein + zeaxanthin were analyzed by HPLC. Subjects eating the olestra-containing diet had substantial decreases in serum beta-carotene, lycopene, and lutein + zeaxanthin, which occurred by 12 wk; these changes were found despite correcting for serum total cholesterol or BMI. Serum beta-carotene and lycopene concentrations were below the lower limit of the reference range (<0.186 and <0.298 mumol/L, respectively) at one or more time points. The slight decline in serum alpha-tocopherol concentration, significant at 24 wk, was caused by the decline in serum cholesterol. Retinol concentrations decreased with time in all 3 groups, but were not affected by olestra. We conclude that supplementation with a multivitamin containing vitamins A and E was adequate to prevent olestra-induced decrease in serum alpha-tocopherol and retinol. Olestra-induced decreases in serum beta-carotene, lycopene, and lutein + zeaxanthin were not prevented by the vitamin supplement used in this study.     

Nonsupplemented children of Latino immigrants have low vitamin E intakes and plasma concentrations and normal vitamin C, selenium, and carotenoid intakes and plasma concentrations

OBJECTIVE: This study sought to determine and evaluate the intakes and plasma concentrations of vitamin E (alpha-tocopherol), gamma-tocopherol, vitamin C, selenium, and carotenoids (alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein/zeaxanthin, and lycopene) of nonsupplemented boys and girls, 4 to 8 years old, of Latino immigrants living in rural Nebraska. DESIGN: Dietary intakes of the Latino children were estimated. Their plasma samples (fasting) were analyzed for vitamin E, vitamin C, selenium, and carotenoid concentrations. Data were evaluated by sex. SUBJECTS: The subjects were a convenience sample of 4- to 8-year-old (n=29), apparently healthy, nonsupplemented children of Latino immigrants living in rural Nebraska. STATISTICAL ANALYSIS: Sex differences in parameter values were determined using general linear models; Pearson r was used for determining correlations. RESULTS: No significant differences in parameter values were observed by sex, with the exception of plasma lutein/zeaxanthin concentration. The majority (69%) had plasma vitamin E (alpha-tocopherol) concentrations<0.516 mg/dL (12 micromol/L), which is indicative of vitamin E inadequacy, and over half (59%) reported consuming less than the Estimated Average Requirement for vitamin E. All subjects had plasma vitamin C and selenium concentrations indicative of adequacy (>0.41 mg/dL or >23 micromol/L, and >6.32 microg/dL or >0.8 micromol/L, respectively), and consumed at least the Recommended Dietary Allowances for these nutrients. The plasma carotenoid concentrations of the children may be useful as norms. CONCLUSIONS: These children of Latino immigrants who did not take supplements had low plasma vitamin E (alpha-tocopherol) concentrations but normal plasma vitamin C and selenium concentrations. IMPLICATIONS: Dietetics professionals and others involved in health care need to work with Latino immigrant parents so that their children consume adequate amounts of vitamin E.     

Dietary and serum alpha-tocopherol,beta-carotene and retinol,and risk for colorectal cancer in male smokers

OBJECTIVE: To study the association between dietary and serum antioxidant vitamins and carotenoids and risk for colorectal cancer in male smokers. DESIGN: A prospective cohort study within a randomised, double-blind, placebo-controlled trial testing supplementation with alpha-tocopherol (50 mg/day), beta-carotene (20 mg/day) or both in preventing cancer. SUBJECTS AND METHODS: Participants of the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study with complete dietary data and serum samples available from baseline. These included 26,951 middle-aged male smokers among whom 184 colorectal cancer cases were diagnosed during 8 y of follow-up. Relative risks were calculated with Cox proportional hazards models adjusting for trial supplementation, age, body mass index, serum cholesterol, cigarettes smoked per day and physical activity. RESULTS: There was no significant association between dietary vitamin C or E, alpha-or gamma-tocopherol, retinol, alpha- or beta-carotene, lycopene or lutein+zeaxanthin and risk for colorectal cancer. Serum alpha-tocopherol, beta-carotene or retinol was also not associated with the risk, neither did the season when baseline blood was drawn modify the relationship between serum beta-carotene and colorectal cancer risk. CONCLUSIONS: Our data support the results from previous studies in which no association between dietary antioxidant vitamins and carotenoids and risk for colorectal cancer has been observed. Likewise, no association between baseline serum antioxidant concentrations and colorectal cancer risk was evident. SPONSORSHIP: The Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study was supported by a contract with the US National Cancer Institute (N01-CN-45165).     

Serum beta-carotene, lycopene and alpha-tocopherol levels of healthy people in northeast Thailand

Human serum contains many different antioxidants which may be important in the maintenance of antioxidant status. beta-carotene and lycopene are carotenoids with potent antioxidant activity. Carotenoids intake probably protects against cancers and may affect the risk of several chronic conditions. alpha-tocopherol is well known for its function as antioxidant and in reduction of heart disease and cancer risk. We aimed to establish baseline values for serum beta-carotene, lycopene and alpha-tocopherol concentrations in healthy northeast Thais. Fasting serum beta-carotene, lycopene and alpha-tocopherol levels from 294 subjects aged 23-75 years old in northeast Thailand were determined by high performance liquid chromatography (HPLC). The mean serum beta-carotene, lycopene and alpha-tocopherol levels were 0.53 +/- 0.32 micromol/L, 0.57 +/- 0.37 micromol/L, and 26.64 +/- 14.85 micromol/L respectively. Serum beta-carotene and lycopene levels in females (N = 118) were significantly higher than the value for males (N = 176), ie 0.60 +/- 0.31 micromol/L versus 0.48 +/- 0.32 micromol/L (p = 0.002) for beta-carotene and 0.74 +/- 0.38 micromol/L versus 0.46 +/- 0.33 micromol/L (p<0.001) for lycopene whereas alpha-tocopherol level in males (28.60 +/- 14.34 micromol/L) was significantly higher than in females (23.72 +/- 15.16 micromol/L) (p = 0.006). beta-carotene level was positively correlated with alpha-tocopherol (r = 0.22, p<0.001) and lycopene levels (r = 0.63, p<0.001). The results from this study give the baseline data of serum beta-carotene, lycopene and alpha-tocopherol levels in healthy northeast Thai population and also suggest future study on the relationship of dietary intake.     

Nutritional and haematological status of Chinese farmers: the influence of 13.5 months treatment with riboflavin, retinol and zinc

A retinol (15 mg), riboflavin (200 mg) and zinc (50 mg) supplement or a placebo (D-mannitol) was given to 610 Chinese farmers weekly for 13.5 months. Riboflavin, retinol, beta-carotene, tocopherol and zinc status were measured in all subjects at the start and end of the intervention and in a subsample at 2 months. Plasma vitamin C, haemoglobin and haematocrits were measured on other subsamples at the end of the supplementation period. At the start vitamin A, zinc and riboflavin status were poor. Plasma retinol and zinc concentrations were higher in men than women but the opposite was observed with respect to beta-carotene. There was no difference between the sexes for tocopherol and riboflavin. Tocopherol:cholesterol ratios suggested vitamin E status was good and vitamin C status also appeared adequate. The supplement increased plasma retinol throughout the whole period but riboflavin status improved only over the first 2 months and then remained constant. Plasma zinc increased in both treatment and placebo groups by approximately 15 to 20 per cent in men and women. Mean concentrations of retinol and tocopherol and beta-carotene (in women only) increased by approximately 20 per cent in the placebo group. It is argued that seasonal factors and/or the placebo may have been responsible for the increase in retinol and beta-carotene in the placebo group. The lack of an increase in beta-carotene in the men may have been due to their higher retinol requirements. Lastly, the increase in retinol may have been responsible for the increase in tocopherol and zinc in plasma since these nutrients increased in those whose plasma retinol increased, irrespective of treatment.     

Supplementation with mixed tocopherols increases serum and blood cell gamma-tocopherol but does not alter biomarkers of platelet activation in subjects with type 2 diabetes

BACKGROUND: Some studies have shown potential benefit of vitamin E on platelet function, but several clinical trials failed to show improved cardiovascular outcome with alpha-tocopherol supplementation. Gamma-tocopherol, a major dietary form of vitamin E, may have protective properties different from those of alpha-tocopherol. OBJECTIVE: We compared the effects of supplementation with alpha-tocopherol (500 mg) and a gamma-tocopherol-rich compound (500 mg, containing 60% gamma-tocopherol) on serum and cellular tocopherol concentrations, urinary tocopherol metabolite excretion, and in vivo platelet activation in subjects with type 2 diabetes. DESIGN: Fifty-eight subjects were randomly assigned to receive either 500 mg alpha-tocopherol/d, 500 mg mixed tocopherols/d, or matching placebo. Serum, erythrocyte, and platelet tocopherol and urinary metabolite concentrations were measured at baseline and after the 6-wk intervention. Soluble CD40 ligand, urinary 11-dehydro-thromboxane B2, serum thromboxane B2, soluble P-selectin, and von Willebrand factor were measured as biomarkers of in vivo platelet activation. RESULTS: Serum alpha-tocopherol increased with both tocopherol treatments. Serum and cellular gamma-tocopherol increased 4-fold (P < 0.001) in the mixed tocopherol group, whereas red blood cell gamma-tocopherol decreased significantly after alpha-tocopherol supplementation. Excretion of alpha-carboxyethyl-hydroxychroman increased significantly after supplementation with alpha-tocopherol and mixed tocopherols. Excretion of gamma-carboxyethyl-hydroxychroman increased significantly after supplementation with mixed tocopherols and after that with alpha-tocopherol, which may reflect the displacement of gamma-tocopherol by alpha-tocopherol due to incorporation of the latter into lipoproteins in the liver. Neither treatment had any significant effect on markers of platelet activation. CONCLUSIONS: Supplementation with alpha-tocopherol decreased red blood cell gamma-tocopherol, whereas mixed tocopherols increased both serum alpha-tocopherol and serum and cellular gamma-tocopherol. Changes in serum tocopherol closely reflect changes in cellular concentrations of tocopherols after supplementation.     

Cognitive function in elderly people is influenced by vitamin E status

The aim of this study was to examine associations between vitamin E status and cognitive performance in elderly people. The study subjects were a group of 34 men and 86 women, aged 65-91 y, who were free of significant cognitive impairment. Dietary intake was monitored using a "weighed food record" for 5 consecutive days including a Sunday. Serum levels of alpha-tocopherol and cholesterol were determined by HPLC and colorimetric methods, respectively. The cognitive capacity of subjects was tested using the Pfeiffer's Mental Status Questionnaire (PMSQ). Subjects with vitamin E intakes lower than 50% of those recommended had higher PMSQ scores, demonstrating a greater number of errors in comparison to participants with a greater intake of the vitamin (0.91 +/- 1.22 vs. 0.47 +/- 0.60, respectively, P < 0.05). Subjects who made no errors in the PMSQ test had significantly higher serum alpha-tocopherol concentrations (19.7 +/- 8.6 micromol/L in men and 20.0 +/- 8.4 micromol/L in women) and alpha-tocopherol/cholesterol ratios (3.5 +/- 2.0 micromol/mmol in men 2.9 +/- 1.4 micromol/mmol in women) compared with those who made errors (alpha-tocopherol 15.1 +/- 5.6 micromol/L in men and 14.9 +/- 6.1 micromol/L in women; alpha-tocopherol/cholesterol ratio 2.4 +/- 0.8 and 2.3 +/- 1.3 micromol/mmol in men and women, respectively). This study shows there to be a relationship between vitamin E status and cognitive function, and that vitamin E status could be improved in this population of elderly individuals.     

Redistribution of vitamin A after iron supplementation in Indonesian infants

BACKGROUND: Deficiencies of iron and vitamin A are prevalent worldwide. Single-micronutrient supplementation is widely used to combat these deficiencies. However, micronutrient deficiencies often occur concurrently, and there are many interactions between micronutrients. OBJECTIVE: This study investigated interactions among 3 important micronutrients--iron, vitamin A, and zinc--when they are given as supplements. DESIGN: In a randomized, double-blind, placebo-controlled supplementation trial, 387 Indonesian infants aged 4 mo were supplemented 5 d/wk for 6 mo with 10 mg Fe, 10 mg Zn, 2.4 mg beta-carotene, 10 mg each of Fe and Zn, 10 mg Zn + 2.4 mg beta-carotene, or placebo. Complete data on micronutrient status, including hemoglobin, ferritin, retinol, zinc, and the modified relative dose response (a measure of liver retinol stores), were available from 256 infants at the end of the study. RESULTS: Iron-supplemented infants had significantly lower plasma retinol concentrations and a significantly higher prevalence of vitamin A deficiency, as defined by a plasma retinol concentration <0.70 micromol/L, than did the non-supplemented infants. In contrast, the modified relative dose response of the iron-supplemented infants indicated greater liver stores of vitamin A. Iron supplementation improved iron status, and zinc supplementation improved zinc status, but beta-carotene supplementation did not significantly improve vitamin A status. CONCLUSIONS: In this study, iron supplementation in infants with marginal vitamin A status led to lower plasma vitamin A concentrations and simultaneously to greater vitamin A liver stores. This implies a redistribution of retinol after iron supplementation, which might induce vitamin A deficiency. Therefore, iron supplementation in infants should be accompanied by measures to improve vitamin A status.     

Effect of beta-carotene supplementation on the concentrations and distribution of carotenoids,vitamin E,vitamin A,and cholesterol in plasma lipoprotein and non-lipoprotein fractions in healthy older women.

We studied the effect of beta-carotene supplementation on the concentrations and distribution in plasma lipoprotein and non-lipoprotein fractions of carotenoids, alpha-tocopherol, retinol, and cholesterol.

Ten women ingested either 90 mg of beta-carotene or placebo daily for 3 weeks while residing in their homes and eating their usual meals. Carotenoids (beta-carotene, lycopene, lutein/zeaxanthin), retinol, alpha-tocopherol, and cholesterol were measured in plasma lipoprotein and non-lipoprotein fractions before and after treatment.

In the beta-carotene-supplemented group, total plasma beta-carotene increased 14-fold from 0.48 +/? 0.13 to 6.83 +/? 2.12 mumol/L (p = 0.04). Although the greatest increase in beta-carotene was in low-density-lipoproteins (LDL), the magnitude of increase was similar in LDL, high-density-lipoproteins (HDL), and very-low-density-lipoproteins (VLDL). Thus, the relative distribution of beta-carotene in lipoproteins was unchanged: approximately 71% was in LDL, approximately 15% in HDL and approximately 12% in VLDL, before and after beta-carotene supplementation. There were no changes in amounts and distribution in lipoproteins of the other carotenoids, alpha-tocopherol, and cholesterol. There was no change in the amount of retinol in lipoprotein-deficient plasma. There were no changes in total plasma triglycerides. Significant positive correlations were found between LDL- or VLDL-cholesterol and alpha-tocopherol in LDL or VLDL, respectively; between LDL- or VLDL-cholesterol and lutein/zeaxanthin in LDL or VLDL, respectively; and between HDL-cholesterol and beta-carotene in HDL.

beta-Carotene supplementation (90 mg/day for 3 weeks) in healthy older women results in an enrichment of all plasma lipoprotein fractions with beta-carotene, but does not alter the relative distribution of beta-carotene in lipoproteins. beta-Carotene supplementation has no effect on the amounts and relative distribution of lycopene, lutein/zeaxanthin, and alpha-tocopherol in lipoproteins, or of retinol in the non-lipoprotein fraction of plasma. Short-term beta-carotene supplementation has no effect on the concentrations of plasma total triglycerides, total cholesterol, HDL-, LDL-, and VLDL-cholesterol.     

Interactions between vitamins C and E in human subjects

Despite convincing in vitro evidence, a vitamin C-E interaction has not been confirmed in vivo. This study was designed to examine the effects of supplementation with either vitamin C or E on their respective plasma concentrations, other antioxidants, lipids and some haemostatic variables. Fasting blood was collected before and after intervention from thirty healthy adults in a double-blinded crossover study. Baselines for measured variables were established after 2 weeks of placebo supplementation, followed by daily supplementation with 73.5 mg RRR-alpha-tocopherol acetate or 500 mg ascorbic acid, and placebo, for 6 weeks. A 2 month washout preceded supplement crossover. Mean values showed that plasma lipid standardised alpha-tocopherol increased with ascorbic acid supplementation: from 4.09 (sem 0.51) to 4.53 (sem 0.66) micromol/mmol total cholesterol plus triacylglycerol (P < 0.05), and plasma ascorbic acid increased from 62.8 (sem 14.9) to 101.3 (sem 22. 2) micromol/l (P < 0.005). Supplementation with (RRR)-alpha-tocopherol acetate increased plasma alpha-tocopherol from 26.8 (sem 3.9) to 32.2 (sem 3.8) micromol/l (P < 0.05), and lipid-standardised alpha-tocopherol from 4.12 (sem 0.48) to 5.38 (sem 0.52) micromol/mmol (P < 0.001). Mean plasma ascorbic acid also increased with vitamin E supplementation, from 64.4 (sem 13.3) to 76. 4 (sem 18.4) micromol/l (P < 0.05). Plasma ferric reducing (antioxidant) power and glutathione peroxidase (U/g haemoglobin) increased in both groups, while urate, total cholesterol and triacylglycerol levels decreased (P < 0.05 throughout). Results are supportive of an in vivo interaction between vitamins C and E.     

Long-term vitamin C supplementation has no markedly favourable effect on serum lipids in middle-aged Japanese subjects

Antioxidant vitamins have been reported to be associated with an improvement in blood lipid profiles, but results are not consistent. The present study was designed to determine whether long-term vitamin C supplementation could alter serum lipid concentrations in subjects who completed a 5-year population-based double-blind intervention trial. A total of 439 Japanese subjects with atrophic gastritis initially participated in the trial using vitamin C and beta-carotene to prevent gastric cancer. Before and upon early termination of beta-carotene supplementation, 134 subjects dropped out of the trial; finally, 161 subjects assigned to the high-dose group (500 mg vitamin C/d) and 144 subjects assigned to the low-dose group (50 mg vitamin C/d) were studied. No favourable effect of vitamin C supplementation on serum concentrations of total cholesterol, HDL- and LDL-cholesterol, and triacylglycerol was observed, although high-dose vitamin C supplementation increased serum vitamin C concentrations substantially. Among women, the mean change in serum triacylglycerol decreased (-0.12 mmol/l, 95 % CI -0.32, 0.09) in the high-dose group, but increased (+0.12 mmol/l, 95 % CI 0.03, 0.22) in the low-dose group. In addition, the mean change in serum triacylglycerol among women with hypertriacylglycerolaemia was statistically significant (-1.21, 95 % CI -2.38, -0.05) after high-dose vitamin C supplementation. The 5-year vitamin C supplementation had no markedly favourable effects on the serum lipid and lipoprotein profile. However, our present results do not preclude the possibility that vitamin C supplementation may decrease triacylglycerol concentrations among women with hypertriacylglycerolaemia.     

Zinc plus beta-carotene supplementation of pregnant women is superior to beta-carotene supplementation alone in improving vitamin A status in both mothers and infants

BACKGROUND: Deficiencies of vitamin A, iron, and zinc are prevalent in women and infants in developing countries. Supplementation during pregnancy can benefit mother and infant. OBJECTIVE: We examined whether supplementation during pregnancy with iron and folic acid plus beta-carotene or zinc or both improves the micronutrient status of mothers and infants postpartum. DESIGN: Pregnant women (n = 170) were supplemented daily only during pregnancy with beta-carotene (4.5 mg), zinc (30 mg), or both or placebo plus iron (30 mg) and folic acid (0.4 mg) in a randomized, double-blind, placebo-controlled trial. Micronutrient status was assessed 1 and 6 mo postpartum. RESULTS: Six months postpartum, plasma retinol concentrations were higher in the women who received zinc during pregnancy than in women who did not. Infants born to mothers supplemented with beta-carotene + zinc had higher plasma retinol concentrations, with the frequency of vitamin A deficiency reduced by >30% compared with the other 3 groups. Breast-milk beta-carotene concentrations were higher in all women supplemented with beta-carotene, but breast-milk retinol concentrations were higher only in women who received beta-carotene + zinc. Zinc concentrations did not differ among groups in mothers and infants. CONCLUSIONS: Zinc supplementation during pregnancy improved the vitamin A status of mothers and infants postpartum, which indicates a specific role of zinc in vitamin A metabolism. Addition of both beta-carotene and zinc to iron supplements during pregnancy could be effective in improving the vitamin A status of mothers and infants.