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Biomedical subjects

J Schrijver

Publications and source records attributed to J Schrijver.

At least 19 recordsLinked to original sources
PubMed2003

[Nutrition and health--vitamins and vitamin supplements].

A balanced diet based on the Guidelines of the Netherlands Nutrition Centre provides a suitable basis for the maintenance of good health. However, there are a number of situations where supplementation with vitamins is clearly indicated. These include infants (vitamin A, D and K), young children, and pregnant and lactating women (vitamin D), future expectant mothers (folic acid) and the elderly (vitamin D). If doubts exist about a sufficient vitamin intake via the regular diet, a daily supplement supplying all vitamins at the level of the recommended daily allowance (RDA) is considered to be a responsible and safe choice. Epidemiological research indicates that the incidence of certain diseases is lower if the intake of vitamins is significantly higher than the RDA. However to date, targeted intervention studies have provided little unequivocal evidence to support this argument. For certain vitamins (A, D, folic acid, B6, nicotinic acid and beta-carotene) excessive intakes are associated with a health risk or clear toxicity. In the case of vitamin B6, nicotinic acid, folic acid and beta-carotene this risk is mainly limited to the use of high-dose supplements.

Age Factors↗
PubMed1995

Stability of blood (pro)vitamins during four years of storage at -20 degrees C: consequences for epidemiologic research.

We studied the effects of frozen storage on (pro)vitamin concentrations in EDTA-plasma and whole blood. Aliquots from 55 samples were analyzed before storage and after 3, 6, 12, 24, 36 and 48 months at -20 degrees C. Dramatic decreases occurred for EDTA-plasma concentrations of vitamin E between 6 and 12 months, vitamin A, total carotenoids and beta-carotene after 1 year, and whole blood niacin. A smaller decrease was observed for folic acid at 1 year of storage, but the level remained constant thereafter. The vitamins D, B6, B12 (EDTA-plasma), B1 and B2 (whole blood) showed no decline during 4 years of storage. With the exception of folic acid, the observed decreases varied considerably among subjects. Therefore using EDTA-plasma stored longer than 1 year at -20 degrees C will result in highly attenuated odds ratios when assessing the relationship between vitamin A, carotenoids, or vitamin E with a given disease. Attenuation will also occur when using niacin concentrations in whole blood stored for 4 years at -20 degrees C.

Adult↗
PubMed1994

Thiamin, riboflavin and vitamin B6: impact of restricted intake on physical performance in man.

OBJECTIVE: A combined marginally deficient status of thiamin, riboflavin, vitamin B6 and vitamin C may affect physical performance, but the relative contribution of each vitamin can only be speculated. In a previous study we did not find any effect of restricted intake of vitamin C individually. Therefore, the functional effect of restriction of thiamin, riboflavin or vitamin B6, individually or in conjunction, was investigated. METHODS: A double-blind, 2 x 2 x 2 complete factorial experiment on the effects of thiamin, riboflavin and vitamin B6 restriction on physical performance was executed with 24 healthy men. During 11 weeks of low vitamin intake, the subjects were given a daily diet of regular food products providing no more than 55% of the Dutch Recommended Dietary Allowances (RDA) for thiamin, riboflavin and vitamin B6. Other vitamins were supplemented at twice the RDA level. RESULTS: In vitamin-restricted subjects, blood vitamin levels, erythrocytic enzyme activities and urinary vitamin excretion decreased and in vitro erythrocytic enzyme stimulation increased. Short-time vitamin restriction had no harmful effects on health. A significant overall decrease was observed in aerobic power (VO2-max; 11.6%), onset of blood lactate accumulation (OBLA; 7.0%) and oxygen consumption at this power output (VO2-OBLA; 12.0%), peak power (9.3%), mean power (6.9%) and related variables (p < 0.01). However, the observed performance decrements could not be attributed to marginal deficiency for any of the vitamins studied. CONCLUSION: The absence of vitamin-specific effects on performance decrements due to thiamin, riboflavin and vitamin B6 restriction suggests quantitatively similar but non-additive effects of these B-vitamins on mitochondrial metabolism.

Adult↗
PubMed1994

Postnatal changes in plasma chain-breaking antioxidants in healthy preterm infants fed formula and/or human milk.

Concentrations of chain-breaking antioxidants were studied in the first 6 postnatal weeks in 29 healthy preterm infants (gestational age 30-35 wk). Vitamin C, uric acid, and sulfhydryl groups declined, whereas vitamin E rose and bilirubin followed its typical biphasic postnatal course. The influence of these changes on the plasma peroxyl radical trapping capacity was assessed in vitro (TRAP assay). The trapping capacity decreased postnatally and this appeared to be related to the coincident fall in uric acid concentrations. Results did not differ between babies fed with only preterm formula (n = 12) and those fed predominantly with human milk (n = 6), except for higher bilirubin and TRAP values in the breast-fed infants. There are major postnatal changes in the concentrations of the plasma chain-breaking antioxidants and this may influence the susceptibility of the preterm baby to oxygen toxicity.

Aging↗
PubMed1993

Vitamin C status in elderly women: a comparison between women living in a nursing home and women living independently.

The vitamin C status in blood fractions in 135 elderly women aged 65 years and older was studied within the framework of the Dutch Nutrition Surveillance System. Mean (+/- standard deviation) vitamin C intake (mg/day) was lower among women living in a nursing home (54 +/- 27 mg/day) than among women living in service flats (97 +/- 55 mg/day) and women living independently (132 +/- 44 mg/day). (Service flats are apartments in which the rent includes housekeeping and, when ordered, meal service.) Marginal vitamin C values (< 23 mumol/L) in blood fractions and even levels as low as those found in clinical scurvy (< 11 mumol/L) were frequently observed. In the nursing home, 35% of the women had plasma vitamin C values below 11 mumol/L, and 23% had values between 11 and 23 mumol/L. Blood levels were not significantly affected by age, smoking status, or use of particular drugs but were strongly (r = .47 or, after logarithmic transformation, r = .64) associated with daily intake of vitamin C. Low intake of vitamin C resulted from an overall low food consumption and selective restriction of food products rich in vitamin C. Vitamin C losses caused by food preparation practices and distribution in the nursing home's catering system reduced actual vitamin C intake levels but these losses were not substantially greater than those that are assumed to occur as a result of preparation practices by women living independently.

Activities of Daily Living↗
PubMed1992

Marginal nutritional status among institutionalized elderly women as compared to those living more independently (Dutch Nutrition Surveillance System).

The nutritional status (assessed by anthropometric indices, and biochemical and hematological variables in blood) of three groups of elderly women (aged > or = 65 years) was evaluated within the framework of the Dutch Nutrition Surveillance System. The groups were composed of women living in a nursing home (n = 51), women living in service flats and receiving their dinners from the nursing home kitchen (n = 29), and women living independently (n = 52). Mean blood levels of folate, pyridoxal 5'-phosphate, 25-hydroxyvitamin D, alpha-tocopherol, vitamin C, albumin, selenium and total cholesterol were significantly (p < 0.05) lower among nursing home women. Among these women a biochemical deficiency was frequently found for 25-hydroxyvitamin D (73%), pyridoxal 5'-phosphate (57%), vitamin C (38%), selenium (30%) and folate (28%). These nutritional risks were largely independent of each other. Since folate and pyridoxal 5'-phosphate were associated with several clinicochemical indicators, health status may be an important determining factor for this unfavorable situation. Low 25-hydroxyvitamin D concentrations were associated with limited exposure to ultraviolet radiation and nonusage of vitamin D supplements. We conclude that dietary intake variables are not the only determinants of a marginal nutritional status among nursing home women. Use of foods with a high nutrient density should be encouraged, whereas other preventive measures are needed to improve vitamin D status.

Aged↗
PubMed1992

Effect of an exchange transfusion on plasma antioxidants in the newborn.

The effect of an exchange transfusion on antioxidants in the plasma of newborns with rhesus hemolytic disease was studied. The antioxidant concentrations in donor blood were similar to normal adult values except for the lower vitamin C concentrations. Exchange transfusion decreased the newborns' iron and ferritin levels and increased their ceruloplasmin and transferrin (primary antioxidants) concentrations and latent iron-binding capacity. The changes in secondary antioxidant concentrations were variable; uric acid and thiols were stable, vitamin C and bilirubin fell, and vitamin E rose. The total peroxyl-radical trapping capacity of the secondary antioxidants did not change significantly. The fall in levels of thiobarbituric acid reactive substances, an index of lipid peroxidation, was related to the lower levels present in the donor blood. Exchange transfusion rapidly produced variable changes in the concentrations of prooxidant and antioxidant substances in plasma and may thus influence free radical metabolism in the newborn.

Adult↗
PubMed1991

Determination of several retinoids, carotenoids and E vitamers by high-performance liquid chromatography. Application to plasma and tissues of rats fed a diet rich in either beta-carotene or canthaxanthin.

A method, using two different systems, is described for the high-performance liquid chromatographic analysis of retinol, retinal, retinoic acid, retinyl acetate, retinyl palmitate, alpha-, beta- and gamma-carotene, beta-apo-6'-, beta-apo-8', beta-apo-10'- and beta-apo-12'-carotenal, ethyl beta-apo-8'-carotenoate, alpha-tocopherol and alpha-tocopheryl acetate. The first system consists of a laboratory-packed Hypersil-ODS 3-microns column and a mobile phase of acetonitrile-methylene chloride-methanol-water (70:10:15:5, v/v). The second system consists of a laboratory-packed Hypersil-ODS 3-microns column and a mobile phase of acetonitrile-methylene chloride-methanol-water (70:10:15:5, v/v). The second system consists of a laboratory-packed Nucleosil C18 3-microns column and a mobile phase of acetonitrile-0.1 M ammonium acetate (80:20, v/v). The detection limits in standard solutions were 10 ng/ml for retinoids and carotenoids and 60 ng/ml for the E vitamers. Analysis of the tissues and plasma of rats, after 2 weeks on a diet supplemented with either beta-carotene or canthaxanthin (both 2 mg/g), led to the conclusion that the rats were able both to transport and store beta-carotene and canthaxanthin and to convert beta-carotene to retinol. Incubation of cytosol preparations from the mucosa of the small intestine of rat with 1 microgram of beta-carotene resulted in the formation of 10-20 ng of retinal within 1 h.

Animals↗
PubMed1991

Nutritional status and food consumption in 10-11 year old Dutch boys (Dutch Nutrition Surveillance System).

As part of the Dutch Nutrition Surveillance System, cardiovascular risk factors and food consumption (24 h recall) as well as haematological, Fe and vitamin status (A, B6, C) were assessed in 126 Dutch boys aged 10-11 years (response 71%). Body mass index (BMI) and the sum of four skinfolds were strongly associated (r 0.85, P less than 0.01) and 8% of the boys were overweight (BMI greater than 20.1 kg/m2). Elevated serum total cholesterol levels (greater than 4.4 mmol/l) were observed in 38%; total cholesterol and low-density-lipoprotein-cholesterol levels were strongly associated (r 0.88, P less than 0.001). Intake of fat was high (38% of energy) and too much fat was saturated (polyunsaturated: saturated 0.44, guideline: 0.5-1.0), whereas intake of carbohydrate (49% of energy) and dietary fibre was low. About 12% of the boys had insufficient Fe stores (plasma ferritin less than 12.0 micrograms/l) and the mean Fe intake (9.0 mg/d) was below recommended daily allowance (10.0 mg/d). Plasma ferritin was, however, not associated with haematological indices and no frank anaemias were observed. No marginal values were observed for vitamins A, B6 and C status. In conclusion, the main nutritional risks in boys aged 10-11 years are cardiovascular risk factors and Fe nutrition.

Ascorbic Acid↗
PubMed1991

Vitamin C analysis in whole blood, plasma and cells using reduced glutathione as preservative (stabilizer): losses and redistribution.

The losses and redistribution of vitamin C in blood fractions (stabilized with reduced glutathione) during 4 hours of storage at room temperature in the dark was studied among 27 elderly women. Storage did not have a statistically significant (p greater than 0.05) effect on the mean vitamin C levels in cells, plasma and whole blood. The results point to a redistribution of vitamin C among blood fractions. It is concluded that vitamin C concentrations in cells rather than in plasma should be the principal indicator of the vitamin C status when blood (stabilized with reduced glutathione) is stored at room temperature before specimen handling.

Aged↗
PubMed1990

Iron overload, free radical damage, and rhesus haemolytic disease.

To test the hypothesis that iron overload induces free radical damage in rhesus haemolytic disease (RHD), cord blood plasma of babies with RHD was compared with that of controls matched for gestational age. Babies with RHD had higher ferritin levels, lower latent iron-binding capacity, increased concentrations of lipid-peroxidation products, and low vitamin C levels. Plasma of 3 RHD babies did not inhibit peroxidation stress. These findings, of iron overload and free radical damage, have implications for treatment of RHD.

Antioxidants↗
PubMed1990

Vitamins and lung cancer.

Several factors are known to promote the development of a lung cancer. Smoking, occupation, environment, chronic bronchitis, and scars in the lung are all risk factors. Many studies have stressed the importance of nutrition, in particular vitamins. Vitamin A is necessary for cell differentiation. Retrospective and prospective studies have proven the inverse relation between provitamin A, beta-carotene, and lung cancer of the squamous and oat cell types. Studies in which beta-carotene or natural vitamin A are supplied to smokers, controls, and patients after resection for lung cancer are in progress. The study of other vitamins such as vitamin C and vitamin E has not led to definitive conclusions. The trace element selenium may also exert a beneficial effect.

Carotenoids↗
PubMed1990

Nutrition and aging: nutritional status of "apparently healthy" elderly (Dutch nutrition surveillance system).

In a nationwide survey the nutritional status was assessed of 539 apparently healthy, independently living elderly aged 65-79 years. Anthropometric data showed no energy deficits. The prevalence of anemia was 4 and 1% among men and women, respectively. Many elderly showed a low level of 25-hydroxyvitamin D in plasma (less than 31 nmol/L: men 35%; women 43%), indicating a marginal status. Although the prevalence of low blood levels of folate, pyridoxal-5'-phosphate, and total carotenoids was higher among the elderly than among younger adults, clear (clinical) signs of nutritional deficiencies were not observed. Prevalence of obesity (13%), hypercholesterolemia (38%), and hypertension (63%) was found to be high, the percentages being higher for women than for men. Several indicators of the nutritional status appeared to differ among age groups. It is concluded that few differences can be considered as being due to physiological aging, which finding should be reflected in reference values for elderly people.

Age Factors↗
PubMed1990

Effect of dietary fiber on the vitamin B6 status among vegetarian and nonvegetarian elderly (Dutch nutrition surveillance system).

To obtain more insight into the effect of dietary fiber on vitamin B6 status among elderly people, we studied dietary interrelationships as well as associations between dietary intake and plasma pyridoxal-5'-phosphate (PLP) and cofactor stimulation of aspartate aminotransferase in erythrocytes (EAST-AC) among 441 nonvegetarian (aged 65-79) and 32 vegetarian elderly (aged 65-94). EAST-AC was found to be inversely related with intake of vitamin B6 and dietary fiber in bivariate regression analyses. After adjustment for age, intake of energy, protein, and fiber, the intake of vitamin B6 was still inversely related with EAST-AC. The association between EAST-AC and dietary fiber disappeared in the multivariate analysis, whereas total protein intake proved to be positively related with EAST-AC in the multivariate analysis only. The differences between bi- and multivariate analyses are most likely due to the observed interrelationships between intake of vitamin B6, fiber, and protein. It is concluded that dietary fiber does not have a significant impact on the vitamin B6 status among Dutch elderly people, since only protein (positively) and vitamin B6 (inversely) intake appeared to be related with EAST-AC in the multivariate analysis.

Aged↗
PubMed1990

Controlled vitamin C restriction and physical performance in volunteers.

A double-blind study on the effects of vitamin C restriction on physical performance was executed with 12 healthy men. During seven weeks of low vitamin C intake six subjects were on a daily diet of regular food products, providing 20% of the Dutch Recommended Dietary Allowances (RDA) for vitamin C (Dutch RDA is 50 mg/day). Other vitamins were supplemented at twice the RDA level. After three weeks of low vitamin intake an additional vitamin C dose of 15 mg/day was provided, resulting in a total intake of 25 mg/day (50% of the Dutch RDA). Six control subjects consumed the same diet supplemented with twice the RDA for all vitamins. In the restriction group blood vitamin C levels decreased significantly (p less than 0.01). Vitamin C restriction had no harmful effects on health, aerobic power (VO2-max), and onset of blood lactate accumulation (OBLA). However, an increased heart rate at OBLA level was observed during the period of low vitamin C intake (p less than 0.05), possibly by interference with either catecholamine or carnitine metabolism. These results suggest that short-term marginal vitamin C deficiency does not affect physical performance in single bouts of intensive exercise.

Adult↗
PubMed1990

Long-term effects of a vegetarian diet on the nutritional status of elderly people (Dutch Nutrition Surveillance System).

The health and nutritional status (anthropometry, and blood and urine biochemistry) of 44 Dutch apparently healthy vegetarians, aged 65-97 years, refraining from meat, fish, and poultry consumption, was assessed for insight into long-term consequences of ovo-lacto- or lacto-vegetarianism. The results indicate that in comparison to omnivorous elderly the vegetarian elderly (especially men) have aged successfully with respect to cardiovascular risk factors. In contrast, vegetarian elderly are at a higher risk for a marginal iron, zinc, and vitamin B12 status. Although several vegetarian elderly showed low levels of 25-hydroxyvitamin D in plasma and many had low values of 24-hr urine volume (per kg body weight), these values are not likely the result of a vegetarian diet per se. It is concluded that, although some nutrition-related risks are prevalent among vegetarian elderly, these risks can probably be prevented by lifestyle changes.

25-Hydroxyvitamin D 2↗
PubMed1990

Dependence of vitamin B-6 status assessment on alcohol intake among elderly men and women (Dutch Nutrition Surveillance System).

To obtain more insight into the effect of moderate alcohol intake on vitamin B-6 status indicators, we studied the associations of alcohol intake (unadjusted and adjusted for intake of vitamin B-6 and protein) with the erythrocyte aspartate aminotransferase activation coefficient (EAST-AC) and plasma pyridoxal 5'-phosphate (PLP) level. Data obtained from men (n = 224) and women (n = 217) aged 65-79 (nationwide sample in the Netherlands) were used for this purpose. Although alcohol intake (a maximum of 21% of the energy came from alcohol) tended to be positively associated with PLP, this association never reached statistical significance (p greater than or equal to 0.05). EAST-AC was inversely associated with alcohol intake, whether or not it was adjusted for vitamin B-6 and protein intake. Similar results were found for the total EAST activity (after adding PLP) or apoenzyme activity; the basal EAST activity (before adding PLP) or holoenzyme activity was not associated with the alcohol intake. These results indicate that caution is needed in the interpretation of the specificity of EAST-AC (i.e., the degree to which EAST-AC is unaffected by other factors) as an indicator of vitamin B-6 intake.

Aged↗