Quantification of the bioavailability of riboflavin from foods by use of stable-isotope labels and kinetic modeling

BACKGROUND

Discrepancies have been reported between estimates of the prevalence of riboflavin deficiency based on intakes of riboflavin and estimates based on measures of riboflavin status. One reason for this may be an overestimate of the bioavailability of riboflavin from foods, about which relatively little is known.

OBJECTIVE

We aimed to quantify the bioavailability of riboflavin from milk and spinach by using stable-isotope labels and a urinary monitoring technique and by a plasma appearance method based on kinetic modeling.

DESIGN

Twenty healthy women aged 18-65 y were recruited for a randomized crossover study performed with extrinsically labeled (13C) milk and intrinsically labeled (15N) spinach as sources of riboflavin. An intravenous bolus of labeled riboflavin was administered with each test meal to assess the apparent volume of distribution of riboflavin in plasma.

RESULTS

No significant differences were noted in riboflavin absorption from the spinach meal and from the milk meal according to either the urinary monitoring technique (60 +/- 8.0% and 67 +/- 5.4%, respectively; P = 0.549) or the plasma appearance method (20 +/- 2.8% and 23 +/- 5.3%, respectively; P = 0.670).

CONCLUSIONS

A large fraction of newly absorbed riboflavin is removed by the liver on "first pass." The plasma appearance method therefore underestimates riboflavin bioavailability and should not be used to estimate riboflavin bioavailability from foodstuffs. Urinary monitoring suggests that riboflavin from spinach is as bioavailable as is riboflavin from milk.

The methylenetetrahydrofolate reductase 677C-->T polymorphism as a modulator of a B vitamin network with major effects on homocysteine metabolism

Folates are carriers of one-carbon units and are metabolized by 5,10-methylenetetrahydrofolate reductase (MTHFR) and other enzymes that use riboflavin, cobalamin, or vitamin B6 as cofactors. These B vitamins are essential for the remethylation and transsulfuration of homocysteine, which is an important intermediate in one-carbon metabolism. We studied the MTHFR 677C-->T polymorphism and B vitamins as modulators of one-carbon metabolism in 10,601 adults from the Norwegian Colorectal Cancer Prevention (NORCCAP) cohort, using plasma total homocysteine (tHcy) as the main outcome measure. Mean concentrations of plasma tHcy were 10.4 micromol/liter, 10.9 micromol/liter, and 13.3 micromol/liter in subjects with the CC (51%), CT (41%), and TT (8%) genotypes, respectively. The MTHFR 677C-->T polymorphism, folate, riboflavin, cobalamin, and vitamin B6 were independent predictors of tHcy in multivariate models (P<.001), and genotype effects were strongest when B vitamins were low (P<or=.006). Conversely, the MTHFR polymorphism influenced B vitamin effects, which were strongest in the TT group, in which the estimated tHcy difference between subjects with vitamin concentrations in the lowest compared with the highest quartile was 5.4 micromol/liter for folate, 4.1 micromol/liter for riboflavin, 3.2 micromol/liter for cobalamin, and 2.1 micromol/liter for vitamin B6. Furthermore, interactions between B vitamins were observed, and B vitamins were more strongly related to plasma tHcy when concentrations of other B vitamins were low. The study provides comprehensive data on the MTHFR-B vitamin network, which has major effects on the transfer of one-carbon units. Individuals with the TT genotype were particularly sensitive to the status of several B vitamins and might be candidates for personalized nutritional recommendations.

Protective association of MTHFR polymorphism on cervical intraepithelial neoplasia is modified by riboflavin status

OBJECTIVES

We previously reported that women polymorphic for the methylenetetrahydrofolate reductase (MTHFR) gene were less likely to have cervical intraepithelial neoplasia (CIN) 2 or 3 (odds ratio [OR] 0.40, 95% confidence interval [CI] 0.21-0.78, P = 0.007). In the present study, we tested whether this protective association is modified by circulating riboflavin status in the same study population.

METHODS

Riboflavin status was assessed by the erythrocyte glutathione reductase assay and expressed in terms of an erythrocyte glutathione reductase activity coefficient. The status of MTHFR polymorphism, riboflavin, and circulating concentrations of folate, vitamins B12, A, E, and C, and total carotene were ascertained in 170 White and 265 African-American women positive for the cervical presence of high-risk human papilloma virus. Presence/absence of CIN 2 or 3 was determined histologically, and associations with risk factors were examined using multiple logistic regression. Eighty women with CIN 2 or 3 lesions were compared with 355 women without cervical lesions. Based on the median erythrocyte glutathione reductase activity coefficient of 1.4, women were grouped into low (>1.4) and high (< or =1.4) riboflavin status.

RESULTS

Women with MTHFR polymorphism and low riboflavin status were significantly less likely to have CIN 2 or 3 than was the referent group of women without the polymorphism and high riboflavin status (OR 0.35, 95% CI 0.13-0.92, P = 0.034). MTHFR polymorphism was not associated with CIN 2 or 3 in women with high riboflavin status (OR 0.51, 95% CI 0.22-1.19, P = 0.119), nor were any of the associations influenced by folate levels.

CONCLUSION

A further inactivation of polymorphic MTHFR by low riboflavin status and a resulting shift in the folate metabolic pathway toward DNA synthesis may explain these observations. The practical implications of this complex gene-nutrient-disease interaction will require further investigation.

Riboflavin status in acute ischaemic stroke

BACKGROUND

There is experimental evidence that riboflavin (vitamin B2) supplementation reduces oxidative damage and cerebral oedema following acute stroke.

OBJECTIVE

To measure riboflavin levels in acute stroke before and after supplementation with this vitamin.

DESIGN

Ninety-six acute ischaemic stroke patients had their riboflavin status measured at baseline and then randomly assigned to receive 5 mg of oral riboflavin and other B-group vitamins within 12 h of the stroke onset and then daily or no B-vitamins for 14 days. Non-fasting venous blood was obtained at baseline, days 7 and 14 post-randomization for measurement of riboflavin status using erythrocyte glutathione reductase activity coefficient (EGRAC). EGRAC is a measure of riboflavin tissue saturation. This assay has the advantage of being extremely stable and sensitive. EGRAC values are inversely proportional to riboflavin status, so that values greater than 1.3 indicate biochemical deficiency.

RESULTS

Fifty-one per cent of patients studied were riboflavin deficient at baseline. Fourteen days of riboflavin supplementation significantly improved the measure of B2 status compared with the control group. Seven out of 37 patients in the supplement group (19%) were riboflavin deficient compared with 22 out of 39 patients (56%) in the control group at the end of the treatment period (P=0.035 for the differences in cumulative changes between groups over 2 weeks).

CONCLUSIONS

A high proportion of acute stroke patients were biochemically deficient of riboflavin immediately post-infarct. Supplementation with 5 mg of riboflavin for 2 weeks significantly improved riboflavin status; however, the clinical significance of these findings is not yet known.

Thiamin and riboflavin status of Taiwanese elementary schoolchildren

In The Nutrition and Health Survey of Taiwan Elementary School Children (NAHSIT Children 2001~2002), erythrocyte activity coefficients of transketolase (ETKAC) and glutathione reductase (EGRAC) were chosen as indices for assessing the functional status of thiamin and riboflavin nutriture. Mean values of the ETKAC for boys and girls, both of which were in a normal range, were 1.07+/-0.00 and 1.06+/-0.01, respectively. The respective prevalence rates of marginal and deficient thiamin states were 10.4% and 7.8% for boys and 9.3% and 7.3% for girls. Mean values of the EGRAC were 1.18+/-0.00 for boys and 1.19+/-0.01 for girls, both of which showed an increasing trend with age. The respective rates of marginal and deficient riboflavin states were as high as 32.5% and 3.5% for boys and 35.9% and 4.5% for girls. The marginal and deficient riboflavin statuses of Taiwanese schoolchildren were associated with a low frequency of dairy food consumption and an elevated risk of anemia.

Separation, identification and quantification of riboflavin and its photoproducts in blood products using high-performance liquid chromatography with fluorescence detection: a method to support pathogen reduction technology

A medical device using riboflavin (RB) and light is being developed for the reduction of pathogens in platelet concentrates (MIRASOL pathogen reduction technology [PRT]). A high-performance liquid chromatography (HPLC) method for the quantification of RB and its main photoproduct, lumichrome (LC) in blood components has been developed and validated. In addition, the same method has been used to identify and quantify the presence of additional photoproducts-catabolites of RB. Levels of these agents before and after treatment as well as endogenous levels present in normal donor blood are reported using this analytical technique. The method allows for quantitative and qualitative analysis of RB and LC in blood components using HPLC-fluorescence detection, a Zorbax SB-CN (stable bond cyano) column and a methanol-water mobile phase. Quantitation and qualitative analysis of additional photoproducts of RB was also performed, but the method has not been validated for these other components. The method described has passed an 8 day validation and has been found to be adequate for its intended use. The range of the method for RB is 0.016-1.500 microM and for LC is 0.060-1.500 microM. The method detection limit for RB is 0.0006 microM and for LC is 0.012 microM. The acceptance criteria for repeatability were met; the relative standard deviation for RB was 0.64% and for LC was 0.76%. The acceptance criteria for bias were met with a 97% average recovery for RB and a 102% recovery for LC. Samples were centrifuged and diluted 1:50 with 0.9% saline before analysis. No protein precipitation or extraction was required. A mass balance of approximately 93.4-94.4% was achieved after exposure of products to UV light in the intended pathogen reduction treatment method. The method permitted the identification of photoproducts in blood that were both naturally occurring and produced after photolysis of blood samples treated with the PRT process. The identity of these photoproducts has been established using HPLC Tandem Mass Spectrometry (MS/MS) and UV spectroscopic methods and has been correlated with known metabolites and catabolites of RB. HPLC with fluorescence detection using a reverse phase cyano-column allows for accurate separation, identification and quantification of both RB and LC in blood products without the need for solvent extraction or protein precipitation. Additional photoproducts could also be identified and quantified using this method. The presence of these agents in normal, untreated blood suggests that their presence in blood is ubiquitous.

Conversion of FAD to FMN and riboflavin in plasma: effects of measuring method

The stability of flavin adenin dinucleotide (FAD) in plasma was studied under a low-intensity light and FAD was found to be converted to flavin mononucleotide (FMN) and riboflavin (RF) in both human and rat plasma. The hydrolysis rates of FAD in plasma at 4 degrees C were lower than those at 37 degrees C. In addition, the hydrolysis rates were markedly inhibited when EDTA, known as an anticoagulant, was added to plasma. These results indicated that plasma samples in pharmacokinetic studies should be pretreated with EDTA, extracted at the earliest convenience and lower temperature like 4 degrees C to keep a high stability. The pharmacokinetic study after intravenous administration of FAD at a dose of 500 nmol/kg as FAD in rats was performed with plasma samples after addition of EDTA under strict light and temperature control. A measurable amount of FAD in plasma together with rapid conversions of FAD to FMN and RF were observed in rat plasma. The AUC values (mean+/-S.D. of 4 rats) for FAD, FMN and RF were 707+/-378, 3643+/-958 and 30095+/-3544 nmol x min/l, respectively. Using excess EDTA under strict temperature and light control may be useful for assessment of vitamin B2 in the in vivo study.

B-vitamin status and concentrations of homocysteine in Austrian omnivores, vegetarians and vegans

BACKGROUND

A vegetarian diet is considered to promote health and longevity and reduce the risk of cardiovascular diseases and cancer. However, a vegetarian diet may be deficient in some nutrients. Exclusion of animal products in vegetarian diets may affect the status of certain B-vitamins, and further cause the rise of plasma homocysteine concentration.

OBJECTIVE

The nutritional status of various B-vitamins (B(1), B(2), B(6), B(12), folic acid) and the concentration of homocysteine in blood plasma of omnivores (n = 40), vegetarians (n = 36) and vegans (n = 42) in Austria was evaluated.

METHODS

The evaluation was done using the functional parameters erythrocyte transketolase (ETK), glutathione reductase (EGR) and glutamic oxaloacetic transaminase (EGOT) activation coefficients. Enzyme activity was measured photometrically. The quantity of vitamins B(1), B(2) and B(6) in urine and the concentrations of vitamin B(6) and homocysteine in plasma were determined by HPLC methods with fluorescence detection. Plasma concentration of vitamin B(12) and folic acid were measured with radioimmunoassay.

RESULTS

Most of the subjects showed a satisfying vitamin B(1) status. Vegans presented a significantly lower mean plasma vitamin B(12) concentration than omnivores and vegetarians and deficiency in 2.4% of the volunteers but the highest mean value of plasma folate among the investigated groups. A deficient status of folate was found in 18% of omnivores and in approximately 10% of vegans and vegetarians. The status of riboflavin is considered to be deficient in about 10% of omnivores and vegetarians and in over 30% of vegans. According to the activation coefficient of GOT, approximately one third of all subjects showed vitamin B(6) deficiency. Elevated homocysteine concentration in plasma was observed in 66% of the vegans and about 45-50% of the omnivores and vegetarians. Vegan subjects had significantly higher mean plasma homocysteine levels than omnivores.

CONCLUSION

Thiamin and folate need not be a problem in a well-planned vegan diet. Vitamins B(12) and B(2) may need attention in the strict vegan diet, especially regarding elevated homocysteine levels in plasma. Pyridoxine status appeared to be independent of the diet.

Antioxidant supplementation with or without B-group vitamins after acute ischemic stroke: a randomized controlled trial

BACKGROUND

Evidence shows that there is a rapid increase in the production of markers of oxidative damage immediately after acute ischemic stroke and that endogenous antioxidant defenses are rapidly depleted, thus permitting further tissue damage. Several studies point to an antioxidant effect of B-group vitamins and a pro-oxidant effect of elevated total plasma homocysteine (tHcy).

METHODS

To test whether supplementary antioxidants with or without B-group vitamins during this critical period enhance antioxidant capacity or mitigate oxidative damage, ninety-six acute ischemic stroke patients within 12 hours of symptom onset were randomly assigned to receive either daily oral 800 IU (727 mg) vitamin E and 500 mg vitamin C (n = 24), or B-group vitamins (5 mg folic acid, 5 mg vitamin B(2), 50 mg vitamin B(6), and 0.4 mg of vitamin B(12); n = 24), both vitamins together (n = 24), or no supplementation (n = 24) for 14 days. Treatment groups and controls were matched for stroke subtype and age. Blood was obtained before treatment, at day 7, and day 14 for measurements of plasma or blood vitamin status, plasma total antioxidant capacity (TAOC), malondialdehyde (MDA), tHcy and C-reactive protein (CRP).

RESULTS

Supplementation with antioxidant vitamins and B-group vitamins separately or together significantly increased the plasma concentration of vitamin C, E, pyridoxal phosphate (B(6) status), red blood cell folate, and improved a measure of B(2) status (red cell glutathione reductase activation coefficient [EGRAC]), compared with the control group. Plasma TAOC increased significantly in the antioxidant treatment groups compared with the nonsignificant decline seen in the control group. tHcy concentrations decreased in subjects who received B-group vitamins and the control group compared with the rise seen in those who received antioxidants alone. There was a significant reduction in plasma MDA concentration in the 3 treatment groups, in contrast to the increase seen in the control group; however, the changes were most evident in antioxidant groups. CRP concentrations (a marker of tissue inflammation) were significantly lower in the 3 treatment groups compared with the control group. There were no additive or synergistic effects of antioxidants and B-group vitamins together on any outcome measure.

CONCLUSIONS

Antioxidants supplementation with or without B-group vitamins enhances antioxidant capacity, mitigates oxidative damage, and may have an anti-inflammatory effect immediately postinfarct in stroke disease.

[Status of vitamin A, vitamin B2, iron and an-oxidantive activity in anemic pregnant women in China]

OBJECTIVE

To investigate the status of vitamin A(VA), vitamin B2 (VB2), iron and anoxidative function in anemic and non-anemic pregnant women.

METHODS

426 anemic and 36 non-anemic pregnant women were included in the study. The survey of 24-hour's diet recall of pregnant women was made to evaluate intake of iron, VB2, folic acid, etc by the nutrition software provided by Beijing 301 hospital, iron and VA were measured by Radioimmunoassay (RIA) and by high-pressure liquid chromatography. VB2 status was detected using the assay for erythrocyte glutathione reductase (Egr; EC 1.6.4.2) activity. SOD and GSH-Px activities and MDA were determined using commercial kits. Peripheral blood erythrocyte membrane fluidity was detected by using 1,6-diphenyl-1,3,5-hexatriene as a probe, the degree of fluorescence polarization (P) at 25 degrees C of disrupted cells plasma membranes were compared for a variety of systems.

RESULTS

Median intakes of protein and vitamin C met the current Chinese RNIs for pregnancy, whereas intakes of(VA) and VB2 were well below the recommendations. Intake of iron were above 90%, but the main sources of iron are vegetables. Plasma VA (1.25 micromol/L) and iron (20.57 microg/L) were lower, BGRAC (1.79) was higher than that in non-anemia group (VA 1.57 micromol/L, SF 33.16 microg/L, BGRAC 1.52). The level of plasma SOD (77.1U/ml) and the activity of GSH-Px (61.9U) were lower than those in non-anemia group (92.2U/ml, 71.6U, P < 0.05), while MDA (4.58 nmol/ml) level and erythrocyte membrane (P = 0.2622, eta = 2.7465) fluidity were higher than those non-anemia group(MDA = 3.78 nmol/ ml, P = 0.2360, eta = 2.3658).

CONCLUSION

Plasam VA, VB2 and iron, antioxidantcapacity and erythrocyte membrane fluidity were decreased in the anemic pregnant women.

Ingestion of milk fermented by genetically modified Lactococcus lactis improves the riboflavin status of deficient rats

Riboflavin deficiency is common in many parts of the world, particularly in developing countries. The use of riboflavin-producing strains in the production of dairy products such as fermented milks, yogurts, and cheeses is feasible and economically attractive because it would decrease the costs involved during conventional vitamin fortification and satisfy consumer demands for healthier foods. The present study was conducted to assess in a rat bioassay the response of administration of milk fermented by modified Lactococcus lactis on the riboflavin status of deficient rats. Rats were fed a riboflavin-deficient diet during 21 d after which this same diet was supplemented with milk fermented by Lactoccus lactis pNZGBAH, a strain that overproduces riboflavin during fermentation. The novel fermented product, with increased levels of riboflavin, was able to eliminate most physiological manifestations of ariboflavinosis, such as stunted growth, elevated erythrocyte glutathione reductase activation coefficient values and hepatomegaly, that were observed using a riboflavin depletion-repletion model, whereas a product fermented with a nonriboflavin-producing strain did not show similar results. A safety assessment of this modified strain was performed by feeding rodents with the modified strain daily for 4 wk. This strain caused no detectable secondary effects. These results pave the way for analyzing the effect of similar riboflavin-overproducing lactic acid bacteria in human trials. The regular consumption of products with increased levels of riboflavin could help prevent deficiencies of this essential vitamin.

Fortification of maize meal improved the nutritional status of 1-3-year-old African children

OBJECTIVE

To evaluate the effectiveness of a vitamin-fortified maize meal to improve the nutritional status of 1-3-year-old malnourished African children.

DESIGN

A randomised parallel intervention study was used in which 21 experimental children and their families received maize meal fortified with vitamin A, thiamine, riboflavin and pyridoxine, while 23 control children and their families received unfortified maize meal. The maize meal was provided for 12 months to replace the maize meal habitually consumed by these households.

METHODS

Sixty undernourished African children with height-for-age or weight-for-age below the 5th percentile of the National Center for Health Statistics' criteria and aged 1-3 years were randomly assigned to an experimental or control group. Baseline measurements included demographic, socio-economic and dietary data, as well as height, weight, haemoglobin, haematocrit, serum retinol and retinol-binding protein (RBP). Anthropometric, blood and serum variables were measured again after 12 months of intervention. Complete baseline measurements were available for 44 children and end data for only 36. Changes in these variables from baseline to end within and between groups were assessed for significance with paired t-tests, t-tests and analysis of variances using the SPSS program, controlling for expected weight gain in this age group over 12 months. Relationships between changes in variables were examined by calculating correlation coefficients.

RESULTS

The children in the experimental group had a significantly (P < or = 0.05) higher increase in body weight than control children (4.6 kg vs. 2.0 kg) and both groups had significant (P < or = 0.05) but similar increases in height. The children in the experimental group showed non-significant increases in haemoglobin and serum retinol, while the control children had a significant (P = 0.007) decrease in RBP. The change in serum retinol showed a significant correlation with baseline retinol (P = 0.014), RBP (P = 0.007) and weight (P = 0.029), as well as with changes in haemoglobin (P = 0.029).

CONCLUSION

Despite a small sample size, this study showed positive effects of a vitamin-fortified maize meal on weight gain and some variables of vitamin A status in 1-3-year-old African children. The study confirmed the relationship between vitamin A and iron status. The results suggest that fortification of maize meal would be an effective strategy to address micronutrient deficiencies in small children in South Africa.

Values of water-soluble vitamins in blood and urine of Japanese young men and women consuming a semi-purified diet based on the Japanese Dietary Reference Intakes

We investigated the levels of water-soluble vitamins except for vitamin B6 in the blood and urine of Japanese college male (n = 10) and female (n = 10) students. They consumed for 7 d a semi-purified diet based on Japanese Dietary Reference Intakes to assess the Recommended Dietary Allowances (RDA) for water-soluble vitamins and to present some new normal values for blood and urine levels of water-soluble vitamins in Japanese. The blood and the 24-h urine samples were collected on the last day of the experiment and measured. The values of total vitamin B1 in whole blood, total vitamin B2 in whole blood, total cyanocobalamin in serum, total nicotinamide in whole blood, total pantothenic acid in whole blood, total folates in serum, total biotin in serum, and ascorbic acid in plasma were 104+/-17 pmol/mL (mean+/-SD), 216+/-25 pmol/mL, 0.34+/-0.05 pmol/mL, 59.1+/- 5.0 nmol/ mL, 2.45+/-0.37 nmol/mL, 15.6+/-4.6 pmol/mL, 8.3+/-0.5 pmol/mL, and 62+/-10 nmol/mL, respectively, in males, and 90+/-23, 234+/-18, 0.67+/-0.20, 61.9+/-6.0, 2.48+/-0.30, 30.2+/-8.6, 8.4+/-0.3, and 67+/-14, respectively, in females. There was a significant difference in the values of cyanocobalamin and total folates between men and women. The urinary excretion of vitamin B1, vitamin B2, cyanocobalamin, sum of the catabolic metabolites of nicotinamide, pantothenic acid, folates, biotin, and ascorbic acid were 665+/-114 nmol/d, 562+/-325 nmol/d, 93+/-31 pmol/d, 84+/-26 micromol/d, 9.3+/-2.3 micromol/d, 19.4+/-2.8 nmol/d, 83+/-18 pmol/d, and 148+/-51 micromol/d, respectively, in males, and 495+/-212, 580+/-146, 145+/-49, 83+/-19, 16.9+/-1.3, 22.7+/-2.7, 83+/-23, and 140+/-51, respectively, in females. There was a significant difference in the urinary excretion of cyanocobalamin, pantothenic acid and total folates between men and women. These values will be useful for the nutritional assessment of water-soluble vitamins for Japanese, although the examination period was short. In future, an experiment with various age groups and re-evaluation by repeated experiments will provide more accurate values.

Effects of short-term folic acid and/or riboflavin supplementation on serum folate and plasma total homocysteine concentrations in young Japanese male subjects

OBJECTIVE

To investigate the effects of short-term folic acid and/or riboflavin supplementation on serum folate and plasma plasma total homocysteine (tHcy) concentrations in young Japanese male subjects.

DESIGN

In a double blind, randomized controlled trial.

INTERVENTION

Subjects were randomly assigned to one of four groups and received a placebo (control group), 800 microg/day folic acid (FA group), 8.4 mg/day riboflavin (R group), or both (FAR group) for 2 weeks.

SETTING

Tokyo, Japan.

SUBJECTS

In total, 32 healthy male volunteers aged 20-29 years.

RESULTS

At the end of the 2 week supplementation period, the tHcy concentration decreased significantly in the FA group. Serum folate concentrations had increased between 2.7 and 2.0-fold in the FA and FAR groups, respectively, but the mean within-group changes in serum folate and plasma tHcy concentrations did not differ between these two groups. At the end of the study, alanine amino transferase was decreased in the R and FAR groups, while alanine amino transferase was increased in the FA group.

CONCLUSION

Supplementation with folic acid, 800 microg/day, for 2 weeks, increased the serum and red blood cell folate concentrations and decreased the plasma tHcy concentrations in healthy young male subjects. Riboflavin supplementation may have blunted the effect of folic acid, which resulted in a diminished reduction of tHcy in our subjects.

Feeding high levels of lupine seeds to broiler chickens: plasma micronutrient status in the context of digesta viscosity and morphometric and ultrastructural changes in the gastrointestinal tract

This work examines the effects of lupine-based diets on the status of the host's riboflavin and zinc. Test diets contained 35% soybean meal (control) or raw (40%) or dehulled (35%) lupine seed meal and were isocaloric (13.4 MJ of AME/kg) and isonitrogenous (23% crude protein). Each diet was offered ad libitum to a group of 16 male commercial broiler chicks for 21 d, starting at 1 d of age. Broilers fed lupine diets had lower feed intakes and growth rates. All sections of the intestinal tract were significantly enlarged (P < 0.01) in all groups fed lupine-based diets in comparison with broilers fed the soybean meal diet, but there were no differences in the morphologies of the mucosa, submucosa, muscularis, or serosa. Increased size of the duodenum, jejunum, and ileum was predominantly attributed to the increase in length rather than intestinal tissue mass. Hence, the enlargement of the intestinal tract was consistent with physiological hyperplasia and not pathological remodeling and hypertrophy. Overall, broilers fed lupine-based diets had more viscous digesta than those fed the soybean meal diet, but the differences were statistically not significant. Blood plasma Zn concentration did not differ between broilers fed lupine-based diets and those fed soybean-meal-based diets, and all broilers fed lupine-based diets had significantly higher (P < 0.001) riboflavin concentrations. In this context, it is apparent that the bioavailability of these micronutrients from lupine diets is not compromised. Intestinal tissue hyperplasia may be interpreted as physiological adaptation to increase absorptive capacity and thus maximize absorption of essential nutrients in the face of antinutritional factors in the diet.

Age as a determinant of nutritional status: a cross sectional study

BACKGROUND

Undenutrition is known to be prevalent and largely unrecognised in older patients; however, aberrations in indicators of nutritional status may simply reflect effects of age and/or functional disability.

OBJECTIVE

The aim of this study was to measure the effect, if any of age on nutritional status in older patients.

DESIGN

445 randomly selected hospitalised patients consented to nutritional status assessment derived from anthropometric, haematological, and biochemical data within 72 hours of admission. Nutritional status was compared between those age < 75 years and those aged 75 years or more. Using multiple regression models, we measured the association between age and nutritional assessment variables after adjusting for disability, chronic illness, medications, smoking and tissue inflammation.

RESULTS

Body weight, body mass index, mid-upper arm circumference, haemoglobin, serum albumin and plasma ascorbic acid were all significantly lower in people aged > or = 75 years compared with those < 75 years of age. Although riboflavin (vitamin B2), 25OH VitD3, red-cell folate and vitamin B12 concentrations were lower in those aged > or = 75 years, differences were not statistically significant. After adjusting for disability and co-morbidity in a multivariate analysis, age alone had a significant and independent effect on important anthropometric and biochemical nutritional assessment variables.

CONCLUSION

Increasing age is independently associated with poor nutritional status. This may partly explain the poor clinical outcome in older patients.

Multianalyte quantification of vitamin B6 and B2 species in the nanomolar range in human plasma by liquid chromatography-tandem mass spectrometry

BACKGROUND

Homocysteine, a risk factor of cardiovascular disease, cognitive disorders, and pregnancy complications, exists at a point of metabolic convergence of several B vitamins, including vitamins B(6) and B(2) (riboflavin). Measurement of the various forms of these vitamins may be useful for the study of hyperhomocysteinemia as well as for the assessment of vitamin status.

METHODS

Plasma (60 microL) was deproteinized by mixing with an equal volume of 50 g/L trichloroacetic acid that contained d(2)-pyridoxal 5'-phosphate, d(3)-pyridoxal, and d(8)-riboflavin as internal standards. Pyridoxal (PL), pyridoxal 5'-phosphate (PLP), pyridoxine (PN), pyridoxine 5'-phosphate, pyridoxamine (PM), pyridoxamine 5'-phosphate, 4-pyridoxic acid (PA), riboflavin, flavin mononucleotide (FMN), and FAD were separated on a C(8) reversed-phase column, which was developed with an acetonitrile gradient in a buffer containing acetic acid and heptafluorobutyric acid. The analytes were detected by tandem mass spectrometry in the positive-ion mode.

RESULTS

The chromatographic run lasted 8 min. Within- and between-day CVs were 3%-20% and 6%-22%, respectively, and recoveries were 78%-163%. Limits of detection (signal-to-noise ratio = 5) were in the range 0.1-4.0 nmol/L, and the response was linear over several orders of magnitude. In samples from 94 healthy persons, we obtained median concentrations (nmol/L) of 35.4 for PLP, 16.9 for PL, 22.4 for PA, 10.3 for riboflavin, 7.5 for FMN, and 63.1 for FAD. PN and PM were also detected in some cardiovascular patients taking B(6) supplements.

CONCLUSIONS

This method based on liquid chromatography-tandem mass spectrometry measures all known plasma forms of vitamins B(6) and B(2), which span a wide range of polarity. The assay is characterized by simple sample processing with no derivatization, low sample volume requirement, and a short run time.

Determination of B2 and B6 vitamers in serum by capillary electrophoresis-molecular fluorescence-charge coupled detector

A method for the separation by capillary zone electrophoresis and determination of vitamers of two important water-soluble vitamins, i.e., B2 and B6, is proposed here. The working conditions for optimal separation were obtained by a multivariate methodology in order to succeed in the best resolution in the shortest analysis time. The optimization of the buffer composition together with other variables, such as analysis and injection voltage, temperature of the capillary cassette, and injection time, resulted in a solution of 30 mM KH2PO4 adjusted to pH 8.5 with formic acid. Concerning the detection step, the target analytes were quantified by molecular fluorescence, for which two different detectors, a photomultiplier tube (PMT) and a charge-coupled detector (CCD), were compared in terms of resolution, sensitivity, and precision. A Xe-Hg lamp was used as an irradiation source in the two cases. The best option was the CCD, which provides three-dimensional electropherograms and enables to solve the overlapped peaks. Besides, the sensitivity of the CCD was similar to that of the PMT, due to the treatment data, obtaining limits of detection and quantification from 1.16 to 27.1 ng/g and from 3.83 to 89.4 ng/g, respectively. The method was applied to the serum samples for which a prior liquid-liquid extraction using ethanol in an acid medium was mandatory for eliminating the interferences and concentrating the analytes by a factor of 5. The rapidity of the analysis (13 min for the electrophoretic separation) and the excellent precision (repeatability and within-laboratory reproducibility between 2.86 and 4.11% and 7.03 and 8.45%, respectively, both expressed as relative standard deviation) demonstrated the capability of the proposed method for a clinical routine analysis.

[Vitamin metabolism and status in patients with gastrointestinal diseases]

Principle differences in vitamin C, B2, B6, A, E and carotenoids sufficiency of healthy suffering from gastrointestinal diseases (gastric and duodenal ulcer, chronic gastritis, dyskinesia bile tracts) ulc adults and children has not been determined by means of the statistic analysis including such parameters as median, mode, insufficiency frequency, curves of vitamin blood plasma concentration distribution. Polyhypovitaminosis frequency among patients is a result of low vitamin content in reduced diets but not reflect vitamin metabolism alteration.

Prevalence of thiamin and riboflavin deficiency among the elderly in Taiwan

The purpose of this study was to perform biochemical assessments of the nutritional status of thiamin and riboflavin in the 2379 elderly persons (1213 males, 1166 females) participating in the Elderly Nutrition and Health Survey in Taiwan (1999-2000) (Elderly NAHSIT). Through analysis of the data we aimed to investigate possible factors related to the prevalence of vitamin deficiency. Activity coefficients of erythrocyte transketolase and glutathione reductase (ETKAC and EGRAC) were the chosen biochemical indicators for thiamin and riboflavin status. The results showed that 14.7% of men and 11.9% of women were marginally thiamin deficient, and 16.5% of men and 14% of women were thiamin deficient. The prevalence rates of marginal riboflavin deficiency were 25.7% for males and 20.1% for females, and the deficiency rates were 6.6% for elderly males and 4.1% for elderly females. Although the average dietary thiamin and riboflavin intakes reached 146%-164% of Taiwan RDAs, the percentage of senior citizens whose thiamin or riboflavin dietary intakes were less than EARs (equivalent to 83.3% of RDAs) was around 30% for males and 40% for females. Some contributing factors to the significant prevalence of thiamin and riboflavin deficiencies are discussed in this article.

[Thiamin and ribovlavin status in populations of Arkhangelsk]

It was been performed the epidemiological study of Thiamine and Riboflavin status of 3579 inhabitants in Arkhangelsk. Establish by 49.6% man and 47.4% woman have lower provision of thiamin. Lack of riboflavin reveal by 23.6% man and 21.7% woman. The analysis of the effect of seasonality on vitamins content shown the worst thiamin level in examined population in January-February and in September-October. The worst Riboflavin content observed in examined population in December-January and in July-August.

Comparative in vitro uptake of zinc by erythrocytes of normal vs Type 2 diabetic individuals and the associated factors

Diabetes is an oxidative stress-related disorder in which erythrocyte zinc uptake may vary as compared to healthy individuals. Since zinc is one of the important antioxidant trace metals, some functional indices of erythrocyte zinc status, ie in vitro zinc uptake, osmotic fragility and glucose uptake, were compared in Type 2 diabetic subjects (n=43) and healthy controls (n=22). The associations of these indices with plasma levels of antioxidants and micronutrients were examined. The trace metals were analyzed by atomic absorption spectrophotometer. Vitamins were estimated using spectrophotometric and spectroflourometric methods. In vitro zinc uptakes of healthy subjects were 17 to 52% higher (p<0.01) than those for diabetic subjects. The osmotic fragility for diabetic cells was 2.2 to 1.5 times higher than the healthy cells in 0.85-0.5% NaCl solutions (p<0.05). Percent hemolysis at 0.75, 0.65 and 0.55% NaCl had significant negative correlations (p<0.05) with in vitro zinc uptakes and that at 0.50% NaCl had a positive correlation with HbA1c levels (p<0.05). The in vitro zinc uptakes of erythrocytes in healthy subjects showed a strong negative correlation (p<0.01) with percent hemolysis at 0.75, 0.65 and 0.55% NaCl, a positive correlation with plasma zinc (r=0.33, p<0.05) and a strong negative correlation with plasma selenium and iron, hemoglobin and serum ceruloplasmin indicating antagonistic behavior of copper, iron and selenium with zinc uptake (p<0.01). Furthermore, erythrocyte super oxide dismutase (SOD), plasma ascorbic acid and status of riboflavin and thiamine were negatively correlated with in vitro zinc uptakes of erythrocytes in healthy subjects (p<0.01). These associations in the diabetic subjects were weaker than normal. Erythrocyte zinc uptake and osmotic fragility could be biomarkers of long-term zinc status and decrease of zinc uptake may be one of the features of diabetic patients.