Dose-response relationships regarding vitamin B-6 in elderly people: a nationwide nutritional survey (Dutch Nutritional Surveillance System)

Factors influencing vitamin B6 status in domestic cats: age, disease, and body condition score

Limited studies are available on vitamin B6 status in domestic cats. To this end, we evaluated glutamate-oxaloacetate transaminase (GOT) activity in hemolysates with and without pyridoxal 5'-phosphate addition in two feline populations: a cohort of 60 healthy, domestic (sexually intact and specific pathogen-free) cats maintained under strictly controlled conditions with appropriate diets housed at the Feline Nutrition and Pet Care Center, and a cohort of 57 cats randomly selected between December 2022 to January 2023 that visited the Veterinary Medicine Teaching Hospital to seek care under different circumstances. The GOT activity expressed as the ratio with and without pyridoxal 5'-phosphate addition (primary activation ratio; PAR) decreased significantly with age in the healthy cohort. The PAR values normalized to age established a cut-off for vitamin B6 deficiency in both cohorts, identifying 17 of 101 animals as vitamin B6 deficient. Using machine learning, a partition-based model (decision tree) was built to identify the most important factors that predicted vitamin B6 deficiency while using the resulting tree to make predictions for new observations. This analysis, performed with all 101 cats, revealed that the diagnosis of an infectious, chronic or acute condition (0.55) was the main contributor, followed by age (0.26), and body condition score (optimal-overweight; 0.19). Thus, our study supports that vitamin B6 supplementation may be indicated in junior to adult animals diagnosed with an infectious, chronic, or acute conditions or healthy cats with body weight ranging from optimal to overweight. In older cats, even if healthy, underweight to optimal cats appear to be at risk of vitamin B6 deficiency.

Direct and Functional Biomarkers of Vitamin B6 Status

Measures of B6 status are categorized as direct biomarkers and as functional biomarkers. Direct biomarkers measure B6 vitamers in plasma/serum, urine and erythrocytes, and among these plasma pyridoxal 5'-phosphate (PLP) is most commonly used. Functional biomarkers include erythrocyte transaminase activities and, more recently, plasma levels of metabolites involved in PLP-dependent reactions, such as the kynurenine pathway, one-carbon metabolism, transsulfuration (cystathionine), and glycine decarboxylation (serine and glycine). Vitamin B6 status is best assessed by using a combination of biomarkers because of the influence of potential confounders, such as inflammation, alkaline phosphatase activity, low serum albumin, renal function, and inorganic phosphate. Ratios between substrate-products pairs have recently been investigated as a strategy to attenuate such influence. These efforts have provided promising new markers such as the PAr index, the 3-hydroxykynurenine:xanthurenic acid ratio, and the oxoglutarate:glutamate ratio. Targeted metabolic profiling or untargeted metabolomics based on mass spectrometry allow the simultaneous quantification of a large number of metabolites, which are currently evaluated as functional biomarkers, using data reduction statistics.

Plasma pyridoxal 5'-phosphate in the US population: the National Health and Nutrition Examination Survey, 2003-2004

BACKGROUND

No large-scale, population-based study has considered the descriptive epidemiology of vitamin B-6 status with use of plasma pyridoxal 5'-phosphate (PLP), the indicator of vitamin B-6 adequacy used to set the current Recommended Dietary Allowance, which is < or = 2 mg/d for all subgroups.

OBJECTIVES

We sought to examine the epidemiology of vitamin B-6 status in the US population.

METHODS

In > 6000 participants aged > or = 1 y in the National Health and Nutrition Examination Survey (2003-2004), we considered relations between plasma PLP and various subject characteristics and examined trends in plasma PLP and homocysteine with vitamin B-6 intake, both overall and in selected subgroups.

RESULTS

In males, plasma PLP decreased with age after adolescence only in nonusers of supplemental vitamin B-6. Regardless of supplement use, plasma PLP concentrations of women of childbearing age were significantly lower than those of comparably aged men, and most oral contraceptive users had plasma PLP < 20 nmol/L. The prevalence of low plasma PLP was significantly > 3% at vitamin B-6 intakes from 2 to 2.9 mg/d in all subgroups and at intakes from 3 to 4.9 mg/d in smokers, the elderly, non-Hispanic blacks, and current and former oral contraceptive users. Intakes from 3 to 4.9 mg/d compared with < 2 mg/d were associated with significant protection from low plasma PLP in most subgroups and from hyperhomocysteinemia in the elderly.

CONCLUSIONS

Vitamin B-6 intakes of 3 to 4.9 mg/d appear consistent with the definition of a Recommended Dietary Allowance for most Americans. However, at that intake level, substantial proportions of some population subgroups may not meet accepted criteria for adequate vitamin B-6 status.

Plasma pyridoxal phosphate and pyridoxic acid and their relationship to plasma homocysteine in a representative sample of British men and women aged 65 years and over

Concentrations of pyridoxal phosphate and pyridoxic acid were measured in fasting plasma samples from British men and women aged 65 years and over, participating in a National Diet and Nutrition Survey during 1994–5, selected to be representative of the population of mainland Britain. In this population, the concentration of pyridoxal phosphate declined, whereas pyridoxic acid rose, with increasing age and frailty; however, both status indicators were strongly and directly (with a positive coefficient) correlated with estimates of vitamin B6intake. This was little affected by the inclusion of food energy and protein intakes in the model. Forty-eight percent of the participants living in the community and 75% of those living in institutions had plasma pyridoxal phosphate concentrations below a range considered normal from other studies. In a univariate regression model, plasma pyridoxal phosphate concentrations were inversely correlated with plasma homocysteine concentrations, consistent with the hypothesis that vitamin B6status may influence plasma homocysteine levels, and hence vascular disease risk. However, this relationship was partly attenuated in a multiple regression model including age, sex, domicile and biochemical status indices, including those of folate and vitamin B12. There was evidence that plasma pyridoxal phosphate was sensitive to metabolic conditions associated with inflammation and the acute-phase reaction, and that plasma pyridoxic acid was sensitive to renal function. Thus, neither index is an ideal predictor of vitamin B6status in older people, unless these confounding factors are allowed for. Since poor vitamin B6status may have health implications, e.g. for immune function, cognition, and for essential intermediary metabolic pathways in older people, it needs to be investigated as a possible public health problem.

The effect of vitamin B6 on cognition

BACKGROUND

Micronutrient status can affect cognitive function at all ages. Vitamin deficiencies could influence memory function and might contribute to age-associated cognitive impairment and dementia. Vitamin B6, comprising three chemically distinct compounds pyridoxal, pyridoxamine, and pyridoxine, is involved in the regulation of mental function and mood. Vitamin B6 is also an essential homocysteine re-methylation cofactor, and deficiency is associated with increase in blood homocysteine levels. Homocysteine is a risk factor for cerebrovascular disease and may also have directly toxic effects on neurons of the central nervous system. Neuropsychiatric disorders including seizures, migraine, chronic pain and depression have been linked to vitamin B6 deficiency. Epidemiological studies indicate that poor vitamin B6 status is common among older people. Hyperhomocysteinaemia has been suggested as a cause or mechanism in the development Alzheimer's disease and other forms of dementia. Supplementation with B vitamins including vitamin B6 has been shown to reduce blood homocysteine levels.

OBJECTIVES

To assess the efficacy of vitamin B6 supplementation in reducing the risk of developing cognitive impairment by older healthy people, or improving cognitive functioning of people with cognitive decline and dementia, whether or not vitamin B6 deficiency has been diagnosed.

SEARCH STRATEGY

The Specialized Register of the Cochrane Dementia and Cognitive Improvement Group was searched on 20 May 2003 using the terms: vitamin B6, pyridoxine, pyridoxamine, pyridoxal. For relevant trials on healthy elderly people MEDLINE, EMBASE and CENTRAL were searched using the previously mentioned terms as well as the term cognit *

SELECTION CRITERIA

All unconfounded, double-blind randomized controlled trials in which the intervention with vitamin B6 was compared with placebo for healthy older people or people with cognitive decline or dementia. The primary outcome of interest was the efficacy of vitamin B6 supplementation on cognitive function.

DATA COLLECTION AND ANALYSIS

The two reviewers independently evaluated all studies identified as possibly meeting the criteria for inclusion. One reviewer independently extracted the data. Studies were rated for their overall quality. The weighted mean differences between treatment and placebo groups, with 95% confidence intervals, were calculated for each outcome. Review Manager version 4.2 was used to analyse the variance.

MAIN RESULTS

No trials of vitamin B6 involving people with cognitive impairment or dementia were found. The two trials included in the review (Bryan 2002; Deijen 1992) used a double-blind, randomized, placebo-controlled design and involved 109 healthy older people. One trial restricted enrolment to women and the other to men. Vitamin B6 supplementation and healthy older women: Bryan 2002 enrolled 211 healthy women from various age groups into a 5-week study. The trial was of multifactorial design with folic acid, vitamin B12, vitamin B6 and placebo in its four arms. Twelve healthy women aged 65 to 92 years received 75 mg vitamin B6 orally per day and were compared with 21 healthy women who were allocated to placebo. No statistically significant benefits from vitamin B6 on mood or cognition were observed. Vitamin B6 supplementation and healthy older men: Deijen 1992 recruited 76 healthy men aged 70 to 79 years. They were divided into 38 matched pairs, one member of each pair randomly allocated to 20 mg of vitamin B6 (pyridoxine hydrochloride) per day for 12 weeks the other to placebo. No statistically significant differences between treatment and placebo were found in their effects on cognition or mood. Effect of vitamin B6 supplementation on vitamin B6 status: Deijen 1992 reported that 20 mg of pyridoxine hydrochloride per day for 12 weeks increased blood vitamin B6 activity as assessed as by plasma pyridoxal-5'-phosphate (WMD 238, 95%CI 211.58 to 264.42, P<0.00001) and erythrocyte enzyme asparate aminotransferase (WMD 0.43, 95%CI 0.30 to 0.56, P<0.00001). Effect of vitamin B6 supplementation on blood homocysteine concentration: Neither of the included trials measured homocysteine levels. Drop-outs: All participants allocated to vitamin B6 or placebo completed the trial protocol. Adverse Events: No adverse effects were reported. Effect of vitamin B6 on carer burden, care costs and institutionalization rate: We found no trials in which these outcomes were assessed.

REVIEWER'S CONCLUSIONS

This review found no evidence for short-term benefit from vitamin B6 in improving mood (depression, fatigue and tension symptoms) or cognitive functions. For the older people included in one of the two trials included in the review, oral vitamin B6 supplements improved biochemical indices of vitamin B6 status, but potential effects on blood homocysteine levels were not assessed in either study. This review found evidence that there is scope for increasing some biochemical indices of vitamin B6 status among older people. More randomized controlled trials are needed to explore possible benefits from vitamin B6 supplementation for healthy older people and those with cognitively impairment or dementia.

Plasma vitamin B6 vitamers before and after oral vitamin B6 treatment: a randomized placebo-controlled study

BACKGROUND

Vitamin B(6) has attracted renewed interest because of its role in homocysteine metabolism and its possible relation to cardiovascular risk. We examined the plasma B(6) vitamers, pyridoxal 5'-phosphate (PLP), pyridoxal (PL), pyridoxine (PN), and 4-pyridoxic acid (4-PA) before and after vitamin B(6) supplementation.

METHODS

Patients (n = 90; age range, 38-80 years) undergoing coronary angiography (part of the homocysteine-lowering Western Norway B-Vitamin Intervention Trial) were allocated to the following daily oral treatment groups: (A), vitamin B(12) (0.4 mg), folic acid (0.8 mg), and vitamin B(6) (40 mg); (B), vitamin B(12) and folic acid; (C), vitamin B(6); or (D), placebo. EDTA blood was obtained before treatment and 3, 14, 28, and 84 days thereafter.

RESULTS

Before treatment, PLP (range, 5-111 nmol/L) and 4-PA (6-93 nmol/L) were the predominant B(6) vitamers identified in plasma. During the 84-day study period, the intraindividual variation (CV) in patients not treated with vitamin B(6) (groups B and D) was 45% for PLP and 67% for 4-PA. Three days after the start of treatment, the increases in concentration were approximately 10-, 50-, and 100-fold for PLP, 4-PA, and PL, respectively. No significant additional increase was observed at the later time points. The PLP concentration correlated to the concentrations of 4-PA and PL before treatment, but not after treatment. The PL concentration correlated with 4-PA before and after treatment.

CONCLUSIONS

Vitamin B(6) treatment has an immediate effect on the concentrations and the forms of B(6) vitamers present in plasma, and the changes remain the same during prolonged treatment. Our results suggest that the B(6) vitamers in plasma reflect vitamin B(6) intake.

Effect of physical activity on thiamine, riboflavin, and vitamin B-6 requirements

Because exercise stresses metabolic pathways that depend on thiamine, riboflavin, and vitamin B-6, the requirements for these vitamins may be increased in athletes and active individuals. Theoretically, exercise could increase the need for these micronutrients in several ways: through decreased absorption of the nutrients; by increased turnover, metabolism, or loss of the nutrients; through biochemical adaptation as a result of training that increases nutrient needs; by an increase in mitochondrial enzymes that require the nutrients; or through an increased need for the nutrients for tissue maintenance and repair. Biochemical evidence of deficiencies in some of these vitamins in active individuals has been reported, but studies examining these issues are limited and equivocal. On the basis of metabolic studies, the riboflavin status of young and older women who exercise moderately (2.5-5 h/wk) appears to be poorer in periods of exercise, dieting, and dieting plus exercise than during control periods. Exercise also increases the loss of vitamin B-6 as 4-pyridoxic acid. These losses are small and concomitant decreases in blood vitamin B-6 measures have not been documented. There are no metabolic studies that have compared thiamine status in active and sedentary persons. Exercise appears to decrease nutrient status even further in active individuals with preexisting marginal vitamin intakes or marginal body stores. Thus, active individuals who restrict their energy intake or make poor dietary choices are at greatest risk for poor thiamine, riboflavin, and vitamin B-6 status.

An appraisal of vitamin B6 status indices and associated confounders, in young people aged 4-18 years and in people aged 65 years and over, in two national British surveys

OBJECTIVE

To compare vitamin B6 status indices with each other and with potential confounding factors, in the datasets from two national British surveys and associated studies.

DESIGN

Vitamin B6 status was measured by plasma pyridoxal phosphate (PLP) and plasma pyridoxic acid (PA) in both surveys, and also by erythrocyte aspartate aminotransferase activation coefficient (EAATAC) in one of the surveys. Plasma alpha1-antichymotrypsin was measured as an index of acute phase status; plasma creatinine was measured as an index of renal function; and plasma total alkaline phosphatase activity was measured as a proxy for PLP hydrolase activity.

SETTING

The survey of people aged 65 years and over was carried out in 80 postcode sectors across mainland Britain during 1994-95 and the survey of young people was carried out in 132 postcode sectors across mainland Britain during 1997.

SUBJECTS

Blood samples from c. 1,000 subjects of both sexes in each survey permitted measurements of plasma PLP and PA. There were also measurements of EAATAC in the young people's survey.

RESULTS

According to published limits of normality, only 5% or less of the young people had unacceptable vitamin B6 status as measured by plasma PLP. About half had apparently unacceptable status by EAATAC, but this observation is difficult to interpret. The young people had considerably higher plasma concentrations of PLP and lower concentrations of PA than the older people. In both surveys, plasma PLP was strongly correlated with plasma PA and in the young persons' survey it was also correlated, although much less strongly, with the basal activity and activation coefficient of aspartate aminotransferase. Both plasma PLP and EAATAC (but not PA nor basal aspartate aminotransferase activity) were influenced by acute phase status in young people, as indicated by significant correlations with alpha1-antichymotrypsin. In people aged 65 years and over, PA (but not PLP) was correlated with renal function, as indicated by its relation with plasma creatinine; however PLP (but not PA) was correlated with plasma alkaline phosphatase activity.

CONCLUSIONS

Several potential confounders - acute phase reaction, kidney malfunction and hydrolase activity - may influence vitamin B6 status indices, although differently for different indices and different age groups. Since older people have relatively poor vitamin B6 status, which may have important health implications for them, more reliable vitamin B6 status indices are needed.

Immunotoxicity of the colour additive caramel colour III; a review on complicated issues in the safety evaluation of a food additive

Food additives can be regarded as the safest constituents of our daily food. Nevertheless, complicated issues with respect to their safety evaluation do also occur. In this review paper, some of these issues are illustrated by the description and evaluation of the research on the immunotoxicity of the food additive Caramel Colour III. Caramel Colour III is commonly used as a color additive in many products for human consumption. Toxicity studies conducted in the seventies demonstrated that administration of Caramel Colour III can cause a reduction in total white blood cell counts in rats, due to reduced lymphocyte counts. Studies reviewed in this paper demonstrated several other effects of Caramel Colour III on the immune system of rodents, including disturbed immune functions and changed resistance in infection models. In addition, studies in rats demonstrated that most of the effects occur only when the animals are fed a diet low in vitamin B6. The imidazole derivative 2-acetyl-4(5)-(1,2,3,4-tetrahydroxy-butyl)-imidazole (THI) was found to be responsible for the immunotoxicity. Issues such as the mechanism of action of THI and the role of vitamin B6 are discussed. Finally, the results of a human intervention study and the observed effect levels of THI in rats are discussed in terms of safety of the use of Caramel Colour III in our daily food supply.

Combinations of low thiamin, riboflavin, vitamin B6 and vitamin C intake among Dutch adults. (Dutch Nutrition Surveillance System)

OBJECTIVE

Clustering of low vitamin intake may entail a greater functional and/or health risk than the summation of separate low intakes may suggest. Therefore, the prevalence of combined low thiamin, riboflavin, vitamin B6 and vitamin C intake in various adult sex-age groups in The Netherlands was estimated.

METHODS

Nutritional risks were evaluated by comparing the calculated intakes with the recommendations for each vitamin. For this purpose the data of a subsample of 3353 adults of a nationwide food consumption survey were used, which had been collected in 1987-88 within the framework of the Dutch Nutrition Surveillance System. Food consumption data were obtained through 2-day dietary records. Respondents were segmented into tertiles based on their vitamin intake per 1000 kcal (4.2 MJ) to adjust for energy intake.

RESULTS

As compared with the RDAs, mean overall intake was lowest for vitamin B6. Based on tertile analyses, the risk for inadequate intake was relatively high for vitamin C, small for riboflavin and intermediate for thiamin and vitamin B6. Low vitamin densities clustered somewhat since the prevalence of combined low intakes for all four vitamins was higher than expected from probability calculations. This interdependence was mainly the result of a higher consumption of alcoholic beverages and of other food products with a low vitamin density.

CONCLUSION

In affluent societies nutritional risk assessment should not be based solely on single vitamins but should also be oriented at combined low intake levels.

Effects of the colour additive caramel colour III on the immune system: a study with human volunteers

Administration of the colour additive Caramel Colour III to rats has been associated with decreased numbers of lymphocytes and several other changes in the immune system, as well as in immune function parameters, specifically in animals fed a diet with a relatively low vitamin B6 content. The effects are caused by the imidazole derivative 2-acetyl-4(5)-tetrahydroxybutylimidazole (THI). Caramel Colour III is commonly used in food products such as bakery products, soya-bean sauces, brown sauces, gravies, soup aromas, brown (dehydrated) soups, brown malt caramel blend for various applications, vinegars and beers, and effects in humans on dietary intake cannot be excluded. Elderly male volunteers with a marginal deficit in vitamin B6 were considered a relevant and potentially sensitive group to study possible effects of Caramel Colour III on blood lymphocyte numbers (total and within subsets) or on proliferative responses of lymphocytes to mitogenic stimulation. In addition, several other haematological parameters, as well as serum immunoglobulin levels and immunoglobulin production in vitro by pokeweed mitogen-stimulated mononuclear blood cells were studied. The results of this double-blind intervention study demonstrated that in a selected test group of apparently healthy elderly male volunteers with a biochemically marginally deficient vitamin B6 status, Caramel Colour III containing 23 (commercial sample) or 143 (research sample) ppm THI and administered at the level of the current acceptable daily intake of 200 mg/kg body weight/day for 7 days did not affect any of the factors investigated.

Institutionalized elderly women have lower food intake than do those living more independently (Dutch Nutrition Surveillance System)

The habitual intake of energy and nutrients (assessed through dietary history) among elderly women (aged 65 and over) living in a nursing home (n = 54), elderly women living in service flats and receiving their dinners from the nursing home kitchen (n = 29), and elderly women living independently (n = 52) was evaluated within the framework of the Dutch Nutrition Surveillance System. Intake of energy and nutrients was lowest among women in the nursing home and highest among those living independently. Almost all differences in absolute intake found were significant, both unadjusted and adjusted for age. In the nursing home the intake of energy and nutrients was lower at higher age. In qualitative terms the differences among the groups of women were less striking. Mean daily intakes of iron, vitamin A, thiamin, vitamin B6 and vitamin C were below the Dutch recommended dietary allowances (RDAs) among the nursing home women. Several interrelationships among nutrient intakes were found, low intake levels clustering somewhat among elderly subjects. Our data indicate that these nutritional risks are due to a lower food intake resulting in a lower intake of energy and nutrients, and owing to differences in food choice resulting in a lower nutrient density. We conclude that it is difficult to design a diet containing all essential nutrients at the RDA level in a nursing home with residents who have a relatively low intake of energy, especially among those at higher age.

Effects of Caramel Colour III on the number of blood lymphocytes: a human study on Caramel Colour III immunotoxicity and a comparison of the results with data from rat studies

Administration of the colour additive Ammonia Caramel Colour (Caramel Colour III) to rats has been associated with decreased lymphocyte counts, specifically in rats fed a diet low in vitamin B6. This effect is rapidly reversible and is caused by an imidazole derivative (THI) in Caramel Colour III. In the present paper, the conduct of a human study with Caramel Colour III is outlined and the results of blood lymphocyte counts are presented. No decrease in the number of blood lymphocytes occurred in marginally vitamin B6-deficient humans who consumed Caramel Colour III at the acceptable daily intake level (200 mg/kg body weight/day) for 7 days. These data are discussed in relation to the effects of Caramel Colour III and THI on blood lymphocyte numbers in rats.

Vitamin B-6 supplementation in elderly men: effects on mood, memory, performance and mental effort

This study evaluates the effects of vitamin B-6 supplementation (20 mg pyridoxine HCL daily for 3 months) on mood and performance in 38 self-supporting healthy men, aged between 70-79 years. Effects were compared with 38 controls who received placebo and were matched for age, plasma pyridoxal-5'-phosphate (PLP) concentration and intelligence score. Before and after drug intervention vitamin B-6 status was determined, and mood and performance were measured by means of a computerized testing system. In addition, the phasic pupil response was measured in order to assess mental effort. Positive effects of vitamin B-6 supplementation were only found with respect to memory, especially concerning long-term memory. In view of the finding that mental performance improvement and delta PLP values were most strongly correlated within an intermediate range of delta PLP, it is suggested that cognitive effects are primarily associated with a certain range of vitamin B-6 status increment. The general conclusion is that vitamin B-6 supplementation improves storage of information modestly but significantly.

Pyridoxal-5'-phosphate and pyridoxal biokinetics in aging Wistar rats

Biokinetic parameters of plasma pyridoxal-5'-phosphate (PLP) and pyridoxal (PL) disposition were studied in male Wistar rats aged 8 and 27 months kept from weaning on a purified diet containing 250 g casein and 6 mg pyridoxine.HCl per kg. Baseline plasma PLP concentration was lower in the older animals (514 +/- 56 nmol/L for young and 317 +/- 124 nmol/L for old animals), whereas baseline plasma PL concentration did not differ between age groups (average 235 nmol/L for both young and old animals). We hypothesized lower baseline plasma PLP in the older animals was caused by an increased PLP elimination rate, a decreased PLP synthesis rate, or a combination of these processes. Observations from earlier in vitro experiments suggest age-related changes occur in vitamin B-6 metabolizing enzyme activities. In the in vivo experiments described here no age-related difference in plasma PLP elimination rate nor in plasma PLP synthesis rate was observed to explain the observed decrease in plasma PLP concentration with age.

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.