Vitamin status in elderly people in relation to the use of nutritional supplements

Abstract

Objective

This study aimed to evaluate the status of several vitamins and to investigate the effect of regular individual supplementation on their status in this population.

Design

An observational study.

Setting

State of Burgenland, Austria.

Participants

A total of 102 non-institutionalized subjects (49% supplementing regularly, 51% without supplementation) aged between 70–90 years were recruited.

Measurements

Plasma levels of vitamins A, D, E, K and C were determined by HPLC. The functional parameters of vitamins B1, B2 and B6, i.e. the activities of the erythrocyte enzymes transketolase, glutathione reductase and glutamic oxaloacetic transaminase, were analyzed photometrically; plasma folate and vitamin B12 were determined by RIA.

Results

The status of vitamins A, E and C was generally satisfactory. Eighty-eight percent and 42% of participants were deficient in vitamins D and K, respectively, as were 29% for B6; up to 10% of participants were deficient in vitamins B1, B2, B12 and folate. A considerable percentage of participants was, however, at risk for vitamin deficiencies (vitamins B1, B6, B12, folate: 20–30%, vitamin B2: 60%). Except for vitamins A and K, regular intake of supplements had a significant positive influence on vitamin levels.

Conclusion

These results indicate that use of supplements significantly improved the status of several vitamins in elderly people. Due to age-related problems concerning the intake and digestion of nutrients, a moderate, regular supplementation might be a useful option for older people who are otherwise unable to satisfy their micronutrient requirements.

Introduction

The remarkable gain of about 30 years in life expectancy in the last century, has produced a growing elderly population, with the oldest-old (aged >85 years) as the most rapidly expanding segment of the population in developed countries (1).

Several studies indicate that many older adults develop nutrition-related problems because they are not getting the proper amount of micronutrients needed on a daily basis (2, 3). Elderly people are often at risk for inadequate nutrient supply due to physiological, metabolic and age-associated factors affecting nutrient and fluid intake (4, 5). Chronic diseases, impaired digestion and absorption from the gastrointestinal tract or nutrient-drug interactions are prevalent in this population and can further compromise the nutritional status (69). The prevalence of an inadequate nutritional status and of risk for malnutrition in older adults has been reported to range from 4% and 25% (>65 years) to 50% of elderly in residental care facilities (average age: 84 years) and further up to 85% in long-term nursing home residents (reviewed by 10).

Several studies have demonstrated a remarkable impact of vitamin status on health benefit and disease prevention in elderly people. The nutritional status has been identified as a major factor influencing immunity in this population (11). Further studies have shown that antioxidants such as vitamins E and C reduce lipid peroxidation and free radical damage, which are important intermediaries in the pathogenesis of atherosclerosis (12, 13). Clinical trials have, however, found conflicting results concerning the effectiveness of supplementation on primary and secondary disease prevention of cardiovascular disease (14, 15, 16). B vitamins, including folate and vitamins B6 and B12 have a remarkable impact on lowering plasma levels of homocysteine, which is assumed to be a cardiovascular risk factor (17, 18), and improve cognitive performance and functions such as memory and information processing (19, 20). Moreover, additional intake of vitamins D and K was found to delay loss of bone and to prevent osteoporosis and osteomalacia with increasing age (21, 22). Low levels of both vitamins are further associated with a higher rate of cardiovascular events in the elderly (23., 24., 25.).

In recent years, there has been a general increase in the use of nutritional supplements, with about half of adults reporting regular multivitamin/mineral supplementation (26, 27). Marketing data show a dramatic increase in sales of supplements since 1997 (28). In 2007, sales of multivitamins, the most commonly purchased supplements, grew about 4% in the US sales of single-nutrient supplements including calcium, B vitamins and magnesium also grew slightly during this period, whereas vitamin E supplement sales declined (reviewed by 29). The growing proportion of older adults using vitamin and mineral supplements largely contributes to this development (27, 29, 30). Data show that in the USA some 60% of persons above age 55 take dietary supplements regularly (31).

Substantial evidence supports the notion that use of nutritional supplements can help some people meet their nutrition needs and optimize health (29). A large proportion of elderly people do not consume sufficient amounts of many nutrients from food alone. Recent data indicate that supplement use significantly increases mean and median intakes of micronutrients in the older population. Additionally, regular use of supplements was found to compensate nutritional inadequacies to some extent in the elderly (32) and so may contriubute to fill the gap between recommended and actual intakes of micronutrients in this population. It should, however, also be taken into account, that an inappropriate use of various supplements might also have adverse effects.

The growing prevalence of nutritional supplementation has increased interest in research evaluating the role of supplements in meeting nutritional requirements in different populations. On that basis, this study aimed to determine the status of several fat and water soluble vitamins and to characterize the effect of regular individual supplementation on their status in elderly people.

Participants and methods

This descriptive study was approved by the State Board of Health in Burgenland, Austria and performed in accordance with the guidelines of the Declaration of Helsinki; all voluntarily participating subjects gave their written informed consent.

Participants & Design

A total of 102 non-institutionalized subjects aged between 70 and 90 years, a population group that has scarcely been investigated, volunteered to be enrolled in this study (Table 1). Elderly subjects in the state of Burgenland were recruited due to data of the central office for demographic statistics and invited by letter to participate in the study. The number of cases that were included in the study was statistically calculated and 102 subjects were considered as a representative sample. Selected respondents had to be between 70 and 90 years of age, non-institutionalized and without specific care, they had to have an overall good health status (self-reported) without former cardiovascular events or another severe disease, had to be on a common mixed diet and had to reflect the demographic situation of this age group in the selected state. Subjects younger than 70 years of age or who were in need of institutional or home care and/or were on a specific diet and/or had any acute or chronic gastrointestinal or renal disease, liver failure, pulmonary disease, or cancer were excluded from the study.

Table 1.

Characteristics of the subjects

	Total	Supplemented Group	Unsupplemented Group
Total Number (n)	102	50	52
Men (n)	45	19	26
Women (n)	57	31	26
Age (years)	76 ± 4	76 ± 4	75 ± 4
BMI (kg/m2)	28.0 ± 4.0	27.7 ± 4.1	28.4 ± 4.0
Most common morbidities (%)
Hypertension	74	84	71
Heart disease	34	34	36
Indication to be on anticoagulants	33	38	30
Hyperlipidemia	25	25	22

Participants were surveyed face-to-face using a questionnaire to determine what supplements, if any, were used and their dosage and frequency of intake.

Measurements

Blood samples were taken from each participant after an overnight fast. Plasma concentrations of vitamin A (including carotenoids such as ß-carotene, ß-cryptoxanthine and a- carotene; expressed as retinol equivalents = RE: all-trans retinol + 0.167 x ß-carotene + 0.083 x ß-cryptoxanthine + 0.083 x a- carotene), vitamin E, i.e. a- and y-tocopherol (expressed as tocopherol equivalents = TE: a-tocopherol + 0.25 x y- tocopherol) and vitamin K (phyllochinone) were analyzed with HPLC [mod. 33]. Moreover, levels of vitamins D (25- hydroxycholecalciferol) and C were determined with certified commercially available HPLC kits (RECIPE, Munich, Germany).

To assess the status of vitamins B1, B2 and B6 functional parameters, i.e. activities of the erythrocyte enzymes transketolase, glutathione reductase and glutamic oxaloacetic transaminase were measured according to the photometric methods described by Fabian et al. (34). These measurements base on the co-enzymes’ stimulation effect and were expressed as activation coefficients (for vitamins B1 and B2 in %) which are the ratio between the enzyme activity with and without addition of the respective co-enzyme; the lower the value the better is the status of these vitamins.

Vitamin B12 and folate were measured by RIA (SimulTRAC-SNB, MP Biochemicals, Eschwege, Germany).

Reference values for plasma levels of vitamins A, E, B12 and folate, and for the functional parameters (activation coefficients) of vitamins B1, B2 and B6 were defined according to Sauberlich (35). Plasma levels of vitamins D, K and C were classified referring to Hart et al. (36), Jakob and Elmadfa (33), and DACH (37), respectively. The minimum value for lipid- adjusted levels of vitamin E was defined as 1.86 µMol (0.8 mg)/g total lipids (38).

Intake of vitamins was assessed by interview-based 24h- recalls. The evaluation of the records was performed using the nutritional software NUT.S (BLS II.3.1., Karlsruhe, Germany).

Statistical analysis

All data are presented as a mean ± standard deviation (sd). Statistical analyses were performed using SPSS 16 (SPSS Inc, Chicago, IL, USA). Normal distribution of the data was assessed by Kolmogorov-Smirnov test. For normally distributed parameters, differences between groups were compared using the independent Student’s t-test for parameters without normal distribution the Mann-Whitney U test was employed. A p value of < 0.05 was considered statistically significant.

Results

Forty-nine percent of our participants reported regular consumption of nutritional supplements providing a wide range of fat and water soluble vitamins (Table 2). Sixty-two percent, 32% and 6% of supplementing subjects stated regular consumption of one, two and three or more supplements, respectively. About half (54%) of supplementing participants reported daily intake of the preparations, 24% took supplements three times and 22% less than three times per week. The majority (60%) of supplementing subjects took multivitamin/multimineral preparations; magnesium and calcium were the most commonly mentioned single nutrient supplements, with 46% and 14% of respondents reporting use. Intake of other nutrient preparations such as vitamin C (2%), selenium (2%) and B-complex supplements (2%) was reported less frequently. Other biologically based preparations such as luteine, omega-3 fatty acids, gingko, garlic, ginseng and chlorella supplements were used by 20% of participants.

Table 2.

Daily values of investigated vitamins provided by the supplements consumed

Vitamin	% reference intake values
Vitamin A”	50-100
Vitamin D*	50
Vitamin Eb	80-203
Vitamin K	0-46
Vitamin B1	140-420
Vitamin B2	133-400
Vitamin B6	143-500
Vitamin B12	33-100
Folate	25-150
Vitamin C	60-180

^*recommended daily allowance (37); a. as retinol equivalents; b. as tocopherol equivalents

Mean intake of vitamins measured by 24h-recalls was comparable in both groups; no statistically significant differnces were observed between the supplemented und unsupplemented subjects (Table 3).

Table 3.

Intake of fat and water soluble vitamins according to interview- based 24h-recalls without consideration of supplements (mean ± sd)

Parameter	Total* n=102	Supplemented Group n=50	Unsupplemented Group n=52
Fat Soluble Vitamins/Day
Vitamin A (mg RE1)	0.7 ± 0.4	0.8 ± 0.4	0.7 ± 0.4
Vitamin E (mg TE2)	10.5 ± 6.0	10.5 ± 6.0	9.0 ± 6.0
Vitamin D (µg)	2.0 ± 0.8	2.1 ± 1.3	1.9 ± 0.4
Water Soluble Vitamins/Day
Vitamin B1 (mg)	0.8 ± 0.4	0.7 ± 0.3	0.8 ± 0.4
Vitamin B2 (mg)	1.0 ± 0.3	1.0 ± 0.4	1.0 ± 0.3
Vitamin B6 (mg)	1.0 ± 0.4	1.0 ± 0.4	1.0 ± 0.5
Folate (µg)	153 ± 75	162 ± 78	143 ± 71
Vitamin B12 (µg)	3.4 ± 2.2	3.3 ± 2.4	3.6 ± 2.1
Vitamin C (mg)	77 ± 26	87 ± 17	67 ± 7

^*total values have also been evaluated in relation to medication (39); 1. RE = retinol equivalents = all-trans retinol + 0.16 × ß-carotene; 2. TE = tocopherol equivalentes = 1 × α-tocopherol + 0.4 × ß-tocopherol + 0.1 × γ-tocopherol + 0.01 × δ-tocopherol + 0.3 × α- tocotrienol + 0.05 × ß-tocotrienol + 0.01 × γ-tocotrienol.

Fat soluble Vitamins

Ninty-nine percent of all participants had a sufficiently high (>0.7 µMol/l) vitamin A level independent of regular intake of supplements (Table 4).

Table 4.

Status data of fat and water soluble vitamins with consideration of the use of nutritional supplements (mean ± sd)

Parameter	Total* n=102	Supplemented Group n=50	Unsupplemented Group n=52
Fat Soluble Vitamins
Vitamin A (µMol RE1/l)	2.2 ± 0.6	2.2 ± 0.6	2.1 ± 0.5
Vitamin E (µMol TE2/l)	31 ± 8	33 ± 9b	29 ± 6
Vitamin E/total lipids (µMol/g)	6.0 ± 1.6	6.6 ± 1.9c	5.5 ± 1.0
Vitamin D (nMol/l)	33 ± 13	37 ± 14c	29 ± 11
Vitamin K (nMol/l)	0.60 ± 0.51	0.64 ± 0.57	0.56 ± 0.44
Water Soluble Vitamins
Vitamin B1 (TPP-effect3, %)	15 ± 7	13 ± 6a	16 ± 7
Vitamin B2 (FAD-effect4, %)	26 ± 12	22 ± 10b	29 ± 13
Vitamin B6 (α-EGOT5)	1.71 ± 0.26	1.63 ± 0.26b	1.78 ± 0.23
Folate (nMol/l)	21 ± 18	26 ± 20b	16 ± 14
Vitamin B12 (pMol/l)	183 ± 60	196 ± 65a	170 ± 53
Vitamin C (µMol/l)	70 ± 22	80 ± 18c	60 ± 20

^*total values have also been evaluated in relation to medication (39); 1. RE = retinol equivalents = all-trans retinol + 0.167 × ß-carotene + 0.083 × ß-cryptoxanthine + 0.083 × α-carotene; 2. TE = tocopherol equivalents = α-tocopherol + 0.25 × γ-tocopherol; 3. TPP- effect = thiamine pyrophosphate-effect = activation coefficient (%); 4. FAD-effect = flavin adenine dinucleotide- effect = activation coefficient (%); 5. α-EGOT = activation coefficient of the erythrocyte glutamic oxaloacetic transaminase; a. difference between supplemented and unsupplemented group: p<0.05; b. difference between supplemented and unsupplemented group: p<0.01; c. difference between supplemented and unsupplemented group: p<0.001

Irrespective of regular supplement use the status of vitamin K was adequate (>0.38 µMol/l) in 58% (supplemented group: 58%, unsupplemented group: 56%) and inadequate in 42% (supplemented group: 42%, unsupplemented group: 44%) of our participants.

Plasma levels of vitamin E were signifcantly (p<0.01) higher in supplemented than unsupplemented subjects (Table 4), but regardless of the use of nutritional supplements adequate (>16.2 µMol/l) and marginal (11.6-16.2 µMol/l) in 98% and 2% of participants, respectively. Adjustment to plasma lipids confirmed that supplemented subjects were significantly (p<0.001) better provided than unsupplemented but revealed that independent of supplement use all participants had an adequate vitamin E status (>1.86 µMol vitamin E/g total lipids).

Of the subjects studied, 12% had an adequate (≥50 nMol/l) vitamin D status and 88% were deficient (<50 nMol/l). Fifty- seven percent, 23% and 8% had a mild (25-49 nMol/l), moderate (12.5-24 nMol/l) and severe (<12.5 nMol/l) vitamin D deficiency. Intake of supplements had a significant (p<0.001) positive effect on the vitamin status (Table 4). Eighteen percent of supplemented but only 4% of unsupplemented subjects were adequately supplied, 82% vs. 96% had an inadequate vitamin D status. Sixty-two percent vs. 54% and 20% vs. 27% of supplemented vs. unsupplemented subjects were mildly and moderately deficient, respectively. Severe vitamin D deficiency was observed in 15% of only unsupplemented elderly.

Water soluble Vitamins

Sixty-one percent, 30% and 9% of participants had an adequate (<15%), marginal (16-24%) and inadequate (≥25%) vitamin B1 status, respectively. Supplemented participants were signifcantly (p<0.05) better supplied with vitamin B1 than unsupplemented (Table 4); 71% of supplemented but just 52% of unsupplemented subjects had an adequate, 25% vs. 38% a marginal, and 4% vs. 10% an inadequate vitamin B1 status.

Supply of vitamin B2 was adequate (<20%), marginal (2040%) and inadequate (>40%) in 31%, 59% and 10% of all participants, respectively. Regular intake of supplements had a signifcant (p<0.01) positive effect on the status of vitamin B2 (Table 4); in 41% of supplemented and just 23% of unsupplemented subjects, the status was adequate, in 55% vs. 62% it was marginal and in 4% vs. 15% it was inadequate.

The status of vitamin B6 was found to be adequate (<1.75), marginal (1.75-1.80) and inadequate (>1.8) in 51%, 20% and 29% of our subjects, respectively. Supplemented participants were significantly (p<0.01) better provided than unsupplemented (Tabel 4). Fifty-three percent of supplemented and 48% of unsupplemented subjects had an adequate status 28% vs. 14% were provided marginally and 19% vs. 38% were supplied inadequately.

Plasma levels of folate were acceptable (≥13.4 nMol/l), marginal (6.7-13.3 nMol/) and deficient (<6.7 nMol/l) in 55%, 35% and 10% of participants, respectively. Regular intake of supplements had a significant (p<0.01) positive effect on the folate status in our participants (Table 4). Sixty-five percent of supplemented but just 46% of unsupplemented subjects were supplied adequately, 35% and 37% had a marginal status and 17% of unsupplemented participants were deficient in folate.

Sixty-seven percent, 28% and 5% of investigated subjects had an adequate (≥147 pMol/l), marginal (110-147 pMol/l) and inadequate (<110 pMol/l) vitamin B12 status, respectively. The plasma levels were significantly (p<0.05) higher in the supplemented than unsupplemented group (Table 4) and could be assessed as satisfactory, marginal and inadequate in 77% vs. 57%, 21% vs. 35% and 2% vs. 8% of supplemented vs. unsupplemented participants, respectively.

The status of vitamin C was optimal (>37 µMol/l) and marginal (20-37 µMol/l) in 91% and 9% of participants, respectively. Plasma levels were significantly (p<0.001) higher in the supplemented than unsupplemented group (Table 4) and could be assessed as optimal in 98% of supplemented and 82% of unsupplemented subjects. Two percent vs. 18% of supplemented vs. unsupplemented participants had a marginal vitamin C status, no one was deficient in this vitamin (<20 ^Mol/l).

Discussion

This study characterizes the vitamin status in elderly people and finds that regular use of nutritional supplements benefited this population in term of a significantly improved status of several fat and water soluble vitamins.

The intake and status of vitamin A was satisfactory in our participants irrespective of regular intake of supplements. Vitamin A deficiency is rarely found in western countries, where only patients with specific gastrointestinal diseases are at risk (14). In elderly people, the role of vitamin A in bone health and its association with fracture risk is still dicussed controversially. Data show that high dietary intake of vitamin A (>3mg/day) for 18 years is associated with an increased risk of osteoporotic fractures (40). Among another cohort, there was no dose-response relationship between hip fracture risk and increased amounts of vitamin A intake, whether from food alone or from supplements (41), suggesting that further studies are needed to determine the influence of vitamin A from different sources on bone health in the elderly.

The association of vitamin D levels with bone health and fracture risk has often been described in older adults (21, 23, 42). In our study, only 12% of participants had an adequate vitamin D status, 88% were insufficently supplied with vitamin D. According to Hart et al (36) we have considered 50 nMol/l as lower limit of adequate vitamin D levels. There are, however, also reports that consider a value of 75 nMol/l as cut off for normal vitamin D levels (43). Intake data revealed a comparable but inadequate supply from nutrients in both groups. Regular supplementation had a significant positive influence on vitamin D levels in our participants, resulting in 18% of supplemented but only 4% of unsupplemented subjects being supplied adequately and leaving 82% vs. 96% deficient in vitamin D. These results substantiate earlier findings showing a significant positve influence of additional vitamin D intake on vitamin D status, bone health and fracture risk in elderly people (21, 23, 42). The importance of an adequate vitamin D supply in older adults, probably best achieved with regular, individually adapted consumption of supplements is further emphasized by the relation of low vitamin D levels to increased cardiovascular risk (23) and impaired cognitive function (44, 45).

Regardless of regular intake of supplements vitamin K status was adequate in about 60% and inadequate in 40% of our participants. Since not all of the consumed multivitamin preparations contained vitamin K and if they did, provided a maximum of 46% of the recommended daily allowance, we found no positive influence of supplement use on vitamin K status. Trials that investigated the impact of specific vitamin K supplementation have, however, found beneficial effects on vitamin K status and hence on bone health (due to its involvement in bone mineralization) (22), vascular calcification and endothelial function in the elderly (24, 25, 46). The high percentage of inadequately provided subjects observed in our study could probably be due to a low intake of vitamin K-rich foods (e.g. green vegetables) resulting of age-related problems concerning food intake, absorption and digestion and/or an overall higher morbidity but could also be adversely affected by nutrient-drug interactions (4., 5., 6., 7., 8., 9.). Specifically, anticoagulants that have an adverse effect on vitamin K metabolism and were prescribed for 33% of our participants may have affected vitamin K levels negatively (39, 47).

In this study, though plasma levels of vitamin E were significantly higher in supplemented than unsupplemented subjects, the status could, however, be assessed as generally adequate in both groups. As the average intake of vitamin E was comparable in both groups, this finding is most likely to be due to the regular consumption of vitamin preparations. Due to its properties such as inhibition of oxidation and inflammation, and increasing release of prostacycline, which promotes blood vessel dilatation and reduces platelet aggregation, supplementation with vitamin E has been suggested to prevent atheroscleosis, cardiovascular disease and cancer (14, 48). Randomized clinical trials have, however, found conflicting results on the beneficial effect of vitamin E supplements on cardiovascular health. Regular intake of vitamin E preparations had a significant positive impact (24% reduction) on cardiovascular death in patients with no history of major chronic illness (15) but did not reduce cardiac death in patients with documented cardiovascular disease, diabetes and other risk factors (16). This suggests that vitamin E supplementation might be useful in health promotion and prevention but not in inhibiting progression of cardiovascular disease. Usage of vitamin E supplements to prevent cancer and cognitive decline in elderly people is still equivocal and needs further cinical studies (14).

Since dietary intake of vitamin C was similar in both groups, consumption of supplements had a significant positive effect on plasma vitamin C levels in our participants; the status was, however, acceptable regardless of regular supplementation. Observational studies evaluating vitamin C for primary prevention of cardiovascular disease have found conflicting results; in clinical trials, supplementation with vitamin C appears to be ineffective for secondary prevention of coronary heart disease (14). There is also limited evidence to support the use of vitamin C peparations in the primary prevention of cancer (49) and for improved cognitive function in the elderly (50) but some data support the notion of a benefit in immune functions in older adults (51).

Due to the various functions of B vitamins in the nervous system and their involvement in homocysteine metabolism, supplementation with them has been associated with improved cognitive/psychological function and decreased cardiovascular risk (14, 20).

In our study, between 31% (B2) and 67% (B12) of subjects were supplied adequately with vitamins B1, B2, B6, B12 and folate; about 20-30% and approximately 60% were at risk for vitamin B1, B6, B12, folate and B2 deficiency, respectively. Except for vitamin B6 (29%), 10% of participants at most had an inadequate status of vitamins B1, B2, B12 and folate.

These results revealed that a considerable percentage of our participants was at risk or supplied inadequately with several B vitamins. This finding may be due to an inadequate intake of nutrients or in case of an acceptable supply may probably result from age-related physiological problems concerning digestion, absorption and metabolism, or nutrient-drug interactions prevalent in this population and compromising nutritional status (6., 7., 8., 9.). Since 62% of investigated subjects took one to three and 26% four and more drugs daily, medication definitely could have had an adverse effect on the B vitamin status (39).

The mean intake of several B vitamins was comparable in both groups, hence, regular supplementation had a significant positve influence on the status of vitamins B1, B2, B6, B12 and folate, so that a significantly higher percentage of supplemented subjects was supplied adequately (B1: 71% vs. 52%, B2: 41% vs. 23%, B6: 53% vs. 48%, B12: 77% vs. 57%, folate: 65% vs. 46%) and a significantly lower percentage was at risk or deficient in B vitamins (B1: 29% vs. 48%, B2: 59% vs. 77%, B6: 47% vs. 52%, B12: 23% vs. 43%, folate: 35% vs. 54%).

Vitamins B6, B12 and folate are essential in the breakdown of homocysteine, which is considered as a risk factor for cardiovascular and cerebrovascular disease and can negatively affect neurons within the central nervous system (52). Our finding of a significant inverse relationship between vitamins B6, B12 and folate, and homocysteine confirm the well- established role of these vitamins in homocysteine metabolism (53). Low plasma levels of B vitamins and/or high levels of homocysteine are related to depression and decreased cognitive performance (reviewed by 20), and are suggested to be involved in the pathogenesis of alzheimer’s disease and related dementias (14). In earlier studies, supplement use was found to lower homocysteine levels and hence probably to reduce cardiovascular risk (54., 55., 56.) and to improve cognitive performance and psychological functioning (17). Existing studies do not, however, provide consistent evidence that supplementation with B vitamins, singly or combined, improves cognitive function in healthy or cognitively impaired older adults (57) though use of a multivitamin preparation has been found to improve subjective mood and cognitive performance on attention tasks (58, 59).

Several studies indicate that elderly people are often at risk for inadequate nutrient supply due to age-related physiological and metabolic changes, impaired digestion and absorption, nutrient-drug interactions and other age-associated factors compromising nutritional status (2., 3., 4., 5., 6., 7., 8., 9.). For a given person there are several choices of intervention for nutritional support. Sometimes the difficulty of receiving a well balanced diet can be solved by simply changing the content, density, consistency or quality of food or increasing the number of times the person eats per day. Fortified foods are also recommended as an option to get a proper amount of nutrients (60). In our study, nutrient intake was similar in both the supplemented and unsupplemented groups, and regular intake of vitamin preparations was found to have a beneficial influence on their status even though various supplements taken by the subjects provided different amounts of vitamins. Supervised administration of a defined supplement over a longer period of time together with recording nutrient intake and consideration of age-related factors confounding the vitamin status (e.g. impaired gastrointestinal functions and metabolism, morbidity and nutrient-drug interactions) would, however, be useful to assess benefits on long-term status and functional paramters in this population. Although there is growing evidence from epidemiologic and observational studies and clinical trials that suggests a relationship between vitamin status and health promotion and disease prevention in older adults, further studies will be needed to evaluate the effect of regular supplementation on clinical outcome.

Conclusion

These results show that the status of vitamins A, E and C was generally satisfactory in elderly people. Eighty-eight percent, 42% and 29% were inadequately supplied with vitamins D, K and B6, respectively; up to 10% of participants were deficient in vitamins B1, B2, B12 and folate. A considerable percentage of elderly people was, however, at risk for vitamin deficiencies (vitamins B1, B6, B12, folate: 20-30%, vitamin B2: 60%). Regular intake of supplements significantly improved the status of several vitamins. Due to age-related problems concerning the intake and digestion of nutrients, moderate regular supplementation might be a useful option for those elderly persons who are otherwise unable to satisfy their micronutrient requirements.

Competing interests

The authors declare that there is no conflict of interest. The study was funded in part by the State Government of Burgenland, Austria.