Use of vitamin and mineral supplements: demographics and amounts of nutrients consumed. The 1987 Health Interview Survey

Prevalence of and Factors Associated with Dietary Supplement Use in a Stratified, Random Sample of US Military Personnel: The US Military Dietary Supplement Use Study

BACKGROUND

About 50% of Americans and 70% of US military service members use dietary supplements (DSs).

OBJECTIVES

This cross-sectional survey examined current prevalence of and factors associated with DS use in service members.

METHODS

A stratified random sample of 200,000 service members from the Air Force, Army, Marine Corps, and Navy was obtained from military manpower records, and these service members were asked to complete a questionnaire on their DS use and personal characteristics. Chi-square statistics and multivariable logistic regression examined differences across various strata of demographic, lifestyle, and military characteristics.

RESULTS

About 18% of successfully contacted service members (n = 26,681) completed the questionnaire between December 2018 and August 2019 (mean ± SD age: 33 ± 8 y, 86% male). Overall, 74% reported using ≥1 DS/wk. Multivitamins/multiminerals were the most commonly used DSs (45%), followed by combination products (44%), proteins/amino acids (42%), individual vitamins/minerals (31%), herbals (20%), joint health products (9%), and purported prohormones (5%). In multivariable analysis, factors independently associated with DS use included female gender [OR (female/male): 1.91; 95% CI: 1.73, 2.11], older age [OR (≥40/18-24 y): 1.25; 95% CI: 1.08, 1.44], higher education level [OR (college degree/high school or less): 1.35; 95% CI: 1.19, 1.53], higher BMI [OR (≥30/<25 kg/m2): 1.37; 95% CI: 1.25, 1.52], more weekly resistance training [OR (>300/≤45 min/wk): 5.05; 95% CI: 4.55, 5.61], smokeless tobacco use [OR (user/nonuser): 1.30; 95% CI: 1.17, 1.44], higher alcohol intake [OR (≥72/0 mL/wk): 1.41; 95% CI: 1.29, 1.54], and higher military rank [OR (senior officer/junior enlisted): 1.26; 95% CI: 1.06, 1.51].

CONCLUSIONS

Compared with civilian data from the NHANES, service members were much more likely to use DSs and used different types of DSs, especially combination products and proteins/amino acids often used to purportedly enhance physical performance. Comparisons with previous military data suggest DS use has increased over time.

Prevalence of and Factors Associated with Dietary Supplement Use in a Stratified, Random Sample of US Military Personnel: The US Military Dietary Supplement Use Study

BACKGROUND

About 50% of Americans and 70% of US military service members use dietary supplements (DSs).

OBJECTIVES

This cross-sectional survey examined current prevalence of and factors associated with DS use in service members.

METHODS

A stratified random sample of 200,000 service members from the Air Force, Army, Marine Corps, and Navy was obtained from military manpower records, and these service members were asked to complete a questionnaire on their DS use and personal characteristics. Chi-square statistics and multivariable logistic regression examined differences across various strata of demographic, lifestyle, and military characteristics.

RESULTS

About 18% of successfully contacted service members (n = 26,681) completed the questionnaire between December 2018 and August 2019 (mean ± SD age: 33 ± 8 y, 86% male). Overall, 74% reported using ≥1 DS/wk. Multivitamins/multiminerals were the most commonly used DSs (45%), followed by combination products (44%), proteins/amino acids (42%), individual vitamins/minerals (31%), herbals (20%), joint health products (9%), and purported prohormones (5%). In multivariable analysis, factors independently associated with DS use included female gender [OR (female/male): 1.91; 95% CI: 1.73, 2.11], older age [OR (≥40/18-24 y): 1.25; 95% CI: 1.08, 1.44], higher education level [OR (college degree/high school or less): 1.35; 95% CI: 1.19, 1.53], higher BMI [OR (≥30/<25 kg/m2): 1.37; 95% CI: 1.25, 1.52], more weekly resistance training [OR (>300/≤45 min/wk): 5.05; 95% CI: 4.55, 5.61], smokeless tobacco use [OR (user/nonuser): 1.30; 95% CI: 1.17, 1.44], higher alcohol intake [OR (≥72/0 mL/wk): 1.41; 95% CI: 1.29, 1.54], and higher military rank [OR (senior officer/junior enlisted): 1.26; 95% CI: 1.06, 1.51].

CONCLUSIONS

Compared with civilian data from the NHANES, service members were much more likely to use DSs and used different types of DSs, especially combination products and proteins/amino acids often used to purportedly enhance physical performance. Comparisons with previous military data suggest DS use has increased over time.

A Cross-Sectional Evaluation of Complementary and Alternative Medicine Use in a Non-urban Malaysian Population

Complementary and alternative medicine (CAM) therapies have been an integral part of Malaysia culture for many centuries. In recent years influences from other parts of the world have gained a foot-hold in Malaysian popular culture. We investigated the engagement with CAM in a non-urban, Malaysian population. We investigated the association of CAM use with cultural influence, perceived health status, gender and age. We recruited 700 adult participants to this study across three sites in central Malaysia. We found massage, Vitamin supplements, Herbal medicine and traditional Chinese medicine to be the most popular CAM modalities with participation at 67.7%, 55.7%, 55.5% and 26.3% respectively. CAM use was equally high at 67% among those people who claimed a predominantly Malay or Chinese cultural influence. The use of vitamins and participation in yoga were at higher prevalence among female participants compared to males. There was no gender difference for other CAM modalities. There were differences between age groups for most CAM modalities, and those over 50 years tended to be the highest frequency users for most modalities. There is a high rate of CAM use in non-urban Malaysia with younger people being more engaged with less traditional modalities such as aromatherapy, yoga and music therapy.

The Cigarette Smoking, Coffee and Supplements Intake at Students of Sarajevo University

Introduction:

The dietary supplements are defined as vitamins and minerals or herbal products and are typically given in the form of a capsule or tablet. The nonsmokers are more attempted to use dietary supplements than individuals who smoke.

Aim:

In our investigation, we examined associations between vitamin B, folic acid, multivitamin or mineral intake among the student population and their correlation with smoking prevalence and drinking coffee.

Materials and methods:

We used a questionnaire to examine the general characteristics of the subjects, age, sex, their lifestyle, cigarette smoking, coffee intake and their use of dietary supplements. Data were collected from participants of the University of Sarajevo and a longitudinal study of 960 men and women aged 18-24 years from 2017 to 2018 was conducted.

Results:

The results showed that 32% of students took vitamin B supplements and 10% folic acid. In opposite, more than half of students took multivitamins (59.5%) and minerals (60.4%) less than one year. About a quarter or less took multivitamins (23.9%) and minerals (24.3%) for years. Less than 20% of students took multivitamins and minerals within a period of one year. In student population smoking prevalence was estimated at 21.2% and coffee intake in 71.2%. The smoking and use of vitamin B supplements were independent of each other, p = 0.201. The use of folic acid did not depend on smoking p = 0.501. There were no observed correlations between multivitamin and mineral supplement consumption compared to smoking status or drinking coffee.

Conclusion:

Deficient dietary intake of folic acid and B vitamins from food and supplemental sources appear to be one of the atherosclerosis incidences. Further studies should examine associations between dietary supplements intake and lifestyle of students, as well as smoking status and coffee intake.

Impact of Frequency of Multi-Vitamin/Multi-Mineral Supplement Intake on Nutritional Adequacy and Nutrient Deficiencies in U.S. Adults

Although >50% of U.S. adults use dietary supplements, little information is available on the impact of supplement use frequency on nutrient intakes and deficiencies. Based on nationally representative data in 10,698 adults from the National Health and Nutrition Examination Surveys (NHANES) 2009 to 2012, assessments were made of intakes from food alone versus food plus multi-vitamin/multi-mineral supplements (MVMS) of 17 nutrients with an Estimated Average Requirement (EAR) and a Tolerable Upper Intake Level (UL), and of the status of five nutrients with recognized biomarkers of deficiency. Compared to food alone, MVMS use at any frequency was associated with a lower prevalence of inadequacy (p < 0.01) for 15/17 nutrients examined and an increased prevalence of intakes >UL for 7 nutrients, but the latter was ≤4% for any nutrient. Except for calcium, magnesium, and vitamin D, most frequent MVMS use (≥21 days/30 days) virtually eliminated inadequacies of the nutrients examined, and was associated with significantly lower odds ratios of deficiency for the examined nutrient biomarkers except for iron. In conclusion, among U.S. adults, MVMS use is associated with decreased micronutrient inadequacies, intakes slightly exceeding the UL for a few nutrients, and a lower risk of nutrient deficiencies.

The Case for Promoting Multiple Vitamin And Mineral Supplements for Women of Reproductive Age in Developing Countries

Women in developing countries often consume inadequate amounts of micronutrients because of their limited intake of animal products, fruits, vegetables, and fortified foods. Intakes of micronutrients less than the recommended values increase a woman's risk of having micronutrient deficiencies. the adverse effects of deficiencies in vitamin A, iron, and folic acid, including night-blindness in pregnant and lactating women and iron-deficiency anaemia, are well known. Low intakes of these and other nutrients, including zinc, calcium, riboflavin, vitamin B6, and vitamin B12, also have consequences for women's health, pregnancy outcome, and the health and nutritional status of breastfed children. Multiple deficiencies coexist, so the benefit of multiple micronutrient supplements is becoming increasingly apparent. Supplementation of women with multiple vitamins and minerals should be one component of a strategy to improve micronutrient status among women in developing countries. However, there are several issues for programme managers to consider before implementing programmes. Which reference standards will be used to determine nutrient levels to include in the supplements? Which nutrients will be included and in what quantities? Which factors need to be considered in purchasing supplements? These issues are discussed, and guidance is provided on the selection of appropriate supplements for pregnant women and women of reproductive age in developing countries.

Vitamin C in Alternative Cancer Treatment: Historical Background

Ascorbic acid is the single-nutrient supplement most commonly used by cancer patients, although in most cases this takes place without the physician's knowledge or supervision. A comprehensive review of the literature is presented on the impact of ascorbic acid on cancer survival. Findings from 6 uncontrolled studies suggest that ascorbic acid may increase survival, whereas 2 controlled trials have yielded null results. The relative strengths and limitations of these studies are discussed. A turning point occurred with the release of the 2 controlled (null) studies, which influenced many physicians to turn away from nutrition in the care of cancer patients. Controversy about these trials still persists, however, in the alternative cancer community.

Demographic Characteristics of Supplement Users in an Elderly Population

This study investigated the association of demographic characteristics with supplement use in 257 elderly participants of the Georgia Centenarian Study in their 60s (n = 89), 80s (n = 92), and 100s (n = 76). Of these elders, 44% used a specific vitamin or mineral supplement. Multivitamins/minerals (28%), vitamin C (13%), and vitamin E (7%) were the most common vitamins reported; whereas calcium (8%) and potassium (5%) were the most common minerals reported. Centenarians were as likely as those in their 60s and 80s to use a supplement. Females were more likely than males to report consuming any supplement and multivitamins/minerals; Whites were more likely than Blacks to report consuming any supplement, vitamin E, and vitamin C. Health care providers must be aware that even the oldest old are frequent users of supplements, but being male and of minority status may be a barrier to the use of nutritional supplements.

Prevalence of Dietary Supplement Use by Athletes: Systematic Review and Meta-Analysis

BACKGROUND

Dietary supplements (DSs) are commercially available products consumed as an addition to the usual diet and are frequently ingested by athletes.

OBJECTIVE

Our objective was to examine the prevalence of DS use by athletes.

DATA SOURCES

PubMed, Ovid MEDLINE, OVID Healthstar, and Cumulative Index to Nursing and Allied Health were searched for original research articles published up to August 2014. Search terms included specific sports, specific DSs, and other terms.

STUDY SELECTION

Studies were selected if they were written in English, involved athletes, and provided a quantitative assessment of the proportion of athletes using specific DSs. Percent of athletes using specific DSs.

SYNTHESIS OF DATA

Methodological quality of studies was assessed by three reviewers using an 8-point scale that included evaluations for sampling methods, sampling frame, sample size, measurement tools, bias, response rate, statistical presentation, and description of the participant sample. Where there were at least two investigations, meta-analysis was performed to obtain summary (pooled) prevalence estimates (SPEs) on (1) DS use prevalence by sport and sex, (2) DS use prevalence by elite versus non-elite athletic status, and (3) specific DS prevalence for all athletic groups combined. Meta-analyses included evaluations of homogeneity and publication bias.

RESULTS

A total of 159 unique studies met the review criteria. Methodological quality was generally low with an average ± standard deviation of 43 ± 16% of available rating points. There was low homogeneity for SPEs when compiled by sport, athletic status, and/or specific DSs. Contributing to the lack of homogeneity were differences in studies' objectives and types of assessments used (e.g., dietary surveys, interviews, questionnaires). Despite these limitations, the data generally indicated that elite athletes used DSs much more than their non-elite counterparts. For most DSs, use prevalence was similar for men and women except that a larger proportion of women used iron while a larger proportion of men used vitamin E, protein, and creatine. No consistent change in use over time was observed because even the earliest investigations showed relatively high use prevalence.

CONCLUSION

It was difficult to generalize regarding DS use by athletes because of the lack of homogeneity among studies. Nonetheless, the data suggested that elite athletes used dietary supplements far more than their non-elite counterparts; use was similar for men and women with a few exceptions; use appeared to change little over time; and a larger proportion of athletes used DSs compared with the general US population. Improvements in study methodology should be considered in future studies especially (1) defining DSs for participants; (2) querying for very specific DSs; (3) using a variety of reporting timeframes (e.g., daily, 2-6 times/week, 1 time/week and <1 time/week); (4) reporting the sampling frame, number of individuals solicited, and number responding; (5) reporting characteristics of volunteers (and non-volunteers, if available); and (6) using similar methods on several occasions to examine possible temporal trends among athletes.

A systematic review and meta-analysis on the prevalence of dietary supplement use by military personnel

Background

Although a number of studies have been conducted on the prevalence of dietary supplement (DS) use in military personnel, these investigations have not been previously summarized. This article provides a systematic literature review of this topic.

Methods

Literature databases, reference lists, and other sources were searched to find studies that quantitatively examined the prevalence of DS use in uniformed military groups. Prevalence data were summarized by gender and military service. Where there were at least two investigations, meta-analysis was performed using a random model and homogeneity of the prevalence values was assessed.

Results

The prevalence of any DS use for Army, Navy, Air Force, and Marine Corps men was 55%, 60%, 60%, and 61%, respectively; for women corresponding values were 65%, 71%, 76%, and 71%, respectively. Prevalence of multivitamin and/or multimineral (MVM) use for Army, Navy, Air Force, and Marine Corps men was 32%, 46%, 47%, and 41%, respectively; for women corresponding values were 40%, 55%, 63%, and 53%, respectively. Use prevalence of any individual vitamin or mineral supplement for Army, Navy, Air Force, and Marine Corps men was 18%, 27%, 25%, and 24%, respectively; for women corresponding values were 29%, 36%, 40%, and 33%, respectively. Men in elite military groups (Navy Special Operations, Army Rangers, and Army Special Forces) had a use prevalence of 76% for any DS and 37% for MVM, although individual studies were not homogenous. Among Army men, Army women, and elite military men, use prevalence of Vitamin C was 15% for all three groups; for Vitamin E, use prevalence was 8%, 7%, and 9%, respectively; for sport drinks, use prevalence was 22%, 25% and 39%, respectively. Use prevalence of herbal supplements was generally low compared to vitamins, minerals, and sport drinks, ≤5% in most investigations.

Conclusions

Compared to men, military women had a higher use prevalence of any DS and MVM. Army men and women tended to use DSs and MVM less than other service members. Elite military men appeared to use DSs and sport drinks more than other service members.

Longitudinal and secular trends in dietary supplement use: Nurses' Health Study and Health Professionals Follow-Up Study, 1986-2006

Most studies on the prevalence of supplement use in the United States were cross-sectional or evaluated trends in limited variety of supplements. The objective of this study was to describe the longitudinal and secular trend of dietary supplement use over the past 20 years in health professionals using data from two large prospective cohorts. We analyzed cohort data from 1986 to 2006 in the Nurses' Health Study (NHS) and the Health Professionals Follow-Up Study (HPFS). In 1986, 74,194 women aged 40 to 65 years in the NHS and 50,497 men aged 40 to 75 years in the HPFS were included. Use of dietary supplements including multivitamins, vitamins, and minerals was repeatedly asked every 4 years. Generalized estimating equation models were used for repeated analysis. Prevalence of use of any supplement increased among both women (71.3% to 88.3%) and men (56.4% to 80.7%) from 1986 to 2006. Notably, longitudinal increases in the prevalence of use of vitamin D (2.2% to 32.2% for women and 1.1% to 6.7% for men), folic acid (0.8% to 10.7% for women and 1.1% to 13.8% for men), and fish oil (1.6% to 18.1% for women and 3.3% to 22.2% for men) supplements were observed from 1990 to 2006. However, the use of vitamin A, beta carotene, vitamin C, and vitamin E supplements peaked in 1994 or 1998, then declined steadily. A secular increase in use of multivitamins, vitamin D, folic acid, and fish oil across same age group was noted. In conclusion, the use of many types of dietary supplements has increased over time, but the use of antioxidant supplements has declined. The secular increase in the prevalence of use of supplements across the same age group suggests that aging of the population is not the primary reason for the increase. These findings in health professionals need to be replicated in the general populations.

Calcium intake and risk of cardiovascular disease: a review of prospective studies and randomized clinical trials

The potential effects of inadequate or excessive calcium supply on cardiovascular disease (CVD) are receiving growing attention. We review experimental, epidemiologic, and clinical evidence regarding the role of calcium intake in the development of CVD in adults. In vitro and in vivo laboratory studies have shown that calcium may affect the risk of developing CVD through multiple mechanisms including blood cholesterol, insulin secretion and sensitivity, vasodilation, inflammatory profile, thrombosis, obesity, and vascular calcification. A number of prospective epidemiologic studies have examined the relationship between dietary calcium intake and CVD incidence or mortality in middle-aged and older adults. The results were inconsistent, and the pooled data do not strongly support a significant effect of greater dietary calcium intake on the risk of coronary artery disease (CAD) or stroke. Only a few prospective studies have examined calcium supplement use in association with risk of CVD. The pooled data show no significant benefits of calcium supplement use in reducing the risk of CAD or stroke. No randomized clinical trial has specifically tested the effect of calcium supplementation on CVD as its primary endpoint. Secondary analyses in existing trials to date suggest a neutral effect of calcium (with or without vitamin D) supplements on CVD events, but do not allow for a definitive conclusion. A large percentage of Americans, particularly older adults, fail to meet the US recommendations for optimal calcium intake and are encouraged to increase daily calcium consumption. More prospective cohort studies and large-scale randomized trials are needed to further evaluate the risks or benefits of calcium supplementation on CVD endpoints as the primary pre-specified outcome.

Monitoring of vitamin B-12 nutritional status in the United States by using plasma methylmalonic acid and serum vitamin B-12

BACKGROUND

Various definitions, criteria, tests, and cutoffs have been used to define vitamin B-12 status; however, a need exists for the systematic study of vitamin B-12 status in the United States because of concerns about high folic acid intakes and the potential for associated adverse effects.

OBJECTIVE

The objective was to determine the effect of different cutoff choices on outcomes and of the different degrees of serum vitamin B-12 status, definable by the concurrent use of a functional and circulating marker as the first steps to developing a data-based consensus on the biochemical diagnosis of vitamin B-12 deficiency.

DESIGN

Data from NHANES, a nationally representative cross-sectional survey, were examined for adults aged >19 y (mean ± SD age: 45 ± 1 y) from 1999 to 2004 (n = 12,612).

RESULTS

Commonly used cutoffs had a greater effect on prevalence estimates of low vitamin B-12 status with the use of vitamin B-12 than with the use of methylmalonic acid (MMA; 3-26% and 2-6%, respectively). A cutoff of >148 pmol/L for vitamin B-12 and of ≤210 nmol/L for MMA resulted in significant misclassifications. Approximately 1% of adults had a clear vitamin B-12 deficiency (low vitamin B-12 and elevated MMA); 92% of adults had adequate vitamin B-12 status. A high percentage of younger women characterized the group with low vitamin B-12 and normal MMA (2% of adults) and may have falsely reflected low vitamin B-12. Adults with elevated MMA (5%) only were demographically similar (ie, by age and race) to the deficient group and may have included some individuals with early vitamin B-12 deficiency.

CONCLUSIONS

These analyses indicate the challenges of assessing vitamin B-12 status when uncertainties exist about the appropriate cutoffs. Future studies should determine definable endpoints to achieve this goal.

Use of vitamin and mineral supplements among Canadian adults

OBJECTIVE

To estimate the prevalence and determinants of use of vitamin and mineral supplements among adult Canadians.

METHODS

Data from adult respondents of the Canadian Community Health Survey Cycle (CCHS) 2.2 were used. Participants were asked about their use of vitamin and mineral supplements in the month prior to being surveyed. The prevalence of vitamin and mineral supplement use was compared across various socio-demographic and lifestyle factors. Logistic regression analysis was used to assess determinants of supplement use.

RESULTS

In the month prior to the interview, 40.1% of adult Canadians took supplements. In the fully adjusted model, females of all ages were more likely to be users than males 19-30 years. Physical activity, fruit/vegetable consumption, and higher levels of household education and income were positively related to supplement use.

CONCLUSIONS

A substantial proportion of adult Canadians take vitamin and mineral supplements. The use was more prevalent among those with healthier lifestyles and of socio-economically advantaged backgrounds. Further investigation is needed to reveal the impact of supplements on nutrient adequacy and health.

Consistency of vitamin and/or mineral supplement use and demographic, lifestyle and health-status predictors: findings from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Heidelberg cohort

Cross-sectional studies suggest that dietary supplement use is associated with favourable demographic and lifestyle factors and certain health conditions. However, factors that affect the consistency of supplement use have not been investigated in prospective cohort studies. The aim of the present study was to seek baseline demographic, lifestyle and health-status predictors of subsequent consistent vitamin and/or mineral supplement use. A total of 8968 men and 10 672 women of the European Prospective Investigation into Cancer and Nutrition (EPIC)-Heidelberg cohort, who answered the supplement-use questions in the baseline survey and two follow-up surveys, were categorised into three groups: consistent, inconsistent and never users. At baseline, 28·5 % of men and 38·6 % of women reported vitamin and/or mineral supplement use. After a median follow-up of 8·5 years, 14·6 % of men and 22·9 % of women were consistent users. During follow-up, 36·0 % of male and 26·6 % of female initial users stopped supplement use, whereas 27·8 % of male and 39·4 % of female initial non-users started supplement use. Women were more likely to be consistent users than men. Older age ( ≥ 50 years), lower BMI ( < 25 kg/m2) and self-reported hyperlipidaemia were common predictors of consistent use for both sexes. Additional predictors included higher educational level for men, and being more physically active and higher lifetime alcohol consumption for women. Consistent users had the highest intake of dairy products, fish, fruits and vegetables, and wine but the lowest intake of total meat. We concluded that supplement use is a fairly unstable behaviour in free-living individuals. Individuals with a favourable lifestyle and healthier diet are more likely to show consistent supplementation.

Maternal diet and risk of childhood acute lymphoblastic leukemia

OBJECTIVE

Intrauterine environmental factors, including maternal diet, may play an etiologic role in acute lymphoblastic leukemia (ALL), a common childhood cancer. Expanding on previous findings from phase 1 of the Northern California Childhood Leukemia Study (NCCLS), a population-based case-control study, we sought to further elucidate and replicate the relationships between maternal diet and ALL risk.

METHODS

We matched 282 case-control sets of children (205 pairs and 77 triplets) from phases 1 and 2 of the NCCLS on sex, date of birth, mother's race, Hispanic racial/ethnic status, and county of residence at birth. We used an interviewer-administered food frequency questionnaire to obtain information on maternal dietary intake in the 12 months prior to pregnancy.

RESULTS

Risk of ALL was inversely associated with maternal consumption of vegetable (adjusted odds ratio [AOR] = 0.65, 95% confidence interval [CI] 0.50, 0.84); protein sources (AOR = 0.55, 95% CI 0.32, 0.96); fruit (AOR = 0.81, 95% CI 0.65, 1.00); and legume food groups (AOR = 0.75, 95% CI 0.59, 0.95). The risk reduction was strongest for consumption of the protein sources and vegetable food groups, independent of the child's diet up to age 2 years, and consistent across phases 1 and 2 of data collection for vegetable consumption.

CONCLUSIONS

These data suggest that it may be prudent for women to consume a diet rich in vegetables and adequate in protein prior to and during pregnancy as a possible means of reducing childhood ALL risk in their offspring.

Trends in dietary supplement use in a cohort of postmenopausal women from Iowa

Although it is widely known that use of dietary supplements is common in the United States, little is known about use patterns among older Americans. The authors examined trends in dietary supplement use and its contribution to total nutrient intake in the Iowa Women's Health Study cohort in 1986 (baseline) and 2004 (follow-up). The proportion of women who reported using dietary supplements increased substantially between baseline (66%) and follow-up (85%). Moreover, a substantial proportion of women reported using multiple dietary supplements, with 27% using 4 or more products in 2004. Dietary supplements contributed substantially to total intake of many nutrients at baseline, and their contribution became relatively greater at follow-up for most nutrients examined. For most nutrients, no decline in intake was observed, as might have been expected in an aging cohort. Rather, intake of many nutrients increased, primarily because of the rising use of dietary supplements. Use of dietary supplements by older individuals is of particular importance because of the potential benefits of maintaining nutrient intake levels despite potentially declining food intake. However, possible risks from obtaining a large proportion of purified nutrients from dietary supplements rather than deriving them from foods should be studied.

Iron supplement use among Danish pregnant women

OBJECTIVES

To evaluate compliance with the national recommendation on supplemental iron to all pregnant women in Denmark and to explore differences between compliers and non-compliers with respect to dietary habits and other lifestyle factors.

DESIGN

Intake of supplemental iron from pure iron supplements and from multivitamin and mineral preparations was estimated in mid-pregnancy.

SETTING

Nationwide cohort study, the Danish National Birth Cohort (DNBC), comprising more than 100,000 women recruited in early pregnancy.

SUBJECTS

Information on diet and dietary supplements was available for 54,371 women. Of these, information on lifestyle factors was available for 50,902 women.

RESULTS

A high compliance with the recommendation was found, as approximately 77% of the women reported use of iron supplements during pregnancy. However, many of the compliers did not obtain the recommended doses of iron, which can partly be explained by the lack of iron preparations of appropriate doses available on the Danish market. Compliance with the recommendation was associated with age above 20 years, primiparity, body mass index<30 kg m- 2, non-smoking and long education. No major differences were seen in dietary intake between compliers and non-compliers.ConclusionOverall, a high compliance rate was found among participants of the DNBC but a clarification on daily dose is needed, and more concern should be paid to vulnerable groups such as young, smoking women and women with no or short education.

Multivitamin and multimineral dietary supplements: definitions, characterization, bioavailability, and drug interactions

Although multivitamins, multiminerals, and similar terms (eg, multis or multiples) are commonly used, they have no standard scientific, regulatory, or marketplace definitions. Thus, multivitamins-multiminerals refers to products with widely varied compositions and characteristics. Multivitamin-multimineral composition databases use label values as surrogates for analyzed values. However, actual vitamin and mineral amounts often deviate from label values. Vitamin and mineral bioavailability for dietary supplements also lacks a standard scientific and regulatory definition and validated in vitro and animal models that accurately reflect human bioavailabilities. Systematic information on the bioavailability and bioequivalence of vitamins and minerals in marketed products and on potential drug interactions is scarce. Because of limited information on product characteristics, our ability to directly compare results across studies, estimate changes in usage patterns or intakes over time, and generalize from published results to marketed products is problematic.

Dietary supplement use by community-living population in Japan: data from the National Institute for Longevity Sciences Longitudinal Study of Aging (NILS-LSA)

BACKGROUND

There are few studies about dietary supplement use and nutrient intake from these products in Japan. The purpose of this study was to clarify (1) the prevalence of dietary supplement use, (2) the characteristics of dietary supplement users, (3) nutrient intake from dietary supplements, and (4) the existence of dietary supplement users who took excessive nutrients from these products.

METHODS

To collect the information on dietary supplement use in the previous year and nutrient intake from these products, we conducted a self-administered dietary supplement frequency questionnaire. The subjects were 2,259 people aged 40-82 years. Dietary supplements were grouped into 8 major categories. A dietary supplement database was developed to estimate nutrient intake from these products. Excess users were defined as people who consumed more nutrient than the tolerable upper intake level of the Dietary Reference Intakes for Japanese.

RESULTS

In the previous year, 55 % of males and 61 % of females consumed dietary supplements. Dietary supplement use was especially prevalent in females, subjects who felt unhealthy, and subjects who were more careful of maintaining an appropriate weight, though the association was affected by the frequency of dietary supplement use. The most common dietary supplements were drink type in males and vitamins in females. Some nutrient values obtained from dietary supplements were higher than those from food. Excess users were found for intake of vitamin A, B₆, K, niacin, iron, and magnesium.

CONCLUSIONS

It is important to clarify dietary supplement use and to estimate nutrient intake from these products.

Vitamin and Mineral Supplement Use among US Medical Students: A Longitudinal Study

OBJECTIVE

To provide data on medical students' multivitamin and calcium supplement use during medical school.

DESIGN

Medical students were anonymously surveyed at three time points: freshman orientation, orientation to wards, and during senior year.

SUBJECTS

Medical students (n = 2,316) at 16 US medical schools (response rate = 80.3%).

OUTCOME MEASURES

Prevalence and correlates of multivitamin and calcium supplement use throughout medical school.

STATISTICAL ANALYSES

Chi2 tests with associated P values, and logistic regression with associated odds ratios and confidence intervals.

RESULTS

Half of medical students surveyed used multivitamins, and 19% used calcium supplements, at least once per week as freshmen. Consumption of calcium, but not multivitamin, supplements increased during subsequent years (P = 0.0001) and both supplements were more commonly used by women (P < 0.0003). Of 970 students tracked across all three time points, 14% of women, compared with only 2% of men (P < 0.0001), took calcium at all three time points. Using multivariate models, we found that medical students were more likely to use multivitamins if they exercised regularly, had children, were underweight, or were women who were not heavy users of alcohol (P < 0.0001 to P < 0.05). Similarly, students who were women, underweight, exercised regularly, or had a personal or family history of osteoporosis were more likely to consume supplemental calcium (P < 0.0001 to P = 0.04).

CONCLUSIONS

Medical students of all types used supplements at moderate rates, and women used supplements more commonly and consistently than did men. Medical students, especially nonunderweight and nonexercising students, may be particularly important targets for messages regarding appropriate and adequate vitamin/mineral use.

Periconceptional multivitamin use reduces the risk of preeclampsia

The objective was to assess the independent effect of regular periconceptional multivitamin use on the risk of preeclampsia. Pregnant women (n=1,835) enrolled in the Pregnancy Exposures and Preeclampsia Prevention Study (Pittsburgh, Pennsylvania, 1997-2001) at less than 16 weeks' gestation were asked whether they regularly used multivitamins or prenatal vitamins in the past 6 months. Women were classified as users or nonusers. The unadjusted prevalence of preeclampsia was 4.4% in nonusers and 3.8% in users. After adjustment for race/ethnicity, marital status, parity, prepregnancy physical activity, and income in a multiple logistic regression model, regular use of multivitamins was associated with a 45% reduction in preeclampsia risk compared with nonuse (odds ratio (OR)=0.55, 95% confidence interval (CI): 0.32, 0.95). Prepregnancy overweight modified this effect. After confounder adjustment, lean multivitamin users had a 71% reduction in preeclampsia risk compared with lean nonusers (OR=0.29, 95% CI: 0.12, 0.65). In contrast, there was no relation between multivitamin use and preeclampsia among overweight women (OR=1.08, 95% CI: 0.52, 2.25). A sensitivity analysis for unmeasured confounding by fruit and vegetable intake supported these conclusions. If confirmed by others, these results suggest that regular use of a multivitamin supplement in the periconceptional period may help to prevent preeclampsia, particularly among lean women.

Prevalence of dietary supplement use in adults with chronic renal insufficiency

OBJECTIVE

There are currently no studies that have investigated dietary supplement use in the chronic renal insufficiency (CRI) population. The objectives of this study were to determine the prevalence of dietary supplement use in a sample of adults with CRI and to examine whether the prevalence of dietary supplement use was higher in the earlier stages of CRI.

DESIGN AND SETTING

Cross-sectional survey conducted at an outpatient nephrology clinic.

PATIENTS

Adults (n = 100) with varying degrees of CRI.

INTERVENTION

Interview-administered questionnaire.

MAIN OUTCOME MEASURES

The questionnaire contained questions related to the use of dietary supplements, attitudes, and beliefs about dietary supplements, as well as medical and demographic data including gender, age, body weight, smoking status, concurrent chronic conditions, prescribed medications, serum creatinine, estimated glomerular filtration rate (GFR), etiology of CRI, income, and education level.

RESULTS

The prevalence of dietary supplement use was 45%, with the most frequent use occurring in subjects with a mild to moderate degree of renal insufficiency. There were no significant differences in gender, age, body mass index, smoking status, number of concurrent chronic conditions, number of prescribed medications, income, or education level between supplement users and supplement nonusers. Further analysis of dietary supplement use showed that the number of supplements used ranged from 1 to 5 or more supplements per day, with an overall total of 36 different supplements. Dietary supplement users were significantly more concerned with their health than were supplement nonusers. The most frequent sources of supplement information were physicians and printed material; however, 75% of the dietary supplement users desired further information about their dietary supplements.

CONCLUSION

This is the first study to investigate the use of dietary supplements in adults with CRI, and it provides valuable information for health care professionals regarding the dietary supplement use of their patients with CRI.

Effect of Aloe vera preparations on the human bioavailability of vitamins C and E

There are no literature references describing the effect of consumption of Aloe vera liquid preparations on the absorption of water- or fat-soluble vitamins. There is a very large population worldwide which consume vitamins and many people also consume Aloe. Thus we report the effect of Aloe on the human absorption of vitamins C and E, the most popular vitamin supplements. The plasma bioavailability of vitamins C and E were determined in normal fasting subjects, with eight subjects for vitamin C and ten subjects for vitamin E. In a random crossover design, the subjects consumed either 500 mg of ascorbic acid or 420 mg of vitamin E acetate alone (control), or combined with 2 oz of two different Aloe preparations (a whole leaf extract, or an inner fillet gel). Blood was collected periodically up to 24 h after consumption. Plasma was analyzed for ascorbate and tocopherol by-HPLC with UV detection. There was no significant difference in the areas under the plasma ascorbate-time curves among the groups sincerely due to large differences within the groups. For comparative purposes the control area was 100%. The Aloe Gel area was 304%, and Aloe Whole Leaf 80%. Only Aloe Gel caused a significant increase in plasma ascorbate after 8 and 24 h. For vitamin E, the results for the relative areas were control 100%, Gel 369%, and Leaf (198%). Only the Aloes produced a significant increase in plasma tocopherol after 6 and 8 h. Both Aloes were significantly different from the control after 8 h. Aloe Gel was significantly different from the baseline after 24 h. The Aloes slowed down the absorption of both vitamins with maximum concentrations 2-4 h later than the control. There was no difference between the two types of Aloe. The results indicate that the Aloes improve the absorption of both vitamins C and E. The absorption is slower and the vitamins last longer in the plasma with the Aloes. Aloe is the only known supplement to increase the absorption of both of these vitamins and should be considered as a complement to them.

Association of dietary supplement use with specific micronutrient intakes among middle-aged American men and women: the INTERMAP Study

OBJECTIVE

To assess dietary supplement use and its association with micronutrient intakes and adequacy among 2,195 US men and women aged 40 to 59 years from eight diverse population samples surveyed by the International Population Study on Macronutrients and Blood Pressure.

DESIGN

Four 24-hour dietary recalls were collected, including information on dietary supplements. The Nutrition Data System (NDS) was used for nutrient analyses. Supplements not in NDS were classified separately (non-NDS). Intake of non-NDS supplements was documented. Participants were classified as not supplement users and supplement users, subclassified-due to concerns about nutritional value-as users of NDS supplements only (mostly vitamins and minerals) and users of non-NDS supplements (eg, botanicals, animal products, and enzymes). To assess effects of supplement use on micronutrient intake and adequacy, mean intakes from supplements, foods, and foods plus supplements were compared with Dietary Reference Intakes.

PARTICIPANTS

Two thousand one hundred ninety-five US participants; 1,136 used supplements.

STATISTICAL ANALYSES

Chi 2 tests, multivariate logistic regression, and means were used to assess differences in and factors related to supplement use and to determine dietary adequacy.

RESULTS

Supplement use was more common among women, older participants, more educated participants, and Asian Americans. Body mass index and current cigarette smoking were significantly and inversely associated with supplement use; past smoking and education were significantly and positively associated with supplement use. Intake from foods plus supplements was considerably higher than from foods alone for vitamins A, C, and E; niacin; folate; and iron.

CONCLUSIONS

Supplement use is common among middle-aged Americans and sizably increases daily intakes of several micronutrients. These data underscore the importance of dietary supplement assessment.

Vitamin or supplement use among adults, behavioral risk factor surveillance system, 13 states, 2001

OBJECTIVE

The authors examined vitamin/supplement (V/S) use and its relationship to sociodemographics, health behaviors, and health conditions among adults in 13 states.

METHODS

This investigation used 2001 data from a cross-sectional study of non-institutionalized adults aged > or = 18 years, the Behavioral Risk Factor Surveillance System.

RESULTS

Of 45,415 respondents with complete data (18,723 males and 26,692 females), 56.5% (n=5,652) reported current V/S use. After adjusting for age, sex, race/ethnicity, and education, the authors found a statistically significant association between V/S use and positive health risk behavior (adjusted odds ratio [OR]=1.46; p<0.001). Also, WS use was found to increase with age (p<0.001). No association was found between V/S use and the absence of specific chronic disease conditions (adjusted OR=0.93; p=0.052).

CONCLUSIONS

People who used V/S in the states surveyed were more likely to demonstrate positive health risk behaviors than those who did not report V/S use. Thus it appears that individuals who are most likely to use V/S are least likely to need V/S. It is crucial that individuals report quantity and frequency of V/S use when providing medical or diet histories to health care providers.

Longitudinal Patterns of Vitamin and Mineral Supplement Use in Young White Children

OBJECTIVES

The objective of this article is to report longitudinal patterns of nutrient supplementation in children, to quantify nutrient intakes from supplements and diet, and to examine relationships between supplement use and sociodemographic factors.

DESIGN AND SUBJECTS

Subjects were followed prospectively from birth to 24 months with periodic questionnaires on vitamin/mineral supplement use. Food diaries were completed to report food and beverage intake. Estimates of daily intakes of vitamins and minerals were calculated. Fisher's Exact tests and t tests were used to assess the association of sociodemographic variables with supplement use.

RESULTS

A substantial proportion of young children used supplements. The prevalence of supplement use increased with age. By the end of 24 months, 31.7% used some supplement. Young supplement users consume supplements regularly, ranging from 40% to 60% of days reported. The majority of young children in this cohort could obtain adequate vitamins and minerals from diet alone for the first 24 months of life. Intakes of some nutrients from diet alone, such as vitamin E and folate, were not sufficient for a large proportion of young children. However, intake above the dietary reference intake was observed for a few nutrients, in particular for vitamin A.

CONCLUSIONS

Use of nutrient supplements is a common behavior during the first 2 years of life. This study shows that most young children obtain adequate nutrients from diet alone. Health professionals should provide recommendations for nutrient supplementation of generally healthy children based on an assessment of their dietary practices.

Multiple sources of dietary calcium-some aspects of its essentiality

The increasing recognition of the important role of calcium in the myriad regulation of cellular processes in the health and well being throughout one's lifetime has focused on the need to ensure a sufficiency of its intake for nutritional, physiological, and medical reasons. Additionally, the recognition of the dynamic dietary changes and preferences of various populations in terms of their consumption of calcium-containing products coupled with large variations of food patterns and availability of calcium, highlights the need to consider and evaluate multiple sources of calcium (dairy, non-dairy, fortified foods, and supplemental). Aspects of the essentiality of calcium are thus considered via an initial consideration of: the salient aspects of absorption and bioavailability, changes in individual and societal dietary habits and preferences and the evaluation of various RDAs, AIs, and DRIs for calcium.

Safety assessment of gamma-cyclodextrin

Gamma-cyclodextrin (gamma-CD) is a cyclic alpha-(1,4)-linked oligosaccharide consisting of eight glucose molecules. Like other cyclodextrins, gamma-CD can form inclusion complexes with a variety of organic molecules because the inner side of the torus-like molecule is less polar than the outer side. In foods, gamma-CD may be used as a carrier for flavors, vitamins, polyunsaturated fatty acids, and other ingredients. It also has useful properties as a stabilizer in different food systems. The daily intake from all its intended uses in food at highest feasible concentrations has been estimated at 4.1g/person/day for consumers of gamma-CD containing foods. The present review summarizes the safety data of gamma-CD. The toxicity studies consist of standard genotoxicity tests, subchronic rat studies with oral and intravenous administration of gamma-CD for up to 3 months, a subchronic (3-month) toxicity study in dogs, a (1-year) oral toxicity study in rats, and embryotoxicity/teratogenicity studies in rats and rabbits. In the studies with oral administration, gamma-CD was given at dietary concentrations of up to 20%. All these studies demonstrated that gamma-CD is well tolerated and elicits no toxicological effects. Metabolic studies in rats showed that gamma-CD is rapidly and essentially completely digested by salivary and pancreatic amylase. Therefore, the metabolism of gamma-CD closely resembles that of starch and linear dextrins. A human study with ingestion of single doses of 8 g gamma-CD or 8 g maltodextrin did not reveal a difference in gastrointestinal tolerance of these two products. An interaction of ingested gamma-CD with the absorption of fat-soluble vitamins or other lipophilic nutrients is not to be expected because the formation of inclusion complexes is a reversible process, gamma-CD is readily digested in the small intestine, and studies with beta-CD, a non-digestible cyclodextrin, have shown that the bioavailability of vitamins (A, D, and E) is not impaired. On basis of these studies it is concluded that gamma-CD is generally recognized as safe (GRAS) for its intended uses in food.

Perceptions of dietary supplements among older women with diabetes

PURPOSE

The purpose of this qualitative study was to explore the meaning of taking dietary supplements from the perspective of being an older woman with type 2 diabetes.

METHODS

Nine women over the age of 65 with type 2 diabetes participated in a single, in-depth semistructured interview that focused on use of, views of, and methods of hearing about supplements. Interviews were audiotaped, transcribed verbatim, and analyzed using phenomenological methodology.

RESULTS

Eight of the 9 participants used some form of dietary supplement daily. Respondents described methods of hearing about supplements ranging from their daughters to the media to "people talk." Individual supplements were used primarily to prevent or treat conditions related to aging, such as osteoporosis, arthritis, and vision loss. They were also taken to prevent or lessen conditions associated with diabetes, including heart disease.

CONCLUSIONS

The older women with type 2 diabetes in this study used dietary supplements. However, taking supplements was not perceived as a means of controlling blood glucose and, as such, supplements were not taken as part of their diabetes treatment regimen.

Use of vitamin, mineral, nonvitamin, and nonmineral supplements in the United States: The 1987, 1992, and 2000 National Health Interview Survey results

OBJECTIVE

To describe trends in use of specific vitamin and mineral (VM) supplements.

DESIGN

The nationally representative National Health Interview Survey queried adult respondents about their use of VM supplements in 1987, 1992, and 2000. Statistical analysis Trends in use of VM supplements from 1987 to 2000 were determined using linear contrasts.

RESULTS

The percentage of adults using any VM supplement daily increased from 23.2% (1987) to 23.7% (1992) to 33.9% (2000). This pattern was consistent for both sexes, all race/ethnic groups, and adults aged >or=25 years. The increase in the percentage of daily users of multivitamins, vitamin A, and vitamin E was 10.5, 1.2, and 7.3 percentage points, respectively, from 1987 to 2000. Increases in daily use of vitamin C (3.3 percentage points) and calcium (6.1 percentage points) occurred between 1992 and 2000. All trend analyses were significant at P<.001. In the 2000 National Health Interview Survey personnel queried the use of nonvitamin/nonmineral supplements for the first time. At that time, 6.0% of respondents reported using them daily.

CONCLUSION

The increasing trend in supplement use over time and the notable use of nonvitamin/nonmineral supplements in 2000 indicates the continued need to monitor the use of all types of dietary supplements for purposes of dietary surveillance and nutrition-related research.

Knowledge of dietary supplement label information among female supplement users

The use of dietary supplements is a popular form of health behavior, especially among women. Little research has been conducted to determine consumers' comprehension of supplement label information. Therefore, this research evaluated comprehension of supplement label information among women 25-45 years of age who consumed a dietary supplement > or =4 times per week. Participants (n=51) completed a written questionnaire about supplement practices, a 10-item knowledge test, and an individual interview about terms used on supplement labels. Participants answered 70% of the questions correctly on the knowledge test indicating adequate knowledge of dietary sources of nutrients. Knowledge of recommended dosages, dosing instructions, and instructions about inappropriate use of supplements for certain people also was adequate. However, misconceptions regarding the term "natural" on supplement labels, product claims, and testing for product safety existed among participants. Supplement users need additional education about supplement claims and testing for product safety and efficacy to make informed health care choices.

The Importance of Breakfast Consumption to Nutrition of Children, Adolescents, and Young Adults

Breakfast consumption has been identified as an important factor in nutrition, especially during growth stages. This article discusses data from nearly 2,500 children, adolescents, and young adults in Louisiana and considers the impact of breakfast consumption on their nutritional well-being.

Decision-making patterns for dietary supplement purchases among women aged 25 to 45 years

Women frequently consume dietary supplements but the criteria used to select supplements have received little investigation. This research identified the decision-making criteria used for dietary supplements among women aged 25 to 45 years who consumed a supplement at least four times per week. Participants (N=51) completed an in-store shopping interview that was audiotaped, transcribed, and analyzed qualitatively for the criteria used to make supplement selections. Qualitative analysis revealed 10 key criteria and the number of times each person used each criterion was quantified. Cluster analysis identified five homogeneous subgroups of participants based on the criteria used. These included brand shopper, bargain shopper, quality shopper, convenience shopper, and information gatherer. Supplement users vary in the criteria used to make point-of-purchase supplement selections. Dietetics professionals can classify supplement users according to the criteria used to tailor their nutrition counseling and better meet the educational needs of consumers.

Consumo de folato em gestantes de um hospital público do Rio de Janeiro

O folato tem importante papel na formação do DNA e RNA, aspecto central do desenvolvimento fetal. Há desconhecimento em relação ao folato ingerido durante a gravidez em gestantes brasileiras, mas uma significante proporção de mulheres em idade reprodutiva em outros países e em condições semelhantes consome dietas com baixos níveis de folato e não usa suplementos contendo ácido fólico. Examinou-se o consumo de folato em 285 gestantes de uma maternidade pública (Instituto Fernandes Figueira - FIOCRUZ) da cidade do Rio de Janeiro. O consumo alimentar de folato foi medido por um questionário semiquantitativo de freqüência de consumo alimentar, previamente validado, com porções padronizadas por alimento. Foram coletados dados sobre características demográficas, socioeconômicas e uso de ácido fólico como suplemento medicamentoso na gestação. A prevalência de deficiência de folato na dieta (ingestão abaixo de 600 µg/dia) foi de 51,3%. Somente 22,4% das gestantes fizeram uso de suplemento medicamentoso contendo ácido fólico. Adicionando-se o suplemento ao folato da dieta, esta prevalência caiu para 43,8%. Mulheres com menores renda consomem mais energia, mais folato e usam mais ácido fólico como suplemento. Os alimentos que explicaram a variação no consumo de folato foram carne bovina, R² = 0,962 (p = 0.02), e leite, R² = 0,038 (p = 0,007). Dada a necessidade de suplementação de folato durante a gravidez, sugerimos como importante medida o aconselhamento para iniciar-se a ingestão de suplemento de ácido fólico nas mulheres que planejam engravidar, e o reforço da importância da sua indicação nas consultas médicas pré-concepcionais e de pré-natal.

Use of vitamins, minerals, and other dietary supplements by 17- and 18-year-old students in Korea

Various types of dietary supplements (DS) are popularly taken by young individuals. We surveyed 1,190 Korean senior high school third grade students for their DS use, motivational factors for this use, and potential dietary consequences of vitamin/mineral supplement (VMS) use. The use prevalence of DS-including VMS, tonic medicines, manufactured health food supplements, cordial food supplements, and drink rehabilitators-was 54%. VMS were taken most frequently, followed by tonic medicines and manufactured health food supplements. VMS use was highest in individuals who had a significant concern for their overall health and in those from families with a high socioeconomic level and with parental use of DS. Total daily study time of DS users was only slightly longer than that of nonusers. The VMS most frequently used were vitamin C and multivitamins. More than 46% of other DS users, and 58% of VMS users, had increased their intake of supplements during third grade relative to the previous year. VMS users had a more positive view of the potential health benefit of VMS than did nonusers. Vitamin and mineral intakes from VMS occurred over a wide range, with mean intakes typically exceeding the Korean and Canadian-U.S. Recommended Dietary Allowances. For a significant number of individuals, intakes of vitamin A, niacin, folic acid, vitamin C, calcium, iron, and zinc exceeded the Tolerable Upper Intake Levels. Given the widespread use of DS by older teenagers, the contribution of these supplements to their overall health and well-being is a subject that clearly merits additional study.

Vitamin C and bone markers: investigations in a Gambian population

Vitamin C is an essential micronutrient. Absence from the diet will result in the deficiency disease scurvy, typically characterised by weakening of collagenous structures. High intakes of vitamin C have been associated with decreased incidence or severity of a number of diseases, including cancer and cardiovascular disease. These beneficial effects may be attributed to its antioxidant properties, although the exact mechanisms of action remain elusive. It is also unclear what intake levels are required for optimal health benefits. The task of defining optimal intakes is hindered by the lack of a reliable functional marker of tissue vitamin C status in man. Many different pathways have been investigated, but none of them have measurable outcome variables relating directly to scorbutic changes. The bone-collagen formation pathway has the potential to provide a functional index of tissue vitamin C adequacy. Vitamin C acts as a cofactor for the enzyme lysyl hydroxylase, which is required for the hydroxylation of lysine residues in procollagen chains. Pyridinoline is a mature collagen cross-link formed from three hydroxylysine residues, deoxypyridinoline is formed from two hydroxylysine and one lysine residue. Guinea-pig studies have shown an alteration in the pyridinium cross-link ratios in response to graded vitamin C intakes (Tsuchiya & Bates, 1998). In order to investigate whether these changes can be seen in a human population group, a study was carried out in rural Gambia, where there is a marked seasonal variation in dietary vitamin C. The present review discusses the rationale behind the study and presents some preliminary results.

Demographics, lifestyles, health characteristics, and dietary intake among dietary supplement users in Japan

BACKGROUND

The associations between supplement use and certain demographics, lifestyles, health characteristics, and dietary intakes have not been studied in a large population in non-Western societies. The objective of our study was to investigate the association between supplement use and demographics, lifestyles, health characteristics, and dietary intake in a population-based cohort study in Japan.

METHODS

Subjects were the 78 531 participants (45-74 years) who completed a self-administered questionnaire in 1995 or 1998 in a 5-year follow-up survey by the Japan Public Health Center-based prospective Study on cancer and cardiovascular disease. The questionnaire included enquiries about supplement use, occupation, height, weight, smoking, alcohol, physical activity, dietary behaviours, working hours, subjective stress, as well as intakes for 138 foods.

RESULTS

The supplement users were likely to have formerly smoked or never smoked. Female supplement users were likely to consume alcohol moderately. The prevalence of users was higher in the elderly, the self-employed, those with lower body mass index, greater physical activity, lower frequency of eating prepared food, higher frequency of eating out, and higher stress level in both sexes after mutual adjustment. Mean intakes of energy and nutrients were lower for users than for non-users.

CONCLUSION

The demographics, lifestyles, health characteristics, and dietary intakes may need to be adjusted when evaluating the effect of dietary supplements on disease because they can become potential confounding factors.

National nutrition data: contributions and challenges to monitoring dietary supplement use in women

Survey data from three nationally representative surveys--the National Health and Nutrition Examination Survey, National Health Interview Survey and Continuing Survey of Food Intakes by Individuals--indicate that, in general, women are greater consumers of dietary supplements than men in terms of overall prevalence of use and number of supplements taken. However, monitoring dietary supplement use over time and aggregation or comparison of findings over different surveys is hampered by a lack of comparability between survey data collection and analysis. Differences exist in the types of dietary supplements queried, use of a referent time frame, specificity regarding the supplement taken and level of detail collected relating to personal usage. Some comparability in supplement data collection may be possible but some inconsistencies may persist because of differences in survey goals or collection procedures. Collection of data on dietary supplement use is challenging and collection of very detailed and precise data are time consuming and expensive. Consequently, the level of detail and precision necessary for monitoring, research, and policy uses is an issue that should be addressed in view of the high monetary and time costs of detailed dietary supplement data collection, as well as increased demands on survey respondent time.