Voluntary food fortification in the United States: potential for excessive intakes.

BACKGROUND: Historically, the voluntary addition of micronutrients to foods in the United States has been regarded as an important means to lessen problems of nutrient inadequacy. With expanding voluntary food fortification and widespread supplement use, it is important to understand how voluntary food fortification has an impact on the likelihood of excessive usual intakes. Our objective was to investigate whether individuals in the United States with greater frequency of exposure to micronutrients from voluntarily fortified foods (vFF) are more likely to have usual intakes approaching or exceeding the respective tolerable upper intake levels (UL). SUBJECTS/METHODS: The National Cancer Institute method was applied to data from the 2007-2008 National Health and Nutrition Examination Survey (NHANES) to estimate the joint distribution of usual intake from both vFF and non-vFF sources for 12 nutrients and determine the probability of consuming these nutrients from vFF on a given day. For each nutrient, we estimated the distribution of usual intake from all food sources by quintile of probability of consuming vFF and compared the distributions with ULs. RESULTS: An increased probability of consuming zinc, retinol, folic acid, selenium and copper from vFF was associated with a greater risk of intakes above the UL among children. Among adults, increased probability of consuming calcium and iron from vFF was associated with a greater risk of intakes above the UL among some age/sex groups. CONCLUSION: The high nutrient exposures associated with vFF consumption in some population subgroups suggest a need for more careful weighing of the risks and benefits of uncontrolled food fortification.

Discretionary addition of vitamins and minerals to foods: implications for healthy eating.

OBJECTIVES: Health Canada proposes to allow manufacturers to add vitamins and minerals to a wide variety of foods at their discretion, a practice that has long been permitted in the United States and Europe. With Health Canada's proposed exclusion of staple and standardized foods from discretionary fortification, questions arise about the nutritional quality of the foods that remain eligible for fortification. To better understand the implications of this policy for healthy eating, this study examined the contribution of foods eligible to be fortified to the dietary quality of Canadians. METHODS: Using 24-h dietary recall data from the 2004 Canadian Community Health Survey, the relationship between intake of fortifiable foods and indicators of dietary quality was assessed. RESULTS: The mean percentage contribution of fortifiable foods to usual energy intake ranged from 19% among men over the age of 70 years to 36% for girls aged 14-18 years. Fortifiable food (as a percentage of total energy) was inversely associated with intake of vegetables and fruit, meat and alternatives, milk products, fiber, vitamins A, B6, B12 and D, magnesium, potassium and zinc. Fortifiable food was positively associated with dietary energy density, total energy intake and grain products. Few relationships were found for folate, vitamin C, iron, calcium, sodium and saturated fat. CONCLUSIONS: Consumption of foods slated for discretionary fortification is associated with lower nutrient intakes and suboptimal food intake patterns. Insofar as adding nutrients to these foods reinforces their consumption, discretionary fortification might function to discourage healthier eating patterns.

Socio-demographic influences on food purchasing among Canadian households.

OBJECTIVE: To characterize the relationships between selected socio-demographic factors and food selection among Canadian households. DESIGN: A secondary analysis of data from the 1996 Family Food Expenditure survey was conducted (n=10,924). Household food purchases were classified into one of the five food groups from Canada's Food Guide to Healthy Eating. Parametric and non-parametric modelling techniques were employed to analyse the effects of household size, composition, income and education on the proportion of income spent on each food group and the quantity purchased from each food group. RESULTS: Household size, composition, income and education together explained 21-29% of the variation in food purchasing. Households with older adults spent a greater share of their income on vegetables and fruit (P<0.0001), whereas households with children purchased greater quantities of milk products (P<0.0001). Higher income was associated with purchasing more of all food groups (P<0.0001), but the associations were nonlinear, with the strongest effects at lower income levels. Households where the reference person had a university degree purchased significantly more vegetables and fruit, and less meat and alternatives and 'other' foods (P<0.0001), relative to households with the lowest education level. CONCLUSIONS: Household socio-demographic characteristics have a strong influence on food purchasing, with the purchase of vegetables and fruit being particularly sensitive. Results reinforce concerns about constraints on food purchasing among lower income households. Furthermore, the differential effects of income and education on food choice need to be considered in the design of public health interventions aimed at altering dietary behaviour.

Household food insecurity with hunger is associated with women's food intakes, health and household circumstances.

This study investigated food intake patterns and contextual factors related to household food insecurity with hunger among a sample of 153 women in families seeking charitable food assistance in Toronto. Women in households characterized by food insecurity with severe or moderate hunger over the past 30 d (as assessed by the Food Security Module) reported lower intakes of vegetables and fruit, and meat and alternatives than those in households with no hunger evident. Women were more likely to report household food insecurity with hunger over the past 12 mo and 30 d if they also reported longstanding health problems or activity limitations, or if they were socially isolated. The circumstances that women identified as precipitating acute food shortages in their households included chronically inadequate incomes; the need to meet additional, unusual expenditures; and the need to pay for other services or accumulated debts. Women who reported delaying payments of bills, giving up services, selling or pawning possessions, or sending children elsewhere for a meal when threatened with acute food shortages were more likely to report household food insecurity with hunger. These findings suggest that expenditures on other goods and services were sometimes foregone to free up money for food, but the reverse was also true. Household food insecurity appears inextricably linked to financial insecurity.

A critical examination of community-based responses to household food insecurity in Canada.

Over the past two decades, household food insecurity has emerged as a significant social problem and serious public health concern in the "First World." In Canada, communities initially responded by establishing ad hoc charitable food assistance programs, but the programs have become institutionalized. In the quest for more appropriate and effective responses, a variety of community development programs have recently been initiated. Some are designed to foster personal empowerment through self-help and mutual support; others promote community-level strategies to strengthen local control over food production. The capacity of current initiatives to improve household food security appears limited by their inability to overcome or alter the poverty that under-pins this problem. This may relate to the continued focus on food-based responses, the ad hoc and community-based nature of the initiatives, and their origins in publicly funded health and social service sectors.

"Are you better?" A qualitative study of the meaning of recovery.

PURPOSE: Research into the meaning of illness has often focused on an individual's transition into a state of being ill, for example the adoption of a sick role. The question "Are you better?" addresses the transition out of this state and is fundamental to the patient-clinician relationship, guiding decisions about treatment. However, the question assumes that all patients have the same meaning for "being better." The purpose of this study was to explore the meaning of the concept of recovery (getting better) in a group of people with upper limb musculoskeletal disorders. METHODS: Qualitative (grounded theory) methods were used. Individual interviews were conducted with 24 workers with work-related musculoskeletal disorders of the upper limb. The audiotaped interviews were transcribed and coded for content. Categories were linked, comparisons made, and a theory built about how people respond to the question "Are you better?" RESULTS: The perception of "being better" is highly contextualized in the experience of the individual. Being better is not only reflected in changes in the state of the disorder (resolution) but could be an adjustment of life to work around the disorder (readjustment) or an adaptation to living with the disorder (redefinition). The experience of the disorder can be influenced by factors such as the perceived legitimacy of the disorder, the comparators used to define health and illness, and coping styles, which in turn can influence being better. CONCLUSION: Two patients could mean very different things when saying that they are better. Some may not actually have a change in disease state as measured by symptoms, impairments, or function.

Measuring the whole or the parts? Validity, reliability, and responsiveness of the Disabilities of the Arm, Shoulder and Hand outcome measure in different regions of the upper extremity.

UNLABELLED: The Disabilities of the Arm, Shoulder and Hand (DASH) outcome measure was developed to evaluate disability and symptoms in single or multiple disorders of the upper limb at one point or at many points in time. PURPOSE: The purpose of this study was to evaluate the reliability, validity, and responsiveness of the DASH in a group of diverse patients and to compare the results with those obtained with joint-specific measures. METHODS: Two hundred patients with either wrist/hand or shoulder problems were evaluated by use of questionnaires before treatment, and 172 (86%) were re-evaluated 12 weeks after treatment. Eighty-six patients also completed a test-retest questionnaire three to five days after the initial (baseline) evaluation. The questionnaire package included the DASH, the Brigham (carpal tunnel) questionnaire, the SPADI (Shoulder Pain and Disability Index), and other markers of pain and function. Correlations or t-tests between the DASH and the other measures were used to assess construct validity. Test-retest reliability was assessed using the intraclass correlation coefficient and other summary statistics. Responsiveness was described using standardized response means, receiver operating characteristics curves, and correlations between change in DASH score and change in scores of other measures. Standard response means were used to compare DASH responsiveness with that of the Brigham questionnaire and the SPADI in each region. RESULTS: The DASH was found to correlate with other measures (r > 0.69) and to discriminate well, for example, between patients who were working and those who were not (p<0.0001). Test-retest reliability (ICC = 0.96) exceeded guidelines. The responsiveness of the DASH (to self-rated or expected change) was comparable with or better than that of the joint-specific measures in the whole group and in each region. CONCLUSIONS: Evidence was provided of the validity, test-retest reliability, and responsiveness of the DASH. This study also demonstrated that the DASH had validity and responsiveness in both proximal and distal disorders, confirming its usefulness across the whole extremity.

Household food insecurity and hunger among families using food banks.

Over the past two decades, the demand for charitable food assistance has steadily grown, and a massive ad hoc system of food banks has become established in Canada. To assess the food insecurity and nutritional vulnerability of one subgroup of food bank users, interviews were conducted with a sample of 153 women in families using emergency food relief programs in Metropolitan Toronto. Ninety percent reported household incomes which were less than two thirds of the 'poverty line', and 94% reported some degree of food insecurity over the previous 12 months. Seventy percent reported some level of absolute food deprivation, despite using food banks. The findings highlight the limited capacity of ad hoc, charitable food assistance programs to respond to problems of household food insecurity which arise in the context of severe and chronic poverty.

Women's dietary intakes in the context of household food insecurity.

A study of food insecurity and nutritional adequacy was conducted with a sample of 153 women in families receiving emergency food assistance in Toronto, Canada. Contemporaneous data on dietary intake and household food security over the past 30 d were available for 145 of the women. Analyses of these data revealed that women who reported hunger in their households during the past 30 d also reported systematically lower intakes of energy and a number of nutrients. The effect of household-level hunger on intake persisted even when other economic, socio-cultural, and behavioral influences on reported dietary intake were considered. Estimated prevalences of inadequacy in excess of 15% were noted for Vitamin A, folate, iron, and magnesium in this sample, suggesting that the low levels of intake associated with severe household food insecurity are in a range that could put women at risk of nutrient deficiencies.

A survey of food problems experienced by Toronto street youth.

A brief survey was undertaken to assess the nature and severity of food scarcity experienced by a sample of 88 street youth in downtown Toronto, and to identify markers of vulnerability to food scarcity. Almost half of the youth reported experiencing involuntary hunger or food deprivation during the previous 30 days. Youth who were literally homeless (i.e., on the street or "squatting" in abandoned buildings) and those relying primarily on street-based activities for income appeared particularly vulnerable to food deprivation. Although limited in scope, the findings raise questions about the nutritional well-being of street youth and highlight the need for more effective interventions to address problems of poverty, hunger, and homelessness among Canadian youth.

Interpreting epidemiologic studies of diet-disease relationships.

The purpose of this paper is to examine key issues in the interpretation of nutritional epidemiologic study results when the focus is on major chronic degenerative diseases of multifactorial etiology. The estimation of disease risk associated with a particular dietary factor is influenced by the presence of other risk factors within the study population, complicating the interpretation of relative risk and odds ratio estimates in this context. Identifying the precise role(s) that dietary factors play in the onset or progression of chronic diseases is further complicated by the intercorrelation of dietary components and by the correlation of dietary patterns with other behavioral and environmental factors which may also impart or exacerbate risk of disease. Issues of study design and measurement make it difficult to identify relationships in nutritional epidemiology, but also thwart the rejection of hypotheses regarding diet-disease relationships when studies fail to yield significant associations. In drawing causal inferences from epidemiologic findings, it is important to examine evidence from a variety of sources and to look for congruence between epidemiologic, clinical and laboratory research findings.

Back pain claim rates and the business cycle.

The causes of reported occupational back pain are controversial. Many observers appear to believe that job insecurity increases back pain compensation claims during recessions. The purpose of this study was to formally examine the impact of macro-economic forces-the business cycle-on the incidence of lost-time back pain claim rates in order to elicit clues to both its aetiology and reporting patterns. For Ontario between 1975 and 1993, age- and sex-adjusted lost-time back pain claim rates, stratified by industry sector (construction, manufacturing and trade), were regressed on the unemployment rate of the industry sector using time series methods. As a comparison group, the association between "acute" claim (fractures, lacerations, etc.) and the business cycle was also tested. Both back pain claim rates and acute claim rates increased during boom periods and decreased during recessionary periods. Time series analyses confirmed that these associations were statistically significant. The elasticities between claim rates and the unemployment rate were similar for back pain claims and acute claims. In addition, these associations were consistent in direction across all three industrial sectors tested. These results rebut the view that back pain claims increase during recessionary times.

Research responses to outbreaks of concern about local environments.

Traditional epidemiological approaches based on biomedical models may be limited with respect to their response to "outbreaks of concern" among work-force or community populations. Three published Canadian "outbreaks" were reviewed in this study. In all three instances, research was initiated because lay persons were concerned about either nonspecific symptoms or hazardous exposures, and individuals publicly called for a response. Epidemiologic analyses were inconclusive as to the reasons for the outbreaks, and they contributed little toward the resolution of concerns. There is a need for a fuller recognition of the role of social context and of the action-oriented nature of such research. The elucidation of multifactorial and culturally mediated causation, as well as the development of remedial actions, require a rethinking of research methods. We specifically call for (a) an expansion of the disciplinary base of research teams to include social scientists, and (b) the adoption of combined qualitative and quantitative research approaches.

Back problems are for life: Perceived vulnerability and its implications for chronic disability.

As part of a qualitative research study of the experience of work-related back problems, a series of in-depth ethnographic interviews were conducted with 15 workers receiving treatment for back injuries. Analysis of these data revealed that the workers perceived their back problems as lifelong problems. Many believed that their back injuries had permanently heightened their vulnerability to reinjury and chronic disability. Accommodating this sense of physical vulnerability required a redefinition of one's self and one's future. For some workers, the perceived threat of future back problems was itself disabling and appeared to discourage a return to normal social roles. Workers' interactions with the health care system shaped their perceptions of their bodies and their notions of the appropriate means to cope with their physical vulnerability. Implications of the perception of permanence for the development of chronic disability among workers who experience back problems are examined.

Estimation of possible impact of non-caloric fat and carbohydrate substitutes on macronutrient intake in the human.

This paper addresses the expected impact of use of macronutrient substitutes by individuals without strong motivation to control macronutrient or energy intake when such modified foods serve as replacements of foods normally ingested rather than as "add-ons". A basic premise of the paper is that individuals are likely to replace a substantial part of the energy equivalent of the original substitution. It further assumes that the macronutrient composition of the additional foods consumed will reflect normal food selection behaviours. The paper derives a description of the expected selection behaviour from examination of the within subject variance in energy and macronutrient intake of 29 subjects followed for 365 consecutive days (the Beltsville One Year Dietary Intake Study). Patterns observed in these subjects were validated through examination of associations between macronutrient intake and energy intake in 600 women, each of whom contributed 6 days of dietary data (USDA CSFII-85). As presently proposed the model suggests that the use of non-caloric fat replacements, by subjects without strong motivation to control fat or energy intake, can be expected to result in a net decrease (less than original substitution) in fat intake and net increases in carbohydrate and protein intakes. Conversely, use of carbohydrate replacements in core foods can be expected to result in net increases in fat and protein intakes and a partial decrease in carbohydrate intake. The magnitude of these net changes is seen to be a function of the extent of replacement of energy.

Day-to-day variation in energy and nutrient intake: evidence of individuality in eating behaviour?

A study of within-subject variation in the reported food intakes and food selections of 29 adults participating in the Beltsville One-Year Dietary Intake Study suggests that individuals possess characteristics levels of day-to-day variation in intake. Application of Bartlett's test of homogeneity of variance indicated heterogeneity of within-subject variance in energy intake and in selected nutrients controlled for energy. Comparisons of estimates of within-subject variation derived from a split sample of days revealed the relative stability of individuals' magnitudes of day-to-day variation in energy and nutrient intake over time. For some nutrient variables, a large proportion of the observed heterogeneity in within-subject variation could be explained by a linear relationship between subjects' standard deviations and their mean intake levels. However, heterogeneity persisted when subjects' coefficients of variation were compared, suggesting that mean intake differences are insufficient to explain the observed differences in subjects' levels of day-to-day variation. The magnitude of observed variation in an individual's food intake and food selection from one day to the next appears to be a meaningful descriptor of that individual's intake behaviour.

Statistical estimation of dietary parameters: implications of patterns in within-subject variation--a case study of sampling strategies.

Patterns within intraindividual variation in energy intake were described previously. Using case studies based on the same Beltsville One-Year Dietary Intake Study data set, we examined the interaction between random and nonrandom variation and the choice of sampling strategy in estimation of individuals' usual intakes over 1 y. Mean intake estimates derived from adjacent-day samples were less reliable and more likely to be biased than were those based on randomly selected days. A finite adjacent-day sample fails to encompass longer-term trends. Because adjacent-day samples underestimate true within-subject variation, by customary tests they appear more reliable. This may present an interpretational problem. Comparisons of random weekend and week-day samples confirm that failure to proportionately sample both will bias the estimation of the usual (1-y mean) intake and the within-subject variance.

The nature and individuality of within-subject variation in energy intake.

Examinations of observed within-subject variation in the energy intake of 29 adults participating in the Beltsville One-Year Dietary Intake Study suggest that individuals possess characteristic patterns of variability in total food intake (expressed as energy intake). Although the day-to-day variation appears to contain a sizable random component, significant nonrandom components were detected in the observed variation of all but one subject. Up to 37% of the total variance observed for a subject could be explained by the long- and short-term patterns identified in food intake. Both the shape and the amplitude of these patterns were unique to the individual subject, suggesting that observed within-subject variance is a function of the particular combination of environmental and biological pressures on the individual's total food intake at any one time and of the methodological errors inherent in the estimation of this intake.

Menstrual-cycle patterns in energy and macronutrient intake.

For 14 subjects drawn from the Beltsville One-Year Dietary Intake Study, patterns of energy, protein, fat, carbohydrate, protein/1000 kcal, fat/1000 kcal, and carbohydrate/1000 kcal were examined across pre- and postmenstrual periods. Individual subjects contributed data for one to four menstrual periods. Energy, fat, and fat/1000 kcal intakes were significantly higher in the 10 premenstrual days than in the 10 postmenstrual days. After elimination of effects attributable to between-subject differences and to balance periods included in the Beltsville study, fitted sine curves explained 14% and 25% of the variance in energy and fat intakes, respectively, across 14 premenstrual and 14 postmenstrual days, and 20% of the variance in fat/1000 kcal. Independent patterns were identified in absolute and relative protein intake. No patterns were discerned for carbohydrate. Physiological or behavioral factors appear to influence both total food intake (energy intake) and food selection (macronutrients/1000 kcal) across the menstrual cycle.