Cohort and cross-sectional data were reviewed to describe the changes in dietary intake with age. Total energy intake decreases varied substantially with age, by 1000 to 1200 kcal in men and by 600 to 800 kcal in women. This resulted in concomitant declines in most nutrient intakes. For some nutrients, substantial numbers of older Americans consumed only one fifth to one third of the recommended dietary allowance. For most nutrients, research is lacking with which to judge the health impact of reduced nutrient consumption with age, although there is some evidence of an age-related decline in absorptive and metabolic function. With the aging of the population, more research is needed on nutrient requirements and health outcomes, and public health efforts are needed to increase physical activity and food intake among older people.

Higher body weight is known to negatively impact plasma vitamin C status. However, despite this well-documented inverse association, recommendations on daily vitamin C intakes by health authorities worldwide do not include particular reference values for people of higher body weight. This suggests that people of higher body weight and people with obesity may be receiving insufficient vitamin C in spite of ingesting the amounts recommended by their health authorities. The current preliminary investigation sought to estimate how much additional vitamin C people with higher body weights would need to consume in order to attain a comparable vitamin C status to that of a lower weight person consuming an average Western vitamin C intake. Data from two published vitamin C dose-concentration studies were used to generate the relationship: a detailed pharmacokinetic study with seven healthy non-smoking men and a multiple depletion-repletion study with 68 healthy non-smoking men of varying body weights. Our estimates suggest that an additional intake of 10 mg vitamin C/day is required for every 10 kg increase in body weight to attain a comparable plasma concentration to a 60 kg individual with a vitamin C intake of ~110 mg/day, which is the daily intake recommended by the European Food Safety Authority (EFSA). Thus, individuals weighing e.g., 80 and 90 kg will need to consume ~130 and 140 mg vitamin C/day, respectively. People with obesity will likely need even higher vitamin C intakes. As poor vitamin C status is associated with increased risk of several chronic diseases including cardiovascular disease, these findings may have important public health implications. As such, dose-finding studies are required to determine optimal vitamin C intakes for overweight and obese people.

BACKGROUND: Physical activity is increasingly recognized as an important factor influencing health and disease status. Total energy expenditure, both low-intensity and high-intensity, contributes to maintenance of healthy body weight. This paper presents the results of a quantitative approach to determining the activities that contribute to total energy expenditure in the United States. METHODS: Data from the National Human Activity Pattern Survey (NHAPS) were used. In 1992-1994 the NHAPS sampled 4,185 females and 3,330 males, aged 18 years and over, weighted to be representative of the 48 contiguous United States. A detailed report of each activity performed in the previous 24 hours was obtained. A score was created for each activity, by multiplying duration and intensity for each individual and summing across individuals. This score was then used to rank each activity according to its contribution to total population energy expenditure, for the total sample and separately for each gender, race, age, region, and season. RESULTS: This analysis reveals our society to be primarily sedentary; leisure time physical activity contributed only approximately 5% of the population's total energy expenditure. Not counting sleeping, the largest contributor to energy expenditure was "Driving a car", followed by "Office work" and "Watching TV". Household activities accounted for 20.1% and 33.3% of energy expenditure for males and females respectively. CONCLUSION: The information presented in this paper may be useful in identifying common activities that could be appropriate targets for behavioral interventions to increase physical activity.

Introduction

The Hispanic population is the most rapidly growing ethnic group in the United States. Culturally appropriate and efficient strategies for dietary assessment for this population are currently lacking. To address this issue and promote a healthy diet for disease prevention, we developed screening tools to assess the fruit, vegetable, and fat intake of Mexican Americans.

Methods

Brief screening tools (screeners) were developed based on national data on Mexican Americans' dietary intake and were then modified after interviews and field testing. The screeners take less than 10 minutes to administer. A reliability study was conducted from June through September 2000, during which 93 Mexican Americans (39 men, 54 women) completed the screeners twice, 1 month apart. The mean age of the study participants was 36.5 years (range 18-71 years), and 91.4% had been born in Mexico.

Results

Correlations between the first and second administration of the screeners were r = 0.64 for fruits and vegetables and r = 0.85 for dietary fat contributors. In addition, estimates of fruit and vegetable consumption frequency were similar to statewide estimates for Hispanics in California. Reproducibility of reported use of vitamin supplements at least once per week was high; 84% were classified in the same way both times (P < .001).

Conclusion

The screening tools provide a reliable assessment of selected dietary factors among Mexican Americans. The tools can be scored immediately to provide feedback to respondents. They may be useful in situations requiring easily administered and economical assessment tools, such as in large-scale studies or in community situations.

Traditional risk factors of a poor clinical outcome and mortality in the general population, including body mass index (BMI), serum cholesterol, and blood pressure (BP), are also found to relate to outcome in patients with chronic heart failure (CHF), but in an opposite direction. Obesity, hypercholesterolemia, and high values of BP have been demonstrated to be associated with greater survival among CHF patients. These findings are in contrast to the well-known associations of over-nutrition, hypercholesterolemia, and hypertension with a poor outcome in the general population. The association between traditional cardiovascular risk factors and an adverse clinical outcome in CHF patients is referred to as "reverse epidemiology." The mechanisms for this inverse association in CHF is not clear. There are other populations with a similar risk factor reversal phenomenon, including patients with end-stage renal disease receiving dialysis, those with advanced malignancies, and individuals with advanced age. Several possible causes are hypothesized: the time discrepancy of the competing risk factors may play a role; the presence of the "malnutrition-inflammation complex syndrome" in CHF patients may explain the existence of reverse epidemiology; and a decreased level of lipoprotein molecules may distort their endotoxin-scavenging role, predisposing CHF patients with a low serum cholesterol level to inflammatory consequences of endotoxemia. It is possible that new goals for such traditional risk factors as BMI, serum cholesterol, and BP should be developed for CHF. Reverse epidemiology of conventional cardiovascular risk factors is observed in CHF and may have a bearing on the management of these patients; thus, it deserves further investigation.

Approximately 15 million Americans including over 5 million children suffer from asthma, the most common chronic disease in childhood. The prevalence of pediatric asthma has risen sharply over the past four decades, with the sharpest increases occurring in children younger than 6 years and in urban, predominantly minority, populations. The reasons for this dramatic increase are not yet clear. Recent epidemiological studies indicate a higher prevalence of dietary antioxidant deficiency among asthmatics patients. However, the results of these studies are inconsistent or even contradictory. Epidemiological studies with robust design and use of novel epidemiological tools are urgently needed to examine the impact of dietary antioxidants on the incidence of asthma in preschool children. An incidence density case-control study which includes non-atopic controls, who are matched for age, gender, race, study center and sampling time to each asthmatic case will offer a robust study design. A validated food frequency questionnaire and an asthma and atopy severity score can be used to interview the parents of the recruited children. Risk set sampling may enable us to explore possible associations between the type and quantity of dietary antioxidants and the development and severity of asthma in such an epidemiological study.

Introduction

Dietary fat and low fruit and vegetable intake are linked to many chronic diseases, and U.S. population intake does not meet recommendations. Interventions are needed that incorporate effective behavior-change principles and that can be delivered inexpensively to large segments of the population.

Methods

Employees at a corporate worksite were invited to participate in a program, delivered entirely by e-mail, to reduce dietary fat and increase fruit and vegetable intake. Behavior-change principles underlying the intervention included tailoring to the participant's dietary lifestyle, baseline assessment and feedback about dietary intake, family participation, and goal setting. Assessment, tailoring, and delivery was fully automated. The program was delivered weekly to participants' e-mail inboxes for 12 weeks. Each e-mail included information on nutrition or on the relationship between diet and health, dietary tips tailored to the individual, and small goals to try for the next week. In this nonrandomized pilot study, we assessed technical feasibility, acceptability to employees, improvement in Stage of Change, increase in fruit and vegetable consumption, and decrease in fat intake.

Results

Approximately one third (n = 84) of employees who were offered the 12-week program signed up for it, and satisfaction was high. There was significant improvement in Stage of Change: 74% of those not already at the top had forward movement (P < .001). In addition, results suggest significant increase in fruit and vegetable consumption (0.73 times/day, P < .001) and significant decrease in intake of fat sources (-0.39 times/day, P < .001).

Conclusion

This inexpensive program is feasible and appears to be effective. A randomized controlled trial is needed.

Conventional risk factors of cardiovascular disease and mortality in the general population such as body mass, serum cholesterol, and blood pressure are also found to relate to outcome in maintenance dialysis patients, but often in an opposite direction. Obesity, hypercholesterolemia, and hypertension appear to be protective features that are associated with a greater survival among dialysis patients. A similar protective role has been described for high serum creatinine and possibly homocysteine levels in end-stage renal disease (ESRD) patients. These findings are in contrast to the well-known association between over-nutrition and poor outcome in the general population. The association between under-nutrition and adverse cardiovascular outcome in dialysis patients, which stands in contrast to that seen in non-ESRD individuals, has been referred to as "reverse epidemiology." Publication bias may have handicapped or delayed additional reports with such paradoxical findings in ESRD patients. The etiology of this inverse association between conventional risk factors and clinical outcome in dialysis patients is not clear. Several possible causes are hypothesized. First, survival bias may play a role since only a small number of patients with chronic kidney disease (CKD) survive long enough to reach ESRD. Hence, the dialysis patients are probably a distinctively selected population out of CKD patients and may not represent the risk factor constellations of their CKD predecessors. Second, the time discrepancy between competitive risk factors may play a role. For example, the survival disadvantages of under-nutrition, which is frequently present in dialysis patients, may have a major impact on mortality in a shorter period of time, and this overwhelms the long-term negative effects of over-nutrition on survival. Third, the presence of the "malnutrition-inflammation complex syndrome" (MICS) in dialysis patients may also explain the existence of reverse epidemiology in dialysis patients. Both protein-energy malnutrition and inflammation or the combination of the two are much more common in dialysis patients than in the general population and many elements of MICS, such as low weight-for-height, hypocholesterolemia, or hypocreatininemia, are known risk factors of poor outcome in dialysis patients. The existence of reverse epidemiology may have a bearing on the management of dialysis patients. It is possible that new standards or goals for such traditional risk factors as body mass, serum cholesterol, and blood pressure should be considered for these individuals.