Timing of energy intake during the day is associated with the risk of obesity in adults.

BACKGROUND: The timing of energy intake is a modifiable behaviour that may influence energy regulation and the risk of obesity. We examined the associations of energy intake in the morning, midday and evening with body mass index (BMI) (n = 239). METHODS: Cross-sectional analyses were performed using data from the University of California, Los Angeles Energetics Study. Energy intake was assessed using three 24-h dietary recalls and stratified by time-of-day: morning (00.00 h to 11.00 h), midday (11.00 h to 17.00 h) and evening (17.00 h to 00.00 h). Sensitivity analysis was conducted among 'true-reporters', whose self-reported energy intake was ±25% of total energy expenditure measured by doubly-labelled water (n = 99). Logistic regression models were performed adjusting for age, sex, race, education, total daily energy intake and physical activity. RESULTS: Energy intake in the morning was not associated with BMI. Participants who consumed ≥33% (versus <33%) of their daily energy intake at 12.00 h were (nonsignificantly) less likely to be overweight/obese [odds ratio (OR) = 0.68; 95% confidence interval (CI) = 0.37-1.24] and this association was stronger and statistically significant among true-reporters (OR = 0.34; 95% CI = 0.12-0.95). Those who consumed ≥33% of daily energy intake in the evening were two-fold more likely overweight/obese (OR = 2.00; 95% CI = 1.03-3.89), although this association was not significant among true-reporters (OR = 2.10; 95% CI = 0.60-7.29). CONCLUSIONS: These data indicate that eating more of the day's total energy intake at midday is associated with a lower risk of being overweight/obese, whereas consuming more in the evening is associated with a higher risk. Randomised trials are needed to test whether shifting energy intake earlier in the day could have a regulatory effect with respect to reducing intake in the evening, thereby promoting weight loss and maintenance.

Using doubly labeled water to validate associations between sugar-sweetened beverage intake and body mass among White and African-American adults.

BACKGROUND: Evidence is mixed regarding sugar-sweetened beverage (SSB) intake and adiposity among adults, perhaps because of reporting bias. OBJECTIVE: The objective of this study is to determine the impact of reporting bias on any associations between increased SSB intake and overweight/obesity. DESIGN: Beverage intake and overweight/obese status (body mass index ≥ 25 kg m(-2)) were examined among adults from a dietary assessment and doubly labeled water study (n=250). Four web-based, 24-h recalls assessed dietary intake. SSB intake was categorized as no intake, 1-99 kcals per day and >99 kcals per day. Logistic regression models adjusted for total caloric intake, age, race, education and diet quality compared SSB intake with overweight/obese status. To investigate dietary self-reporting bias, analyses were replicated in a subset of 'true reporters': those with self-reported total caloric intake within 25% of total energy expenditure per doubly labeled water assessments (n=108). RESULTS: One-half of participants were overweight/obese; more overweight/obese participants consumed SSB than normal-weight participants (69% vs 47%; P<0.001). Intake of other beverages did not differ by adiposity. Less number of White participants (48%) consumed SSB compared with African-American participants (68%; P=0.002). Compared with no intake, SSB intake up to the median intake doubled the risk of being overweight/obese (odds ratio: 2.1, 95% confidence interval: 1.0-4.3; P=0.046) and SSB intake over the median more than doubled the risk (odds ratio: 2.6, 95% confidence interval: 1.2-6.0; P=0.018). When limited to true reporters, SSB intake significantly increased the risk of being overweight/obese by nearly fourfold. CONCLUSION: Underreporting of SSB intake may be attenuating true associations of SSB intake and the risk of being overweight/obese.

Serum carotenoids and risk of cervical intraepithelial neoplasia in Southwestern American Indian women.

The objective of this research was to evaluate the association between serum carotenoids and cervical intraepithelial neoplasia (CIN) among Southwestern American Indian women. Cases were American Indian women with biopsy-proven CIN II/III cervical lesions (n = 81) diagnosed between November 1994 and October 1997. Controls were American Indian women from the same clinics with normal cervical epithelium (n = 160). All of the subjects underwent interviews and laboratory evaluations. Interviews evaluated demographic information, sexual history, and cigarette smoking. Serum concentrations of alpha-carotene, beta-carotene, beta-cryptoxanthin, lycopene, and lutein/zeaxanthin were measured by high performance liquid chromatography. Cervical human papillomavirus infection was detected using a PCR-based test. Increasing levels of alpha-carotene, beta-cryptoxanthin, and lutein/zeaxanthin were associated with decreasing risk of CIN II/III. In addition, the highest tertiles of beta-cryptoxanthin (odds ratio = 0.39, 95% confidence interval = 0.17-0.91) and lutein/zeaxanthin (odds ratio = 0.40, 95% confidence interval = 0.17-0.95) were associated with the lowest risk of CIN. In conclusion, specially targeted intervention efforts to increase consumption of fruits and vegetables may protect Southwestern American Indian women from developing CIN.

Dietary supplement use in the Prostate Cancer Prevention Trial: implications for prevention trials.

Nutrients included in commonly used dietary supplements, such as vitamins C and E, may affect cancer risk. To better understand how supplement use may affect the interpretation of cancer prevention trials, we examined dietary supplement use among participants in the Prostate Cancer Prevention Trial, a double-blind, placebo-controlled trial of the drug finasteride (Proscar) for the primary prevention of prostate cancer. Of 15,387 men who completed food frequency questionnaires and dietary supplement questionnaires, 44.3% used a multivitamin, 35% used single supplements of vitamin C or E, and 10-15% used antioxidant mixtures or single supplements of vitamins A and D, zinc, or beta-carotene at least three times per week. The strongest correlates of supplement use were higher education and lower body mass index (p < 0.001), and whites and Asians were more likely to use multivitamins and single supplements of vitamins C and E than were blacks and Hispanics. Supplement users obtained 87% of their total daily vitamin E intake, 61-64% of vitamins A, C, and D, and about half of beta-carotene, folate, and zinc from supplements. Because supplements, especially antioxidants, may confer independent cancer-preventive effects, analytic models of study findings should include exposure measurement of dietary supplements with appropriate tests for interaction. Our results can be generalized to similar chemoprevention trials.

Use of alternative medicine by children with cancer in Washington state.

BACKGROUND: Use of alternative medicine is widespread among adult cancer patients, but considerably less is known about the use of these therapies by pediatric cancer patients. Our objective was to investigate the distribution and patterns of alternative medicine use by children diagnosed with cancer in Washington State. METHODS: Pediatric cancer patients (< or =18 years) with first primary neoplasms were identified from the Cancer Surveillance System of western Washington. Telephone interviews were conducted with parents of 75 patients to obtain data on the prevalence and types of alternative medicine used, satisfaction with conventional and alternative medicine, motivations for use of alternative medicine, adverse effects, and costs. RESULTS: Seventy-three percent of patients used at least one alternative treatment or therapy. Twenty-one percent of patients consulted an alternative provider (e.g., acupuncturist, naturopathic doctor), and insurance companies covered 75% of these costs. Twenty-eight percent used high-dose dietary supplements such as vitamins C or E, and 35% used herbal preparations. Although use of alternative medicine was associated with parental dissatisfaction with their child's physician (P = 0.02), no patient used alternative medicine as a substitute for standard medical care. Most patients used alternative medicine to cope with disease symptoms or the side effects of the medical treatments. CONCLUSIONS: Pediatric oncology patients use alternative treatments as adjuncts to conventional care. Both researchers and health care providers should remain informed about the benefits and adverse effects of alternative therapies in order to discuss treatment options with patients and their families and to monitor treatment efficacy.

Effect of health lifestyle pattern on dietary change.

PURPOSE: To examine the effect of lifestyle on the effectiveness of a low-intensity dietary intervention. DESIGN: A secondary data analysis was performed using data from the Eating Patterns Study, a randomized controlled trial that found that self-help materials with physician advice was effective in changing dietary intake and behavior. SETTING: Primary care clinics in a large health maintenance organization. SUBJECTS: A total of 2111 patients with a routine scheduled appointment with their primary care physicians. MEASURES: Participants were grouped into one of six health lifestyle patterns based on similarities in baseline measures of alcohol intake, smoking, diet quality, and exercise. Within each lifestyle pattern, changes from baseline in usual fat and fiber intake (based on a food frequency) and a fat and fiber behavior score were compared at 3 months and 12 months for intervention vs. control participants. INTERVENTION: Self-help materials delivered by a physician with advice to change diet. RESULTS: Intervention participants in the fitness lifestyle group made the largest changes relative to controls for each dietary outcome at 3 and 12 months. For intervention participants defined by their alcohol intake or current smoking, either no changes in diet were observed compared with controls, or early changes were not sustained over time. Intervention-control comparisons within the remaining lifestyle patterns showed smaller dietary changes compared with the fitness lifestyle. This finding was similar to previously published results. CONCLUSIONS: This randomized controlled trial had limited power to detect subgroup differences; however, these results suggest that lifestyle patterns may be useful in the development of effective, targeted interventions to change behavior.

Measurement characteristics of 2 different self-monitoring tools used in a dietary intervention study.

OBJECTIVE: To examine the measurement characteristics of 2 self-monitoring tools, a food diary and fat scan, used in the dietary intervention of the Women's Health Trial: Feasibility in Minority Populations study. DESIGN: Comparison of fat intake reported on the self-monitoring tools to a criterion measure of fat intake, specifically the mean of a food frequency questionnaire and a 4-day food record. The main outcome measures were differences in fat grams and correlations between each of the self-monitoring tools and the criterion measure. SUBJECTS/SETTING: Six-month postrandomization data from 313 women aged 50 to 79 years who participated in the intervention group of the Women's Health Trial: Feasibility in Minority Populations study. RESULTS: Both self-monitoring tools underestimated fat intake compared to the criterion measure, the food diary by 9 g and the fat scan by 6 g. The self-monitoring instruments were better than chance at detecting a low-fat dietary pattern, however, and did not differ from each other in their ability to do so. APPLICATIONS/CONCLUSIONS: The self-monitoring tools were modestly precise as measures of fat intake, but neither was sufficiently accurate to be reliable as a sole assessment of dietary adherence. Dietetics professionals are encouraged to assess the measurement properties of self-monitoring tools to use them appropriately in supporting dietary changes.

Serum concentrations of retinol, alpha-tocopherol and the carotenoids are influenced by diet, race and obesity in a sample of healthy adolescents.

An important part of understanding the functions of vitamin A, vitamin E and the carotenoids in nutritional status assessment, health promotion and disease prevention is knowledge of factors that influence their distribution in human tissues. Our objective was to examine serum concentrations of these nutrients and compounds in a sample of 285 healthy participants, 12-17 y old, from three U. S. cities. Pearson correlations between diet measured with a food frequency questionnaire and serum nutrient concentrations among these adolescents (adjusted for total serum cholesterol, age, sex, race and body mass index) were as follows: retinol, 0.23; alpha-tocopherol, 0.16; alpha-carotene, 0.31; beta-carotene, 0.15; beta-cryptoxanthin, 0.38; lycopene, 0.08; and lutein + zeaxanthin, 0.25. Multivariate linear regression modeled associations of demographic, dietary and physiologic variables with serum concentrations of these nutrients. African-American participants had significantly lower concentrations of serum retinol (P < 0.001), alpha-tocopherol (P < 0.01) and alpha-carotene (P < 0.02), but higher concentrations of lutein + zeaxanthin (P = 0.001) compared with Caucasians. Obese participants had serum nutrient concentrations that were 2-10% (P < 0.05) lower than normal weight participants. Dietary intake was a significant predictor of all serum analytes (P < 0.01) except lycopene. These models explained 20% of the variability in serum retinol, 28% of the variability in serum alpha-tocopherol, and 14-24% of the variability in serum carotenoids.

Indirect calorimetry protocol development for measuring resting metabolic rate as a component of total energy expenditure in free-living postmenopausal women.

An objective measure of energy intake is needed in epidemiologic studies to evaluate random and systematic error associated with dietary self-report tools. Total energy expenditure in weight-stable humans is accepted as a measure of energy intake, but doubly labeled water remains cost prohibitive for large studies. Our purpose was to develop a practical indirect calorimetry (IC) protocol for estimating resting metabolic rate (RMR) in free-living, postmenopausal women. We conducted duplicate IC measures 1 wk apart using a canopy system on 102 women ages 50-79 y from the Seattle area. We compared RMR for 0-5, 5-10, 5-15, 5-20, 5-25, 5-30, and 0- to 30-min IC segments and segments meeting stability criteria. The mean RMR for the first 5 min was significantly higher than other time segments (P = 0.001). Correlation coefficients between duplicate measures were high (r = 0.90). Use of defined stability criteria produced RMR measures that were 10-30 kcal (42-126 kJ) higher than the 5- to 10-min RMR measures and 40-60% of subjects did not achieve these stability criteria. For protocols including IC to assess RMR as a component of total energy expenditure in free-living, postmenopausal women, a single 10-min canopy study, excluding the first 5 min of data, produces reliable results with minimal subject burden.

Predictors of self-initiated, healthful dietary change.

OBJECTIVE: To examine demographic and psychosocial factors that predict healthful dietary change. DESIGN: A cohort study, examining how factors assessed at baseline predicted change in fat-related dietary habits and fruit and vegetable intakes 2 years later. PARTICIPANTS: Participants were recruited in 1995 and 1996 by random-digit dialing (response rate 0.63), and followed-up in 1997 and 1998 (follow-up rate 0.82). The final sample included 336 men and 502 women. MAIN OUTCOME MEASURES: Fruit and vegetable intake and fat-related dietary patterns, measured by telephone-administered surveys. STATISTICAL ANALYSES: Chi2 tests and linear regression were used to test associations of baseline characteristics with dietary change. RESULTS: Fat intake (energy from fat) decreased by approximately 2 percentage points and fruits and vegetables intake increased by 0.17 servings per day (both P<.001). Changes were significantly larger among women and persons who were well educated. Persons in the maintenance stage of change and persons who believed there was a strong relationship between diet and cancer made the largest dietary changes. Use of food labels was strongly associated with fat reduction, but not with increases in fruits and vegetables. APPLICATIONS: These results suggest that food labels are useful for helping people reduce fat intake, that interventions should target persons at all stages of dietary change, and that new efforts are needed to reach men and persons who are less well educated.

Development of scales to measure dietary acculturation among Chinese-Americans and Chinese-Canadians.

OBJECTIVE: To develop simple scales to measure a Chinese immigrant's adoption of Western eating patterns (dietary acculturation). STUDY DESIGN AND PARTICIPANTS: Data are from 244 less-acculturated women of Chinese ethnicity living in Seattle, Wash, and Vancouver, British Columbia, Canada. Interviewers collected information on sociodemographic characteristics, acculturation indices, items that reflect Western and Chinese dietary behavior, and consumption of fruits, vegetables, and fat. STATISTICAL ANALYSES: Analysis of variance and linear regression analyses examined associations among dietary measures and acculturation variables, controlling for age, education, and city of residence. RESULTS: We developed 2 scales to assess dietary acculturation: the Western Dietary Acculturation Scale and the Chinese Dietary Acculturation Scale, measuring Western and Chinese eating behavior, respectively. Although the population in this study was a less-acculturated sample, most participants reported some Western dietary practices, such as drinking milk (78%), eating cheese (78%), eating at Western fast-food restaurants (56%), and eating between meals (72%). Younger, highly educated women employed outside the home had the highest Western dietary acculturation scores (P < .001). Women with high scores on the Western scale reported higher-fat dietary behaviors and had increased fruit and vegetable intake since immigration compared to those with lower scores (P < .001). There was good agreement between the dietary acculturation scales and traditional acculturation indicators (P < .001). APPLICATIONS: Nutrition programs for immigrant/minority groups may be more effective if they are tailored to level of dietary acculturation. Therefore, the ability to accurately assess dietary acculturation is an important component of nutrition education, interventions, and counseling in these populations.

A brief dietary assessment instrument for assessing target foods, nutrients and eating patterns.

OBJECTIVE: To develop and validate a new dietary assessment tool, the focused recall, and to use this to measure co-consumption of carotenoid-containing fruits and vegetables with savory snacks. DESIGN: Participants completed a telephone-administered focused recall and a 24-hour recall on the same day. We compared mean estimates of fruit, vegetable, savory snack and carotenoid consumption from both instruments. We also assessed the ability of each method to measure co-consumption of carotenoids with full-fat, reduced/non-fat and olestra-containing savory snacks. SETTING AND SUBJECTS: Data are from 245 male and 244 female adult participants in the Olestra Post-Marketing Surveillance Study (OPMSS). RESULTS: The mean (=/- SD) intake of fruit was 1.8(1.1) servings day(-1) from the focused recall and 1.6 (1.4) servings day(-1) from the 24-hour recall (r=0.56). The mean vegetable intake was 2.1 (1.3) and 2.2 (1.7) servings day(-1) (r=0.42), respectively, from each instrument. Estimates of total carotenoid and beta-carotene intake were within 5% of each other (r= 0.63 for total carotenoids and r= 0.70 for beta-carotene). Both instruments estimated that approximately 14% of total daily carotenoids were co-consumed with savory snacks (r= 0.63). CONCLUSIONS: The focused recall provides valid information about fruit, vegetable and savory snack consumption and allows researchers to examine associated eating patterns more easily.

A household food inventory for North American Chinese.

OBJECTIVE: To determine whether a short set of questions about foods in the household can provide information about the fat-related dietary behaviour of individual household members in less-acculturated Chinese populations. DESIGN: Cross-sectional survey. PARTICIPANTS: The study population included 244 adult females of Chinese ethnicity in Seattle, WA, and Vancouver, BC, Canada. SETTING: Bilingual interviewers collected information on the presence of 14 high-fat foods and seven reduced-fat foods in the household. Respondents were also asked about the consumption of foods and behaviour reflective of adoption of Western dietary practices, fat-related dietary behaviour, changes in consumption of high-fat foods since immigration, and sociodemographic characteristics. RESULTS: Although this was a less-acculturated sample, many households had Western foods such as butter (58%), lunchmeats (36%), snack chips (43%), and 1% or skim milk (48%). Households with respondents who were younger, married, employed outside the home, and lived with young children had significantly more high-fat foods, while high education and longer percentage of life in North America were significantly associated with having more reduced-fat foods (P , or = 0.05). Participants living in households with more high-fat foods had higher-fat dietary behaviour than those with fewer high-fat foods (fat-related dietary behaviour score, 1.54 versus 1.28; P < 0.001). Women in households with more reduced-fat foods had a significantly decreased consumption of high-fat foods since immigration compared with those in households with fewer reduced-fat foods (P < 0.001). Western dietary acculturation was higher among women in households both with more high-fat foods and more reduced-fat food counterparts (P < or = 0.05). CONCLUSIONS: Our inventory of household foods was strongly associated with current dietary behaviour, changes in food consumption, and westernization of dietary patterns. This simple, practical measure may be a useful alternative dietary assessment tool in less-acculturated Chinese populations.

Is there a consumer backlash against the diet and health message?

OBJECTIVE: Anecdotal evidence exists that the public is becoming skeptical about nutrition messages. This article examines whether there is a backlash against dietary recommendations and whether it is associated with less healthful diets. DESIGN/PARTICIPANTS: Data are from a 1997-1998 Washington State random-digit-dial survey of 1,751 adults designed to monitor attitudes and behavior related to cancer risk and prevention. STATISTICAL ANALYSES: Responses to the nutrition backlash survey were weighted to reflect the Washington State population. Linear regression was used to examine associations of nutrition backlash with fat and fruit and vegetable intake. RESULTS: This survey did not find strong evidence that nutrition backlash was widespread. However, 70% of respondents thought that Americans are obsessed with the fat in their diet and that the government should not tell people what to eat. More than a quarter agreed with the statement that eating low-fat foods takes the pleasure out of eating. Nutrition backlash was associated with less healthful diets: individuals showing high backlash had a fat-related diet habits score of 2.11 compared with a score of 1.73 among those showing low backlash (P for trend = .001), which corresponds to a difference of roughly 4 percentage points in percentage energy from fat. Individuals showing high backlash reported eating only 2.72 servings of fruits and vegetables per day, compared with 3.35 servings among those showing low backlash (P for trend = .001). APPLICATIONS/CONCLUSIONS: Nutrition professionals need to ensure that dietary recommendations are clear and positive to avoid the possibility that consumers may disregard nutrition messages entirely.

Evaluation of chest pain in patients with low to intermediate pretest probability of coronary artery disease by electron beam computed tomography.

Despite its limited sensitivity and specificity in patients with low to intermediate probability of coronary artery disease (CAD), exercise treadmill testing (ETT) is frequently used as the initial test for investigation of chest pain. Although myocardial perfusion imaging is a significantly more accurate test, its added cost to ETT is considerable. The cost of a non-contrast electron beam computed tomography (EBCT) scan is comparable to that of ETT and the calcium score (CS) correlates closely with the volume of atherosclerotic plaque. Therefore, we tested the hypothesis that EBCT might be an effective and cost-beneficial technique for the identification of angiographically obstructive CAD (> or = 50% stenosis) in patients with low to intermediate pretest probability of disease. We calculated the theoretic cost of attaining a diagnosis of CAD based on a Bayesian model that utilizes published sensitivity and specificity levels for ETT, EBCT, and stress myocardial perfusion imaging. We then submitted a cohort of 207 patients with low to intermediate probability of disease both to EBCT and ETT in random order, and estimated the cost of achieving a correct diagnosis by either route based on the number of expected further tests. An EBCT calcium score of 150 was chosen as a cut-point with a sensitivity of 74% and a specificity of 89% for the presence of obstructive CAD. The theoretic Bayesian model predicted substantial cost savings when EBCT was used as the initial test instead of ETT, with decreasing benefit as the prevalence of disease increased (44% saving at 0% prevalence; 15% saving at 100% prevalence). In the patient cohort, the diagnostic pathway starting with EBCT provided a 45% to 65% cost saving over the ETT pathway. We conclude that in patients with low to intermediate pretest probability of disease, a pathway based on EBCT as the initial test to investigate presence of obstructive CAD provides a substantial cost benefit over a pathway based on ETT. Such cost advantages decrease as the prevalence of disease increases.

Precision and bias of food frequency-based measures of fruit and vegetable intakes.

Accurate assessment of fruit and vegetable intakes is critical for cancer control research and public health surveillance. This report examines the bias and precision of two commonly used food frequency questionnaire methods to assess fruit and vegetable intakes: (a) the 5 A Day method, based on seven items; and (b) the summation method, based on adding total servings of all fruit and vegetable items on a comprehensive (100+ item) food frequency questionnaire. Data are from three studies in which 24-h dietary recalls, food records, or serum carotenoid concentrations could be used as criterion measures (n = 260, 1031, and 342). Studies differed markedly in distributions of participants' age, race/ethnicity, sex, and socioeconomic status. Mean intakes of total fruit and vegetables based on the 5 A Day method were consistently lower than those from either the summation method (3.11 versus 4.06), 24-h recalls (3.32 versus 4.07), or food records (3.11 versus 3.46; all P < 0.01), and this was due primarily to underestimates of vegetable intake. Correlations of the 5 A Day and summation measures with all criterion measures were similar and were consistently higher for fruit (range, 0.33-0.57) than for vegetables (range, 0.24-0.32). These results, which were consistent across diverse participant samples, suggest that the 5 A Day method yields both biased and imprecise measures of vegetable intake and that research to improve this measure is needed.

Changes in diet, weight, and serum lipid levels associated with olestra consumption.

BACKGROUND: Specially manufactured low-fat and nonfat foods have become increasingly available over the past 2 decades and controversy has surrounded the issue of whether these products have beneficial or adverse effects on the health and nutritional status of Americans. METHODS: This study examines the association of olestra consumption with changes in dietary intakes of energy, fat, and cholesterol and changes in weight and serum lipid concentrations. Data are from a cohort of 335 participants in the Olestra Post-Marketing Surveillance Study sentinel site in Marion County (Indianapolis, Ind). Diet, weight, and serum lipid levels were assessed before the market release of olestra and 1 year later, after olestra-containing foods were widely available. Olestra intake at the 1-year follow-up was categorized as none, low (>0 to 0.4 g/d), moderate (0.4 to 2.0 g/d), and heavy (>2.0 g/d). RESULTS: Participants in the heavy olestra consumption category significantly reduced dietary intake of percentage of energy from fat (2.7 percentage points, P for trend,.003) and saturated fat (1.1 percentage points, P for trend,.02). Consumers in the highest category of olestra consumption had statistically significantly reduced total serum cholesterol levels of -0.54 mmol/L (-21 mg/dL)compared with -0.14 mmol/L (-5 mg/dL) among olestra nonconsumers (P for trend,.03). CONCLUSIONS: These results indicate that introduction of a new fat substitute (olestra) in the US market was associated with healthful changes in dietary fat intake and serum cholesterol concentrations among consumers who chose to consume olestra-containing foods.

Use of qualitative methods to study diet, acculturation, and health in Chinese-American women.

Improving the health status of minority populations in the United States is a major public health challenge. This report describes an anthropological approach to obtaining information needed for designing and evaluating a culturally appropriate dietary intervention for Chinese-Americans. Ninety-minute qualitative interviews were conducted with 30 less-acculturated Chinese-American women in their native language (Cantonese or Mandarin), soliciting information from participants regarding usual food consumption; knowledge, attitude, and beliefs about diet and disease; and factors that influence food choices. Interviews were recorded, translated, transcribed, and coded for themes. Two focus groups with 6 participants each were conducted to cross-validate the interview findings. Among our participants, breakfast was usually the first meal to be "Westernized," largely for reasons of convenience. Food quality, cost, and availability were some of the most important predictors of dietary change after immigration to the United States. Respondents said that there was a strong connection between diet and disease. However, they were not familiar with US dietary guidelines, food labels, or other sources of dietary information, but reported that friends and Chinese newspapers were their primary source of nutrition information. We used these findings to develop quantitative dietary survey instruments adapted for Chinese-Americans. This type of qualitative groundwork is an important precursor to the design, implementation, and evaluation of dietary interventions for minorities.

Nutrition, genetics, and risks of cancer.

Dietary patterns, nutrients, and other constituents of food are major components of the environmental influences that contribute to risk for cancer, and the study of interactions between nutritional and genetic factors is a new and important area or research. This review describes the concepts and principles underlying this area of study and types of relationships between nutritional and genetic factors, and it provides examples of specific diet-gene interactions that are of current interest, with an emphasis on implications for cancer prevention and public health. Polymorphisms exist in the genes for the activating and conjugating metabolizing enzymes, and the induction of metabolizing enzyme activity by nutritional factors may result in either the activation of a carcinogen or the detoxification of a reactive intermediate metabolite. The relationship between the methylenetetrahydrofolate reductase gene and dietary folate is an example of a diet-gene interaction that involves a polymorphism in a vitamin metabolism gene, and the presence of the variant appears to influence both risk for cancer and folate requirements. Diet-gene interactions likely contribute considerably to the observed inter-individual variations in cancer risk in response to exposures to the nutritional factors that have the potential to promote or protect against cancer. Insights into mechanisms by which nutritional factors affect the process of carcinogenesis are provided by knowledge of the targeted gene function and enzyme activity. Increased knowledge in this area will allow a more refined approach to reducing risk for cancer, with diet interventions targeted toward individuals and subgroups that are genetically susceptible and responsive to the effects of nutritional factors.

Correlates of serum lycopene in older women.

Experimental and epidemiological evidence suggests that lycopene, a predominant carotenoid found in human serum, may reduce the risk of certain cancers. We examined the association of dietary, physiological, and other factors with serum lycopene concentrations in a subsample of 946 postmenopausal women participating in the Women's Health Initiative. Pearson partial correlation coefficients and linear regression coefficients were calculated after adjustment for age, ethnicity, and serum low-density-lipoprotein (LDL) cholesterol. Serum lycopene was correlated with serum LDL cholesterol (r = 0.23) and dietary lycopene (r = 0.17, both p < 0.001). Individual food items found to be correlated with serum lycopene after adjustment included fresh tomatoes or tomato juice (r = 0.11), cooked tomatoes, tomato sauce, or salsa (r = 0.17), and spaghetti with meat sauce (r = 0.19, all p < 0.01). Age and body mass index were negatively associated with serum lycopene levels (both p < 0.001). Serum lycopene levels were highest in the summer and highest for those living in the northeastern United States. If we postulate that high serum lycopene levels reduce cancer risk, it becomes apparent that we have limited ability to detect this association from studies of lycopene intake. An understanding of factors associated with serum lycopene levels can be useful for the interpretation of studies of dietary lycopene and disease risk.