Implementation of a 4-y, high-fiber, high-fruit-and-vegetable, low-fat dietary intervention: results of dietary changes in the Polyp Prevention Trial

Dietary Fiber Intake: Assessing the Degree of Agreement between Food Frequency Questionnaires and 4-Day Food Records

OBJECTIVE

To assess the degree of agreement (comparability) between dietary fiber intakes reported on a food frequency questionnaire (FFQ) with 4-day food records (4DFR) and determine whether demographic, behavioral and biological factors influence comparability.

METHODS

At baseline and year one, all participants in the Polyp Prevention Trial (PPT), a multi-center randomized, clinical trial of a low-fat, high fiber, high fruit/vegetable eating plan and recurrence of large bowel adenomatous polyps were instructed in dietary assessment and completed a 106-item FFQ and 4DFR that trained nutritionists reviewed. A random sub-cohort of participants (n = 399) was selected from the intervention and control arms of the PPT for analysis of both FFQ and 4DFR.

RESULTS

Baseline crude and energy-adjusted fiber intakes were significantly higher in the 4DFR than the FFQ (P = 0.001). Using Bland-Altman statistics, the mean difference (FFQ-4DFR) was -0.11 g/MJ; while the limits of agreement were -1.45, 1.23 g/MJ. The mean fiber difference increased with increasing average intake (FFQ + 4DFR)/2, (P = 0.004) for men, but not women (P = 0.10), suggesting that fiber intake was under-estimated in the FFQ, relative to the 4-DFR, for men with low fiber intakes and over-estimated for men with high intakes. Smoking and gender significantly influenced the average intake at baseline, whereas other demographic and behavioral factors did not. Education was significantly associated with average difference in fiber intake at baseline, but not at year 1.

CONCLUSIONS

This study of clinical trial volunteers revealed differences in the ability to comparably report fiber intake across tools by gender, smoking, and education, however participants' repeated training in dietary assessment improved comparability in reporting over time.

Differences in fruit and vegetable intake and determinants of intakes between children of Dutch origin and non-Western ethnic minority children in the Netherlands - a cross sectional study

BACKGROUND

Fruit and vegetable consumption is low in the Netherlands and a key target in healthy diet promotion. However, hardly any information is available on differences in fruit and vegetable consumption between Dutch children and ethnic minority children. Therefore, the aim of present study was to determine differences in usual fruit and vegetable intake between native Dutch and non-Western ethnic minority children and to study differences in and mediating effects of potential psychosocial and environmental determinants.

METHODS

Ethnicity, usual fruit and vegetable consumption, psychosocial and environmental determinants and mothers' educational level were measured with a self-administered questionnaire during school hours in primary schools in Rotterdam, the Netherlands. Complete data was available for 521 10-11 year-old-children, of which 50.5% of non-Western origin. Differences between the groups regarding potential determinants and fruit and vegetable intake were assessed with Mann Whitney tests or multiple regression analyses. Multiple regression analyses were also conducted to assess mediating effects.

RESULTS

Ethnic minority girls ate fruit more frequently (1.41 +/- 1.0 times/day) than Dutch girls (1.03 +/- 0.82 times/day); no differences in frequency of intake were found for vegetables or among boys. Ethnic differences were found for almost all potential determinants. The Dutch children reported lower scores on these determinants than the ethnic minority children, except for perceived self-efficacy and barriers to eat fruit and vegetables. Knowledge of recommendations and facilitating behaviors of the parents mediated the association between ethnicity and fruit consumption among girls.

CONCLUSION

Ethnic minority girls in the Netherlands appear to have more favorable fruit intakes than Dutch girls, and ethnic minority children in general show more positive prerequisites for fruit and vegetable consumption. Interventions addressing multi-ethnic populations of children must take such differences into account.

Women Participating in a Dietary Intervention Trial Maintain Dietary Changes Without Much Effect on Household Members

This study examined whether subjects who participated in a 12-mo intervention would maintain their diets 1 yr after the study ended and whether the diets of household members were affected. Premenopausal women, who had at least one first-degree relative with breast cancer (n = 122), were randomized to one of four diets: control, low fat (15% of energy), high fruit and vegetable (FV, nine servings per day), and combination low fat, high FV. Study subjects and one household member were asked to complete the Block '95 food-frequency questionnaire (FFQ) at baseline, 1 yr, and 2 yr. Study subjects also completed 24-h recalls and 4-day food records at baseline and Year 1. Fat and FV intakes by all three assessment methods compared reasonably well except that fat intakes by FFQ were somewhat higher. FV intakes by FFQ in the high-FV and combination arms increased significantly from 4 servings per day to about 10 servings per day at Year 1 and 7 servings per day at Year 2. FV intakes increased much more modestly in the low-fat and control arms. Fat intakes in the low-fat and combination arms were lower at Year 1 than Year 2, but mean Year 2 fat intakes of 26-28% were still significantly lower than those at baseline. In household members, the only significant change was a small decrease in energy from fat at Year 1 in the household members of subjects who were in the combination arm. These results indicate that study subjects were making large dietary changes independently of their household members and that fat and FV intakes in study subjects 1 yr after intervention stopped were still substantially different from intakes at baseline.

High dry bean intake and reduced risk of advanced colorectal adenoma recurrence among participants in the polyp prevention trial

Adequate fruit and vegetable intake was suggested to protect against colorectal cancer and colorectal adenomas; however, several recent prospective studies reported no association. We examined the association between fruits and vegetables and adenomatous polyp recurrence in the Polyp Prevention Trial (PPT). The PPT was a low-fat, high-fiber, high-fruit, and vegetable dietary intervention trial of adenoma recurrence, in which there were no differences in the rate of adenoma recurrence in participants in the intervention and control arms of the trial. In this analysis of the entire PPT trial-based cohort, multiple logistic regression analysis was used to estimate the odds ratio (OR) of advanced and nonadvanced adenoma recurrence within quartiles of baseline and change (baseline minus the mean over 3 y) in fruit and vegetable intake, after adjustment for age, total energyy intake, use of nonsteroidal anti-inflammatory drugs, BMI, and gender. There were no significant associations between nonadvanced adenoma recurrence and overall change in fruit and vegetable consumption; however, those in the highest quartile of change in dry bean intake (greatest increase) compared with those in the lowest had a significantly reduced OR for advanced adenoma recurrence (OR = 0.35; 95% CI, 0.18-0.69; P for trend = 0.001). The median in the highest quartile of change in dry bean intake was 370% higher than the baseline intake. The PPT trial-based cohort provides evidence that dry beans may be inversely associated with advanced adenoma recurrence.

Predicting fruit consumption: cognitions, intention, and habits

OBJECTIVE

To study predictors of fruit intake in a sample of 627 adults.

DESIGN

Potential predictors of fruit intake were assessed at baseline, and fruit intake was assessed at two-week follow-up with self-administered questionnaires distributed by e-mail.

SETTING

The study was conducted among Dutch adult members of an Internet research panel.

PARTICIPANTS

A random sample of 627 adults aged 18-78.

VARIABLES MEASURED

Attitudes, subjective norms, self-efficacy, expected pros and cons, habit strength, intention, and fruit intake. Fruit intake was assessed with a validated food-frequency questionnaire.

ANALYSIS

Hierarchical linear and logistic regression analyses. Alpha < .05 was considered statistically significant.

RESULTS

Sex, attitudes, subjective norms, perceived pros, different self-efficacy expectations, and habit strength were significantly associated with the intention to eat two or more servings of fruit per day. Age, intentions, and habit strength were significant predictors of consumption of two or more servings of fruit per day.

CONCLUSIONS AND IMPLICATIONS

The results confirm that Theory of Planned Behavior constructs predict fruit intake, and that habit strength and different self-efficacy expectations may be additional determinants relevant to fruit intake. Because habitual behavior is considered to be triggered by environmental cues, fruit promotion interventions should further explore environmental change strategies.

A randomized trial of an intervention to increase fruit and vegetable intake in curatively treated patients with early-stage head and neck cancer

The leading cause of death in patients who have had curatively treated early-stage head and neck cancer is a second primary cancer of the upper aerodigestive tract (lung, esophagus, larynx, pharynx, and oral cavity cancers). Low fruit and vegetable intake has been associated with increased risk of primary head and neck cancer and the available data suggest that increasing intake following diagnosis may reduce the risk of a second primary cancer. The goal of this study was to develop and test an easily administered intervention to increase fruit and vegetable intake in these patients following diagnosis and treatment. The 6-month intervention was based on the Stage of Change model. Seventy-five early-stage head and neck cancer patients were randomized to either the intervention group or to the "blinded" control group, with diet change data available on 65 patients. Fruit and vegetable intake, assessed using a food frequency questionnaire, and plasma carotenoid concentrations were measured at baseline and at the end of the study period. The change in self-reported intake of fruit and vegetables (servings per day) over the study period was significantly greater (P = 0.009) in the intervention group (n = 35; +2.1) compared with the control group (n = 30; +0.5). Total plasma carotenoids, a biomarker of fruit and vegetable intake, increased by 70 nmol/L in the intervention group as compared with a reduction of 42 nmol/L in the control group, a relative difference of 12% (nonsignificant). An intervention that can be delivered in a physician's office resulted in a significant increase in intake of fruit and vegetables in early-stage head and neck cancer patients.

Does nonsteroidal anti-inflammatory drug use modify the effect of a low-fat, high-fiber diet on recurrence of colorectal adenomas?

The Polyp Prevention Trial was designed to evaluate the effects of a high-fiber (18 g/1,000 kcal), high-fruit and -vegetable (3.5 servings/1,000 kcal), low-fat (20% energy) diet on recurrence of adenomatous polyps. Participants > or =35 years of age, with histologically confirmed colorectal adenoma(s) removed in the prior 6 months, were randomized to the intervention or control group. Demographic, dietary, and clinical information, including use of nonsteroidal anti-inflammatory drugs (NSAID), was collected at baseline and four annual visits. Adenoma recurrence was found in 754 of 1,905 participants and was not significantly different between groups. NSAID use was associated with a significant reduction in recurrence [odds ratio (OR), 0.77; 95% confidence interval (95% CI), 0.63-0.95]. In this analysis, NSAIDs modified the association between the intervention and recurrence at baseline (P = 0.02) and throughout the trial (P = 0.008). Among participants who did not use NSAIDs, the intervention was in the protective direction but did not achieve statistical significance (OR, 0.87; 95% CI, 0.69-1.09). The intervention was protective among males who did not use NSAIDs at baseline (OR, 0.71; 95% CI, 0.54-0.94), but not among NSAIDs users (OR, 1.09; 95% CI, 0.74-1.62). For females, corresponding OR estimates were 1.28 (95% CI, 0.86-1.90) and 2.30 (95% CI, 1.24-4.27), respectively. The protective association observed for NSAID use was stronger among control (OR, 0.63; 95% CI, 0.47-0.84) than for intervention group participants (OR, 0.97; 95% CI, 0.74-1.28). These results should be interpreted cautiously given that they may have arisen by chance in the course of examining multiple associations and Polyp Prevention Trial study participants were not randomly assigned to both dietary intervention and NSAID use. Nevertheless, our results suggest that adopting a low-fat, high-fiber diet rich in fruits and vegetables may lower the risk of colorectal adenoma recurrence among individuals who do not regularly use NSAIDs.

Interventions designed to increase adult fruit and vegetable intake can be effective: a systematic review of the literature

International recommendations advise increasing intakes of fruit and vegetables to help reduce the burden of chronic diseases worldwide. This project systematically reviewed evidence on the effectiveness of interventions and programs promoting fruit and/or vegetable intake in adults. In April 2004, we contacted experts in the field and searched 14 publication databases. We considered all papers published in English, French, Spanish, Portuguese, Russian, Danish, Norwegian, and Swedish, and reporting on interventions and promotion programs encouraging higher intakes of fruit and/or vegetables in free-living not acutely ill adults, with follow-up periods > or = 3 mo, that measured change in intake and had a control group. Forty-four studies (mainly from developed countries) were included in the review and stratified by study setting. Larger effects were generally observed in individuals with preexisting health disorders. In primary prevention interventions in healthy adults, fruit and vegetable intake was increased by approximately 0.1-1.4 serving/d. Consistent positive effects were seen in studies involving face-to-face education or counseling, but interventions using telephone contacts or computer-tailored information appeared to be a reasonable alternative. Community-based multicomponent interventions also had positive findings. This literature review suggests that small increases in fruit and vegetable intake are possible in population subgroups, and that these can be achieved by a variety of approaches. More research is required to examine the effectiveness of specific components of interventions in different populations, particularly less developed countries. There is also a need for a better assessment of the effectiveness and cost-effectiveness of large community-based interventions.

Achieving substantial changes in eating behavior among women previously treated for breast cancer--an overview of the intervention

OBJECTIVE

To describe the intervention in a clinical trial examining the effect of a plant-based diet on breast cancer recurrence. To report baseline to 12-month dietary change and investigate whether cooking-class attendance influenced adherence to the study's dietary targets.

DESIGN

A descriptive analysis of baseline and 12-month dietary intake data and other variables from a subcohort of participants in the Women's Healthy Eating and Living Study.

SUBJECTS/SETTING

Seven hundred thirty-nine women (primarily non-Hispanic white and well educated) who had been treated for early stage breast cancer. All were intervention group participants and had adhered to the Women's Healthy Eating and Living Study counseling and dietary assessment protocols. Mean age at study entry was 54 years, and mean body mass index was 26.7.

INTERVENTION

Telephone counseling, complemented by an orientation meeting, cooking classes, and newsletters.

MAIN OUTCOME MEASURES

The change in intake of vegetables, vegetable juice, fruit, fiber, and fat between baseline and 12 months is reported, and the association between cooking classes attended and overall dietary adherence is examined.

STATISTICAL ANALYSES PERFORMED

Mean intake for vegetables, vegetable juice, fruit, fiber, and fat were calculated. Percentage of women meeting select Healthy People 2010 objectives were tabulated.

RESULTS

Total daily vegetable, vegetable juice, fruit, and fiber intake increased significantly (P <.01), while fat decreased significantly (P <.01). The percentage of women meeting the Healthy People 2010 fruit and vegetable objectives increased substantially. Overall dietary adherence was associated with increased cooking-class attendance (P for trend <.01).

CONCLUSIONS

A multimodal approach to dietary modification, based largely on individualized telephone counseling, can substantially change the overall dietary pattern of women previously treated for breast cancer.

Association between 6-n-propylthiouracil (PROP) bitterness and colonic neoplasms

Inadequate vegetable intake appears to increase colon cancer risk. Since genetic variation in taste influences vegetable preference, we tested associations between bitterness of 6-n-propylthiouracil (PROP), a measure of taste genetics, and number of colonic polyps, a measure of colon cancer risk, in 251 men who underwent screening lower endoscopy. Patients used the general Labeled Magnitude Scale to rate bitterness of 1.6 mg PROP delivered via filter paper. A subset of 86 patients reported weekly vegetable intakes, excluding salad or potatoes. PROP bitterness correlated significantly with polyp number, an effect separate from age-associated increases in polyp number. The PROP-polyp relationship was strongest in men over 66 years, and older men with polyps were most likely to be overweight or obese. In the subset reporting vegetable intake, men who tasted PROP as more bitter consumed fewer vegetables. These preliminary findings suggest that taste genetics may influence colon cancer risk, possibly through intake of vegetables.

The association of calcium and vitamin D with risk of colorectal adenomas

The Polyp Prevention Trial (PPT) was a multicenter randomized clinical trial designed to determine the effects of a high-fiber, high-fruit and vegetable, low-fat diet on the recurrence of adenomatous polyps in the large bowel. Detailed dietary intake and supplement use data were collected at baseline and at each of 4 annual study visits. Adenoma recurrence was ascertained by complete colonoscopy at baseline and after 1 and 4 y. Recurrence was found in 754 of the 1905 trial participants. We evaluated the association between calcium and vitamin D intake and adenomatous polyp recurrence after adjusting for intervention group, age, gender, nonsteroidal anti-inflammatory drug use, total energy intake, and the interaction of gender and intervention group. Vitamin D models were also adjusted for the location of the clinic site. Dietary variables were adjusted for total energy intake via the residual method. There were no overall significant associations between adenoma recurrence and dietary calcium intake [odds ratio (OR) for the 5th compared with the lowest quintile = 0.91; 95% CI = 0.67-1.23; P-trend = 0.68], total calcium intake (OR = 0.86; 95% CI = 0.62-1.18; P-trend = 0.20), or dietary vitamin D intake (OR = 0.93; 95% CI = 0.69-1.25; P-trend = 0.43) averaged over follow-up. Total vitamin D intake was weakly inversely associated with adenoma recurrence (OR = 0.84; 95% CI = 0.62-1.13; P-trend = 0.03). Supplemental calcium and vitamin D use during follow-up also were inversely associated with adenoma recurrence (OR for any compared with no use = 0.82; 95% CI = 0.68-0.99; and OR = 0.82; 95% CI = 0.68-0.99; for calcium and vitamin D, respectively). Slightly stronger associations were noted for the prevention of multiple recurrences. Our analyses did not suggest a significant effect modification between total calcium and total vitamin D intake (P = 0.14) on risk for adenoma recurrence. This trial cohort provides some evidence that calcium and vitamin D may be inversely associated with adenoma recurrence.

Nutrition and cancer prevention: a multidisciplinary perspective on human trials

More than one million Americans were expected to be diagnosed with cancer in 2003 (7a). Compelling experimental, epidemiological, and clinical evidence indicates that many cancers are preventable, especially because diet and nutrition are key factors in the modulation of cancer risk. The road to nutritional intervention in cancer prevention has led to successful trials as well as trials that did not reach their intended endpoints. This chapter reviews four case studies of trials, with two ending in success and two ending in null findings or adverse effects. The goal is to identify lessons learned from all four case studies and from the investigations of the complexities inherent to nutritional intervention trials. Additional insights are presented by the research addressing potential mechanisms underlying the endpoints of human trials. Future progress in nutrition and cancer prevention will require expertise from multidisciplinary teams to develop new knowledge about specific nutrients and dietary modifications within a framework of interaction between animal and human research.

Is dietary counselling effective in increasing dietary calcium, protein and energy intake in patients with osteoporotic fractures? A randomized controlled clinical trial

To determine the feasibility of increasing the calcium, protein and calorie intake of osteoporotic fracture patients by repeated dietary counselling delivered by a dietitian, a randomized controlled trial was conducted. Among 189 patients presenting with osteoporotic fractures to an Orthopaedics and Traumatology Department of a large regional hospital, 98 patients were randomized to the intervention group and 91 were randomized to the control group (with usual care). Intervention group received three sessions of dietary counselling with tailored made recommendations over a period of 4 months, while the control group only received dietary assessment and pamphlets on the prevention of osteoporosis. Almost all subjects in both intervention and control groups had calcium intake below the recommended level of 1000 mg at baseline. Half and 60% of subjects in both groups had total energy and protein intake below recommended levels respectively. The mean weights of control and intervention groups at baseline were 51.5 and 50.9 kg respectively, while the body mass index (BMI) were 22.6 (kg m(-2)) and 22.6 (kg m(-2)) respectively. After dietary intervention, significant increase of intake was seen in calcium intake (P = 0.0095 by t-test) in the intervention group. No significant increase was seen in protein or calorie intake. No significant change was observed in the body weight or BMI although there was a positive trend in the intervention group for all these parameters. We concluded that there was general malnutrition in Chinese elderly who presented with osteoporotic fractures. Dietary calcium could be increased by repeated professional dietary counselling. Future studies with longer duration and more objective clinical outcomes will be helpful to further demonstrate the long-term effects of dietary intervention on osteoporosis and other chronic diseases.

Antioxidant supplements for preventing gastrointestinal cancers

BACKGROUND

Oxidative stress may cause gastrointestinal cancers. The evidence on whether antioxidant supplements are effective in preventing gastrointestinal cancers is contradictory.

OBJECTIVES

To assess the beneficial and harmful effects of antioxidant supplements in preventing gastrointestinal cancers.

SEARCH STRATEGY

We identified trials through the trials registers of the four Cochrane Review Groups on gastrointestinal diseases, The Cochrane Central Register of Controlled Trials on The Cochrane Library (Issue 1, 2003), MEDLINE, EMBASE, LILACS, and SCI-EXPANDED from inception to February 2003, and The Chinese Biomedical Database (March 2003). We scanned reference lists and contacted pharmaceutical companies.

SELECTION CRITERIA

Randomised trials comparing antioxidant supplements to placebo/no intervention examining the incidence of gastrointestinal cancers.

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected trials for inclusion and extracted data. The outcome measures were incidence of gastrointestinal cancers, overall mortality, and adverse events. Outcomes were reported as relative risks (RR) with 95% confidence interval (CI) based on fixed and random effects meta-analyses.

MAIN RESULTS

We identified 14 randomised trials (170,525 participants), assessing beta-carotene (9 trials), vitamin A (4 trials), vitamin C (4 trials), vitamin E (5 trials), and selenium (6 trials). Trial quality was generally high. Heterogeneity was low to moderate. Neither the fixed effect (RR 0.96, 95% CI 0.88 to 1.04) nor random effects meta-analyses (RR 0.90, 95% CI 0.77 to 1.05) showed significant effects of supplementation with antioxidants on the incidences of gastrointestinal cancers. Among the seven high-quality trials reporting on mortality (131,727 participants), the fixed effect (RR 1.06, 95% CI 1.02 to 1.10) unlike the random effects meta-analysis (RR 1.06, 95% CI 0.98 to 1.15) showed that antioxidant supplements significantly increased mortality. Two low-quality trials (32,302 participants) found no significant effect of antioxidant supplementation on mortality. The difference between the mortality estimates in high- and low-quality trials was significant by test of interaction (z = 2.10, P = 0.04). Beta-carotene and vitamin A (RR 1.29, 95% CI 1.14 to 1.45) and beta-carotene and vitamin E (RR 1.10, 95% CI 1.01 to 1.20) significantly increased mortality, while beta-carotene alone only tended to do so (RR 1.05, 95% CI 0.99 to 1.11). Increased yellowing of the skin and belching were non-serious adverse effects of beta-carotene. In four trials (three with unclear/inadequate methodology), selenium showed significant beneficial effect on gastrointestinal cancer incidences.

REVIEWERS' CONCLUSIONS

We could not find evidence that antioxidant supplements prevent gastrointestinal cancers. On the contrary, they seem to increase overall mortality. The potential cancer preventive effect of selenium should be studied in adequately conducted randomised trials.

Carotenoids, vitamin A and risk of adenomatous polyp recurrence in the polyp prevention trial

One trial reported beta-carotene supplementation was protective of adenomatous polyp recurrence in nonsmokers. We now examine the relation of serum and dietary carotenoids and vitamin A to adenomatous polyp recurrence in a subcohort of 834 participants in a low fat, high fiber, high fruit and vegetable dietary intervention, the Polyp Prevention Trial. Multivariate odds ratio (OR) and 95% confidence intervals (CI) of polyp recurrence were obtained using baseline or the average (first 3 years of the trial) carotenoid and vitamin A values after adjustment for covariates. Compared to the lowest quartile of baseline alpha-carotene concentrations, the OR of multiple polyp recurrence for the highest quartile was 0.55 (95% CI = 0.30-0.99) and the OR of right-sided recurrence was 0.60 (95% CI = 0.37-0.95). Baseline dietary intakes of alpha-carotene and vitamin A from food with/without supplements were inversely associated with any recurrence (p for linear trend = 0.03-alpha-carotene; p = 0.004 and p = 0.007 -intakes of vitamin A). Compared to the lowest quartile of averaged beta-carotene concentrations, the OR of multiple adenomas for the highest quartile was 0.40 (95% CI = 0.22-0.75) with an inverse trend (p = 0.02). The risk was inversely related to averaged: alpha-carotene concentrations and right-sided polyps; alpha-carotene intake and recurrence of any, multiple and right-sided polyps; beta-carotene intake and multiple adenoma recurrence; vitamin A from food (with supplements) and each adverse endpoint. Thus, alpha-carotene and vitamin A may protect against recurrence in nonsmokers and nondrinkers or be indicative of compliance or another healthy lifestyle factor that reduces risk.

Low plasma lycopene concentration is associated with increased mortality in a cohort of patients with prior oral, pharynx or larynx cancers

OBJECTIVE

This analysis was conducted to evaluate the association between plasma beta-carotene, alpha-carotene, lycopene, lutein/zeaxanthin, total carotenoids, retinol, alpha-tocopherol and subsequent mortality.

METHODS

Blood samples collected longitudinally from 259 participants in a chemoprevention trial aimed at the prevention of second cancers of the oral cavity, pharynx, or larynx were analyzed by high performance liquid chromatography for selected micronutrients. All-cause mortality (primary outcome) and cause-specific mortality (secondary outcomes) were evaluated in relation to plasma micronutrient concentrations at baseline and longitudinally.

RESULTS

A total of 61 deaths occurred over a follow-up time of up to 90 months. Cox proportional hazards models with time-dependent covariates were used for data analyses. In models adjusted for age, plasma cholesterol, time-dependent smoking, treatment arm, study site and gender, only plasma lycopene was significantly inversely associated with total mortality [hazard ratio (HR) above versus below median = 0.53, 95% confidence interval (CI) 0.30-0.93]. Plasma alpha-carotene was inversely associated (HR 0.24, 95% CI 0.08-0.75) while plasma retinol was positively associated (HR 5.12, 95% CI 1.54-17.05) with cardiovascular death. Smoking status modified plasma nutrient associations with total mortality. Lycopene (HR 0.08, 95% CI 0.02-0.36), alpha-carotene (HR 0.25, 95% CI 0.09-0.73) and total carotenoids (HR 0.22, 95% CI 0.07-0.70) were inversely associated with mortality in non-smokers, while plasma retinol (HR = 3.56, 95% CI 1.40-9.09) and alpha-tocopherol (HR = 2.47, 95% CI 1.02-5.98) were positively associated with mortality in smokers.

CONCLUSIONS

Only plasma lycopene was significantly associated (inversely) with total mortality in the full study population. Smoking modifies associations between nutrients and mortality.

Relationship of visceral adipose tissue to recurrence of adenomatous polyps

OBJECTIVES

Insulin is a growth factor for colorectal cancer. Visceral adipose tissue (VAT) is strongly associated with insulin levels, and insulin and visceral obesity have been associated in cohort studies with colorectal cancer. The aim of this investigation was to determine whether VAT is associated with recurrence of adenomatous polyps, the precursor to colorectal cancer.

METHODS

As an ancillary study to the Polyp Prevention Trial, a randomized clinical trial that evaluated the effect of a low-fat, high-fiber, high vegetable and fruit diet on adenomatous polyp recurrence, subjects at one clinical center underwent measurement of VAT with a single-slice CT scan through the L4-L5 interspace. The scan was performed around the time of the subject's year 4 colonoscopy that determined adenoma recurrence.

RESULTS

Of 119 subjects, 44 of 84 men (52%) and 16 of 35 women (46%) had a recurrent adenoma (p= 0.51). Body mass index (BMI) and weight at baseline and at year 4 colonoscopy were unrelated to adenoma recurrence. In a multivariate model including visceral fat quartile, remote history of polyps, gender, age, and randomization group, only remote history of polyps was statistically significantly associated with recurrent adenoma with a relative risk of 4.6 (95% CI 1.7, 12.4, p= 0.001). There was no consistent monotonic trend of increased or decreased risk of recurrence as one ascended quartiles of adipose tissue for visceral, subcutaneous, or total abdominal fat.

CONCLUSION

In this study, no association between visceral adipose tissue and adenomatous polyp recurrence was observed. Further study and exploration of the role of VAT in adenoma progression is required.

Telephone counseling intervention increases intakes of micronutrient- and phytochemical-rich vegetables, fruit and fiber in breast cancer survivors

Although a large body of evidence suggests that diet may play an important role in cancer prevention, randomized controlled trials reported to date have not achieved sufficient increases in protective micronutrients and phytochemicals to adequately test the hypothesis that diet can reduce cancer risk. The Women's Healthy Eating and Living (WHEL) Study, a randomized controlled trial of the role diet modification may play in future breast cancer events, introduced an innovative theory-based telephone counseling intervention to teach participants to consume a high fiber, low fat diet emphasizing vegetables and fruits rich in carotenoids and other potentially protective phytochemicals. This report examines the baseline to 12-mo changes in dietary intakes of 2970 participants, assessed through 24-h recalls and validated with plasma carotenoid concentrations. At 12 mo, the intervention group reported a significantly increased daily vegetable intake (+vegetable juice) of 7.1 servings (+82%) and fruit intake of 3.9 servings (+18%). Fiber intake increased from 3.04 to 4.16 g/(MJ. d), whereas energy from fat decreased significantly from 28.6 to 23.7%. Plasma carotenoid concentrations increased significantly, i.e., alpha-carotene (+223%); beta-carotene (+87%); lutein (+29%); and lycopene (+17%). In the comparison group, dietary intake and plasma carotenoid concentrations were essentially identical to those of the intervention group at baseline and were unchanged at 12 mo. The WHEL Study showed that a telephone counseling intervention can achieve major increases in micronutrient- and phytochemical-rich vegetables, fruit and fiber intakes, enabling an investigation of the potential cancer preventive effects of these food components.

What Can Intervention Studies Tell Us about the Relationship between Fruit and Vegetable Consumption and Weight Management?

Given the recent surge in obesity, effective dietary strategies for weight management are required. Because fruits and vegetables are high in water and fiber, incorporating them in the diet can reduce energy density, promote satiety, and decrease energy intake. Although few interventions have specifically addressed fruit and vegetable consumption, evidence suggests that coupling advice to increase intake of these foods with advice to decrease energy intake is a particularly effective strategy for weight management. This approach may facilitate weight loss because it emphasizes positive messages rather than negative, restrictive messages.

A population-based dietary intervention trial in a high-risk area for stomach cancer and stroke: changes in intakes and related biomarkers

BACKGROUND

Dietary intervention is one of the important fields in cancer and cardiovascular disease prevention. The Hiraka Dietary Intervention Study is a community-based randomized cross-over trial designed to develop an effective dietary modification tool and system in an area with high mortality of stomach cancer and stroke.

METHODS

The subjects were 550 healthy volunteers and were randomized into two groups with tailored dietary education to decrease sodium intake and to increase vitamin C and carotene intakes either in the first year (intervention group) or in the second year (control group). Dietary changes were assessed using a validated self-administered diet history questionnaire, fasting blood samples, and 48-hour urine samples, which were obtained before and after the one year period.

RESULTS

During the first year, changes differed significantly between the intervention and control group for both dietary sodium intake (-384 and +255 mg/day, intervention and control respectively, p < 0.001) and urinary sodium excretion (-1003 and -84 mg/day, p < 0.001). Although favorable net changes were also observed in dietary carotene (+418 and +220 mug/day, p < 0.05) and vitamin C (+13 and +2 mg/day, p < 0.05), the serum level differences were modest (+13 and -25 mg/L, p = 0.09 for carotene, +0.1 and -0.5 mg/L, p = 0.07 for ascorbic acid).

CONCLUSION

The present dietary intervention strategy effectively decreased sodium and increased carotene and vitamin C intakes, although the former was more distinct.

Epidemiologic evidence of the protective effect of fruit and vegetables on cancer risk

BACKGROUND

Diets rich in fruit and vegetables have been recommended for preventing cancer. The evidence supporting this recommendation is based on observational studies, although results of several prospective studies have cast some doubts on whether fruit and vegetables are associated with cancer risk reduction.

OBJECTIVE

We sought to summarize evidence from case-control and prospective studies on fruit and vegetable intake and cancer risk with a meta-analytic approach.

DESIGN

Published case-control and cohort studies that reported on total vegetable and fruit intake and risk of cancer of several sites were included. Relative risks were estimated by using linear logistic regression models.

RESULTS

Case-control studies overall support a significant reduction in the risks of cancers of the esophagus, lung, stomach, and colorectum associated with both fruit and vegetables; breast cancer is associated with vegetables but not with fruit; and bladder cancer is associated with fruit but not with vegetables. The overall relative risk estimates from cohort studies suggest a protective effect of both fruit and vegetables for most cancer sites considered, but the risk reduction is significant only for cancers of the lung and bladder and only for fruit.

CONCLUSIONS

Prospective studies provide weaker evidence than do case-control studies of the association of fruit and vegetable consumption with reduced cancer risk. The discrepancies may be related to recall and selection biases in case-control studies. In contrast, the association may have been underestimated in prospective studies because of the combined effects of imprecise dietary measurements and limited variability of dietary intakes within each cohort.

Methods to increase fruit and vegetable intake with and without a decrease in fat intake: compliance and effects on body weight in the nutrition and breast health study

Dietary patterns that involve a decrease in fat and an increase in fruit and vegetable (FV) intake have been suggested to decrease cancer risks. In this study, intervention methods to selectively modify dietary fat and/or FV intakes were developed. Compliance to the diets and the effects on body weight are shown, because both of these dietary changes can impact on and be confounded by changes in energy intake. A total of 122 women with a family history of breast cancer were randomized onto one of four diets for 12 mo. Counseling methods were devised to increase amount and variety of FV consumed with or without a decrease in fat intake using modified exchange list diets. Women on the low-fat and combination low-fat/high-FV diet arms decreased their fat intakes to approximately 16% of energy. Women on the high-FV and the combination low-fat/high-FV diet arms increased FV intakes to approximately 11 servings/day. Despite counseling efforts to maintain baseline energy intakes, mean body weight increased significantly by 6 pounds in women in the high-FV diet arm and decreased significantly by 5 pounds in women in the low-fat diet arm. Percent body fat also was increased in the high-FV diet arm and decreased in the low-fat diet arm. Body weight and percent body fat in the combination diet arm did not change significantly. Control of energy intake, therefore, appears to have been achieved only when the addition of FV to the diet was balanced by a decrease in fat intake and both dietary components were enumerated daily. Maintenance of energy intake, therefore, did not appear to be attained intrinsically when individuals were counseled to make changes in the composition of their diets.

Nondigestible carbohydrates in the diets of infants and young children: a commentary by the ESPGHAN Committee on Nutrition

The consumption of nondigestible carbohydrates is perceived as beneficial by health professionals and the general public, but the translation of this information into dietary practice, public health recommendations, and regulatory policy has proved difficult. Nondigestible carbohydrates are a heterogeneous entity, and their definition is problematic. Without a means to characterize the dietary components associated with particular health benefits, specific attributions of these cannot be made. Food labeling for "fiber" constituents can be given only in a general context, and the development of health policy, dietary advice, and education, and informed public understanding of nondigestible carbohydrates are limited. There have, however, been several important developments in our thinking about nondigestible carbohydrates during the past few years. The concept of fiber has expanded to include a range of nondigestible carbohydrates. Their fermentation, fate, and effects in the colon have become a defining characteristic; human milk, hitherto regarded as devoid of nondigestible carbohydrates, is now recognized as a source for infants, and the inclusion of nondigestible carbohydrates in the diet has been promoted for their "prebiotic" effects. Therefore, a review of the importance of nondigestible carbohydrates in the diets of infants and young children is timely. The aims of this commentary are to clarify the current definitions of nondigestible carbohydrates, to review published evidence for their biochemical, physiologic, nutritional, and clinical effects, and to discuss issues involved in defining dietary guidelines for infants and young children.

REAP and WAVE: new tools to rapidly assess/discuss nutrition with patients

Dietary changes can be helpful in preventing or treating a variety of prevalent health problems. Physicians can be helpful in helping patients make positive dietary changes, be physically active and lose weight, but, for a variety of reasons, many physicians do little nutrition counseling. There is a need for brief, user-friendly tools to enable physicians to rapidly and accurately assess patients' diets and exercise habits as well as provide information to aid the physician in delivering effective nutrition counseling. The purpose of this paper is to discuss two new tools, WAVE and REAP, that have been developed by the Nutrition Academic Award to help physicians and other health care providers conduct nutrition assessment and counseling with their patients in a practical and effective manner. The WAVE acronym and tool is designed to encourage provider/patient dialogue about the pros and cons of the patients' current status related to Weight, Activity, Variety and Excess. The Rapid Eating and Activity Assessment for Patients (REAP) is a brief validated questionnaire that is designed to aid providers in performing a brief assessment of diet and physical activity. An accompanying Physician Key aids the provider in discussing the patient's answers and counseling them appropriately. REAP and WAVE can be helpful tools to facilitate nutrition assessment and counseling in the provider office. Depending on patients' health priorities and how much time is available, these tools can be used in a variety of ways to discuss nutrition with patients during a clinical encounter in 1-9 min.