Assessment of dietary nutrients that influence perception of intra-oesophageal acid reflux events in patients with gastro-oesophageal reflux disease.

BACKGROUND: Gastro-oesophageal reflux disease symptoms are most commonly reported postprandially, suggesting that some diet components are likely to induce symptoms more than others. AIMS: To determine which of the various dietary nutrients is a strong predictive factor for symptom generation in association with an acid reflux event. METHODS: Subjects with typical heartburn symptoms were evaluated by the gastro-oesophageal reflux disease Symptom Checklist, demographics questionnaire, upper endoscopy and pH testing. During the pH study, patients completed a detailed 24-h dietary intake record. This included time of meals, description of food components and the amount and type of food preparation. RESULTS: Fifty gastro-oesophageal reflux disease patients completed all stages of the study. A total of 112 (78%) symptoms were considered as sensed reflux event. Body mass index did not correlate with having perceived reflux. Patients who consumed more cholesterol, saturated fatty acids and had more percentage calories from fat were significantly more likely to experience a perceived reflux event. Regression analysis and beta-coefficient were specifically significant for cholesterol. CONCLUSION: Of all dietary nutrients, cholesterol enhances the most the perception of intra-oesophageal acid reflux events in patients with gastro-oesophageal reflux disease.

Reproducibility and relative validity of a questionnaire to assess intake of black tea polyphenols in epidemiological studies.

Epidemiological studies suggest that tea drinking may reduce the risk of cardiovascular diseases and cancers. Although tea is an important source of antioxidant phytochemicals, variation in preparation techniques may translate to variation in antioxidant capacity. However, most large-scale epidemiological studies use regular food frequency questionnaires to estimate tea intake, and nationally available nutrient analysis databases do not include levels of black tea polyphenols. The Arizona Tea Questionnaire (ATQ) was designed as a tool for collecting more complete dietary tea consumption information, and a database was developed after analyzing 40 black tea samples (brewed, instant, and sun tea) for polyphenols. This study assesses the reliability and relative validity of the ATQ and polyphenol database. Relative validity of estimates of black tea consumption was tested by comparing the ATQ with the traditional Arizona Food Frequency Questionnaire and four days of food records. The ATQ was tested for reproducibility of estimates of black (hot and iced) tea consumption and levels of black tea polyphenol intake. Correlations between two measures of intake taken 2 months apart ranged from 0.72 for black hot tea to 0.86 for black sun tea. Mean intakes (range) of total flavonoids for black tea consumers were 80.8 (3.0-588.0) mg/day at the first ATQ and 102.4 (4.5-802.3) mg/day at the second ATQ (r = 0.83, P < 0.001). The ATQ provided highly reproducible estimates of both total tea consumption and individual tea polyphenol intake. This instrument may be a useful tool in studies of the associations between tea consumption, tea polyphenols intake, and risk for chronic disease.

Beta-carotene produces sustained remissions in patients with oral leukoplakia: results of a multicenter prospective trial.

BACKGROUND: Beta-Carotene has been reported to produce regressions in patients with oral leukoplakia, a premalignant lesion. However, previous studies have all been of short duration, with clinical response as the end point. OBJECTIVE: To evaluate the duration of response and the need for maintenance therapy in subjects who respond to beta-carotene. METHODS: In this multicenter, double-blind, placebo-controlled trial, subjects were given beta-carotene, 60 mg/d, for 6 months. At 6 months, responders were randomized to continue beta-carotene or placebo therapy for 12 additional months. RESULTS: Fifty-four subjects were enrolled in the trial, with 50 being evaluable. At 6 months, 26 subjects (52%) had a clinical response. Twenty-three of the 26 responders completed the second, randomized phase. Only 2 (18%) of 11 in the beta-carotene arm and 2 (17%) of 12 in the placebo arm relapsed. Baseline biopsies were performed in all patients, with dysplasia being present in 19 (38%) of the 50 evaluable patients. A second biopsy was obtained at 6 months in 23 subjects who consented to this procedure. There was improvement of at least 1 grade of dysplasia in 9 (39%), with no change in 14 (61%). Nutritional intake was assessed using food frequency questionnaires. There was no change in carotenoid intake during the trial. Responders had a lower intake of dietary fiber, fruits, folate, and vitamin E supplements than did nonresponders. Beta-carotene levels were measured in plasma and oral cavity cells. Marked increases occurred during the 6-month induction. However, baseline levels were not restored in subjects taking placebo for 6 to 9 months after discontinuation of beta-carotene therapy. CONCLUSIONS: The activity of beta-carotene in patients with oral leukoplakia was confirmed. The responses produced were durable for 1 year.

Reliability and validity of a self-administered food frequency questionnaire in a chemoprevention trial of adenoma recurrence.

Various chemoprevention trials have assessed dietary intake by means of food frequency questionnaires. However, it is important to assess the degree to which such questionnaires can measure diet. We conducted reproducibility and validity analyses of our Arizona Food Frequency Questionnaire (AFFQ) in our recently completed, randomized, Phase III chemoprevention trial testing the effects of a wheat bran fiber supplement on colorectal adenoma recurrence. A total of 139 individuals provided a baseline and year 1 AFFQ and a set of 4-day dietary records collected over a period of 1 month. The reproducibility analyses of the AFFQ administered 1 year apart showed a mean intraclass correlation of 0.54 for unadjusted nutrients and 0.48 for energy-adjusted nutrients. The relative validity of the AFFQ, as compared with the average of the 4-day diet records, showed a mean deattenuated correlation of 0.49 (range, 0.22-0.65) for the baseline AFFQ and 0.49 (range, 0.25-0.67) for the year 1 AFFQ. When data from both AFFQs were combined and compared with the diet records, there was a slight improvement in the overall deattenuated correlations (mean, 0.56; range, 0.33-0.71). The correlations we observed for macro- and micronutrient intake were within the overall range of those reported in the literature. Reliability and validity studies of dietary instruments are feasible in the setting of a chemoprevention trial and should be conducted when the instrument's performance has not been previously assessed in the target population.

Effect of ambulatory 24-hour esophageal pH monitoring on reflux-provoking activities.

Ambulatory 24-hr esophageal pH monitoring is considered the gold standard for diagnosing gastroesophageal reflux disease (GERD). The current approach is to encourage patients to pursue their everyday activity in order to obtain near-physiological recordings. However, the effect of the test itself on reflux-provoking activities has never been evaluated. Thus, the aim of our study was to assess daily food consumption, habits, symptoms, sleep, and perceived experience of patients undergoing pH testing as compared to an off test (normal) day. Patients reported type and time spent in each activity pursued, food ingested and length of each meal, habits, frequency and severity of GERD and other related symptoms, sleep disturbances, side effects, and overall perceived experience during pH testing and four weeks later, during a normal day. Fifty-four patients enrolled. pH testing significantly reduced time spent being active, number of meals and cups of coffee consumed, and frequency of GERD symptoms. Almost half of the patients reported having dysphagia during the test. Most patients experienced side effects and stated that the test bothered them most of the time. In conclusion, pH testing has a significant effect on decreasing reflux-provoking activities-patients tend to assume a more sedentary lifestyle. This may influence the reliability of the test as a physiologic measure of acid reflux.

Kinetics of the response of milk and serum beta-carotene to daily beta-carotene supplementation in healthy, lactating women.

Changes in concentrations of milk and serum carotenoids, retinol, and alpha-tocopherol of five healthy, well-nourished, lactating women were measured over a 28-d supplementation trial with 30 mg beta-carotene and for 4 wk thereafter. Beta-carotene supplementation increased mean beta-carotene concentrations in milk and serum 6.4- and 7.4-fold, respectively. Concentrations of other major carotenoids, retinol, and alpha-tocopherol did not change substantially in either milk or serum. Uptake of beta-carotene into both serum and milk followed apparent first-order kinetics, occurring more rapidly into serum (t(1/2) = 5.5 d) than into milk (t(1/2) = 9 d). After supplementation, milk and serum beta-carotene concentrations decayed slowly, reaching approximately twofold initial concentrations by 4 wk. Kinetics of uptake and decay in milk beta-carotene concentrations paralleled those in serum. The data show that short-term supplementation of healthy, lactating mothers with purified beta-carotene at approximately fivefold the average daily dietary intake substantially increased milk and serum beta-carotene concentrations while not interfering with concentrations of other carotenoids, retinol, or alpha-tocopherol in milk or serum. Thus, an increased intake of beta-carotene by healthy, lactating women increases the supply of milk beta-carotene available to their breast-feeding infants.

beta-Carotene in breast milk and serum is increased after a single beta-carotene dose.

Normal lactating mothers were administered a single dose of 60 or 210 mg beta-carotene and changes in serum and milk retinol, alpha-tocopherol, and carotenoids were monitored for 8 d. Average serum beta-carotene concentrations increased 4.1- and 4.0-fold after the 60- and 210-mg doses, respectively. Milk beta-carotene concentrations increased 4.1- and 3.0-fold after the 60- and 210-mg doses, respectively. Maximum serum concentrations were reached 24 h after both supplements, although concentrations of milk beta-carotene continued to rise for 2-3 d. After 8 d, both serum and milk beta-carotene continued to rise for 2-3 d. After 8 d, both serum and milk beta-carotene concentrations remained about twofold higher than baseline concentrations. Increases in serum or milk beta-carotene concentrations were not dose-dependent. Initial serum and milk concentrations of beta-carotene predicted increases after supplementation, and increases in serum beta-carotene concentrations predicted those in milk. Concentrations of milk carotenoids were less than one-tenth their respective concentrations in serum. Lutein, beta-cryptoxanthin, lycopene, alpha-carotene, retinol, and alpha-tocopherol concentrations in serum or milk did not change significantly after beta-carotene supplementation. Retinol esters account for most of the retinol equivalents in the milk of well-nourished mothers. Initial and maximum concentrations of beta-carotene in serum and milk were strongly correlated for individual mothers. Collectively, the data showed that a single 60-mg supplement of beta-carotene sustained elevated beta-carotene concentrations in serum and milk for > 1 wk in normal mothers but did not affect concentrations of other major carotenoids, retinol, or alpha-tocopherol.

Use of a food frequency questionnaire to screen for dietary eligibility in a randomized cancer prevention phase III trial.

Cancer prevention clinical trials use food frequency questionnaires (FFQs) to assist in eligibility screening. FFQ reliability and validity studies are available, but these studies do not evaluate FFQs as screening tools. The Wheat Bran Fiber Trial of the University of Arizona used a FFQ as an eligibility screen with the goal of screening out subjects whose true daily calcium intake was less than 500 mg per day (for safety) and whose true dietary fiber intake was greater than 30 g per day (for safety and trial efficiency). Subjects ineligible by FFQ were interviewed for final dietary eligibility determinations. A study was undertaken within the Wheat Bran Fiber Trial to evaluate the sensitivity, specificity, positive predictive value, and negative predictive value (NPV) of the FFQ used in this context. Four-day food records were collected on 183 potential participants before entry into the study. Using the 4-day averages as the "true" value, sensitivity, specificity, positive predictive value, and NPV were calculated for men and women separately under two screening conditions: using the target calcium and dietary fiber values and using "revised" values identified in interim analysis within the study. NPV was acceptable in all analyses. Sensitivity for low calcium intake was inadequate under the original criteria (0.33 for men and 0.09 for women) but acceptable under the revised criteria (0.80 for men and 0.81 for women). With the revised criteria, specificity declined, resulting in heavy screening burdens deemed worthwhile for the safety considerations. Dietary fiber eligibility screening worked well at target values. These differences were not predicted by reliability/validity studies.

New carotenoid values for foods improve relationship of food frequency questionnaire intake estimates to plasma values.

Carotenoid consumption is of great interest in disease prevention studies. Until recently, carotenoid food composition data have not been available from a single laboratory source with high validity/reliability characteristics. With the availability of a new carotenoid food composition data base, we examined the impact of the new data base on the intake estimates as measured by a food frequency questionnaire and on the relationship of those estimates to plasma values to ascertain what, if any, improvement is achieved through use of the new values. Plasma samples were available for 162 healthy adults participating in cancer prevention studies at the Arizona Cancer Center, including men and women, smokers and nonsmokers. A single laboratory analyzed plasma samples for beta-carotene, alpha-carotene, lutein, and lycopene. All subjects had completed a modified version of the Block food frequency questionnaire, which calculates carotenoids using a literature-based algorithm. A new carotenoid composition data base using recently published data (A.R. Mangels et al., J. Am. Diet. Assoc., 93: 284-296, 1993) was then directly substituted for the Block data base. There were high correlations between intake estimates derived from the two data bases for all four carotenoids (range, r = 0.76-0.96). Average intake estimates based on the Mangels et al. data base were significantly higher for beta-carotene and lycopene; however, correlations between intakes and plasma values were significantly different only for beta-carotene (r = 0.44 for Mangels versus 0.32 for Block, P = 0.015).

An association of human congenital cardiac malformations and drinking water contaminants.

During an informal study in 1973 it was noted that approximately one third of patients with congenital heart disease lived in a small area in the Tucson Valley. In 1981 groundwater for a nearly identical area was found to be contaminated with trichloroethylene and to a lesser extent with dichloroethylene and chromium. Contamination probably began during the 1950s. Affected wells were closed after discovery of contamination. This sequence of events allowed investigation of the prevalence of congenital heart disease in children whose parents were exposed to the contaminated water area as compared with children whose parents were never exposed to the contaminated water area. The contaminated water area contained 8.8% of the Tucson Valley population and 4.5% of the labor force. Using their case registry, the authors interviewed parents of 707 children with congenital heart disease who, between 1969 and 1987, 1) conceived their child in the Tucson Valley, and 2) spent the month before the first trimester and the first trimester of the case pregnancy in the Tucson Valley. Two random dialing surveys showed that only 10.5% of the Tucson Valley population had ever had work or residence contact, or both, with the contaminated water area, whereas 35% of parents of children with congenital heart disease had had such contact (p less than 0.005). The prevalence of congenital cardiac disease (excluding syndromes, children with atrial tachycardia or premature infants with patent ductus arteriosus) in the Tucson Valley was 0.7% of live births and with syndromes was calculated to be 0.82%. The odds ratio for congenital heart disease for children of parents with contaminated water area contact during the period of active contamination was three times that for those without contact (p less than 0.005) and decreased to near unity for new arrivals in the contaminated water area after well closure. The proportion of infants with congenital heart disease as compared with the number of live births was significantly higher for resident mothers in the contaminated water area than for mothers with no exposure. No other environmental agent could be identified that was localized to the contaminated water area, but one could have been missed. The data show a significant association but not a cause and effect relation between parental exposure to the contaminated water area and an increased proportion of congenital heart disease among live births as compared with the proportion of congenital heart disease among live births for parents without contaminated water area contact.

Growth and adiposity of term infants fed whey-predominant or casein-predominant formulas or human milk.

Growth, estimated composition of weight gained, and stool patterns of term infants who were fed either a whey-predominant formula or a casein-predominant formula in a random design and of breast-fed infants were compared. All infants (N = 111) were healthy, singleton products of uncomplicated pregnancies. Birth weights and other anthropometric measures in the first few days of life were not different among the three feeding groups. Formula or breast milk was the infants' principal source of energy from birth to age 16 weeks. Average energy intakes of formula-fed infants and change of intakes with age were similar in both groups at all ages. Feeding groups were not significantly different at any age in weight, length, weight or length gain, head circumference, skinfold measurements, upper arm fat area and muscle area, or estimated total body fat. Stools of infants on the whey-predominant formula differed from both the breast-fed and casein-predominant formula groups.