Grapefruit Intake Research Articles

Flavonoid-Rich Fruit Intake in Midlife and Late-Life and Associations with Risk of Dementia: The Framingham Heart Study

BackgroundFruits are an important source of flavonoids, and greater intake of dietary flavonoids in older adults has been shown to be associated with decreased risk of dementia. It is unclear whether this relationship is similar or different between younger adults and older adults.ObjectivesWe examined for associations between midlife and late-life intake of flavonoid-rich fruits and incident dementia. We hypothesized that greater total cumulative intake of flavonoid-rich fruits in midlife and late-life adults would be associated with reduced risk of all-cause dementia.DesignLongitudinal, cohort study design.SettingFramingham Heart Study, which is a longitudinal, multi-generational community-based cohort based in Framingham, Massachusetts, USA.ParticipantsParticipants from the Framingham Heart Study Offspring cohort were included (n = 2,790) who attended the fifth core exam between 1991 to 1995, and were dementiafree and at least 45 years of age at that time, as well as had valid food frequency questionnaires from the fifth to ninth core exams.MeasurementsConsumption of fruits with high flavonoid content or are important contributors to overall flavonoid intake was collected via food frequency questionnaire. Flavonoid-rich fruits from the food frequency questionnaire included raisins or grapes, prunes, bananas, fresh apples or pears, apple juice or cider, oranges, orange juice, grapefruit, grapefruit juice, strawberries, blueberries, and peaches, apricots, or plums. Dementia ascertainment was based on a multidisciplinary consensus committee, and included all-cause dementia and Alzheimer’s disease dementia diagnoses based on research criteria. Cox models were used to examine associations between cumulative fruit intake and incident dementia, stratified by midlife (45–59 years; n = 1,642) and late-life (60–82 years; n = 1,148).ResultsGreater cumulative total fruit intake in midlife, but not late-life, was significantly associated with a 44% decreased risk of all-cause dementia (HR = 0.56; 95% CI = 0.32–0.98; p = 0.044). Decreased risk of all-cause dementia was also associated with higher intake of apples or pears in midlife and late-life, as well as higher intake of raisins or grapes in midlife only, and higher intake of oranges, grapefruit, blueberries, and peaches, apricots, or plums in late-life only.ConclusionsAmong participants from the Framingham Heart Study, greater overall consumption of flavonoid-rich fruits in midlife was associated with reduced risk of dementia, though intake of specific fruits in midlife and late-life may have a protective role against developing dementia. These findings may help to inform future recommendations on when dietary interventions may be most beneficial to healthy brain aging across the life course.

The Validation and Determination of Empagliflozin Concentration in the Presence of Grapefruit Juice Using HPLC for Pharmacokinetic Applications.

Type 2 diabetes mellitus is a multifactorial disorder whose primary manifestation usually initiates with elevated blood sugar levels. Several antidiabetic agents are used to manage type 2 diabetes mellitus, of which empagliflozin is an oral sodium-glucose co-transporter (SGLT-2) inhibitor in the kidney. This research aims to develop and validate a simple analytical method for determining empagliflozin levels in biological fluid and to further evaluate grapefruit juice's impact on empagliflozin pharmacokinetics in rats. High-Performance Liquid Chromatography (HPLC) was used to establish a simple, rapid, and accurate method for determining empagliflozin levels in rat plasma, in the presence of grapefruit juice. Four groups of rats (n = 10 rats in each) were used in the preclinical study. Group A (healthy rats) received empagliflozin alone; Group B (healthy rats) received empagliflozin with grapefruit; Group C (diabetic rats) received empagliflozin with grapefruit; and Group D (healthy, negative control) received no medication. The rats (n = 10) were given grapefruit juice instead of water for seven days before receiving the empagliflozin dose (0.16 mg/kg). Some pharmacokinetic parameters for each group were determined. The maximum plasma concentration (Cmax) and area under the curve (AUC) of empagliflozin in Group A without grapefruit intake were 730 ng/mL and 9264.6 ng × h/mL, respectively, with Tmax (2 h). In Group B, Cmax was 1907 ng/mL and AUC was 10,290.75 ng × h/mL in the presence of grapefruit, with Tmax (1 h); whereas, in Group C, the Cmax was 2936 ng/mL and AUC was 18657 ng × h/mL, with Tmax (2 h). In conclusion, our results showed that the co-administration of grapefruit with empagliflozin should be cautiously monitored and avoided, in which grapefruit elevates the plasma level of empagliflozin. This may be attributed to the inhibition of the uridine enzyme in the grapefruit by hesperidin, naringin, and flavonoid.

Questionnaire-based exposome-wide association studies (ExWAS) reveal expected and novel risk factors associated with cardiovascular outcomes in the Personalized Environment and Genes Study

While multiple factors are associated with cardiovascular disease (CVD), many environmental exposures that may contribute to CVD have not been examined. To understand environmental effects on cardiovascular health, we performed an exposome-wide association study (ExWAS), a hypothesis-free approach, using survey data on endogenous and exogenous exposures at home and work and data from health and medical histories from the North Carolina-based Personalized Environment and Genes Study (PEGS) (n = 5015). We performed ExWAS analyses separately on six cardiovascular outcomes (cardiac arrhythmia, congestive heart failure, coronary artery disease, heart attack, stroke, and a combined atherogenic-related outcome comprising angina, angioplasty, atherosclerosis, coronary artery disease, heart attack, and stroke) using logistic regression and a false discovery rate of 5%. For each CVD outcome, we tested 502 single exposures and built multi-exposure models using the deletion-substitution-addition (DSA) algorithm. To evaluate complex nonlinear relationships, we employed the knockoff boosted tree (KOBT) algorithm. We adjusted all analyses for age, sex, race, BMI, and annual household income. ExWAS analyses revealed novel associations that include blood type A (Rh-) with heart attack (OR[95%CI] = 8.2[2.2:29.7]); paint exposures with stroke (paint related chemicals: 6.1[2.2:16.0], acrylic paint: 8.1[2.6:22.9], primer: 6.7[2.2:18.6]); biohazardous materials exposure with arrhythmia (1.8[1.5:2.3]); and higher paternal education level with reduced risk of multiple CVD outcomes (stroke, heart attack, coronary artery disease, and combined atherogenic outcome). In multi-exposure models, trouble sleeping and smoking remained important risk factors. KOBT identified significant nonlinear effects of sleep disorder, regular intake of grapefruit, and a family history of blood clotting problems for multiple CVD outcomes (combined atherogenic outcome, congestive heart failure, and coronary artery disease). In conclusion, using statistics and machine learning, these findings identify novel potential risk factors for CVD, enable hypothesis generation, provide insights into the complex relationships between risk factors and CVD, and highlight the importance of considering multiple exposures when examining CVD outcomes.

Measurement of Effective Dose Detox for Workers Exposed to Benzene Toxins in Sidoarjo Paint Industry

One of the aromatic hydrocarbon compounds, namely benzene. Benzene is a colorless liquid with a sweetodor (sweet odor), volatile in the air, soluble in water and flammable. Today the use of benzene used bythe paint manufacturing industry. However, the concentration of benzene that exceed standards requiredthreshold value will negatively impact the health of workers in Sidoarjo Paint Industry. Benzene can threatenthe safety and human health if inhaled because it can damage the blood forming system profile in humans.The purpose of this research is to reduce the exposure of benzene by determining the effective dose of toxindetox benzene in the paint industry, Sidoarjo, East Java. This study was an observational study with crosssectionalapproach.result the average concentration of benzene in the workplace respondents was 3.28 mg /m3. The average effective dose should be consumed by the respondent for the avocado intake is 0,011 mg /day, chicken intake 0,026 mg / day, intake of grapefruit 0.033 mg/day, and carrot intake was 0.063 mg /day.

Polymorphism of TAS2R3, TAS2R5, TAS2R19, and TAS2R50 genes and bitter food intake frequency inelderly woman.

Taste sensitivity is one of the most important biological determinants of food choice. Polymorphisms within the bitter taste receptor genes TAS2R3 (rs765007), TAS2R5 (rs2234012), TAS2R19 (rs10772420), and TAS2R50 (rs1376251) may affect bitter taste sensitivity and thus food choices and thereby metabolic biomarkers in blood. The aim of this study was to investigate associations between selected TAS2Rs  single nucleotide polymorphisms (SNPs) and the choice of the most popular bitter food items in    a Polish population, BMI and blood biomarkers in elderly women. The study group included 116 Polish women over 60 years of age. Intake of Brassica vegetables, grapefruit and coffee was assessed using a food frequency questionnaire. Biochemical parameters were measured using the spectrophotometric method. Genotyping was performed using the high resolution melting method. We show an association between SNPs of the TAS2R3 gene and the frequency of Brassica vegetable intake, between SNPs of the TAS2R5 gene and the frequency of grapefruit intake, and between the simultaneous effects of polymorphisms within TAS2R3 and TAS2R5 and the frequency of eating Brassica vegetables in general. We found no association between the genetic polymorphisms of TAS2R19 or TAS2R50 that were examined and the frequency of bitter-tasting food intake. Moreover, the SNPs of the selected TAS2Rs genes may be associated with the lipid profile, serum level of glucose and CRP, depending on the frequency of consumption of particular bitter-tasting items. The genetic polymorphisms analyzed in the study seem not to contribute significantly to variability in bitter-tasting food intake in elderly women, although they may influence metabolic biomarkers dependent on the intake of particular bitter-tasting food items.

TAS2R38 and CA6 genetic polymorphisms, frequency of bitter food intake, and blood biomarkers among elderly woman

ObjectiveTaste sensitivity is one of the most important biological determinants of food choice. Three SNPs of the TAS2R38 gene (rs713598, rs1726866, and rs10246939) give rise to two common haplotypes: PAV and AVI. These haplotypes, as well as an SNP within the CA6 gene (rs2274333) that encodes carbonic anhydrase VI (CA6), correlate with bitterness perception. The extent of consumption of bitter food may influence some health outcomes. The aim of this study is thus to investigate the impact of the TAS2R38 and CA6 genetic polymorphisms on the choice of bitter food, BMI, blood lipoprotein, and glucose concentrations as well as systemic inflammation in elderly women. MethodsThe associations between the TAS2R38 diplotype, CA6 genotype, and the intake of bitter-tasting foods were studied in a group of 118 Polish women over 60 years of age. The intake of Brassica vegetables, grapefruit, and coffee was assessed using a food frequency questionnaire. Biochemical parameters were measured using the spectrophotometric method. Genotyping was performed using the high resolution melting method. ResultsWe found a correlation between lipid profile, glucose and CRP levels, and frequency of bitter food intake. The AVI/AVI subjects drank coffee more frequently than did the PAV/PAV homozygotes, as did the A carriers of CA6 in comparison with the GG homozygotes. We also observed that simultaneous carriers of the PAV haplotype and A allele of TAS2R38 and CA6, respectively, choose white cabbage more frequent and had lower plasma levels of CRP and glucose than did AVI/AVI and GG homozygotes. ConclusionsIn elderly women, the TAS2R38 and CA6 polymorphisms may affect the frequency of consumption of coffee and white cabbage, but not of other bitter-tasting foods.

Daily Consumption of Grapefruit for 6 Weeks Reduces Urine F2-Isoprostanes in Overweight Adults with High Baseline Values but Has No Effect on Plasma High-Sensitivity C-Reactive Protein or Soluble Vascular Cellular Adhesion Molecule1–3

Individuals with obesity and metabolic syndrome (MetS) are at increased risk of cardiovascular disease, in part due to heightened inflammatory/oxidative processes. Results from epidemiologic and experimental studies suggest that citrus, and grapefruit in particular, may have a role in promoting vascular health, although clinical trial data are lacking. Here, we evaluated the anti-inflammatory/antioxidant effects of habitual grapefruit consumption in 69 overweight/obese men and women and in a subsample of participants with MetS (n = 29). Participants were randomly assigned to either a grapefruit group in which they consumed a low bioactive diet plus 1.5 grapefruit/d for 6 wk (n = 37, n = 14 with MetS) or to a control condition in which a low bioactive diet devoid of citrus was consumed (n = 32, n = 15 with MetS). Plasma soluble vascular adhesion molecule-1 (sVCAM-1), plasma high-sensitivity C-reactive protein (hsCRP), and urinary F2-isoprostanes were evaluated before and after the intervention phase. F2-isoprostane concentrations were not different in the grapefruit versus control arm after the intervention (12.4 ± 6.4 vs. 15.9 ± 9.0 ng/mg creatinine, P = 0.16), whereas plasma hsCRP concentrations tended to be lower in the grapefruit versus control arm postintervention (2.1 ± 1.5 vs. 2.8 ± 2.0 mg/L, P = 0.09). In adults with MetS, grapefruit consumption tended to result in lower postintervention F2-isoprostane concentrations compared with the control condition (12.0 ± 4.5 vs. 18.3 ± 10.9 ng/mg creatinine, P = 0.06). Furthermore, those with high baseline F2-isoprostane concentrations experienced significant reductions in this biomarker in response to grapefruit consumption (P = 0.021). Change in sVCAM-1 concentrations did not vary by treatment arm nor were there differences between arms postintervention. These results suggest that intake of grapefruit twice daily for 6 wk does not significantly reduce inflammation and oxidative stress, although there is a suggestion of favorable modulation of oxidative stress in overweight and obese adults with MetS or those with high baseline urine F2-isoprostane concentrations.

The Effect of Grapefruit Intake on Endogenous Serum Estrogen Levels in Postmenopausal Women

Although grapefruit intake leads to elevated serum estrogen levels when hormones are taken orally, there are no published data on the effect on endogenous levels. We conducted a pilot dietary intervention study among healthy postmenopausal volunteers to test whole grapefruit, 2 juices, and 1 grapefruit soda. Fifty-nine participants were recruited through the Love/Avon Army of Women. The study consisted of a 3-wk run-in, 2 wk of grapefruit intake, and a 1-wk wash-out. Eight fasting blood samples were collected. An additional 5 samples drawn at 1, 2, 4, 8, and 10 hr after grapefruit intake were collected during an acute-phase study for 10 women. Serum assays for estrone (E1), estradiol (E2), estrone-3-sulfate (E1S), dehydroepiandrosterone sulfate, and sex hormone-binding globulin were conducted. Whole grapefruit intake had significant effects on endogenous E1S. Peak effects were seen at 8 hr, increasing by 26% from baseline. No changes in mean E1 or E2 with whole fruit intake were observed. In contrast, fresh juice, bottled juice, and soda intake all had significant lowering effects on E2. The findings suggest an important interaction between grapefruit intake and endogenous estrogen levels. Because endogenous estrogen levels are associated with breast cancer risk, further research is warranted.

Hidden Sources of Grapefruit in Beverages: Potential Interactions with Immunosuppressant Medications

The interaction between grapefruit-containing beverages and immunosuppressants is not well defined in the literature. This study was conducted to investigate possible sources of grapefruit juice or grapefruit extract in common US-manufactured beverages. The goal was to identify those products that might serve as hidden sources of dietary grapefruit intake, increasing a transplant patient's risk for drug interactions. A careful review of the ingredients of the 3 largest US beverage manufacturer's product lines was conducted through manufacturer correspondence, product labeling examination, and online nutrition database research. Focus was placed on citrus-flavored soft drinks, teas, and juice products and their impact on a patient's immunosuppressant regimens. Twenty-three beverages were identified that contained grapefruit. Five did not contain the word "grapefruit" in the product name. In addition to the confirmed grapefruit-containing products, 17 products were identified as possibly containing grapefruit juice or grapefruit extract. A greater emphasis should be placed upon properly educating patients regarding hidden sources of grapefruit in popular US beverages and the potential for food-drug interactions.

Abstract 639: The effect of grapefruit intake on endogenous serum estrogen levels in postmenopausal women

Abstract The inhibitory effect of grapefruit juice on the intestinal cytochrome P450 3A4 system interacts with more than 60% of orally administered drugs leading to elevation of their serum concentrations. While grapefruit has been shown to lead to elevated serum levels of estrogens when hormones are administered orally, there are no published data on the effect of grapefruit intake on endogenous levels. To begin to address that data gap, we conducted a dietary intervention study among healthy postmenopausal volunteers to determine whether endogenous estrogen levels are significantly affected by grapefruit consumption. We tested 4 grapefruit products: whole fresh grapefruit, fresh squeezed juice “not from concentrate,” shelf-stable juice from concentrate, and grapefruit soda. The majority of volunteers were recruited through the Love/Avon Army of Women. The six-week study consisted of a run-in period of three weeks, a two-week period of grapefruit consumption, and a one-week wash-out period. Eight fasting blood samples were collected during the study. An additional 5 samples drawn at 1, 2, 4, 8 and 10 hours after initial grapefruit intake were collected during an acute-phase study. Serum assays for estrone (E1), estradiol (E2), estrone-3- sulfate (E1S), and sex hormone-binding globulin (SHBG) were conducted. Sixty-two women participated in the study, 10 of whom also participated in the acute phase. Only the whole grapefruit had statistically significant effects on endogeneous estrogen levels. The largest increases were seen in the women with the highest BMI. The changes were evident at 24 hours and remained relatively constant over the 2 week period. With whole grapefruit at the average BMI of 26.6 kg/m2, E1S increased overall by 10.6% (p=0.031), and at a BMI of 30 kg/m2 this increased to 16.4% (p=0.003). Approximately double the effects were seen around 10 hours after whole grapefruit consumption. The effects of fresh juice consumption were around 25% of these increases but were not statistically significant. Small increases in E1 were seen with whole grapefruit, but no increase was seen in E2. The findings of the present study suggest an important interaction between grapefruit consumption and serum levels of endogenous E1S. The increase in E1S is difficult to interpret in term of risk of breast cancer as we found only a small increase in E1 and failed to find any increase in E2. More detailed studies are needed to gain an understanding how the increased levels of E1S are not reflected in similar increases in E1 and E2, and whether the increased E1S levels are reflected in an increase in E1 and E2 levels in the breast itself. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 639. doi:1538-7445.AM2012-639

Grapefruit consumption is associated with benefits to the intake of certain nutrients, body composition, and select physiologic parameters in U.S. women

The purpose of this study was to estimate usual intake (UI) of total grapefruit (GF) (fruit and juice) by women age 19+ y and to compare certain nutrient intakes and select health‐related parameters between consumers (GFC) and non‐consumers (GFNC) using data collected in NHANES 2003–8. GFC (n=180) were defined as women reporting intake of GF on either of 2 days of dietary recall. UI of vitamin C by GFC was significantly higher (p<0.0001) than intake by GFNC (n=6219) (145±3.9 vs 76±1.2 mg/d); UI of beta‐carotene, vitamin B6, magnesium, fiber and potassium by GFC also were higher compared to GFNC while intakes of added sugars, total fat, saturated fat and cholesterol were lower (p<0.05); energy intakes were comparable. Mean body weight (70.2±1.6 vs 75.4±0.5 kg), waist circumference (91±1.5 vs 95±0.4 cm) and BMI (26.9±0.6 vs 28.6±0.2 kg/m2) of GFC were significantly lower (p<0.01) as compared to GFNC, though the risk of overweight/obesity did not differ. HDL‐cholesterol levels were significantly higher (p<0.01) in GFC (63±1.8 vs 58±0.3 mg/dL) and triglyceride (TG) levels were lower (106±5.7 vs 130±2.5 mg/dL). There were no differences between groups in serum total or LDL‐cholesterol, blood pressure, plasma glucose or insulin. GF consumption may have a positive impact on nutrient intakes and is associated with lower body measures and higher HDL‐cholesterol among women. Supported by the Florida Department of Citrus.

Selected Dietary Flavonoids Are Associated with Markers of Inflammation and Endothelial Dysfunction in U.S. Women ,

Flavonoids show antiinflammatory effects in vitro and human intervention studies have suggested beneficial effects of flavonoid-rich foods on biomarkers of inflammation and endothelial function. In the present study, we assessed the relationship between flavonoid intake and biomarkers of inflammation and endothelial dysfunction in a cross-sectional study of participants from the Nurses' Health Study cohort. Intake of 6 flavonoid subclasses (flavonols, flavones, flavanones, flavan-3-ols, anthocyanidins, and polymeric flavonoids) was assessed using a FFQ administered in 1990. Also, the main food sources of these flavonoids were examined. Blood samples were collected in 1989–1990 and plasma C-reactive protein (CRP), IL-6, IL-18, soluble tumor necrosis factor receptor-2 (sTNF-R2), soluble intercellular adhesion molecule-1, soluble vascular adhesion molecule-1 (sVCAM-1), and E-selectin were measured in 1194–1598 women. The multivariate-adjusted geometric mean of plasma IL-8 were lower for women in the highest intake quintile of flavones, flavanones, and total flavonoids compared with those in the lowest quintiles by 9% (Q1: 264 ng/L, Q5: 241 ng/L; P-trend = 0.019), 11% (Q1: 273 ng/L, Q5: 244 ng/L; P-trend = 0.011), and 8% (Q1: 276 ng/L, Q5: 55 ng/L; P-trend = 0.034), respectively. The multivariate-adjusted geometric mean for women in the highest intake quintile of flavonol compared with those in the lowest quintile was 4% lower for sVCAM-1 (Q1: 578 μg/L, Q5: 557 μg/L; P-trend = 0.012). Among flavonoid-rich foods, higher intake of grapefruit was significantly associated with lower concentrations of CRP and sTNF-R2. In summary, higher intakes of selected flavonoid subclasses were associated with modestly lower concentrations of inflammatory biomarkers. In particular, flavonoids typically found in citrus fruits were modestly associated with lower plasma IL-18 concentrations.

Effect of Grapefruit Intake on Postprandial Plasma Glucose

Objective: Previous epidemiological surveys of diet indicated a potential relationship between fruit intake and the pathogenesis of lifestyle-related disease. Recent reports indicate grapefruit (GF) may affect sugar metabolism. The present study measured glucose, triglyceride and insulin levels in human blood after GF ingestion with and without other foods.Methods: Twelve healthy, non-smoking female volunteers, non-obese (age 40.5 ± 4.2 years old, BMI 22.0 ± 0.9) were provided with five different breakfasts on successive days: GF, bread or fried vegetables alone, GF + bread, GF + fried vegetables. In meals that included GF, the GF was eaten before the bread or fried vegetables. Blood samples were taken after meals to measure plasma glucose, immuno reactive insulin (IRI), triglyceride and vitamin C.Results: Plasma glucose following a meal of bread or fried vegetables or a meal of bread and fried vegetables with GF was similar. Insulin secretion was slower after a meal of GF alone compared to bread alone (p < 0.001) and the area under curve (AUC) of glucose per carbohydrate intake was lower when GF was eaten prior to bread or fried vegetables than after a single intake of bread or fried vegetables alone (p < 0.001). The AUC of triglyceride after a prior intake of GF before fried vegetables was slower than that after an intake of fried vegetables alone (p < 0.05). Blood vitamin C concentration increased after GF intake (p < 0.001).Conclusion: GF contains saccharides and a variety of dietary elements, including fiber, vitamins, citric acid, naringenin and bergamottin. It is possible that these compounds may affect sugar and lipid metabolism.

Dynamic modelling of time series data in nutritional metabonomics — A powerful complement to randomized clinical trials in functional food studies

Functional foods are foods or dietary ingredients that provide a health benefit beyond basic nutrition. A new legislation, known as the Nutrition and Health Claims Regulation, defines the legal framework for such claims within the European Union. Any claim about the nutritional or physiological effects of a product must be scientifically demonstrated. In this study, we have focused on the exploration of metabonomics as a complementary profiling technology to establish monitoring/data analysis procedures of randomized nutritional trials. More specifically, a combined intake of soybean and grapefruit in a human intervention study was analyzed with respect to both pharmacological and physiological effects. Resulting multivariate models showed a diet-induced decrease of lactate, cholesterols and triglycerides. The most drastically elevated metabolite, myo-inositol, was found to accompany a marked reduction of triglyceride levels. Suggestively, this is due to the biotransformation of myo-inositol to phosphatidylinositol, which results in a decrease of available precursors to form triglycerides. Strong inter-subject variation was present that required special attention. Dynamic modelling of collected time series data that provided the opportunity to identify slow, medium or fast responders as well as groups of subjects showing different response profiles, was also highlighted in the study. The applied strategy of time series data has proven to be a powerful complement to randomized nutritional studies adopting a clinical trial design.

Prospective study of the association between grapefruit intake and risk of breast cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC)

Grapefruit inhibits cytochrome P450 3A4 and may affect estrogen metabolism. In the European Prospective Investigation into Cancer and Nutrition (EPIC), we examined the relationships of grapefruit intake with risk of breast cancer and with serum sex hormone levels. 114,504 women with information on dietary intake of grapefruit and on reproductive and lifestyle risk factors were followed for a median 9.5 years and 3,747 incident breast cancers were identified. Fifty-nine percent of women reported eating grapefruit, 4% ate > or = 60 g/day. Cox proportional hazard models were used to estimate the hazard ratio (HR) for breast cancer according to grapefruit intake, adjusting for study centre, reproductive factors, body mass index, energy intake, and alcohol intake. Grapefruit intake was not related to the risk of breast cancer: compared with women who ate no grapefruit, women with the highest intake of > or =60 g/day had a HR of 0.93 (95% CI 0.77-1.13), p for linear trend = 0.5. There was no relationship between grapefruit intake and breast cancer risk among premenopausal women, all postmenopausal women, or postmenopausal women categorized by hormone replacement therapy use (all p>0.05). There was no association between grapefruit intake and estradiol or estrone among postmenopausal women. In this study, we found no evidence of an association between grapefruit intake and risk of breast cancer.

Comparison of CYP1A2 and NAT2 phenotypes between black and white smokers

The lower incidence rate of transitional cell carcinoma of the urinary bladder in blacks than in whites may be due to racial differences in the catalytic activity of enzymes that metabolize carcinogenic arylamines in tobacco smoke. To examine this, we compared cytochrome P4501A2 (CYP1A2) and N-acetyltransferase-2 activities (NAT2) in black and white smokers using urinary caffeine metabolites as a probe for enzyme activity in a community-based study of 165 black and 183 white cigarette smokers. The paraxanthine (1,7-dimethylxanthine, 17X)/caffeine (trimethylxanthine, 137X) ratio or [17X + 1,7-dimethyluric acid (17U)]/137X ratio was used as an indicator of CYP1A2 activity. The 5-acetyl-amino-6-formylamino-3-methyluracil (AFMU)/1-methylxanthine (1X) ratio indicated NAT2 activity. The odds ratio for the slow NAT2 phenotype associated with black race was 0.4; 95% confidence intervals 0.2–0.7. The putative combined low risk phenotype (slow CYP1A2/rapid NAT2) was more common in blacks than in whites (25% vs. 15%, P < 0.02). There were no significant racial differences in slow and rapid CYP1A2 phenotypes, and in the combined slow NAT2/rapid CYP1A2 phenotype. Age, education, cigarette smoking amount, body mass index, GSTM1 and GSTM3 genotypes were unrelated to CYP1A2 and NAT2 activity. Intake of cruciferous vegetables (primarily broccoli), red meat, carrots, grapefruit and onions predicted CYP1A2 activity either for all subjects or in race-specific analyses. Carrot and grapefruit consumption was related to NAT2 activity. Collectively, these results indicated that phenotypic differences in NAT2 alone or in combination with CYP1A2 might help explain the higher incidence rates of transitional cell bladder cancer in whites.

A prospective study of grapefruit and grapefruit juice intake and breast cancer risk

Sir, In a recent interesting study by Monroe et al (2007), grapefruit intake was associated with an increase in breast cancer risk, and they hypothesised that this might be mediated by an effect on endogenous oestrogen levels. However, the researchers were unable to examine grapefruit juice intake. Therefore, we examined grapefruit and grapefruit juice intake and breast cancer risk in the Nurses' Health Study. Briefly, the Nurses' Health Study is a prospective cohort consisting of women aged 30–55 years in 1976 (Kim et al 2006). Medical and lifestyle information was obtained with general follow-up questionnaires every 2 years and with semi quantitative food frequency questionnaires that included intakes of grapefruit and grapefruit juice in 1984, 1986, 1990, 1994, and 1998. In both age-adjusted (not shown) and multivariate analyses adjusted for standard breast cancer risk factors, we found no overall association with either grapefruit or grapefruit juice intake and breast cancer risk among all women in the cohort, and among postmenopausal women only (Table 1). Furthermore, our results did not change once additional covariates – alcohol, saturated fat, dietary fibre, and soluble fibre – included by Monroe et al were added to our models. Table 1 Multivariate relative risks of breast cancer incidence between 1984 and 2002 by cumulatively averaged grapefruit and grapefruit juice intake Stratification by BMI did not alter the breast cancer risk with either grapefruit or grapefruit juice intake. However, stratification by hormone therapy showed a significant decrease in risk of breast cancer with greater intake of grapefruit in women who never used hormone therapy (multivariate RR comparing ¼ grapefruit or more per day to none=0.78, 95% CI, 0.59–1.04, P trend=0.03). This is contrary to the findings of Monroe et al, who observed a significant increase in risk of breast cancer with greater consumption of grapefruit in this subgroup. Furthermore, the association between grapefruit (not grapefruit juice) intake and breast cancer risk differed significantly by oestrogen and progesterone receptor status of the tumours. No association was observed in women with oestrogen and progesterone receptor positive cancers. However, in women with oestrogen and progesterone receptor negative cancers, there was a significant decrease in breast cancer risk with increased consumption of grapefruit (multivariate RR comparing ¼ grapefruit or more per day to none=0.60, 95% CI, 0.37–0.98, P trend=0.03). We also examined cross-sectionally the relationship between consumption of grapefruit and grapefruit juice and plasma levels of oestrogens among 701 postmenopausal women not using hormone replacement. No significant correlation was observed (grapefruit, grapefruit juice) for plasma oestradiol (r=0.02, −0.04), oestrone (r=0.00, −0.02), or oestrone sulphate (0.09, 0.01). Our findings do not support an adverse effect of consumption of grapefruit or grapefruit juice on risk of breast cancer or on endogenous hormone levels.

Prospective study of grapefruit intake and risk of breast cancer in postmenopausal women: the Multiethnic Cohort Study

In vitro and in vivo studies have shown that cytochrome P450 3A4 (CYP3A4) is involved in the metabolism of oestrogens. There is evidence that grapefruit, an inhibitor of CYP3A4, increases plasma oestrogen concentrations. Since it is well established that oestrogen is associated with breast cancer risk, it is plausible that regular intake of grapefruit would increase a woman's risk of breast cancer. We investigated the association of grapefruit intake with breast cancer risk in the Hawaii–Los Angeles Multiethnic Cohort Study, a prospective cohort that includes over 50 000 postmenopausal women from five racial/ethnic groups. A total of 1657 incident breast cancer cases were available for analysis. Grapefruit intake was significantly associated with an increased risk of breast cancer (relative risk=1.30, 95% confidence interval 1.06–1.58) for subjects in the highest category of intake, that is, one-quarter grapefruit or more per day, compared to non-consumers (Ptrend=0.015). An increased risk of similar magnitude was seen in users of oestrogen therapy, users of oestrogen+progestin therapy, and among never users of hormone therapy. Grapefruit intake may increase the risk of breast cancer among postmenopausal women.

Tacrolimus severe overdosage after intake of masked grapefruit in orange marmalade

Tacrolimus severe overdosage after intake of masked grapefruit in orange marmalade

Age-related variations in flavonoid intake and sources in the Australian population

AbstractObjectiveTo estimate flavonoid intake in the Australian population.DesignFlavonoid consumption was estimated from 24-hour recall data and apparent consumption data using US Department of Agriculture flavonoid composition data.SubjectsThe National Nutrition Survey 1995 assessed dietary intake (24-hour recall) in a representative sample (n = 13 858) of the Australian population aged 2 years and over.ResultsAnalysis of the 24-hour recall data indicated an average adult intake (&gt;18 years) of 454 mg day− 1 (92% being flavan-3-ols). Apple was the highest quercetin source until age 16–18 years, after which onion became an increasingly important prominent source. Variations in hesperetin consumption reflected orange intake. Apple, apricot and grapes were the major sources of epicatechin and catechin for children, but subsided as wine consumption increased in adulthood. Wine was the main source of malvidin. Naringenin intake remained static as a percentage of total flavonoid intake until age 19–24 years, corresponding to orange intake, and then increased with age from 19–24 years, corresponding to grapefruit intake. Apparent dietary flavonoid consumption was 351 mg person− 1 day− 1, of which 75% were flavan-3-ols. Black tea was the major flavonoid source (predominantly flavan-3-ols) representing 70% of total intake. Hesperetin and naringenin were the next most highly consumed flavonoids, reflecting orange intake. Both 24-hour recall and apparent consumption data indicated that apigenin intake was markedly higher in Australia than reported in either the USA or Denmark, presumably due to differences in consumption data for leaf and stalk vegetables and parsley.ConclusionsTea was the major dietary flavonoid source in Australia. Flavonoid consumption profiles and flavonoid sources varied according to age. More consistent methodologies, survey tools validated for specific flavonoid intakes and enhanced local flavonoid content data for foods would facilitate better international comparisons of flavonoid intake.