Raw and processed fruit and vegetable consumption and 10-year stroke incidence in a population-based cohort study in the Netherlands
Oude Griep, L.M. ; Verschuren, W.M.M. ; Kromhout, D. ; Ocké, M.C. ; Geleijnse, J.M. - \ 2011
European Journal of Clinical Nutrition 65 (2011)7. - ISSN 0954-3007 - p. 791 - 799.
potentially anticarcinogenic flavonoids - food frequency questionnaire - cardiovascular-disease - relative validity - ischemic-stroke - antioxidant vitamins - risk - reproducibility - metaanalysis - carotenoids
Background/Objectives: Prospective cohort studies have shown that high fruit and vegetable consumption is related to a lower risk of stroke. Whether food processing affects this association is unknown. We evaluated the associations of raw and processed fruit and vegetable consumption independently from each other with 10-year stroke incidence and stroke subtypes in a prospective population-based cohort study in the Netherlands. Subjects/Methods: We used data of 20¿069 men and women aged 20–65 years and free of cardiovascular diseases at baseline who were enrolled from 1993 to 1997. Diet was assessed using a validated 178-item food frequency questionnaire. Hazard ratios (HRs) were calculated for total, ischemic and hemorrhagic stroke incidence using multivariable Cox proportional hazards models. Results: During a mean follow-up time of 10.3 years, 233 incident stroke cases were documented. Total and processed fruit and vegetable intake were not related to incident stroke. Total stroke incidence was 30% lower for participants with a high intake of raw fruit and vegetables (Q4: >262¿g/day; HR: 0.70; 95% confidence intervals (95% CIs): 0.47–1.03) compared with those with a low intake (Q1: 92¿g/day) and the trend was borderline significant (P for trend=0.07). Raw vegetable intake was significantly inversely associated with ischemic stroke (>27 vs 27¿g/day; HR: 0.50; 95% CI: 0.34–0.73), and raw fruit borderline significantly with hemorrhagic stroke (>120 vs 120¿g/day; HR: 0.53; 95% CI: 0.28–1.01). Conclusions: High intake of raw fruit and vegetables may protect against stroke. No association was found between processed fruit and vegetable consumption and incident stroke
Dietary Flavonol Intake May Lower Stroke Risk in Men and Women
Hollman, P.C.H. ; Geelen, A. ; Kromhout, D. - \ 2010
The Journal of Nutrition 140 (2010)3. - ISSN 0022-3166 - p. 600 - 604.
potentially anticarcinogenic flavonoids - coronary-heart-disease - cardiovascular-disease - postmenopausal women - blood-pressure - male smokers - metaanalysis - mortality - antioxidant - zutphen
Flavonols are strong antioxidants in plant foods and tea is a major dietary source. There is evidence from prospective cohort studies that tea and flavonols are inversely related to stroke incidence. We conducted a metaanalysis of prospective cohort studies to assess quantitatively the strength of the association between flavonol intake and stroke incidence. Prospective cohort studies with data from individuals free of cardiovascular diseases (CVD) or stroke at baseline were included in the metaanalysis. Persons were followed for between 6 and 28 y. Data from 6 cohorts involving 111,067 persons with at least 2155 nonfatal and fatal cases were pooled. A random effects model was used. In all studies included, adjustments were made for major CVD risk factors except for 2 that did not adjust for alcohol and energy intake. A high intake of flavonols compared with a low intake was inversely associated with nonfatal and fatal stroke with a pooled relative risk of 0.80 (95% Cl: 0.65, 0.98). Visual inspection of Begg's funnel plot and Egger's test (P = 0.01) indicated potential publication bias. We conclude that flavonols may reduce stroke risk. J. Nutr. 140: 600-604, 2010.
Flavonoids and heart health: Proceedings of the ILSI North America Flavonoids Workshop may 31-june 1, 2005, Washington DC
Erdman, J.W. ; Balentine, D. ; Arab, L. ; Beecher, G. ; Dwyer, J.T. ; Folts, J. ; Harnly, J. ; Hollman, P.C.H. ; Keen, C.L. ; Mazza, G. ; Messina, M. ; Scalbert, A. ; Vita, J. ; Williamson, G. ; Burrows, J. - \ 2007
The Journal of Nutrition 137 (2007)3. - ISSN 0022-3166 - p. 718s - 737s.
low-density-lipoprotein - coronary-artery-disease - potentially anticarcinogenic flavonoids - environmental estrogenic compounds - estradiol-induced tumorigenesis - improves endothelial function - liquid-chromatographic method - catechol o-methyltransferase - ran
This article provides an overview of current research on flavonoids as presented during a workshop entitled, "Flavonoids and Heart Health," held by the ILSI North America Project Committee on Flavonoids in Washington, DC, May 31 and June 1, 2005. Because a thorough knowledge and understanding about the science of flavonoids and their effects on health will aid in establishing dietary recommendations for bioactive components such as flavonoids, a systematic review of the science of select flavonoid classes (i.e., flavonols, flavones, flavanones, isoflavones, flavan-3-ols, anthocyanins, and proanthocyanidins) was presented. The objectives of the workshop were to 1) present and discuss current research on flavonoid intake and the relation between flavonoids and heart health; 2) develop information that could lead to expert consensus on the state-of-the-science of dietary intake of flavonoids on heart health; and 3) summarize and prioritize the research needed to establish the relations between specific flavonoids and heart health. Presentations included the basics of the biology of flavonoids, including the types and distribution in foods, analytical methodologies used to determine the amounts in foods, the bioavailability, the consumption patterns and potential biomarkers of intake, risk assessment and safety evaluation, structure/function claims, and the proposed mechanism(s) of the relation between certain flavonoids and heart health endpoints. Data presented support the concept that certain flavonoids in the diet can be associated with significant health benefits, including heart health. Research gaps were identified to help advance the science.
Myricetin stimulates the absorption of the pro-carcinogen PhIP
Schutte, M.E. ; Sandt, J.J.M. van de; Alink, G.M. ; Groten, J.P. ; Rietjens, I.M.C.M. - \ 2006
Cancer Letters 231 (2006)1. - ISSN 0304-3835 - p. 36 - 42.
potentially anticarcinogenic flavonoids - multidrug-resistance protein-1 - apparent drug permeability - caco-2 - expression - cells - transport - localization - modulation - mutagen
The effect of the flavonoid myricetin on the transport of the pro-carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) through differentiated Caco-2 monolayers, a model for the intestinal epithelium, is described. Myricetin causes an increase of the transport of PhIP from the apical to the basolateral compartment. This effect was observed at physiologically relevant concentrations of PhIP and myricetin. Cyclosporin A (MRP2 inhibitor) but not PSC833 (P-gp inhibitor) showed a similar effect on PhIP transport. The results indicate that myricetin induces an increased basolateral uptake of the pro-carcinogen PhIP, in part through inhibition of the MRP2 mediated excretion of PhIP from the intestinal cells back to the lumen
Polyphenols and disease risk in epidemiologic studies
Arts, I.C.W. ; Hollman, P.C.H. - \ 2005
American Journal of Clinical Nutrition 81 (2005)suppl.. - ISSN 0002-9165 - p. 317S - 325S.
coronary heart-disease - breast-cancer risk - potentially anticarcinogenic flavonoids - cardiovascular-disease - postmenopausal women - phytoestrogen intake - dietary flavonoids - united-states - male smokers - antioxidant flavonols
Plant polyphenols, a large group of natural antioxidants, are serious candidates in explanations of the protective effects of vegetables and fruits against cancer and cardiovascular diseases. Epidemiologic studies are useful for evaluation of the human health effects of long-term exposure to physiologic concentrations of polyphenols, but reliable data on polyphenol contents of foods are still scarce. The aim of this review is to summarize available epidemiologic data on the health effects of polyphenols, focusing on the flavonoid subclasses of flavonols, flavones, and catechins and on lignans. Data obtained to date suggest beneficial effects of both flavonoids and lignans on cardiovascular diseases but not on cancer, with the possible exception of lung cancer. There is a need for more research on stroke and lung diseases such as asthma and chronic obstructive pulmonary disease. Most studies to date have included only flavonols and flavones. With data becoming available for other polyphenols, these compounds should be included in future studies. Careful design of prospective studies is important to offset some of the major drawbacks of epidemiologic studies, including residual confounding (by smoking and other dietary factors) and exposure assessment.
Dietary intake of flavonoids and asthma in adults
Garcia, V. ; Arts, I.C.W. ; Sterne, J.A.C. ; Thompson, R.L. ; Shaheen, S.O. - \ 2005
European Respiratory Journal 26 (2005)3. - ISSN 0903-1936 - p. 449 - 452.
potentially anticarcinogenic flavonoids - antiinflammatory activity - catechin contents - fruit juices - netherlands - vegetables - antioxidants - optimization - diseases - release
Epidemiological studies have suggested that a high consumption of apples may protect against asthma and chronic obstructive pulmonary disease. This effect has been attributed to their high flavonoid content, but few studies have investigated the relationship between flavonoid intake and obstructive lung disease directly. In a population-based, case-control study of 1,471 adults aged 16¿50 yrs in London (UK), the present study examined whether dietary intake of catechins, flavonols and flavones was negatively associated with asthma, asthma severity and chronic sputum production. Asthma was defined by positive responses to a standard screening questionnaire in 1996 and information about usual diet was obtained by a food frequency questionnaire in 1997. After controlling for potential confounders, dietary intake of these three flavonoid subclasses was not significantly associated with asthma, (odds ratio per quintile (95% confidence interval) = 0.94 (0.86¿1.02); 1.00 (0.92¿1.09); 0.98 (0.88 ¿1.08) for flavones, flavonols and total catechins, respectively) nor was it associated with asthma severity, or chronic sputum production. In conclusion, no evidence was found for a protective effect of three major subclasses of dietary flavonoids on asthma. It is possible that other flavonoids or polyphenols present in apples may explain the protective effect of apples on obstructive lung disease
Identification of 14 quercetin phase II mono- and mixed conjugates and their formation by rat and human phase II in vitro model systems.
Woude, H. van der; Boersma, M.G. ; Vervoort, J.J.M. ; Rietjens, I.M.C.M. - \ 2004
Chemical Research in Toxicology 17 (2004)11. - ISSN 0893-228X - p. 1520 - 1530.
potentially anticarcinogenic flavonoids - catechol-o-methyltransferase - induced lipid-peroxidation - low-density-lipoprotein - dietary flavonoids - plasma metabolites - bioavailability - antioxidant - regioselectivity - derivatives
In this study, the HPLC, T TV-vis, LC-MS, and H-1 NMR characteristics of 14 different phase II mono- and mixed conjugates of quercetin were determined, providing a useful tool in the identification of quercetin phase II metabolite patterns in various biological systems. Using these data, the phase 11 metabolism of quercetin by different rat and human liver and intestine in vitro models, including cell lines, S9 samples, and hepatocytes, was investigated. A comparison of quercetin phase II metabolism between rat and human liver and intestinal cell lines, S9, and hepatocytes showed considerable variation in the nature and ratios of quercetin conjugate formation. It could be established that the intestine contributes significantly to the phase II metabolism of quercetin, especially to its sulfation, that organ-dependent phase II metabolism in rat and man differ significantly, and that human interindividual variation is higher for quercetin sulfation than for glucuronidation or methylation. Furthermore, quercetin conjugation by different in vitro models from corresponding origins may differ significantly. The identification of the various mono- and mixed quercetin phase II conjugates revealed significant differences in phase II conjugation by a variety of in vitro models and led to the conclusion that none of the in vitro models converted quercetin to a phase II metabolite mixture similar to the in vivo plasma metabolite pattern of quercetin. Altogether, the identification of a wide range of phase II metabolites of quercetin as presented in this study allows the determination of quercetin phase II biotransformation patterns and opens the way for a better-funded assessment of the biological activity of quercetin in a variety of biological systems.
Chlorogenic acid, quercetin-3-rutinoside and black tea phenols are extensively metabolized in humans
Olthof, M.R. ; Hollman, P.C.H. ; Buijsman, M.N.C.P. ; Amelsvoort, J.M.M. van; Katan, M.B. - \ 2003
The Journal of Nutrition 133 (2003)6. - ISSN 0022-3166 - p. 1806 - 1814.
potentially anticarcinogenic flavonoids - caffeic acid - human plasma - derivatives - quercetin - bioavailability - consumption - microflora - catechins - lithium
Dietary phenols are antioxidants, and their consumption might contribute to the prevention of cardiovascular disease. Coffee and tea are major dietary sources of phenols. Dietary phenols are metabolized extensively in the body. Lack of quantitative data on their metabolites hinders a proper evaluation of the potential biological effects of dietary phenols in vivo. The aim of this study was to identify and quantify the phenolic acid metabolites of chlorogenic acid (major phenol in coffee), quercetin-3-rutinoside (major flavonol in tea) and black tea phenols in humans, and determine the site, of metabolism. Healthy humans (n = 20) with an intact colon participated in a dietary controlled crossover study, and we identified and quantified similar to60 potential phenolic acid metabolites in urine. Half of the ingested chlorogenic acid and 43% of the tea phenols were metabolized to hippuric acid. Quercetin-3-rutinoside was metabolized mainly to phenylacetic acids, i.e., 3-hydroxyphenylacetic acid (36%), 3-methoxy-4-hydroxyphenylacetic acid (8%) and 3,4-dihydroxyphenylacetic acid (5%). In contrast, in seven humans without a colon, we found only traces of phenolic acid metabolites in urine after they had ingested chlorogenic acid and quercetin-3-rutinoside. This implies that the colonic microflora convert most of these dietary phenols into metabolites that then reach the circulation. Metabolites of dietary phenols have lower antioxidant activity than their parent compounds; therefore, the contribution of dietary phenols to antioxidant activity in vivo might be lower than expected from in vitro tests. J. Nutr. 133: 1806-1814, 2003.
Dealing with variability in food production chains: a tool to enhance the sensitivity of epidemiological studies of phytochemicals
Dekker, M. ; Verkerk, R. - \ 2003
European Journal of Nutrition 42 (2003)1. - ISSN 1436-6207 - p. 67 - 72.
potentially anticarcinogenic flavonoids - brassica vegetables - prospective cohort - cancer - fruit - netherlands
Background Many epidemiological studies have tried to associate the intake of certain food products with a reduced risk for certain diseases. Results of these studies are often ambiguous, conflicting, or show very large deviations of trends. Nevertheless, a clear and often reproduced inverse association is observed between total vegetable and fruit consumption and cancer risk. Examples of components that have been indicated to have a potential protective effect in food and vegetables include antioxidants, allium compounds and glucosinolates. Aim The food production chain can give a considerable variation in the level of bioactive components in the products that are consumed. In this paper the effects of this variability in levels of phytochemicals in food products on the sensitivity of epidemiological studies are assessed. Methods Information on the effect of variation in different steps of the food production chain of Brassica vegetables on their glucosinolate content is used to estimate the distributions in the levels in the final product that is consumed. Monte Carlo simulations of an epidemiological cohort study with 30,000 people have been used to assess the likelihood of finding significant associations between food product intake and reduced cancer risk. Results By using the Monte Carlo simulation approach, it was shown that if information on the way of preparation of the products by the consumer was quantified, the statistical power of the study could at least be doubled. The statistical power could be increased by at least a factor of five if all variation of the food production chain could be accounted for. Conclusions Variability in the level of protective components arising from the complete food production chain can be a major disturbing factor in the identification of associations between food intake and reduced risk for cancer. Monte Carlo simulation of the effect of the food production chain on epidemiological cohort studies has identified possible improvements in the set up of such studies. The actual effectiveness of food compounds already identified as cancer-protective by current imprecise methods is likely to be much greater than estimated at present.