Evaluation of Bioflavonoid Intake in the Diets of 50 Year Old Inhabitants of Wrocław*

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1 ORIGINAL PAPERS Adv Clin Exp Med 2008, 17, 3, ISSN X Copyright by Silesian Piasts University of Medicine in Wrocław RAFAŁ ILOW 1, BOŻENA REGULSKA ILOW 1, GRZEGORZ WALKIEWICZ 1, JADWIGA BIERNAT 1, ALICJA KOWALISKO 2 Evaluation of Bioflavonoid Intake in the Diets of 50 Year Old Inhabitants of Wrocław* Ocena pobrania bioflawonoidów z dietą w grupie 50 letnich mieszkańców Wrocławia 1 Department of Food Science and Dietetics, Silesian Piasts University of Medicine in Wrocław, Poland 2 Cardiovascular Disease Prevention Program organized by the Health Division of the Municipal Office, Wrocław, Poland Abstract Background. Epidemiological studies point to an inverse correlation between the dietary intake of bioflavonoids and the risk of cardiovascular disease. Bioflavonoids improve endothelial function and decrease blood pressure. Objectives. The aim of the study was to evaluate bioflavonoid intake the diets in a group of 50 year old inhabi tants of Wrocław, Poland. Material and Methods. The study group included 50 year old inhabitants of Wrocław who in 2005 participated in the Cardiovascular Disease Prevention Program organized by the Health Division of the Municipal Office in Wrocław. Altogether, 203 subjects were investigated, including 121 women and 82 men. Their bioflavonoid intake was evaluated by means of a food frequency questionnaire. Following preliminary standardization of the list of products included in the questionnaire, it finally contained questions about 20 vegetable products, 14 fruit prod ucts, wine, chocolate, and tea. Dietary content of bioflavonoid was assessed by means of database made available through the Internet in 2003 by the US Department of Agriculture. Results. The daily intake of bioflavonoids from fruits was mg in women and mg in men. The main source of fruit flavonoids was apples. Vegetables provided a daily intake of 4.64 mg of flavonoids in women and 4.38 mg in men. The subjects consumed on average 500 cm 3 of black tea daily, which provided mg/day of flavonoids. Fruit juices provided 0.59 mg of flavonoids in women and 2.74 mg in men. Total daily intake of flavonoids in the group of 50 year olds was mg for women and mg for men. The main sources of bioflavonoids in the diet of 50 year olds were tea, fruit, and vegetables. Tea provided 96% of all consumed bioflavonoids. Conclusions. Increased consumption of vegetables and fruit would increase the amount and variety of bioflavonoids in the diet of the investigated population (Adv Clin Exp Med 2008, 17, 3, ). Key words: bioflavonoids, intake, diet, 50 year olds. Streszczenie Wprowadzenie. Wyniki badań epidemiologicznych wskazują na odwrotną korelację między pobraniem bioflawo noidów z dietą a ryzykiem wystąpienia chorób układu krążenia. Bioflawonoidy wpływają na poprawę czynności śródbłonka, a także na obniżenie ciśnienia tętniczego krwi. Cel pracy. Ocena pobrania bioflawonoidów z dietą w grupie 50 letnich mieszkańców Wrocławia. Materiał i metody. Grupę badaną stanowili 50 letni mieszkańcy Wrocławia, uczestniczący w 2005 roku w Pro gramie Prewencji Chorób Naczyniowo Sercowych, który był zorganizowany przez Wydział Zdrowia Urzędu Miej skiego Wrocławia. Ogółem zbadano 203 osoby, w tym 121 kobiet i 82 mężczyzn. Do oceny pobrania bioflawonoi dów przez badanych wrocławian posłużono się metodą wywiadu żywieniowego częstotliwościowo ilościowego. Po wstępnych badaniach standaryzujących listę produktów w kwestionariuszu, ostatecznie w ankiecie znalazły się pytania dotyczące spożycia: 20 produktów warzywnych, 14 produktów owocowych, wina, czekolady oraz herbaty. * This study was performed as part of research project No. 2 P05F of the Ministry of Science and Higher Education.

2 328 R. ILOW et al. Do oceny zawartości flawonoidów w diecie posłużono się bazą danych udostępnioną w Internecie w 2003 roku przez Ministerstwo Rolnictwa Stanów Zjednoczonych. Wyniki. Dzienne pobranie bioflawonoidów z owoców wynosiło 15,62 mg w grupie kobiet i 15,02 mg w grupie mężczyzn. Głównym źródłem flawonoidów zawartych w owocach były jabłka. Warzywa dostarczały dziennie 4,64 mg flawonoidów w grupie kobiet i 4,38 mg w grupie mężczyzn. Badane osoby spożywały średnio 500 cm 3 /dzień czarnej herbaty, która dostarczała 588,3 mg/dzień flawonoidów. Soki owocowe dostarczały dzien nie 0,59 mg flawonoidów w grupie kobiet i 2,74 mg w grupie mężczyzn. Całkowite dzienne pobranie bioflawonoi dów w populacji 50 latków wynosiło 609,2 mg w grupie kobiet i 612,0 mg w grupie mężczyzn. Głównymi źródła mi bioflawonoidów w diecie 50 latków były: herbata, owoce i warzywa. Herbata dostarczała około 96% wszyst kich spożywanych bioflawonoidów. Wnioski. Wzrost spożycia warzyw i owoców spowodowałby zwiększenie ilości i różnorodności bioflawonoidów w diecie badanej populacji (Adv Clin Exp Med 2008, 17, 3, ). Słowa kluczowe: bioflawonoidy, pobranie, dieta, 50 latkowie. The findings of epidemiological studies point to an inverse correlation between the intake of bioflavonoids in the diet and the risk of cardiovas cular disease [1 5]. Bioflavonoids improve the function of the endothelium [6], decrease blood pressure [7], inhibit platelet aggregation, and pre vent thrombus formation [8]. Moreover, there is evidence of an antioxidative effect of flavonoids, which counteract the oxidative stress associated with civilization related diseases [2]. Epidemi ological studies [1 3, 9] demonstrate that the main dietary sources of flavonoids include vegetables, fruits, tea, wine, fruit and vegetable juices, and chocolate. Reports providing evidence of the car dioprotective effects of a diet containing products rich in cocoa and chocolate [7], vegetables and fruit [10 12], wine [13], and tea [14] have also been published. The dietary sources of flavonoids are different in different countries. According to Hertog [3], the main sources in Denmark and the Netherlands are tea, onions, and apples, in Finland onions and apples, in the USA onions and black tea, in Greece vegetables and fruit, and in Japan green tea. In Italy the main dietary sources of these compounds are red wine, vegetables, fruit, and soups. The aim of this study was to assess the dietary bioflavonoid intake in a population of 50 year old inhabitants of Wrocław, Poland. Material and Methods The study group consisted of 50 year old inhabitants of Wrocław who participated in the Cardiovascular Disease Prevention Program orga nized by the Health Division of the Municipal Office in Wrocław. Altogether, 5237 persons who were 50 years old in 2005 were invited to partici pate in the study; 2829 of them accepted the invi tation. Of this number, 203 subjects, including 121 women and 82 men, gave their consent to answer an extended dietary questionnaire. They were interviewed in medical centers by instructed nurs es. The interviews were collected in the second half of 2005 year. Mean height, body weight, and body mass index (BMI) in the women were cm, 67.6 kg, and 26.0 kg/m 2, respectively, and in men cm, 85.1 kg, and 27.5 kg/m 2. To evaluate the intake of flavonoids, the consumption of food products which are potential sources of bioflavonoids was assessed in the first stage of the study. The intake of vegetables, fruit, tea, wine, chocolate, as well as meals containing these foods was evaluated. The intake of vegetables and fruit was investigated by means of a food frequency questionnaire (FFQ). The list of food products which were potential sources of bioflavonoids included in the questionnaire was established on the basis of the present authors own studies [15, 16] as well as data from a pilot study. The participants were asked to evaluate their consumption of the following 20 vegetables: carrots, cauliflower, onions, garlic, peppers, tomatoes, raw cabbage, sauerkraut, cooked cabbage, beets, cucumber, corn, green beans, lettuce, radishes, mixed cooked vegetables, vegetable salad, vegetable soups, and vegetable and vegetable fruit juices. The questions also involved the consumption of 14 fruits: apples, bananas, pears, plums, oranges, tangerines, grape fruits, kiwis, peaches, lemons, strawberries, grapes, frozen fruits, and fruit juices. Then the par ticipants were asked about their consumption of red and white wine as well as milk chocolate and bitter chocolate. The questions concerned the con sumption of these food products during the three months prior to the survey. The participants were asked to determine the size of the food portion and frequency of con sumption. A mean portion size was proposed in the questionnaire (e.g. 1 medium cucumber, 1 glass of wine) and the size of the portion was determined on the basis of the Album of Photographs of Food Products and Dishes [17]. The participants could introduce changes and propose their known por tion size, both larger (e.g. a large cucumber, 2 glasses of wine) and smaller (e.g. half a cucum

3 Bioflavonoids in the Diets of 50 Year Olds 329 ber, half a glass of wine). The customary frequen cy of consumption of the particular product group was evaluated using four frequency categories: per day, per week, per month, and rarely or not at all. The first three categories were modifi able, i.e. the participant answering the question concerning the frequency of consumption could state that he/she consumes a given food product once a week, twice a week, three times a week, etc. To calculate the mean frequency, the above fre quencies were converted into mean consumption per day. The daily intake was calculated by taking into consideration the mean portion or modified portion size proposed by the participant. For example half a carrot eaten three times a week corresponded to 0.5 (mean portion) 0.43 (consumption frequency in a day) 80 g (mass of a mean portion for carrot [g]) = 17.2 g//day. Juices were divided into three categories in the food frequency questionnaire: fruit, vegetable, and fruit vegetable. The mass of consumed juice was determined on the basis of the food frequen cy interview. The structure of juice consumption was evaluated on the basis of data collected at the nutrition interview (one day dietary record), which was performed simultaneously with the food frequency questionnaire. The composition of vegetable salads was determined on the basis of the percentages of the individual vegetables of all the raw vegetables included in the FFQ. The amount and kind of consumed tea was determined on the basis of two closed questions. The first question concerned the daily consumption of tea. The participants could choose from nine possible volumes: 0.25, 0.50, 0.75, 1.0, 1.25, 1.5, or 2.0 liters, more than 2.0 liters, and I don t drink regularly. For calculating the daily intake of tea it was assumed that the answers more than 2 liters and I don t drink regularly correspond ed to 2.5 liters and 0 liters, respectively. The sec ond question concerned the kind of tea consumed. The participant could choose from the following answers: black, green, herbal+fruit, black+ +green, black+herbal+fruit, green+herbal+ +fruit, and black+green+herbal+fruit. When calculating the amount of consumed tea, the kinds of tea were aggregated. The dietary content of bioflavonoid was assessed using the U.S. Department of Agriculture Database for the Flavonoid Content of Selected Foods database made available on the Internet in 2003 by the US Department of Agriculture [18]. The database contains 225 food products in which the content of 26 flavonoids divided into five sub classes was determined. The following flavonoid subclasses were included: flavonols: (quercetin, kaempferol, myricetin, isorhamnetin), flavones: (luteolin, apigenin), flavanones: (hesperetin, narin genin, eriodictyol), flavan 3 ols: (catechin, gallo catechin, epicatechin, epigallocathechin, epicate chin 3 gallate, epigallocatechin 3 gallate, theaflavin, theaflavin 3 gallate, theaflavin 3 gal late, theaflavin 3,3 digallate, thearubigins), and anthocyanidins (cyanidin, delphinidin, malvidin, pelargonidin, peonidin, petunidin). The flavonoid content in the database has been converted into gly cosides, only flavan 3 oles being converted into aglycones. The content of the individual flavonoids was given in mg/100 g of the food product. The database contains data on the content of flavonoids in tea leaves and in 1% infusion. In the present study only the tea leaf infusion was used in the eval uation of the flavonoid content. Not all the vegeta bles and fruits which were included in the question naire were in the database with flavonoid content. Such cooked vegetables as cauliflower, cabbage, corn, beets, green beans, and mixed cooked vegeta bles were missing. Among fruits, the database did not include tangerines and frozen fruits. These foods were therefore not included in the evaluation of bioflavonoid intake. The amounts of vegetable and fruit products which were not evaluated were 11% and 1.6%, respectively, of the total mass of consumed vegetables and fruits. The flavonoid content in vegetable salads was calculated as the sum of the flavonoid contents in the individual raw vegetables which were ingredi ents of the salad, taking into account their per centages. In the group of fruit juices the flavonoid content was evaluated only in orange, apple, grapefruit, and grape juices. These juices consti tuted 83.7% of the total consumption of juices. The flavonoid content of vegetable juices was not determined because the mean consumption medi ans for this type of juice were 0.0. Moreover, the flavonoid content of vegetable fruit juices was not evaluated due to a lack of data in the database on the flavonoid content of carrot juice, which is the main ingredient in all the consumed veg etable fruit juices. The flavonoid content in white and red wines as well as in bitter and milk choco late was evaluated on the basis of the American database. Data analysis was performed using the Microsoft FoxPro 2.6 WIN relational database and Microsoft Excel 2003 spreadsheet. Statistical analysis of the findings was performed using STATISTICA 6.0 PL software manufactured by StatSoft Inc. USA. Comparison between groups was assessed by the non parametric U Mann Whitney test. The level of statistical significance was determined at p < 0.05.

4 330 Results The analysis of vegetables and fruit consump tion among 50 year old inhabitants of Wrocław revealed high values of the standard deviation for individual sources of daily intake. The means dif fered significantly from the medians. This evi dences a lack of normality of the distribution of the variables representing the daily consumption of these foods. Thus the median was considered to better represent the average consumption, as it is not affected by extreme amounts. The flavonoid intake was evaluated using medians and sums of medians. Apples constituted about 80% of all consumed fruits for both women and men. Other fruits con sumed in higher amounts by the participants were bananas (7.5 g/day), oranges (5.0 g/day), and grapes (women: 14.7 g/day, men: 4.4 g/day). No statistically significant differences were observed between women and men in the consumption of fruit. The total daily consumption of fruit, present ed as the sum of the medians, was g in women and g in men. As for vegetables, both women and men most commonly consumed tomatoes, which constituted over 50% of all vegetables. Onion, peppers, and vegetable salads also had significant participation in vegetable consumption. The consumption of sauerkraut was statistically significantly higher in men than in women (p = ). On the other hand, women ate vegetable salads more often than men, and this difference was statistically signifi R. ILOW et al. cant (p = ). Total daily consumption of veg etables in the form of the sum of the medians was g in women and g in men. The evalu ation of the consumption of juices revealed that fruit juices were drunk most commonly. The 50 year old inhabitants of Wrocław most commonly drink apple juice, which constitutes 36.6% of all the consumed fruit juices. Tables 1 and 2 demonstrate the intake of flavonoids in the fruit consumed by the 50 year olds. The daily flavonoid intake in fruit was mg in women and mg in men. Among the fruits, the main sources of flavonoids were apples and grapes. About 68% of the flavonoids present in these foods were flavan 3 oles. Tables 3 and 4 demonstrate the flavonoid content in vegeta bles in the group of 50 year old inhabitants of Wrocław. Vegetables were the source of 4.64 mg of flavonoids daily in women and 4.38 mg in men. Onion, tomatoes, vegetable salads, lettuce, and peppers constituted the main sources of vegetable flavonoids, 98% of them being flavonols. Vegetables provided the participants with over three times less flavonoid than fruit and, in contrast to fruit, they were the main source of flavonols and flavones, but they did not contain flavan 3 ols. Tables 5 7 present the mean consumption of tea, fruit juices, and chocolate expressed as medi ans and the mean intake of flavonoids with these products. The participants consumed 500 cm 3 of black tea daily (Table 5); however, they did not drink green tea. Black tea was the source of mg of flavonoids per day, of which Table 1. Flavonoid intake in fruit by 50 year old women Tabela 1. Spożycie flawonoidów z owocami przez 50 letnie kobiety Fruit Intake Content [mg/day] (Owoce) g/day (Zawartość) median (Spożycie) Apple (Jabłko) Banana (Banan) Pear (Gruszka) Plum (Śliwka) Orange (Pomarańcza) Grapefruit (Grejpfruit) Kiwi (Kiwi) Peach (Brzoskwinia) Strawberry (Truskawka) Grape (Winogrona) Tangerine (Mandarynka) Frozen fruits (Owoce mrożone) Total (Suma)

5 Bioflavonoids in the Diets of 50 Year Olds 331 Table 2. Flavonoid intake in fruit by 50 year old men Tabela 2. Spożycie flawonoidów z owocami przez 50 letnich mężczyzn Fruit Intake Content [mg/day] (Owoce) g/day (Zawartość) median (Spożycie) Apple (Jabłko) Banana (Banan) Pear (Gruszka) Plum (Śliwka) Orange (Pomarańcza) Grapefruit (Grejpfruit) Kiwi (Kiwi) Peach (Brzoskwinia) Strawberry (Truskawka) Grape (Winogrona) Tangerine (Mandarynka) Frozen fruits (Owoce mrożone) Total (Suma) Table 3. Flavonoid intake in vegetables by 50 year old women Tabela 3. Spożycie flawonoidów z warzywami przez 50 letnie kobiety Vegetables Intake Content [mg/day] (Warzywa) g/day (Zawartość) median (Spożycie) Carrot (Marchew) Onion (Cebula) Pepper (Papryka) Tomato (Pomidor) Raw cabbage (Kapusta surowa) Sauerkraut (Kapusta kiszona) Cucumber (Ogórek) Lettuce (Sałata) Radish (Rzodkiewka) Vegetable salad (Surówki warzywne) Garlic (Czosnek) Cauliflower (Kalafior) Cooked cabbage (Kapusta gotowana) Beet (Burak) Corn (Kukurydza) Green beans (Fasola szparagowa) Mixed cooked vegetables (Sałatki jarzynowe) Total (Suma)

6 332 R. ILOW et al. Table 4. Flavonoid intake in vegetables by 50 year old men Tabela 4. Spożycie flawonoidów z warzywami przez 50 letnich mężczyn Vegetables Intake Content [mg/day] (Warzywa) g/day (Zawartość) median (Spożycie) Carrot (Marchew) Onion (Cebula) Pepper (Papryka) Tomato (Pomidor) Raw cabbage (Kapusta surowa) Sauerkraut (Kapusta kiszona) Cucumber (Ogórek) Lettuce (Sałata) Radish (Rzodkiewka) Vegetable salad (Surówki warzywne) Garlic (Czosnek) Cauliflower (Kalafior) Cooked cabbage (Kapusta gotowana) Beet (Burak) Corn (Kukurydza) Green beans (Fasola szparagowa) Mixed cooked vegetables (Sałatki jarzynowe) Total (Suma) Table 5. Flavonoid intake in tea in the investigated group of 50 year olds Tabela 5. Spożycie flawonoidów z herbatą w grupie badanych 50 latków Gender Tea kind Intake Content [mg/day] (Płeć) (Rodzaj g/day (Zawartość) herbaty) median (Spożycie) Women (F) black tea (Kobiety) Men (M) black tea (Mężczyźni) F + M black tea (Kobiety + mężczyźni) mg were flavan 3 ols and 19.3 mg flavonols. The flavonoid intake in tea was the same in women as in men. Tea flavonoids consti tuted about 96% of all the consumed flavonoids in the group of 50 year old inhabitants of Wrocław. Table 6 illustrates the intake of flavonoids in fruit juices. Fruit juices were the source of 0.59 mg of flavonoids daily in women and 2.74 mg in men (women drank 5 times less fruit juices than men). Fruit juices were sources of flavanones and flavonols. The medians of the daily consumption of milk chocolate were 0, both in women and in men. The consumption of bitter chocolate expressed as a median was 0 in women and 3 g/day in men (Table 7). Bitter chocolate was the source of

7 Bioflavonoids in the Diets of 50 Year Olds 333 Table 6. Flavonoid intake in fruit juice in the investigated group of 50 year olds Tabela 6. Spożycie flawonoidów z sokami owocowymi w grupie badanych 50 latków Gender Fruit juices Content [mg/day] (Płeć) intake g/day (Zawartość) median (Spożycie soków owo cowych) Women (F) (Kobiety) Men (M) (Mężczyźni) F + M (Kobiety + mężczyźni) Table 7. Flavonoid intake in chocolate in the investigated group of 50 year olds Tabela 7. Spożycie flawonoidów z czekoladą w grupie badanych 50 latków Gender Kind of Intake Content [mg/day] (Płeć) chocolate g/day (Zawartość) (Rodzaj median czekolady) (Spożycie) Women (F) bitter (Kobiety) chocolate Men (M) bitter (Mężczyźni) chocolate F + M bitter (Kobiety chocolate + mężczyźni) 1.6 mg of flavan 3 ols daily. The median of flavonoid intake in chocolate was 0.8 mg/day in the investigated group (men and women). The par ticipants did not report consumption of wine (mean consumption expressed as the median was 0). Wine was not a significant source of flavonoids. Table 8 presents the total dietary intake of flavonoids in the investigated group of inhabitants of Wrocław. Total daily intake of flavonoids was mg in women and mg in men. The main sources of flavonoids in the diets of the 50 year olds were tea, fruit, and vegetables. Discussion The consumption of fruits and vegetables in the group of 50 year old inhabitants of Wrocław did not follow WHO and EU recommendations, as it was lower than 400 g of fruits and vegetables daily [19]. Low intake of fruits and vegetables may result in an increased risk of civilization related diseases in the investigated population. In EU countries in which the this morbidity is lower, the consumption of fruits and vegetables is at least two times higher. For instance in Greece it is 511 g/day and in Italy 480 g/day [20]. Lower con sumption of fruits and vegetables was reported in Ireland (208 g/day) and Great Britain (215 g/day) [20]. The Program Fruits and Vegetables Five Times Daily initiated by the Health Promotion Foundation in 1996 [21] aims at changing the dietary habits in Poland and increasing the con sumption of fruits and vegetables to five and more portions a day. The intake of flavonoids in the present study was several times higher than in other epidemio logical reports discussed in the review by Beecher [22]. The flavonoid intake with food was estimat ed at 20 mg/day in the USA, Denmark, and Finland and over 70 mg/day in the Netherlands.

8 334 R. ILOW et al. Table 8. Evaluation of total bioflavonoid intake in the diet in the investigated group of 50 year olds mg/day Tabela 8. Całkowite dzienne oszacowane spożycie flawonoidów z podziałem na podklasy w grupie 50 latków mg/dzień Food products Flavonoid subclasses F M F + M (Produkty spożywcze) (Podklasy flawonoidów) Fruit flavones (Owoce) flavonols flavanones flavan 3 ols flavonoids total Vegetables flavones (Warzywa) flavonols flavanones flavan 3 ols flavonoids total Tea flavones (Herbata) flavonols flavanones flavan 3 ols flavonoids total Fruit juices flavones (Soki owocowe) flavonols flavanones flavan 3 ols flavonoids total Chocolate flavones (Czekolada) flavonols flavanones flavan 3 ols flavonoids total All products flavonoids total (Wszystkie produkty) F women, M men. F kobiety, M mężczyźni. However, these investigations involved the intake of selected compounds, not the total flavonoid intake. They also did not include such a large vari ety of products or flavan 3 ols as in the present study. No complex studies on total flavonoid con tent in the diet could be found in the world litera ture. In a prospective study of American women, Sesso et al. [23] did not observe any effect of flavonoid intake on a reduction of mortality due to cardiovascular disease. In a commentary on this report published in the American Journal of Clinical Nutrition, Donovan [24] stated that the investigation involved only the effect of two out of five major dietary flavonoid subclasses on cardio vascular mortality. The evaluation involved the effect of flavonols and flavones but did not include flavan 3 ols (catechins), which occur in large amounts in tea and apples, and for this reason the conclusions drawn by Sesso [23] may be incom plete. Donovan [24] also remarked that the use of the term total flavonoid in publications which do not involve the five major flavonoid subclasses may be misleading. She also stated that the west ern diet provides about 650 mg/day flavonoids, and the mean intake in the study by Sesso [23] was only 25 mg/day and represented only a small part of the total flavonoid intake. Some studies report the consumption of spe cific flavonoid subclasses or several flavonoid compounds [25, 26] or the flavonoid content in a given food product [27, 28]. Total flavonoid intake is estimated at mg/day in the world literature [29]. Hollman and Katan [30] esti mated flavonoid intake converted into aglycones at several hundred milligrams daily. Kuhnau [31], in a 1976 study, estimated that the mean dietary flavonoid intake in the USA was g/day (con verted into glycosides) and 650 mg/day (converted into aglycones). Zduńczyk [32] reported a mean daily intake of flavonoids in the diet amounting to 320 mg.

9 Bioflavonoids in the Diets of 50 Year Olds 335 In the present study over 96% of all flavonoids was provided in tea. This is consistent with the evaluation that tea is the source of almost 90% of all dietary flavonoids in an American diet [14]. The relatively high intake of flavonoids in the investigated population of 50 year old inhabitants of Wrocław resulted from a high consumption of black tea (daily consumption of tea expressed as the median was 500 cm 3 /day). Bitter chocolate is one of the most abundant sources of flavonoids. However the consumption of bitter chocolate in the investigated group was low and did not have any major effect on the total supply of flavonoids in the diet. The high flavonoid content in tea was also confirmed in a Polish study [33]. In this study the content of polyphenols (including flavonoids) in black tea was from to mg/250 cm 3. The amounts were lower than in the American database [18]. This is probably due to the fact that in the Polish study the polyphenol concentration was evaluated by high performance liquid chro matography (HPLC), which did not detect thearu bigins. These compounds, according to the American database, constituted 62% of all the flavonoids contained in brewed black tea. In summary, it should be stressed that the diet of the investigated population contained fairly high amounts of flavonoids. The high flavonoid content in tea compensated for the low supply of flavonoids in fruits and vegetables, which were consumed in inadequate amounts. Dietary flavonoids may significantly decrease the risk of civilization related diseases. The authors concluded that the investigated population revealed a too low consumption of fruits and vegetables in comparison with the rec ommended amounts. Increased consumption of these food products would increase the amount and variety of dietary bioflavonoids. Thus the implementation of prophylactic programs aimed at promoting a healthy lifestyle and widespread edu cation in healthy nutrition is highly justified and necessary. References [1] Sampson L, Rimm E, Hollman PCH, de Vries JHM, Katan MB: Flavonol and flavone intakes in US health professionals. J Am Diet Assoc 2002, 102, [2] Hertog MGL, Feskens EJM, Hollman PCH, Katan MB, Kromhout D: Dietary antioxidant flavonoids and risk of coronary heart disease: The Zutphen Elderly Study. Lancet 1993, 342, [3] Hertog MG, Kromhout D, Aravanis C, Blackburn H, Buzina R, Fidanza F, Giampaoli S, Jansen A, Menotti A, Nedeljkovic S et al.: Flavonoid intake and long term risk of coronary heart disease and cancer in the Seven Countries Study. Arch Intern Med 1995, 155, [4] Keli SO, Hertog MGL, Feskens EJM, Kromhout D: Dietary flavonoids, antioxidant vitamins and incidence of stroke: the Zutphen Study. Arch Intern Med 1996, 156, [5] He FJ, Nowson CA, MacGregor GA: Fruit and vegetable consumption and stroke: meta analysis of cohort stud ies. Lancet 2006, 367, [6] Duffy SJ, Keaney JFjr, Holbrook M, Gokce N, Swerdloff PL, Frei B, Vita JA: Short and long term black tea consumption reverses endothelial dysfunction in patients with coronary artery disease. Circulation 2001, 104, [7] Engler MB, Engler MM: The vasculoprotective effects of flavonoid rich cocoa and chocolate. Nutr Res 2004, 24, [8] Bawa S: Rola bioflawonoidów w zapobieganiu chorób cywilizacyjnych. In: Wybrane problemy nauki o żywieniu człowieka u progu XXI wieku. Eds.: Brzozowska A, Gutkowska K, Wydawnictwo SGGW, Warsaw [9] Erlund I: Review of the flavonoids quercetin, hesperetin, and naringenin. Dietary sources, bioactivities, bioavail ability, and epidemiology. Nutr Res 2004, 24, [10] Bazzano LA, He J, Ogden LG, Loria CM, Vupputuri S, Myers L, Whelton PK: Fruit and vegetable intake and risk of cardiovascular disease in US adults: the first National Health and Nutrition Examination Survey Epidemiologic Follow up Study. Am J Clin Nutr 2002, 76, [11] Ness AR, Powles JW: Fruit and vegetables and cardiovascular disease: a review. Int J Epidemiol 1997, 26, [12] Joshipura KJ, Ascherio A, Manson JE, Stampfer MJ, Rimm EB, Speizer FE, Hennekens CH, Spiegelman D, Willett WC: Fruit and vegetable intake in relation to risk of ischemic stroke. JAMA 1999, 282, [13] Renaud S, de Lorgeril M: Wine, alcohol, platelets and the French paradox for coronary heart disease. Lancet 1992, 339, [14] Kris Etherton PM, Keen CL: Evidence that the antioxidant flavonoids in tea and cocoa are beneficial for car diovascular health. Curr Opin Lipidol 2002, 13, [15] Ilow R, Regulska Ilow B, Szarzała Kruk D, Biernat J: Ocena spożycia owoców i warzyw w populacji liceal istów z Oleśnicy. Bromat Chem Toksykol 2006, supplement: [16] Ilow R, Płonka K, Regulska Ilow B, Biernat J: Assessment of fruit and vegetable intake among the population of junior high school students from Oleśnica. Roczn PZH 2006, 58, [17] Szponar L, Wolnicka K, Rychlik E: Album fotografii produktów i potraw. Wydawnictwo IŻŻ, Prace IŻŻ 96, Warszawa 2000.

10 336 R. ILOW et al. [18] USDA Database for the Flavonoid Content of Selected Foods. Nutrient Data Laboratory, Food Composition Laboratory. Beltsville Human Nutr Res Center, Agricultural Research Service, U.S. Department of Agriculture Accessed 4 February [19] Promoting Heart Health. A European Consensus. Prepared by the Irish Presidency for Meeting in Cork, Ireland, February 24 th to 26 th Accessed 4 February [20] Joffe M, Robertson A: The potential contribution of increased vegetable and fruit consumption to health gain in the European Union. Public Health Nutr 2001, 4, [21] Fundacja Promocja Zdrowia: 5 razy dziennie warzywa i owoce. /5wio/5wio_xt.html. Accessed 4 February [22] Beecher GR: Overview of dietary flavonoids: Nomenclature, occurrence and intake. J Nutr 2003, 133, 3248S 3254S. [23] Sesso HD, Gaziano JM, Liu S, Buring JE: Flavonoid intake and the risk of cardiovascular disease in women. Am J Clin Nutr 2003, 77, [24] Donovan JL: Flavonoid and the risk of cardiovascular disease in women. Am J Clin Nutr 2004, 79, [25] Arts ICW, Hollman PCH, Feskens EJM, Bueno de Mesquita HB, Kromhout D: Catechin intake and associ ated dietary and lifestyle factors in a representative sample of Dutch men and women. Eur J Clin Nutr 2001, 55, [26] Lagiou P, Samoli E, Lagiou A, Tzonou A, Kalandidi A, Peterson J, Dwyer J, Trichopoulos D: Intake of spe cific flavonoid classes and coronary heart disease a case control study in Greece. Eur J Clin Nutr 2004, 58, [27] Arts ICW, Hollman PCH, Kromhout D: Chocolate as a source of tea flavonoids. Lancet 1999, 354, 488. [28] Ariefdjohan MW, Savaiano DA: Chocolate and Cardiovascular Health: Is It Too Good To Be True? Nutr Rev 2005, 63, [29] Peterson J, Dwyer J: Flavonoids: Dietary Occurrence And Biochemical Activity. Nutr Res 1998, 18, [30] Hollman PCH, Katan MB: Dietary Flavonoids: Intake, Health Effects and Bioavailability. Food Chem Toxicol 1999, 37, [31] Kuhnau J: The flavonoids: a class of semi essential food components: their role in human nutrition. World Rev Nutr Diet 1976, 24, [32] Zduńczyk Z: Znaczenie biologiczne aktywnych nieodżywczych składników diet w zapobieganiu chorobom cywilizacyjnym. Żywność 1999, 4, Supl. 21, [33] Lenort A: Ocena zawartości naturalnych związków polifenolowych w różnych rodzajach herbat z zastosowaniem metody HPLC. Praca magisterska, AM, Wrocław Address for correspondence: Rafał Ilow Department of Food Science and Dietetics Silesian Piasts University of Medicine Nankiera Wrocław Poland Tel.: E mail: ilow@bromat.am.wroc.pl Conflict of interest: None declared Received: Revised: Accepted: