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History and characteristics of Okinawan longevity food.

Okinawan food culture in the Ryukyu island is one of the world's most interesting culture because its consumers have the longest life expectancies and low disability rates. It is a product of cultural synthesis, with a core of Chinese food culture, inputs through food trade with South-East Asia and the Pacific and strong Japanese influences in eating style and presentation. The Satsamu sweet potato provides the largest part of the energy intake (and contributes to self-sufficiency), there is a wide array of plant foods including seaweed (especially konbu) and soy, and of herbaceous plants, accompanied by fish and pork, and by green tea and kohencha tea. Infusing multiple foodstuff and drinking the broth is characteristic. Raw sugar is eaten. The concept that 'food is medicine' and a high regard accorded medical practice are also intrinsic of Okinawan culture. Again, food-centered and ancestral festivities keeep the health dimensions well-developed. Pork, konbu and tofu (soy bean-curd) are indispensable ingredients in festival menus, and the combination of tofu and seaweed are used everyday. Okinawan food culture is intimately linked with an enduring belief of the system and highly developed social structure and network.

Diet↗

Iron intake and iron status of preschool children: associations with breakfast cereals, vitamin C and meat.

OBJECTIVE: To examine associations between breakfast cereal consumption and iron status and identify dietary patterns that might improve iron status in this vulnerable group. DESIGN: Analysis of data from the UK National Diet and Nutrition Survey (NDNS) of children aged 1.5-4.5 years, including dietary intakes calculated from 4-day weighed records. SUBJECTS: Data were used from 904 children with haematological measurements, excluding those taking iron supplements; 20% had low iron stores (ferritin < 10 microgl-1) while 8% were anaemic (Hb < 11 g dl-1). RESULTS: High cereal consumers had significantly higher iron intakes than low cereal consumers (classified by tertiles) but the 10% difference in mean ferritin levels was not significant (P= 0.067). Lower intakes of vitamin C and meat among high consumers of cereal may have diluted the impact of cereal iron on iron status. When children were reclassified according to their intakes of vitamin C and iron from meat and breakfast cereals, the group with high (above median) intakes of two or more factors had a higher mean haemoglobin (Hb) level and a lower prevalence of anaemia compared with the group with low (below median) intakes of all three dietary constituents. CONCLUSIONS: Nutritional advice that aims to improve iron status should emphasize not only rich sources of iron but also factors that may enhance or inhibit absorption. Strategies to optimize iron status in this vulnerable age group include consuming an iron-fortified breakfast cereal, vitamin C-rich fruit or drink at breakfast, and avoiding tea with (or after) meals.

Anemia, Iron-Deficiency↗

Coffee and methylxanthines and breast cancer: a case-control study.

A dietary case-control study based on 818 newly diagnosed breast cancer (BC) patients was conducted in Israel between 1975 and 1978. The role of coffee and total methylxanthine intake from coffee, tea, cola, chocolate, and cocoa drinks was evaluated in the BC patients as compared to that in two matched control populations [surgical controls (SC) and neighborhood controls (NC)]. Because it has been suggested that caffeine enhances mammary carcinogenesis in rats fed high polyunsaturated fat diets, analysis was done also in relation to fat consumption. When comparison was done to both matched control groups, a nonsignificant negative association was found between consumption of cups of coffee and BC (odds ratios of greater than or equal to 4 cups of coffee/day vs. less than or equal to 1 per week = 0.6 for BC/NC and 0.7 for BC/SC). This association was observed in all 3 ethnic subgroups studied. The pattern was stronger among the high-fat consumers after controlling for several hormonal confounding factors (two-tailed P-value for linear trend = 0.06 for SC and P = 0.05 for NC). In addition, when the consumption of methylxanthine of BC patients was compared to that of benign breast patients, adjusted by age and ethnic group, a diminished risk was found (odds ratio for BC of the highest level of methylxanthine vs. lowest level = 0.59).

Adult↗

The fading links between tradition and oral health in Singapore.

Singapore is an island republic of 616 km2. Four main ethnic groups make up its population of 2.4 million; these are the Chinese, Malays, Indians and others. Singapore's successful housing, industrialization and modernization programmes have caused tremendous changes in the lifestyles and expectations of the people. This very success has rendered some traditional customs impractical and irrelevant. Older Indians and Malay women still chew betel-nut. During the Hindu Thaipusam ceremony a traditional practice of dental interest is the piercing of devotees' cheeks and tongues with slivers of silver. There is no pain, bleeding or permanent tissue damage. The Chinese pick their teeth, crack melon seeds and scrape their tongues every morning. They also drink large quantities of unsweetened tea. Yet they remain caries-prone. Singaporeans have recently adopted the practice of eating at all hours of the day and night. This may have a bearing on their future caries state. Singapore has two categories of dental practitioner: the graduate and the registered but unqualified dentist who is invariably of Chinese descent. The swaged metal crown over sound and diseased tooth structure is frequently the unfortunate trademark of the latter. Often abscesses and cysts develop beneath these crowns. Successful dental health programmes have produced a DMFT of 2.8 in 12-year-old children, which betters the DMF target of 3.0 set by WHO for the year 2000. The progressive outlook of Singaporeans may eventually reduce further the number of traditional practices which are harmful to oral health.

Adolescent↗

[Changes in eating habits and disease symptoms in the 16th and 17th centuries].

The Renaissance period in Europe saw many dietary changes due to imports of new ingredients from the Far East as well as from newly discovered Central and South America. Maize and potatoes rapidly conquered European markets and because of their easier cultivation and higher calorie content, displaced grains such as wheat and rye. Drinking habits too changed, when tea, coffee and chocolate were introduced, first as strengthening medicines, later as 'delicatessen' in the aristocratic British and French cafés. These new foods and beverages may have helped diminish the periods of famine typical of Medieval and Early Renaissance times. In the 16th and 17th century, new diseases were described that were directly related to dietary intake. Ergotism and scurvy, particularly, sometimes decimated whole populations in rural areas or at sea. It was not until the 18th century that scientific research elucidated the cause of such diseases and helped us to understand the importance of a balanced diet.

Beverages↗

[Effects of tea on DMBA-induced oral carcinogenesis in hamsters].

The preventive effects of green tea, tea pigments and mixed tea (a composite of whole water extract from green tea, tea polyphenols, and tea pigments) on 7, 12-dimethylbenz(a) anthracene(DMBA)-induced oral carcinogenesis in golden Syrian hamsters were studied. The hamsters were divided into five groups. i.e. the positive control group(the right buccal pouches of animal was topically treated with 0.5% DMBA in acetone three times per week for 15 weeks), three tea treated groups(1.5% green tea, 0.1% tea pigments and 0.5% mixed tea as the sole source of drinking water from two weeks before starting the DMBA treatment to the end of the experiment) and the negative control group(acetone applied topically). The results showed that in the 1.5% green tea, 0.1% tea pigments and 0.5% mixed tea groups, the inhibitory rates of the average number of tumor per hamster were 42.6%, 50.8% and 67.2% respectively, and the mean tumor burdens were 79% 89% and 95% respectively, compared with the positive control group. In the three tea groups, the frequency of micronucleated cells, the number of silver-stained nucleolar organizer regions (AgNOR), labeling index of proliferating cell nuclear antigen(PCNA) and the level of epidermal growth factor receptor(EGFR) expression in the oral mucosa cells were also less than those in the positive control group. These results clearly indicated that the mixed tea could effectively inhibit DMBA-induced oral carcinogenesis in hamsters. The mixed tea was more effective than green tea or tea pigments in this animal model. Protection of DNA from damage by carcinogen and suppression of cell proliferation was considered as important mechanisms of the anticarcinogenic effects of the mixed tea preparations.

9,10-Dimethyl-1,2-benzanthracene↗

Estimation of minerals and trace elements provided by beverages for the adult in France.

The total average amount of beverages absorbed daily (1,378 ml) is split up as follows: tap water (650 ml where from 170 ml are used for the preparation of coffee and tea); bottled water (190 ml); alcoholic drinks (481 ml) and soft drinks (57 ml). Under these conditions, the intake is estimated at (mg/day): Na: 50, K: 450, P: 83, Ca: 141, Mg: 54, Fe: 2.9, Zn: 0.64, Cu: 0.46, Mn: 0.40, F: 0.64, I: 0.09, Cr: 0.013, Se: 0.031. The most significant supplies for both quantity and quality are those of calcium (18% of the needs), iron (29%), copper (19%), fluorine (24%) and magnesium (16%) for the adult. Alcoholic drinks represent 35% of the daily intake of beverages; they are likewise the main source of minerals such as: iodine and iron (wine), selenium (beer), fluorine, calcium and copper (in all alcoholic drinks). Calcium and fluorine are the main minerals provided by the different types of water. We have shown the influence of the geographical origin of the tap water on the Ca and F intake, as well as the influence of individual behaviour with respect to the selection of his main drink.

Alcoholic Beverages↗

Stimulation of rat hepatic UDP-glucuronosyl transferase activity following treatment with green tea.

Studies were conducted to investigate whether aqueous extracts of green tea, administered to rats at concentrations consumed by humans, could influence the phase II conjugation reactions in the liver, and so contribute to its established anticarcinogenic activity. Exposure of rats to green tea (2.5%, w/v), as the sole drinking fluid, for 4 wk did not influence sulfotransferase, epoxide hydrolase nor glutathione S-transferase activities. UDP glucuronosyl transferase activity, when determined using 2-aminophenol as the substrate, was increased by 100% following treatment with tea. Finally, green tea had no effect on the enzymes affording protection against reactive oxygen species, namely catalase, glutathione peroxidase and superoxide dismutase. It is postulated that the enhanced glucuronidation may contribute to the anticarcinogenic effect of green tea by facilitating the metabolism of chemical carcinogens into inactive, readily excretable products.

Aminophenols↗

Prognostic significance of selected lifestyle factors in urinary bladder cancer.

To examine the prognostic significance of lifestyle factors in urinary bladder cancer, we conducted a follow-up study of 258 incident bladder cancer patients, who were originally recruited in a case-control study in metropolitan Nagoya. Information on individual survivals was obtained from the computer data-file of the tumor registry of the Nagoya Bladder Cancer Research Group. Univariate analyses revealed significant associations of 5-year survivorship with educational attainment, marital status, drinking habits and consumption of green tea in males, and age at first consultation, histological type and grade of tumor, stage and distant metastasis in both sexes. After adjustment for age, stage, histology (histological type and grade) and distant metastasis by means of a proportional hazards model, drinking of alcoholic beverages was significantly associated with the prognosis of bladder cancer in males. Its adjusted hazard ratio was 0.46 (95% confidence interval: 0.26-0.79), favoring patients who had taken alcoholic beverages. In detailed analysis, ex-drinkers and all levels of current drinkers demonstrated hazard ratios smaller than unity, although no clear dose-response relationship was detected. No prognostic significance was found for such lifestyle factors as smoking habit, uses of artificial sweeteners and hairdye, and consumption of coffee, black tea, matcha (powdered green tea) and cola.

Adult↗

Inhibition of N-nitrosomethylbenzylamine-induced esophageal tumorigenesis in rats by green and black tea.

In this study, we investigated the effects of green tea and black tea, when given either during or after carcinogen treatment, on esophageal tumorigenesis in male Sprague-Dawley rats. Rats were treated with N-nitrosomethylbenzylamine (NMBzA) (2.5 mg/kg, s.c., twice weekly) for 5 weeks; 39 weeks after the initial dose of NMBzA, 65% of the rats had esophageal tumors with an average of 1.4 +/- 0.3 tumors per rat. In the groups of rats receiving 0.6% of decaffeinated green tea (DGT) or decaffeinated black tea (DBT) (6 mg tea solids/ml) as the sole source of drinking fluid during the NMBzA-treatment period, esophageal tumor incidence and multiplicity were reduced by approximately 70%. When the tea preparations were given after the NMBzA treatment period, the esophageal papilloma incidence and multiplicity were reduced by approximately 50%. The volume per tumor was much smaller in rats that received black tea after the carcinogen treatment period. In a second experiment, NMBzA was given to rats at a dose of 3.5 mg/kg (s.c., twice weekly) for 5 weeks; after 16 weeks, the tumor incidence was 82% and tumor multiplicity was 6.7 +/- 1.2 tumors per rat. In the groups of rats receiving 0.9% regular green tea (RGT) or DGT after the NMBzA treatment period, tumor multiplicity was decreased by > 55%. The volume per tumor was reduced by approximately 60% in the rats receiving 0.9% RGT. Histological analysis indicated that both the incidence and multiplicity of esophageal carcinoma was decreased by either RGT or DGT. The blood and urine levels of green tea polyphenols due to tea administration were determined in rats, and the levels were comparable to those in humans after tea ingestion. The above results indicate that both green tea and black tea can inhibit the tumorigenic action of NMBzA during the period of carcinogen treatment and the subsequent molecular events important for esophageal tumorigenesis.

Animals↗

The relation between single/double or repeated tea catechin ingestions and plasma antioxidant activity in humans.

OBJECTIVE: The purpose of this study was to investigate the effects of single/double or repeated intake of a normal amount of tea catechin on plasma catechin concentrations and antioxidant activity in young women. DESIGN: First, after an overnight fast, five healthy subjects were given water or single/double dose(s) of tea polyphenol extract (164 mg tea catechins containing 61% epigallocatechin gallate in 190 ml water). Blood samples were taken before and 30, 60 and 180 min after the ingestion. Second, 16 healthy subjects ingested the tea polyphenol extract three times a day at mealtimes for 7 days followed by withdrawal of tea polyphenol extract for 7 days. Blood samples were taken before and after ingestion, and 7 days after the withdrawal of tea catechin. Subjects were prohibited from drinking any beverages containing polyphenols or antioxidant supplements during the study period. Catechin and other antioxidant concentrations in the plasma were measured, and changes in antioxidant activity were evaluated by ferric reducing ability of plasma assay. RESULTS: Single/double ingestion of tea polyphenol extract did not cause an increase in the antioxidant activity. There was no also change in antioxidant activity after the ingestion of tea polyphenol extract for 7 days. Plasma-free epigallocatechin gallate concentration remained at the pre-study level; however, the plasma FRAP value decreased significantly at 7 days after the withdrawal of tea polyphenol extract. Decreases in endogenous antioxidants in the plasma, including vitamin C and bilirubin, were also observed 7 days after withdrawal of tea polyphenol. CONCLUSIONS: The results suggest that continuous daily intake of tea catechins affects the concentrations of endogenous antioxidants in the plasma and has the potential to maintain total antioxidant activity.

Adult↗

Mutagens in coffee and tea.

Coffee prepared in the usual way for drinking contains a substance(s) that is mutagenic to Salmonella typhimurium TA100 without mammalian microsomal enzymes. One cup of coffee (200 ml) contains mutagen(s) inducing 1.4-4.6 X 10(5) revertants under standard conditions. Instant coffee too is mutagenic to TA100 and one cup of instant coffee prepared from 1 g of coffee powder and 200 ml of water induced 5.6-5.8 X 10(4) revertants of TA100. Caffeine-free instant coffee also has similar mutagenicity. Addition of microsomal enzymes abolished the mutagenicity. Black tea, green tea and Japanese roasted tea were also mutagenic to TA100 without S9 mix and one cup of these teas prepared in the ordinary way produced 1.7-3.8 X 10(4) revertants of TA100. Black tea and green tea were also mutagenic to TA98 in the presence of S9 mix after treatment with a glycosidase from Aspergillus niger, hesperidinase. This type of mutagen in one cup of black tea induced 2.4 X 10(5) revertants of TA98.

Coffee↗

Bioactivity of well-defined green tea extracts in multicellular tumor spheroids.

The effect of green tea extracts (GTE) of a reproducible, well-defined composition on cellular viability, proliferation, and antioxidant defense was investigated in multicellular spheroids derived from WiDr human colon adenocarcinoma cells. The maximum GTE concentration investigated, i.e. 100 micro g GTE/ml, was equivalent to the plasma concentration commonly measured in humans drinking 6-10 cups of green tea per day. This GTE concentration lead to a substantial retardation of spheroid volume growth with diameters reaching only half the size of untreated aggregates. Flow cytometric analysis and immunocytochemistry showed an enhanced accumulation of cells in G2/M and in the non-proliferating compartment, respectively. The emergence of central necrosis occurred at larger spheroid diameters compared to control conditions leading to a significant increase (p<0.05) in the thickness of the viable cell rim (mean +/- SD) from 240+/-49.9 micro m to 294+/-69.5 micro m. This was associated with an elevation of the intracellular GSH concentration and, thus, of cellular antioxidant defense, as shown by HPLC analysis. A considerable toxicity, however, was found at these GTE levels in single cells. Cells did not adhere to culture dishes nor did they aggregate to form spheroids when plated as a suspension with GTE already in the culture medium. The findings show that green tea constituents interfere with early phases of tumorigenesis at a cellular level, e.g., by reducing cell-substratum and cell-cell interaction, enhancing G2/M arrest, and retarding spheroid volume growth. The differences in GTE effects between single cells and cell spheroids underline the importance of inclusion of spheroids in pharmaco-/toxicological testing.

Adenocarcinoma↗

Tea consumption and the prevalence of coronary heart disease in Saudi adults: results from a Saudi national study.

BACKGROUND: The aim of the study was to determine whether there was a relationship between tea consumption and the prevalence of coronary heart disease (CHD) in Saudi Arabia. METHODS: The relationship between tea consumption and the prevalence of CHD was investigated using multiple logistic regression analysis in the Saudi Coronary Artery Disease Study. A total of 3,430 men and women aged 30-70 years was studied. RESULTS: Of the 3,430 subjects who were assigned a category, 6.3% were classified as having indications of CHD. Those who did drink more than 6 cups of tea (>480 mL) per day had a significantly lower prevalence of CHD than the nontea drinkers (P < 0.001). Adjustments for risk factors including age, gender, occupation, education, smoking, family history, blood lipids, diabetes, blood pressure, BMI, physical activity, and coffee and fat intake did not remove the significance (OR = 0.49; 95% CI = 0.24-0.96). There was a positive dose-response effect between tea consumption and CHD (P < 0.001) that was persistent after adjustment for various risk factors (P = 0.022). CONCLUSIONS: These findings support a potential protective effect of tea consumption in relation to CHD in this Saudi study in which all tea consumed was black tea.

Adult↗

The role of tubular necrosis in the pathophysiology of acute renal failure.

Renal tubular function was evaluated in vitro by kidney slice uptakes of p-aminohippurate (PAH) and tetraethylammonium (TEA) at 24 and 48 h in water-drinking rats and at 24 h in chronic saline-loaded rats after induction of acute tubular necrosis (ATN) by HgCl2 and glycerol injection. Significant correlations between decrease tubular uptake of PAH and TEA and elevated serum creatinine levels were noted in both models of ATN in water- and saline-drinking rats. However, with the same degree of impairment of PAH and TEA uptakes the creatinine was significantly lower in saline-loaded rats than in water-drinking rats in both forms of ATN. The correlation between impaired tubular function and elevated creatinine suggests that tubular damage and glomerular filtration reduction might be pathophysiologically related in ATN.

Acute Kidney Injury↗

Effects of oral administration of tea, decaffeinated tea, and caffeine on the formation and growth of tumors in high-risk SKH-1 mice previously treated with ultraviolet B light.

Treatment of SKH-1 mice with ultraviolet B light (UV-B, 30 mJ/cm2) twice a week for 22-23 weeks resulted in tumor-free animals with a high risk of developing malignant and nonmalignant tumors during the next several months in the absence of further UV-B treatment (high-risk mice). In three separate experiments, oral administration of green tea or black tea (4-6 mg tea solids/ml) as the sole source of drinking fluid for 18-23 weeks to these high-risk mice inhibited the formation and decreased the size of nonmalignant squamous cell papillomas and keratoacanthomas as well as the formation and size of malignant squamous cell carcinomas. In one experiment all these inhibitory effects of tea were statistically significant, whereas in the two other experiments many but not all of the inhibitory effects of tea were statistically significant. The decaffeinated teas were inactive or less effective inhibitors of tumor formation than the regular teas, and adding caffeine back to the decaffeinated teas restored biological activity. Oral administration of caffeine alone (0.44 mg/ml) as the sole source of drinking fluid for 18-23 weeks inhibited the formation of nonmalignant and malignant tumors, and this treatment also decreased tumor size in these high-risk mice.

Administration, Oral↗

[A preliminary study of the preventive and blocking effect of green tea grown in mengding mountain area on the esophageal cancer in rats].

Three groups (positive control or nitrosamine alone group, test group and control group) were included in this experiment. After the begining of the experiment, the rats of test group were given 2% green tea (common grade) solution by free drinking daily for 24 weeks. After 2 weeks of the begining of the experiment, the rats of the nitrosamine alone group and test group were injected with MANA, 5 mg/kg weekly for 20 weeks. The animals were sacrificed at 4 intervals. The incidence rates of esophageal cancer in the rats of the two groups sacrified at every interval were significantly different. The result suggested that green tea should have a preventive and blocking effect on the occurrence of esophageal cancer in rats.

Animals↗