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BACKGROUND : Anthocyanins, which are found in high concentrations in fruit and vegetable, may play a beneficial role in retarding or reversing the course of chronic degenerative diseases. However, little is known about the biotransformation and the metabolism of anthocyanins so far. AIM OF THE STUDY : The aim of the study was to investigate possible transformation pathways of anthocyanins by human faecal microflora and by rat liver microsomes as a source of cytochrome P450 enzymes as well as of glucuronyltransferases. METHODS : Pure anthocyanins, an aqueous extract of red radish as well as the assumed degradation products were incubated with human faecal suspension. The incubation mixtures were purified by solid-phase extraction and analysed by HPLC/DAD/MS and GC/MS. Quantification was done by the external standard method. Furthermore the biotransformation of anthocyanins by incubation with rat liver microsomes in the presence of the cofactor NADPH (as a model for the phase I oxidation) and in the presence of activated glucuronic acid (as a model for the phase II glucuronidation) was investigated. RESULTS : Glycosylated and acylated anthocyanins were rapidly degraded by the intestinal microflora after anaerobic incubation with a human faecal suspension. The major stable products of anthocyanin degradation are the corresponding phenolic acids derived from the B-ring of the anthocyanin skeleton. Anthocyanins were not metabolised by cytochrome P450 enzymes, neither hydroxylated nor demethylated. However they were glucuronidated by rat liver microsomes to several products. CONCLUSIONS : The gut microflora seem to play an important role in the biotransformation of anthocyanins. A rapid degradation could be one major reason for the poor bioavailability of anthocyanins in pharmacokinetic studies described so far in the literature. The formation of phenolic acids as the major stable degradation products gives an important hint to the fate of anthocyanins in vivo. [ABSTRACT FROM AUTHOR]

Background Anthocyanins, which are found in high concentrations in fruit and vegetable, may play a beneficial role in retarding or reversing the course of chronic degenerative diseases. However, little is known about the biotransformation and the metabolism of anthocyanins so far. Aim of the study The aim of the study was to investigate possible transformation pathways of anthocyanins by human faecal microflora and by rat liver microsomes as a source of cytochrome P450 enzymes as well as of glucuronyltransferases. Methods Pure anthocyanins, an aqueous extract of red radish as well as the assumed degradation products were incubated with human faecal suspension. The incubation mixtures were purified by solid-phase extraction and analysed by HPLC/DAD/MS and GC/MS. Quantification was done by the external standard method. Furthermore the biotransformation of anthocyanins by incubation with rat liver microsomes in the presence of the cofactor NADPH (as a model for the phase I oxidation) and in the presence of activated glucuronic acid (as a model for the phase II glucuronidation) was investigated. Results Glycosylated and acylated anthocyanins were rapidly degraded by the intestinal microflora after anaerobic incubation with a human faecal suspension. The major stable products of anthocyanin degradation are the corresponding phenolic acids derived from the B-ring of the anthocyanin skeleton. Anthocyanins were not metabolised by cytochrome P450 enzymes, neither hydroxylated nor demethylated. However they were glucuronidated by rat liver microsomes to several products. Conclusions The gut microflora seem to play an important role in the biotransformation of anthocyanins. A rapid degradation could be one major reason for the poor bioavailability of anthocyanins in pharmacokinetic studies described so far in the literature. The formation of phenolic acids as the major stable degradation products gives an important hint to the fate of anthocyanins in vivo. [ABSTRACT FROM AUTHOR]

OBJECTIVE:: To investigate whether the daily intake of red wine (RW) at a dose which inversely correlates with cardiovascular disease (CVD) risk modulates immune functions in healthy men. DESIGN:: Randomized single-blind trial with four intervention periods. SETTING:: The Institute of Nutritional Physiology, Federal Research Centre for Nutrition, Karlsruhe, Germany. SUBJECTS:: A total of 24 healthy males with moderate alcohol consumption patterns were recruited and all completed the study. INTERVENTION:: Participants consumed 500?ml of RW (12% ethanol (ETOH)) or 500?ml of a 12% ETOH dilution per day for a period of 2 weeks. To control the potential effects of RW polyphenols, accordingly 500?ml/day of dealcoholized red wine (DRW) and of red grape juice (RGJ) were given. The following immune parameters were measured before beverage consumption and at 1 and 2 weeks following beverage consumption: phagocytic activity of neutrophils and monocytes, production of tumor necrosis factor-alpha (TNFa), interleukin-2 and -4, transforming growth factor-ß, TNFa mRNA, lymphocyte proliferation, lytic activity of natural killer cells, and percentage of apoptotic lymphocytes. RESULTS:: Consumption of a moderate volume of alcohol with RW and with a 12% ETOH dilution had no effect on immune functions in healthy males. Consumption of polyphenol-rich beverages (DRW and RGJ) did not affect immunity-related parameters. CONCLUSIONS:: Daily moderate consumption of alcohol and of RW for 2 weeks at doses which inversely correlate with CVD risk has no adverse effects on human immune cell functions. Polyphenol-rich beverages such as RGJ and DRW further do not suppress immune responses in healthy men. SPONSORSHIP:: The Federal Ministry of Consumer Protection, Food, and Agriculture, Germany.European Journal of Clinical Nutrition (2004) 58, 40-45. doi:10.1038/sj.ejcn.1601742 [ABSTRACT FROM AUTHOR]

Background: The oxidative modification of LDL is considered to play a central role in the pathogenesis of atherosclerosis and coronary heart disease (CHD). Paraoxonase (PON1) protects LDL from oxidation and may therefore retard the developement of atherosclerosis. The PON 1-192 polymorphism is associated with diminished PON1 concentrations and an increased risk for CHD in RR-allele subjects. Aim of the study: To investigate the effect of tomato juice consumption on PON 1 activity and other parameters related to oxidative stress in healthy elderly subjects. Furthermore, the PON 1-192 genotype has been determined in the volunteers in order to see whether possible treatment effects are related to the PON1-192 polymorphism. Methods: Fifty elderly subjects were randomly assigned to control (mineral water) or intervention group (tomato juice). Subjects of the tomato juice group consumed daily 330 mL tomato juice for 8 weeks. Antioxidant status was measured as LDL oxidation, plasma malondialdehyde, ferric reducing ability of plasma (FRAP) and PON 1 activity. The PON 1-192 polymorphism was determined by restriction fragment length polymorphism polymerase chain reaction (RFLP-PCR). Plasma carotenoids were analyzed by HPLC. Results: Tomato juice consumption reduced LDL-oxidation and improved antioxidant status in R-allele carriers, but not in the QQ genotype group. PON1 activity increased irrespective of the genotype in both, control and intervention group. Conclusions: The changes in antioxidant status after tomato juice consumption seem to depend on the PONI-192 genotype. Healthy elderly, carrying the R-allele, could specificly reduce their higher cardiovascular risk by changing dietary habits. [ABSTRACT FROM AUTHOR]

Presents a study that examined the degradation of phytate salt in the gut of pigs. Background on phytate salt; Analysis of the inositol phosphates; Evaluation of enzyme activity during phytate degradation.

The human colon carcinoma cell line HT29 cl.19A was studied for organic anion transporter activity by determining intracellular fluo-3 and fura-red accumulation and by measuring fluo-3 efflux. Modulators of organic anion transport systems were used to identify the transporters that are involved in dye extrusion. Addition of probenecid to the dye-loading medium, containing 10 µM fluo-3/AM and fura-red/AM, resulted in a dose-dependent increase in fluo-3 and fura-red accumulation in the cells. The increase in fluo-3 accumulation in the cells in the presence of probenecid was explained by the inhibitory effect of this compound on fluo-3 efflux. Fluo-3 efflux from the cells was also inhibited by sulfinpyrazone, another inhibitor of organic anion transport. Substrates of renal probenecid-sensitive organic anion exchange mechanisms as well as modulators of multidrug resistance associated protein (MRP) activity did not influence fluo-3 extrusion rates. However, reducing intracellular ATP contents completely blocked fluo-3 extrusion. Moreover, MK571, an inhibitor of MRP, significantly stimulated dye accumulation, whereas inhibitors of the multidrug resistance gene (MDR1) product P-glycoprotein, cyclosporin A and verapamil, did not. As probenecid inhibits fluo-3 efflux across the apical membrane of cells grown on permeable supports, we conclude that a probenecid-sensitive organic anion transporter is present in the apical membrane of HT29 cl.19A cells. This organic anion transport system differs from MDR1 and MRP2. [ABSTRACT FROM AUTHOR]

Because of their antioxidant properties, carotenoids may have beneficial effects in preventing cancer and cardiovascular disease. However, in humans consuming carotenoid-rich vegetables, data concerning the antioxidant effects of carotenoids are rather scarce. A human intervention trial was conducted, therefore, to determine whether a moderately increased consumption of carotenoid-rich vegetables would influence the antioxidant status in 23 healthy men. This short-term feeding study lasted 8 wk during which the men consumed a low carotenoid diet. A 2-wk low carotenoid period was followed by daily consumption of 330 mL tomato juice, then by 330 mL carrot juice and then by 10 g of spinach powder, each for 2 wk. Antioxidant status [water-soluble antioxidants in serum, ferric reducing ability of plasma (FRAP) and antioxidant enzyme activities] and lipid peroxidation (plasma malondialdehyde and ex vivo oxidation of LDL) were determined. In a subgroup of 10 men, lipoprotein carotenoids were measured. The consumption of carotenoid-rich vegetables significantly increased selected carotenoids in lipoproteins but had only minor effects on their relative distribution pattern. Tomato juice consumption reduced plasma thiobarbituric acid reactive substances (TBARS) by 12% (P: < 0.05) and lipoprotein oxidizability in terms of an increased lag time (18%, P: < 0.05). Carrot juice and spinach powder had no effect on lipid peroxidation. Water-soluble antioxidants, FRAP, glutathione peroxidase and reductase activities did not change during any study period. In evaluating the low carotenoid diet, we conclude that the additional consumption of carotenoid-rich vegetable products enhanced lipoprotein carotenoid concentrations, but only tomato juice reduced LDL oxidation in healthy men. [ABSTRACT FROM AUTHOR]

The immunomodulatory potential of carotenoids has been investigated thoroughly only for beta-carotene. Data on the immunomodulatory activity of other carotenoids such as lycopene are scarce. The objective of this study was to investigate the effects of prolonged tomato juice consumption on cell-mediated immunity of well-nourished healthy elderly persons. In an intervention study, 33 female and 20 male subjects (aged 63-86 y) consumed 330 mL/d tomato juice (47.1 mg/d lycopene) or mineral water for 8 wk. Immune status was assessed by measuring number and lytic activity of natural killer (NK) cells, secretion of cytokines [interleukin (IL)-2, IL-4, tumor necrosis factor-alpha (TNF-alpha)] by activated peripheral blood mononuclear cells (PBMC), lymphocyte proliferation, and delayed-type hypersensitivity (DTH) skin responses. Tomato juice consumption resulted in significantly increased plasma lycopene and beta-carotene concentrations over time. In both treatment groups, TNF-alpha and IL-4 secretion were increased at the end of the intervention period, whereas IL-2 secretion was decreased. Tomato juice consumption had no effect on lymphocyte proliferation, DTH or the number of NK cells. Lytic activity of NK cells was increased in both groups at the end of the intervention period. In conclusion, these results show that prolonged tomato juice consumption increased plasma lycopene concentrations without significantly affecting cell-mediated immunity in well-nourished elderly subjects. [ABSTRACT FROM AUTHOR]

Summary Anthocyanins are common colored plant flavonoids, occurring as glycosides of the respective anthocyanidin-chromophores. Like other flavonoids, anthocyanidins are also expected to have antioxidative and antimutagenic properties in vivo, although only few data are available. To gain more knowledge on possible protective mechanisms in mammalian cells, we have compared their extracellular and intracellular antioxidative potential in vitro and in human colon tumor cells. We used Aronia melanocarpa Elliot anthocyanin (AA) concentrates, fractions thereof, concentrates from Elderberry, Macqui, and Tintorera fruits, as well as pure compounds. In vitro, antioxidative properties of the samples were studied with the ferric reducing ability assay (FRA assay). As a measure of intracellular oxidative/ antioxidative effects, H202-induced strand breaks as well as oxidized DNA bases were determined in human tumor HT29 clone 19A cells using a microgelelectrophoresis assay (comet test). Major results were that isolated compounds (aglycons and glycosides) and complex plant samples are powerful antioxidants in vitro. In fact their activities by far exceeded those of Trolox and vitamin C in the FRA assay. Also, H202-induced DNA strand breaks were reduced in cells treated with the complex plant extracts. In contrast, endogenous generation of oxidized DNA bases was not prevented. In summary, the intracellular steady state of oxidized DNA bases is not altered by anthocyanins or anthocyanidins. This finding raises questions with respect to the cancer preventive potential of anthocyanidins within specific tissues, such as the colon. Extracellularly, however, the compounds are potent antioxidants. This points to their potential for providing systemic protection in vivo, e.g., by scavenging oxidants... [ABSTRACT FROM AUTHOR]

Summary Background Glutathione S-transferases (GSTs) are an important class of phase II, predominantly detoxifying, enzymes. The supergene family is composed of several isoenzymes, hetero- and homodimers, with tissue specific distribution and levels of expression. The hypothesis is that a higher expression of individual proteins within a specific tissue may be associated with a decreased burden of exposure to reactive carcinogens and ultimately with a decreased cancer risk in this tissue. [ABSTRACT FROM AUTHOR]

Summary Aim of the study: The present study was conducted to investigate changes in the plasma concentration of carotenoids and carotenoid oxidation products, vitamin A, α- and γ-tocopherol, and ubiquinone-10 during a dietary intervention trial with 23 male healthy volunteers. Method: A two week carotenoid depletion period was followed by a daily consumption of 330 mL tomato juice (40 mg lycopene), then by 330 mL carrot juice (15.7 mg α-carotene and 22.3 mg β-carotene), and then by a 10 g spinach powder preparation (11.3 mg lutein and 3.1 mg β-carotene) served with main meals for two weeks, respectively. Blood samples were collected in the morning after an overnight fasting and carotenoids, vitamin A, tocopherols, and ubichinone were analyzed by reversed-phase HPLC. Results: During the tomato juice intervention, plasma concentrations of trans- and cis-lycopene increased 2-fold compared to the depletion period. Lycopene oxidation products could be demonstrated in plasma and were significantly elevated compared to control (p<0.001). After two weeks of carrot juice consumption, α-carotene and β-carotene concentrations increased 8.6- and 3.2-fold, respectively. Finally, during the spinach consumption period the lutein concentration increased 2-fold, while the β-carotene concentrations were still elevated 2-fold. Conclusions: The moderate change in dietary habits, e.g., the consumption of 330 mL of carotenoid-rich vegetable juices caused significant changes in the plasma carotenoid concentrations, indicating a high bioavailability of carotenoids from the processed vegetable products. The changes in plasma carotenoid concentrations reflected the carotenoid composition of the consumed foods. However, particularly during the tomato juice intervention period the occurrence of lycopene oxidation products and cis-lycopene isomers in plasma was eminent. The formation may be due to antioxidant reactions of lycopene in the organism. [ABSTRACT FROM AUTHOR]

Short chain fatty acids (SCFA) are considered to be beneficial fermentation products in the gut by exerting trophic effects in non-transformed colon cells and by slowing proliferation and enhancing differentiation in colonic tumour cells. We have studied the further effects of SCFA on cellular events of early carcinogenesis, genotoxicity and cytotoxicity in rat distal colon cells. Cytotoxicity was assessed by measuring trypan blue exclusion and by determining the H2O2-induced changes in intracellular calcium concentration ([Ca2+]i) using a fluorospectrophotometer and the calcium-sensitive fluorescent dye Fura-2. The microgel electrophoresis technique (COMET assay) was used to assess oxidative DNA damage. Individual SCFA and physiological SCFA mixtures were investigated for their potential to prevent DNA and cell damage induced by H2O2. For this, freshly isolated colon cells were treated with H2O2. For this, freshly isolated colon cells were treated with H2O2 (100-500 μM) and 6.25 mM SCFA. We have found 100-500 μM H2O2 to cause a fast initial increase in [Ca2+]i, whereafter the levels gradually further increased. Addition of SCFA did not affect [Ca2+]i nor did it reduce the H2O2-induced increase in [Ca2+]i. Butyrate and acetate were able to reduce the induction of DNA damage by 100, 200 and 500 μM H2O2, respectively. In contrast, i-butyrate and propionate were ineffective. The degree of reduction of DNA damage for the two protective SCFA was similar. Physiological mixtures containing acetate, propionate and butyrate in ratios of 41:21:38 or 75:15:10 that are expected to arise in the colon after fermentation of resistant starches and pectin, respectively, did not show significant anti-genotoxic effects. The major difference between butyrate and acetate, on one hand, and i-butyrate and propionate, on the other hand, is that the former compounds are utilized best as energy sources by the colon cells. Therefore, our results on antigenotoxicity coupled with the findings on [Ca2+]i homeostasis indicate that molecular effects on the energy system render these non-transformed, freshly isolated colon cells to be less susceptible to H2O2. [ABSTRACT FROM PUBLISHER]

A human intervention study with vegetable products has been performed in twenty three healthy, non smoking males aged 27-40. It was the aim of the study to assess whether consumption of vegetables containing different carotenoids could protect against DNA damage and oxidative DNA damage. The subjects consumed their normal diets, but abstained from vegetables high in carotenoids throughout the study period. After a 2 week depletion period, they received daily 330 ml tomato juice with 40 mg lycopene (weeks 3 and 4), 330 ml carrot juice with 22.3 mg beta-carotene and 15.7 mg alpha-carotene (weeks 5 and 6), and 10 g dried spinach powder (in water or milk) with 11.3 mg lutein (weeks 7 and 8). Blood was collected weekly and DNA damage was detected in peripheral blood lymphocytes with the 'COMET' assay. Oxidised DNA bases were detected by including an incubation step with endonuclease III. The supplementation of the diet with tomato, carrot or spinach products resulted in a significant decrease in endogenous levels of strand breaks in lymphocyte DNA. Oxidative base damage was significantly reduced during the carrot juice intervention. These findings support the hypothesis that carotenoid containing plant products exert a cancer-protective effect via a decrease in oxidative and other damage to DNA in humans. [ABSTRACT FROM PUBLISHER]

Absorption of short-chain fatty acids has been studied in the proximal and the distal colon of anaesthetized guinea pigs. Segments were perfused with a solution similar in chemical composition to that of normal colonic fluids. In the proximal colon the permeability of the mucosa was similar for acetate, propionate and butyrate. For acetate the permeability was significantly higher in the proximal than in the distal colon, and the reverse was seen for butyrate. In the distal colon the short-chain fatty acids seem to be absorbed mainly in the undissociated form due to their lipid solubility; a paracellular pathway for the dissociated molecules is of no major importance. In the proximal colon, on the other hand, a considerable portion of acetate and propionate disappears in the ionized form. Light microscopy (semithin sections) and electron microscopy (freeze-fracture replicas) showed remarkable morphological differences between the proximal and the distal colon. "Leaky spots" with only few strands were present in the zonulae occludentes between the epithelial cells at the surface of the proximal colon. In the distal colon the junctions between the cells were more compact, and significantly more strands separated the lumen from the intercellular space. These results suggest that short-chain fatty acids could be absorbed by a paracellular pathway in the proximal colon, and not in the distal colon. In the proximal colon the number of strands of the zonulae occludentes between surface cells and that between cryptal cells was similar. On the contrary, in the distal colon significantly more strands were present between surface cells than between cryptal cells. Morphological and physiological considerations suggest that absorption of short-chain fatty acids in the crypts is negligible. [ABSTRACT FROM AUTHOR]

The mammalian distal colon, which is composed of different cell types, actively transports Na, K and Cl in absorptive and K and Cl in secretory directions. To further characterize the K absorption process and to identify the cells involved in K absorption, unidirectional Rb fluxes and luminal Rb uptake into different epithelial cell types were determined in isolated guinea-pig distal colon. Net Rb absorption (1.5–2.5 µmol·h–1·cm–2) was not influenced by inhibition of Na transport with amiloride or by incubating both sides of the epithelium with Na-free solutions, but was almost completely abolished by luminal ouabain, ethoxzolamide or by incubating both sides of the epithelium with Cl-free solutions. Luminal Rb uptake, blockable by luminal ouabain, preferentially occurred in columnar surface and neck cells, to a lesser extent in surface goblet cells and to an insignificant degree in lower crypt cells. Employing a luminal Rb-Ringer (5.4 mM Rb) the Rb concentration increased within 10 min in columnar surface and neck, surface goblet and lower crypt cells to 70, 32 and about 10 mmol·kg–1 wet weight, respectively. The presence of 5.4 mM K in the luminal incubation solution reduced Rb uptake almost completely indicating a much higher acceptance of the luminal H-K-ATPase for K than for Rb. The increase in Na and decrease in K concentrations in surface and neck cells induced by luminal ouabain might indicate inhibition of the basolateral Na-K-ATPase or drastic enhancement of cellular Na uptake by the Na-H exchanger. Bilateral Na-free incubation did not alter Rb uptake, but bilateral Cl-free incubation drastically reduced it. Inhibition of net Rb absorption by ethoxzolamide and inhibition of both Rb absorption and Rb uptake by bilateral Cl-free incubation support the notion that cellular CO2 hydration is a necessary prerequisite for K absorption and that HCO3 leaves the cell via a Cl-HCO3 exchanger. Since ouabain-inhibitable transepithelial Rb flux and luminal Rb uptake rate by surface and neck cells were about the same, Rb(K) absorption seems to be accomplished mainly by columnar surface cells. [ABSTRACT FROM AUTHOR]

The intracellular pH (pH) of the colonic tumour cell line HT29 cl.19A was studied by microspectrofluorometry using the pH-sensitive dye BCECF. Single cells within a confluent monolayer, grown in a polarized manner on permeable supports, were examined. An amiloride-sensitive Na/H exchange and a stilbene-insensitive Cl /HCO exchange mechanism have been identified in the basolateral membrane. Removal of Na from the basolateral solution caused a decrease of pH by 0.50±0.09 unit ( n=4). Amiloride or Na-free solution at the apical side had no effect on pH. Cl removal at the basolateral side led to an increase of pH by 0.20±0.03 unit ( n=4) whereas apical removal had no influence on pH. This effect was independent of Na and was insensitive to 0.2 mM 4,4′-diisothiocyanatodihydrostilbene-2, 2′-disulphonic acid. A basolateral Cl/ HCO exchanger is the most likely explanation for this observation. The Na/H exchange mechanism in the basolateral membrane is an acid extruder, whereas the C1/HCO exchanger is an acid loader. Both of these mechanisms are important for the maintenance of intracellular pH in HT29 cl.19A cells. [ABSTRACT FROM AUTHOR]

The article focuses on the International Life Sciences Institute (ILSI), which advances the understanding of scientific issues relating to nutrition, food safety, toxicology, risk assessment and the environment. By bringing together scientists from academia, government, industry, and the public sector, ILSI seeks a balanced approach to solving problems of common concern for the well-being of the general public. ILSI is headquartered in Washington, D.C. ILSI Europe was established in 1986 to identify and evaluate scientific issues related to the above topics through symposia, workshops, expert groups and resulting publications.

BACKGROUND: The role of dietary factors in the aetiology of human cancer is an area, which has attracted intense interest in recent years. The suggestion that approximately one third of all cancers may be caused by an 'inappropriate' balance of food components has led to the attractive contention that we can significantly decrease cancer incidence through dietary recommendations and a change in dietary habits in populations. Thus, a key issue must be to establish clear criteria, which must be met in order to be able to make 'cancer risk reduction' claims for food components. In this area, the one true marker is the malignant human tumour, which for practical reasons is usually not accessible to claims. In its absence, we must rely on alternative markers--biomarkers/surrogate endpoints. This paper mainly deals with the link of these biomarkers to the endpoint tumour and their usefulness for making claims. Some claims have been made based on epidemiological studies. AIM: Can we identify targets/ biomarkers in the chain of events from initial 'exposure' to overt malignant tumour, whose modification can be used to make 'anticancer' claims for food components? RESULTS: We identified 18 targets/markers in the above chain of events whose modification 'have the potential' to be used for 'reduction of cancer risk' claims for food components. These targets/markers fall under 5 broad headings: tumours and preneoplastic changes; cellular targets/markers; gut luminal markers; angiogenesis and metastasis; carcinogen metabolising enzymes; genetic events. CONCLUSIONS: The strongest markers presently available are precancerous lesions (e. g. polyps or aberrant crypt foci) in humans and precancerous lesions and tumours in animal models. The only marker that presently can be used for a 'reduction of disease risk' claim (type B) for food components is 'polyp recurrence'. Type B claims cannot be made on the basis of results in animal models. All of the other biomarkers examined presently lack validation against the 'true endpoint', the tumour, and thus cannot be used for type B claims. 'Reduction of disease risk' claims in the area of 'diet-related cancer' should be based primarily on human intervention studies using relevant/acceptable endpoints. An important area for future research will be the validation of these surrogate endpoints. [ABSTRACT FROM AUTHOR]