Vegetables, fruit, and cancer prevention: a review

Fruit juice consumption modulates antioxidative status, immune status and DNA damage

Polyphenolic compounds exert a variety of physiological effects in vitro including antioxidative, immunomodulatory and antigenotoxic effects. In a randomized crossover study in healthy men on a low-polyphenol diet, we determined the effects of 2 polyphenol-rich juices (330 ml/d) supplemented for 2 weeks on bioavailability of polyphenols, markers of antioxidative and immune status, and reduction of DNA damage. Juices provided 236 mg (A) and 226 mg (B) polyphenols with cyanidin glycosides (A) and epigallocatechin gallate (B) as major polyphenolic ingredients. There was no accumulation of plasma polyphenols after two weeks of juice supplementation. In contrast, plasma malondialdehyde decreased with time during juice interventions. Moreover, juice consumption also increased lymphocyte proliferative responsiveness, with no difference between the two juices. Interleukin-2 secretion by activated lymphocytes and the lytic activity of natural killer cells were significantly increased by both juices. Juice intervention had no effect on single DNA strand breaks, but significantly reduced oxidative DNA damage in lymphocytes. A time-delay was observed between the intake of fruit juice and the reduction of oxidative DNA damage and the increase in interleukin-2 secretion. We conclude that consumption of either juice enhanced antioxidant status, reduced oxidative DNA damage and stimulated immune cell functions. However, fruit juice consumption for 2 weeks did not result in elevated plasma polyphenols in subjects after overnight fasting. Further studies should focus on the time-delay between juice intake and changes in measured physiological functions, as well as on active polyphenolic metabolites mediating the observed effects.

Inhibitory effect of dibenzoylmethane on mutagenicity of food-derived heterocyclic amine mutagens

Dibenzoylmethane (DBM), a structural analogue of curcumin (a bioactive phytochemical present in a widely used spice turmeric) was screened for its inhibitory effect against seven cooked food mutagens (heterocyclic amines): 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1), in both TA98 and TA100 strains of Salmonella typhimurium using Ames Salmonella/reversion assay in the presence of Aroclor1254-induced rat liver S9 homogenate. DBM has been reported to antagonize the mutagenicity of several chemical carcinogens in vitro and has recently been shown to be even more effective than curcumin in suppressing the 7,12-dimethylbenz[a]anthracene (DMBA)-induced mammary tumors in rats. But there are no reports regarding its antimutagenic properties against cooked food mutagens. Results of the present investigations clearly indicate that dibenzoylmethane is a very potent antimutagenic agent, that could effectively inhibit mutagenicity induced by all the tested cooked food mutagens in both the frame shift (TA98) as well as the base pair mutation sensitive (TA100) strains of S. typhimurium. These highly potent inhibitory effects of dibenzoylmethane against heterocyclic amines observed in our preliminary investigations strongly warrant further studies of its efficacy as a cancer chemopreventive agent.

Nutritional and physiological responses of young growing rats to diets containing raw cowpea seed meal, protein isolate (globulins), or starch

The nutritional and physiological effects of raw cowpea (Vigna unguiculata (L) Walp.) seed meal, protein isolate (globulins), or starch on the metabolism of young growing rats have been evaluated in 14-day trials. Wet and dry weight gain, feed conversion efficiency, and lipid and protein accretion were significantly reduced as a result of inclusion of seed meal, globulins, or starch in the diet, with growth retardation being most marked with the seed meal. The proportional weights of the small intestine and pancreas were increased by meal diets, and serum cholesterol levels were slightly reduced. The globulins and raw starch also increased relative small intestine weights but had no effect on the pancreas or serum constituents. The effects of cowpeas on rats appeared to be due primarily to the combined actions of globulins, resistant starches, protease inhibitors, and possibly fiber and non-starch polysaccharides on intestinal and systemic metabolism.

Antioxidant capacity of lettuce leaf tissue increases after wounding

Wounding induced the accumulation of phenolic compounds in Iceberg and Romaine lettuce leaf tissue. Phenolic concentrations were quantified after holding the leaf tissue at 10 degrees C for 48 h as the absorbance of a methanol extract at 320 nm, and by the Folin-Ciocalteu method. Heat-shock treatments applied by immersing tissue in 45 degrees C water for 2.5 min before or after wounding reduced the accumulation of phenolic compounds. Compared to the nonwounded, nonheat-shocked controls, these and other wounding and heat-shock treatments produced leaf tissue with a 4-fold range in phenolic content. The antioxidant capacity of the tissue, measured as DPPH (alpha,alpha-diphenyl-beta-picrylhydrazyl)-radical scavenging activity, or as ferric-reducing antioxidant power (FRAP), increased after wounding. The increase was linearly correlated with the increase in phenolic compounds in Iceberg (R(2) > 0.97) and in Romaine (R(2) > 0.95) lettuce leaf tissue. Increased consumption of diets rich in phenolic antioxidants may contribute to reducing human diseases. Treatments that reduce the browning of wounded lettuce leaf tissue by preventing the oxidation of the accumulated wound-induced phenolic compounds may produce a healthier fresh-cut product than treatments that prevent the wound-induced synthesis and accumulation of phenolic compounds with antioxidant properties.

Comparison of the antioxidant effects of Concord grape juice flavonoids alpha-tocopherol on markers of oxidative stress in healthy adults

BACKGROUND

Concord grape juice (CGJ) is a rich source of flavonoids, which have greater antioxidant efficacy in vitro than does alpha-tocopherol; however, the efficacies of flavonoids and alpha-tocopherol in vivo have not been compared.

OBJECTIVE

We compared the in vivo antioxidant efficacy of CGJ with that of alpha-tocopherol in healthy adults.

DESIGN

Subjects were randomly assigned to receive either 400 IU RRR-alpha-tocopherol/d (n = 17) or 10 mL CGJ. kg(-1). d(-1) (n = 15) for 2 wk. Serum oxygen radical absorbance capacity, plasma protein carbonyls, urinary F(2)-isoprostanes, and resistance of LDL to ex vivo oxidation were measured before and after supplementation as markers of antioxidant status and oxidative stress.

RESULTS

After supplementation, plasma alpha-tocopherol increased 92% in subjects who received alpha-tocopherol (P < 0.001); plasma total and conjugated phenols increased 17% (P < 0.01) and 22% (P < 0.001), respectively, in subjects who received CGJ. There was a significant change in plasma triacylglycerols in both groups, but the concentrations were within the normal range. CGJ supplementation was associated with significantly higher triacylglycerols than was alpha-tocopherol supplementation. Both supplementation regimens significantly increased serum oxygen radical absorbance capacity (P < 0.001) and LDL lag time (P < 0.001) and significantly decreased the LDL oxidation rate (P < 0.01), with no significant difference in effectiveness. Protein carbonyl concentrations in native plasma decreased 20% after CGJ supplementation, which was a significantly different response than that after alpha-tocopherol supplementation (P < 0.05).

CONCLUSIONS

In healthy adults, 10 mL CGJ. kg(-1). d(-1) increased serum antioxidant capacity and protected LDL against oxidation to an extent similar to that obtained with 400 IU alpha-tocopherol/d but decreased native plasma protein oxidation significantly more than did alpha-tocopherol. CGJ flavonoids are potent antioxidants that may protect against oxidative stress and reduce the risk of free radical damage and chronic diseases.

Potent suppressive activity of fresh and dried peels from Satsuma mandarin Citrus unshiu (Marcorv.) on hydroperoxide generation from oxidized linoleic acid

The effects of various extracts prepared from fresh and dried peels of Satsuma mandarin (Citrus unshiu Marcov.) on hydroperoxide generation from oxidized linoleic acid were compared under different extraction conditions. The cold-and hot-water extracts of fresh peels showed significant suppressive activity against hydroperoxide generation in a dose-dependent manner. However, the methanol or acetone extract of fresh peels did not exhibit significant suppressive effects. The commercially available ascorbic acids equivalent to their concentrations in the water extracts of fresh peels showed roughly equal antioxidative activities compared with those of the water extracts of fresh peels. Although the cold- and hot- water extracts of dried peels indicated a considerable reduction of ascorbic acid concentration, they exhibited much higher antioxidative activities than those of the fresh peels. The methanol extract of dried peels also showed significant antioxidative activities, but did not contain significant ascorbic acid. These results suggest that the fresh peels of Satsuma mandarin have potential antioxidant activities, and the drying treatment of fresh peels caused an enhancement of the antioxidant activity. The pharmacological significance of this finding is discussed.

Primary prevention of uterine cervix cancer: focus on vaccine history and current strategy

Primary prevention of uterine cervix cancer spans the gamut of human papillomavirus vaccine development, dietary adjustment, chemoprevention, and risk reduction. Lifestyle and social behaviors impact on risk for cervical cancer. Before examining the growing body of molecular evidence, animal studies, and phase I clinical trials that suggest that a virus-based vaccine for cervical cancer may soon become a reality, one must reflect on what has gone before in the vaccine-based battle with viral disease.

Dietary interventions to prevent disease

Changing dietary behaviors to prevent chronic disease has been an important research focus for the last 25 years. Here we present a review of published articles on the results of research to identify methods to change key dietary habits: fat intake, fiber intake, and consumption of fruits and vegetables. We divided the research reviewed into sections, based on the channel through which the intervention activities were delivered. We conclude that the field is making progress in identifying successful dietary change strategies, but that more can be learned. Particularly, we need to transfer some of the knowledge from the individual-based trials to community-level interventions. Also, more research with rigorous methodology must be done to test current and future intervention options.

Antioxidant and antiproliferative activities of common vegetables

Epidemiological studies have shown that consumption of fruits and vegetables is associated with reduced risk of chronic diseases. Increased consumption of fruits and vegetables containing high levels of phytochemicals has been recommended to prevent chronic diseases related to oxidative stress in the human body. In this study, 10 common vegetables were selected on the basis of consumption per capita data in the United States. A more complete profile of phenolic distributions, including both free and bound phenolics in these vegetables, is reported here using new and modified methods. Broccoli possessed the highest total phenolic content, followed by spinach, yellow onion, red pepper, carrot, cabbage, potato, lettuce, celery, and cucumber. Red pepper had the highest total antioxidant activity, followed by broccoli, carrot, spinach, cabbage, yellow onion, celery, potato, lettuce, and cucumber. The phenolics antioxidant index (PAI) was proposed to evaluate the quality/quantity of phenolic contents in these vegetables and was calculated from the corrected total antioxidant activities by eliminating vitamin C contributions. Antiproliferative activities were also studied in vitro using HepG(2) human liver cancer cells. Spinach showed the highest inhibitory effect, followed by cabbage, red pepper, onion, and broccoli. On the basis of these results, the bioactivity index (BI) for dietary cancer prevention is proposed to provide a simple reference for consumers to choose vegetables in accordance with their beneficial activities. The BI could be a new alternative biomarker for future epidemiological studies in dietary cancer prevention and health promotion.

The biochemistry and medical significance of the flavonoids

Flavonoids are plant pigments that are synthesised from phenylalanine, generally display marvelous colors known from flower petals, mostly emit brilliant fluorescence when they are excited by UV light, and are ubiquitous to green plant cells. The flavonoids are used by botanists for taxonomical classification. They regulate plant growth by inhibition of the exocytosis of the auxin indolyl acetic acid, as well as by induction of gene expression, and they influence other biological cells in numerous ways. Flavonoids inhibit or kill many bacterial strains, inhibit important viral enzymes, such as reverse transcriptase and protease, and destroy some pathogenic protozoans. Yet, their toxicity to animal cells is low. Flavonoids are major functional components of many herbal and insect preparations for medical use, e.g., propolis (bee's glue) and honey, which have been used since ancient times. The daily intake of flavonoids with normal food, especially fruit and vegetables, is 1-2 g. Modern authorised physicians are increasing their use of pure flavonoids to treat many important common diseases, due to their proven ability to inhibit specific enzymes, to simulate some hormones and neurotransmitters, and to scavenge free radicals.

Transepithelial transport of fluorescein in Caco-2 cell monolayers and use of such transport in in vitro evaluation of phenolic acid availability

Fluorescein is a marker-dye customary applied to the evaluation of tight-junctional permeability of epithelial cell monolayers. However, the true mechanism for the permeation has not been elucidated. Transepithelial transport of fluorescein in Caco-2 cell monolayers was therefore examined. Fluorescein transport was dependent on pH, and in a vectorical way in the apical-basolateral direction, but it was independent of the tight-junctional permeability of monolayers of these human intestinal cells. The permeation of fluorescein was concentration-dependent and saturable; the Michaelis constant was 7.7 mM and the maximum velocity was 40.3 nmol min(-1) (mg protein)(-1). Benzoic acid competitively inhibited fluorescein transport, suggesting that fluorescein is transported by a monocarboxylic acid transporter (MCT). Antioxidative polyphenolic compounds such as ferulic acid from dietary sources, competitively inhibited the permeation of fluorescein. These compounds probably share a transport carrier with fluorescein. Measurement of the effects of phenolic acids on fluorescein transport across Caco-2 monolayers would be a useful way to evaluate the intestinal absorption or bioavailability of dietary phenolic acids.

Extraction of anthocyanins and other phenolics from black currants with sulfured water

Health benefits of fruits, vegetables, and red wine are attributed to anthocyanins and other phytochemicals. In this research, the extraction of phenolics from black currants was optimized using different SO(2) concentrations (28, 300, 700, 1100, and 1372 ppm), temperatures (6, 20, 40, 60, and 74 degrees C), and solvent to solid ratios (S/S) (6, 20, 40, 60, and 74 mL/g). Surface response methodology was used to optimize yields of anthocyanins and total phenolics, as well as their antiradical and antioxidant activities. The extraction of phenolics varied with the SO(2) concentration, S/S, and temperature. Maximum yields of total phenolics and anthocyanins were obtained at an SO(2) concentration of 1000-1200 ppm and 19 L of solvent/kg of milled frozen berries. The increase of extraction temperature increased the rate of extraction and, thus, times to reach equilibrium for the extraction of total phenolics and anthocyanins were reduced. However, for the extraction of anthocyanins it is recommended that temperatures of 30-35 degrees C be used, as higher temperatures will degrade these compounds. Antioxidant activity was affected by all three experimental variables evaluated; however, the main variable affecting it was S/S. The higher the S/S, the lower the antioxidant index.

Color and antioxidant properties of cyanidin-based anthocyanin pigments

A series of cyanidin-based anthocyanin pigments was investigated to determine the effect of structural variation on a number of chemical and physical properties: CIELAB color coordinates, visual detection thresholds, hydration constants (pK(H)), and in vitro antioxidant activities (ORAC). In addition to individual isolated compounds, purified total pigment isolates from blackberry, elderberry, black carrot, red cabbage, and sweet potato were also examined. Acylation with cinnamic acids shifted color tonality (hue angle) to purple, and markedly increased pK(H) and antioxidant activity, but lowered the visual detection threshold. Glycosidic substitution at the 5 position moved tonalities toward purple and decreased pK(H), and tended to lower the ORAC value, but raised the visual detection threshold. Increasing the number of sugar substituents at the 3 position also affected all of these parameters, however, the extent was not predictable. Antioxidant levels of purified anthocyanin extracts were much higher than expected from anthocyanin content indicating synergistic effect of anthocyanin mixtures.

The effect of wild blueberry (Vaccinium angustifolium) consumption on postprandial serum antioxidant status in human subjects

The aim of the present study was to determine whether the consumption of wild blueberries (Vaccinium angustifolium), a concentrated source of non-nutritive antioxidant phytochemicals, would enhance postprandial serum antioxidant status in healthy human subjects. A single-blinded crossover study was performed in a group of eight middle-aged male subjects (38-54 years). Subjects consumed a high-fat meal and a control supplement followed 1 week later by the same high-fat meal supplemented with 100.0 g freeze-dried wild blueberry powder. Upon brachial vein catheterization, fasting and postprandial serum samples were taken sequentially and analysed for lipids and glucose and for serum antioxidant status. Serum antioxidant status was determined using the oxygen radical absorbance capacity (ORAC) assay and the total antioxidant status (TAS) assay. The wild-blueberry treatment was associated with a significant treatment effect as determined by the ORAC assay (water-soluble fraction ORAC(perchloric acid (PCA)), P=0.04). Significant increases in serum antioxidant status above the controls were observed at 1 h (ORAC(PCA) (8.5 % greater), P=0.02; TAS (4.5 % greater), P=0.05), and 4 h (ORAC(total) (15.0 % greater), P=0.009; ORAC(acetone) (16.0 % greater), P=0.007) post-consumption of the high-fat meal. In conclusion, the consumption of wild blueberries, a food source with high in vitro antioxidant properties, is associated with a diet-induced increase in ex vivo serum antioxidant status. It has been suggested that increasing the antioxidant status of serum may result in the reduced risk of many chronic degenerative diseases.

Chemoprotective potential of phase 2 enzyme inducers

In this review we summarize recent data on the use of phase 2 enzyme inducers as cancer chemopreventive agents in preclinical and clinical studies. These agents elevate the expression of genes involved in the detoxication of electrophiles and free radicals that contribute to carcinogenesis. Their mechanisms of action, efficacy and limitations are discussed. Particular attention is paid to isothiocyante and dithiolethione classes of agents, as these are the most developed.

Dietary carotenoids and risk of breast cancer

BACKGROUND

Many studies of fruit and vegetable consumption showed inverse associations with breast cancer risk, suggesting the potential importance of carotenoids (and other phytochemicals) contained in these foods. To date, however, only one prospective cohort study has examined dietary carotenoids other than beta-carotene in relation to breast cancer risk.

OBJECTIVE

Our aim was to examine the relations between dietary intakes of beta-carotene, alpha-carotene, beta-cryptoxanthin, lycopene, and lutein + zeaxanthin and breast cancer risk in a large cohort study of Canadian women.

DESIGN

A case-cohort analysis was undertaken in a cohort of 56 837 women who were enrolled in the Canadian National Breast Screening Study and who completed a self-administered dietary questionnaire. During follow-up to the end of 1993 a total of 1589 women were diagnosed with biopsy-confirmed incident breast cancer. For comparison, a subcohort of 5681 women was randomly selected. After exclusions for various reasons, the analyses were based on 1452 cases and 5239 noncases.

RESULTS

We found no clear association between intakes of any of the studied carotenoids and breast cancer risk in the study population as a whole or in subgroups defined by smoking status; relative body weight (assessed by body mass index); intakes of total fat, energy, alcohol, or folic acid; family history of breast cancer; or menopausal status.

CONCLUSIONS

Our data do not support any association between dietary intakes of the studied carotenoids and breast cancer risk. However, prospective cohort studies of carotenoids in relation to breast cancer are scarce and further studies are warranted.

Socio-economic differences in fruit and vegetable consumption among Australian adolescents and adults

OBJECTIVES

To determine whether socio-economic groups differ in their fruit and vegetable consumption, and the variety eaten, and whether socio-economic differences are similar for adolescents and adults. The study also examined whether socio-economic groups vary in their reported desire to increase the amount of fruit and vegetables consumed, and the perceived barriers to achieving this.

DESIGN, SETTING AND SUBJECTS

The 1995 Australian National Nutrition Survey collected fruit and vegetable intake data from adolescents aged 13-17 years and adults 18-64 years using a 24-hour dietary recall. Gross annual household income was used to measure socio-economic position.

RESULTS

Approximately 44% of males and 34% of females did not consume fruit in the 24 hours preceding the survey, and 20% of males and 17% of females did not consume vegetables. Among adolescents and adults, fruit and vegetable consumption was positively related to income. The only exception was vegetable consumption among adolescent males, which did not vary by income. Lower-income adults consumed a smaller variety of fruits and vegetables than their higher-income counterparts. Fruit and vegetable variety did not vary by income among adolescents. Lower-income adults expressed less desire to increase their fruit and vegetable consumption, and were more likely to report that price and storage were barriers to doing so. Socio-economic differences in consumption and variety were more apparent for adults than for adolescents.

CONCLUSIONS

In addition to increasing the consumption of fruits and vegetables among the general population, nutrition interventions, programmes and policy aiming to improve diet should target adolescents and adults from low socio-economic groups. Strategies should address price and storage barriers.

Validation of a soy food frequency questionnaire with plasma concentrations of isoflavones in US adults

OBJECTIVE

To validate assessment of soy intake using food frequency questionnaires (FFQs) compared with plasma isoflavone (genistein and daidzein) concentrations.

DESIGN

Cross-sectional analysis of soy isoflavone intake and plasma analysis of isoflavones.

SUBJECTS

77 men and women, age range 20 to 40 years, recruited from the Seattle metropolitan area.

MAIN OUTCOME MEASURES

Isoflavone intake was determined from responses to a 40-item soy FFQ and from tofu and soymilk intake assessed as part of a comprehensive FFQ used for the Women's Health Initiative (WHI FFQ). Isoflavone concentrations in fasting blood samples were determined by liquid chromatography-mass spectrometry.

STATISTICAL ANALYSES

Correlation coefficients were calculated for: a) isoflavone intake assessed by the soy FFQ and the WHI FFQ, b) intake assessed by the soy FFQ and plasma isoflavone concentrations, and c) intake assessed by the WHI FFQ and plasma isoflavone concentrations.

RESULTS

Isoflavone intake was highly correlated between the soy FFQ and the WHI FFQ (r = 0.84). Genistein and daidzein intakes determined by the soy FFQ were significantly correlated with plasma concentrations (r = 0.53 and 0.45, respectively). Isoflavone intake assessed from the WHI FFQ was also correlated with plasma concentration (r = 0.46 and 0.45). Soymilk and tofu were the two major contributors to isoflavone intake (38.6%).

CONCLUSIONS

A soy-specific, 40-item FFQ assessed isoflavone intake with good validity. Isoflavone intake assessed by the WHI FFQ (tofu and soymilk) had lower correlations with plasma concentrations compared with the soy FFQ. Nonetheless, assessment of the two foods is a reasonably good marker for soy food consumption in this sample.

Total antioxidant potential of fruit and vegetables and risk of gastric cancer

BACKGROUND & AIMS

Dietary antioxidants, with additive and synergistic effects, can mediate the observed inverse association between plant food intake and risk of gastric cancer. We investigated whether the total dietary antioxidant potential of fruit and vegetables is an appropriate means of estimating the antioxidant impact on gastric cancer risk in a large population-based study.

METHODS

With a population-based case-control design, data were collected through face-to-face interviews with 505 newly diagnosed gastric adenocarcinoma patients and 1116 control subjects to assess dietary habits 20 years before interview. The total radical-trapping antioxidant potential (TRAP) of different plant foods was used to convert food frequency intake into antioxidant potential. Gastric cancer risk in groups exposed to higher levels of oxidative stress (smoking and Helicobacter pylori infection) was also examined.

RESULTS

Intake of antioxidant equivalents was inversely associated with the risk of both cardia and distal gastric cancer (odds ratio [OR], 0.65; 95% confidence interval [CI], 0.48-0.89 for the highest quartile of TRAP). Controlling for smoking, the inverse relationship between TRAP values displayed a clearer dose-response pattern. Never-smokers with the highest antioxidant intake had the lowest risk of cancer, 0.44 (95% CI, 0.27-0.71). Among H. pylori-infected subjects, the ORs varied between 0.66 and 0.41 for increasing levels of antioxidant potential.

CONCLUSIONS

Our results suggest that dietary intake of antioxidants measured as total antioxidant potential is inversely associated with risk of both cardia and distal cancer. The innovative approach used in this study provides a new tool for investigating the relationship between dietary antioxidants and oxidative stress-related carcinogenesis.

Epigallocatechin gallate, a constituent of green tea, represses hepatic glucose production

Herbs have been used for medicinal purposes, including the treatment of diabetes, for centuries. Plants containing flavonoids are used to treat diabetes in Indian medicine and the green tea flavonoid, epigallocatechin gallate (EGCG), is reported to have glucose-lowering effects in animals. We show here that the regulation of hepatic glucose production is decreased by EGCG. Furthermore, like insulin, EGCG increases tyrosine phosphorylation of the insulin receptor and insulin receptor substrate-1 (IRS-1), and it reduces phosphoenolpyruvate carboxykinase gene expression in a phosphoinositide 3-kinase-dependent manner. EGCG also mimics insulin by increasing phosphoinositide 3-kinase, mitogen-activated protein kinase, and p70(s6k) activity. EGCG differs from insulin, however, in that it affects several insulin-activated kinases with slower kinetics. Furthermore, EGCG regulates genes that encode gluconeogenic enzymes and protein-tyrosine phosphorylation by modulating the redox state of the cell. These results demonstrate that changes in the redox state may have beneficial effects for the treatment of diabetes and suggest a potential role for EGCG, or derivatives, as an antidiabetic agent.

Endocrine disruption by indole-3-carbinol and tamoxifen: blockage of ovulation

Immature Sprague-Dawley rats received daily doses of indole-3-carbinol (I3C, 0-1.5 g/kg/day), 3,3'-diindolymethane (DIM, 0-400 mg/kg/day), tamoxifen (TAM, 0-0.5 mg/kg/day), or vehicle to determine if their antiestrogenic effects occur by the same mechanism and whether I3C's action is mediated by DIM. Follicular development was induced on day 24 of age by equine chorionic gonadotropin (eCG, 5 IU) 1 day after the initial dose. In a hormone replacement study, human chorionic gonadotropin (hCG, 10 IU sc, 48 h post-eCG) was used to mimic a normal preovulatoy luteinizing hormone (LH) surge following treatment with either I3C or TAM. Blood and ovaries were collected throughout follicular development and the number of ova shed was measured on the morning following expected ovulation (72 h post-eCG). I3C but not TAM reduced body weight gain at higher doses after 4 days of dosing. Ovarian weight gain and ovulation were inhibited by both I3C and TAM in a dose-dependent fashion. During the preovulatory period, both I3C and TAM blocked normal LH and follicle-stimulating hormone (FSH) surges and suppressed serum progesterone (P(4)) profoundly without changing circulating levels of estrogen (E(2)). At the time of expected ovulation, serum E(2) was increased in rats receiving I3C or tamoxifen, whereas serum P(4) was dose-dependently decreased. DIM exerted no significant effects on any of the endpoints studied, even at the highest dose, indicating that the antiestrogenic effects of I3C are not mediated by this metabolite of I3C. hCG successfully restored ovarian weight gain and ovulation in TAM-treated rats. However, hCG only partially reversed the blockage of ovulation by I3C, although ovarian weight gain was restored to normal. In summary, both I3C and TAM block ovulation by altering preovulatory concentrations of LH and FSH, but I3C appears to exert its effect(s) by (a) different mechanism(s) of action. I3C seems to act at both the ovarian and hypothalamic levels by mechanisms similar to those seen in TCDD-treated rats, whereas TAM appears to act only on the hypothalamic-pituitary axis as an anti-estrogen.

The role of nutrition and nutrients in the prevention of chronic diseases

The nutritional factors that increase risk of heart disease, many cancers, and diabetes are identical. Controlling body weight, being physically active, limiting intake of saturated fats, and eating ample amount of fruits and vegetables can all reduce the risk for many different chronic diseases. Physicians have many opportunities to assist their patients in reducing their nutritional risk of chronic diseases.

Are vitamin and mineral deficiencies a major cancer risk?

Diet is estimated to contribute to about one-third of preventable cancers -- about the same amount as smoking. Inadequate intake of essential vitamins and minerals might explain the epidemiological findings that people who eat only small amounts of fruits and vegetables have an increased risk of developing cancer. Recent experimental evidence indicates that vitamin and mineral deficiencies can lead to DNA damage. Optimizing vitamin and mineral intake by encouraging dietary change, multivitamin and mineral supplements, and fortifying foods might therefore prevent cancer and other chronic diseases.

Primary prevention: phytoprevention and chemoprevention of colorectal cancer

Considering the various stages of carcinogenesis and the numerous tumor types and available chemoprevention agents, knowledge of the etiology and the type of cancer to be treated, or possibly prevented, and understanding of the mechanisms by which agents exert their chemoprevention benefits may provide for improved strategy in designing therapeutic regimens. Because cancer usually develops over a 10- to 20-year period, it may be necessary for some agents to be provided before or early in the initiation steps of carcinogenesis to have beneficial effects. On the other hand, some agents may be more suitable for CRC prevention if provided at a later stage of carcinogenesis. Gene array, genomics, and proteomics are useful tools in advancing our understanding of the molecular events involved in carcinogenesis and in identifying markers of risk and surrogate end-points for colorectal cancer progression. These techniques may also serve for screening, identifying, and providing treatment targets for high-risk patients populations. Treatment could be developed depending on a patient's individual needs and genomic tumor profile. Clinical markers and surrogate end-points should be considered, together with molecular measurements, to more accurately assess risk. NSAIDs and COXIBs are clinically recognized as chemoprevention agents, and clinical trials evaluating their efficacy are ongoing. Treatment protocols, including dose and timing, remain to be determined, however. DFMO may best be used in combination with other chemoprevention agents. Dietary fiber and calcium supplements, as part of an overall low-fat diet, may decrease CRC risk. Long-term compliance with this regimen may be necessary to effect a beneficial outcome. Folate holds promise but needs further investigation, especially because its beneficial effects may depend on cancer type. Phytochemicals have been identified as strong candidates for use as agents to prevent colorectal cancer in cell culture and in rodent models of carcinogenesis. Their potential as chemoprevention agents must be demonstrated in clinical trials. In vitro and animal studies indicated that combination therapy may be a promising strategy over the monotherapy approach; clinical trials addressing the safety and efficacy of some combinations (DFMO/sulindac, fiber/calcium) are underway. The gastrointestinal tract and other organs are constantly exposed to a mixture of potentially toxic compounds and molecules considered favorable to health. Homeostasis between stress-mediated by toxic compounds and defensive mechanisms, is key for the maintenance of health and the prevention of disease. Whereas aggressive pharmacologic treatment may be necessary for patients at high risk for cancer, dietary supplements may be useful for populations at normal risk. The message for cancer prevention in the general population may well remain: keep a balanced healthy diet, eating a variety from all food groups, as part of a healthy lifestyle that includes moderate exercise.

Construção de um questionário de freqüência alimentar como subsídio para programas de prevenção de doenças crônicas não transmissíveis

O presente estudo avaliou a adequação de uma lista de alimentos e a distribuição do tamanho das porções alimentares em versão simplificada de um questionário quantitativo de freqüência alimentar, visando sua adoção em programas de prevenção e controle de doenças crônicas não transmissíveis. Para esta análise, um inquérito recordatório de 24 horas (IR24) foi obtido em amostra aleatória de funcionários da Administração Central da Secretaria de Estado da Saúde de São Paulo (n =212), durante um estudo piloto do programa de combate ao tabagismo. A lista de alimentos do questionário de freqüência alimentar foi avaliada pela contribuição percentual de alguns de seus nutrientes em relação ao consumo total estimado através do IR24. O tamanho das porções alimentares do questionário de freqüência alimentar foi classificado em pequeno, médio e grande de acordo com a distribuição percentual dos pesos correspondentes às medidas caseiras referidas no IR24, utilizando-se os percentis 25, 50 e 75, respectivamente.

Search for dietary antimutagens and anticarcinogens: methodological aspects and extrapolation problems

It is well documented that dietary factors play a crucial role in the aetiology of human cancer and strong efforts have been made to identify protective (antimutagenic and anticarcinogenic) substances in foods. Although numerous studies have been published, it is problematic to use these results for the development of nutritional strategies. The aim of this article is a critical discussion of the pitfalls and problems associated with the search for protective compounds. The main obstacles in regard to the extrapolation of the data to the human situation arise from: (i) the use of inadequate experimental in vitro models, which do not reflect protective mechanisms in man and therefore give misleading results; (ii) the use of genotoxins and carcinogens that are not relevant for humans; (iii) the lack of knowledge about dose-effect relationships of DNA-protective and cancer protective dietary constituents; (iv) the use of exposure concentrations in animal models which exceed by far the human exposure levels; and finally (v) the lack of knowledge on the time-kinetics of protective effects. More relevant data can be expected from in vitro experiments with cells possessing inducible phase I and phase II enzymes, short-term in vivo models with laboratory animals which enable the measurement of effects in organs that are targets for tumour formation, and human biomonitoring studies in which endpoints are used that are related to DNA damage and cancer.

Evaluation of a theater production about eating behavior of children

This study evaluated "All's Well That Eats Well," a theater production performed in 20 schools in the Twin Cities, Minn., metropolitan area in winter 2000. The production sought to change food-related knowledge and food choices concerning fruits and vegetables among children in grades 1-6. The study used a pretest-posttest design with two randomly-assigned, sequential intervention-control groups (N = 4,093). All students completed surveys prior to and then following the theater production and the classroom and home activities. No differences existed between the groups at pretest. Significant differences occurred in food-related knowledge, food choices, and food recall from pretest to posttest for all students. Significant differences also occurred between intervention groups in food-related knowledge and food choices. The study indicates that professional theater productions in schools can create at least a short-term effect on children's nutrition knowledge and behavior.

Effects of anthocyanins and other phenolic compounds on the production of tumor necrosis factor alpha in LPS/IFN-gamma-activated RAW 264.7 macrophages

Flavonoids have been reported to demonstrate their benefits in lowering oxidative stress and beneficial effects on cardiovascular and chronic inflammatory diseases. Common phenolic compounds, including phenolic acids, flavonols, isoflavones, and anthocyanins, present in fruits, vegetables, and grains were investigated for their effects on the production of tumor necrosis factor alpha (TNF-alpha) in LPS/IFN-gamma-activated RAW 264.7 macrophages. Gallic acid and (+)-catechin showed small but significant effects, whereas chlorogenic acid had no effect on TNF-alpha production. The flavonol quercetin inhibited TNF-alpha production, but kaempferol and myricetin induced the secretion of TNF-alpha. The isoflavone genistein was an inhibitor of TNF-alpha, whereas daidzein induced TNF-alpha production. Glycosylation of genistein changed its inhibitory effects to TNF-alpha induction, and glycosylation of daidzein had no effect on its activity. Anthocyanidins/anthocyanins and anthocyanin-rich extracts induced TNF-alpha production and acted as modulators of the immune response in activated macrophages. This is the first study to report the effects of anthocyanins and berry extracts on TNF-alpha production.

Polyphenols: do they play a role in the prevention of human pathologies?

Polyphenols are the most abundant antioxidants in our diets. The main classes of polyphenols are phenolic acids (mainly caffeic acid) and flavonoids (the most abundant in the diet are flavanols (catechins plus proanthocyanidins), anthocyanins and their oxidation products), which account for one- and two-thirds, respectively. Polyphenols are reducing agents, and together with other dietary reducing agents, such as vitamin C, vitamin E and carotenoids, referred to as antioxidants, protect the body's tissues against oxidative stress and associated pathologies such as cancers, coronary heart disease and inflammation. The biological properties, bioavailability, antioxidant activity, specific interactions with cell receptors and enzymes, are related to the chemical structure of polyphenols. It is, therefore, essential to know the nature of the main polyphenols ingested, their dietary origin, the amounts consumed in different diets, their bioavailability and the factors controlling their bioavailability.

Metabolism of sinigrin (2-propenyl glucosinolate) by the human colonic microflora in a dynamic in vitro large-intestinal model

Cruciferous vegetables, such as Brassica, which contain substantial quantities of glucosinolates, have been suggested to possess anticarcinogenic activity. Cutting and chewing of cruciferous vegetables releases the thioglucosidase enzyme myrosinase, which degrades glucosinolates to isothiocyanates and other minor metabolites. Cooking of cruciferous vegetables inactivates the myrosinase enzyme, allowing intact glucosinolates to reach the large intestine, where they can be degraded by the indigenous microflora into isothiocyanates. This local release of isothiocyanates may explain the protective effect of cruciferous vegetables on the colon epithelium. However, little is known about the amounts and identities of glucosinolate metabolites produced by the human microflora. The production of allyl isothiocyanate from sinigrin was investigated in a dynamic in vitro large-intestinal model, after inoculation with a complex microflora of human origin. Sinigrin and allyl isothiocyanate concentrations were analysed in the lumen and dialysis fluid of the model. Peak levels of allyl isothiocyanate were observed between 9 and 12 h after the addition of sinigrin. The model was first set up with a pooled and cultured human microflora, in which 1 and 4% of, respectively, 1 and 15 mM sinigrin, was converted into AITC. However, the conversion rate was remarkably higher if different individual human microflora were used. Between 10% and 30% (mean 19%) of the sinigrin was converted into allyl isothiocyanate. The results of this study suggest that allyl isothiocyanate is converted further into other, yet unknown, metabolites.

Relation between PROP (6-n-propylthiouracil) taster status, taste anatomy and dietary intake measures for young men and women

Previous studies have related 6-n-propylthiouracil (PROP) taster status to preference for, and consumption of various (bitter-tasting) foods recognized for their cancer-preventive properties. The aim of this study was to examine PROP taster status in relation to general measures of dietary intake as well as the consumption of specific food groups. College students (n=183) were classified as non-tasters (n=49), medium tasters (n=89) and supertasters (n=45) of PROP based on intensity ratings of NaCl and PROP solutions. Dietary intake measures were derived from a food frequency questionnaire and body mass indices (BMI) were derived from self-reported height and weight. Supertasters had higher fungiform papillae counts on the anterior tongue than tasters and non-tasters, yet the distributions of papillae counts overlapped across PROP taster groups. No significant differences were found for BMI values and energy intake among taster groups. PROP-tasting women derived a greater percentage of their dietary energy from fat, and consumed less fruit than non-tasters. PROP supertasters did not differ from tasters and non-tasters in intake of bitter fruits, vegetables or beverages except for a lesser intake of green salad. The hypothesis that PROP supertasters, through heightened sensitivity to, and avoidance of, bitter-tasting fruits, vegetables and other foods with antioxidant properties, may therefore be at increased risk for diet-linked diseases such as cancer, is not supported by these findings.

Changes in vegetable and fruit consumption and awareness among US adults: results of the 1991 and 1997 5 A Day for Better Health Program surveys

OBJECTIVE

The purpose of this study is to assess population-based changes in vegetable and fruit consumption and psychosocial correlates.

DESIGN

Two nationally representative random digit dial surveys conducted in 1991 and 1997; respondents were queried regarding consumption of and attitudes and knowledge about vegetables and fruit.

SUBJECTS/SETTING

Respondents were 2,755 and 2,544 adults (in 1991 and 1997, respectively) older than 18 years.

STATISTICAL ANALYSIS PERFORMED

Vegetable and fruit consumption and message awareness were measured using weighted-only and regression model-adjusted analyses to assess changes.

RESULTS

Mean vegetable and fruit consumption was significantly (P=.007) higher in 1997 than in 1991 using weighted-only analyses, but remained significant only for Hispanic (P=.03) and nonsmoker (P=.004) subgroups when adjusted for demographic shifts. Significantly higher percentages were found in the model-adjusted analyses for those consuming 5 or more (daily servings (23.4% to 25.8%), message awareness (7.7% to 19.2%), and knowledge of the 5 A Day Program (2.0% to 17.8%).

APPLICATIONS/CONCLUSIONS

A significantly positive change in vegetable and fruit consumption occurred between 1991 and 1997 according to traditional methods of survey data analysis, but null findings resulted when the data were adjusted for demographic shifts. Nutrition professionals should continue targeting specific demographic subgroups with tailored interventions to move all Americans toward achievement of dietary guidelines for vegetable and fruit consumption.

Antioxidant capacity of honeys from various floral sources based on the determination of oxygen radical absorbance capacity and inhibition of in vitro lipoprotein oxidation in human serum samples

Honeys from seven different floral sources were analyzed for in vitro antioxidant capacity and total phenolic content. Antioxidant capacity was measured by the oxygen radical absorbance capacity (ORAC) assay and by monitoring the formation of conjugated dienes as an index of the inhibition of copper-catalyzed serum lipoprotein oxidation. ORAC values ranged from 3.1 to 16.3 micromol Trolox equivalent/g honey. The darkest colored honeys, such as buckwheat honey, had the highest ORAC values. A linear correlation was observed between phenolic content and ORAC activity of the investigated honeys (p < 0.0001, R (2) = 0.9497). The relationship between the ORAC activity and inhibition of lipoprotein oxidation by the honeys yielded a correlation coefficient of 0.6653 (p = 0.0136). This work shows that honey may be used as a healthy alternative to sugar in many products and thereby serve as a source of dietary antioxidants.

Bioflavonoid-rich botanical extracts show antioxidant and gene regulatory activity

Reactive oxygen and nitrogen metabolites are obligatory and essential products of metabolism. Unregulated increase in their production is associated with a number of chronic illnesses. Diets rich in fruits, vegetables, and wines are implicated in the prevention of chronic diseases. Molecular mechanisms by which fruits and vegetables confer their disease-preventive actions are poorly defined. However, recent developments in the fields of genomics and bioinformatics provide powerful tools to investigate the mechanisms by which botanicals affect cellular functions. This monograph illustrates the potential of large-scale messenger RNA analysis to unravel the role of transcription in mediating the effects of botanical extracts with antioxidant properties. The application of microarrays and oligonucleotide arrays shows multiple effects of antioxidant extracts on the expression of a broad spectrum of genes.

Estimation of carotenoid accessibility from carrots determined by an in vitro digestion method

OBJECTIVE

To develop an in vitro digestion method to assess the impact of heat treatment, particle size and presence of oil on the accessibility (available for absorption) of alpha- and beta-carotene in carrots.

DESIGN

Raw and cooked carrots were either homogenized or cut into pieces similar to chewed items in size. The carrot samples, with or without added cooking oil, were exposed to an in vitro digestion procedure. Adding a pepsin-HCl solution at pH 2.0 simulated the gastric phase. In the subsequent intestinal phase, pH was adjusted to 7.5 and a pancreatin-bile extract mixture was added. Carotenoids released from the carrot matrix during the digestion were extracted and quantified on high-performance liquid chromatography (HPLC).

RESULTS

Three percent of the total beta-carotene content was released from raw carrots in pieces. When homogenized (pulped) 21% was released. Cooking the pulp increased the accessibility to 27%. Addition of cooking oil to the cooked pulp further increased the released amount to 39%. The trends for alpha-carotene were similar to those for beta-carotene.

CONCLUSION

The described in vitro digestion method allows a rapid estimation of carotene accessibility in processed carrots, which may reliably predict in vivo behavior.

SPONSORSHIP

This study was supported by the Swedish International Development Cooperation Agency (SIDA) and the International Program in the Chemical Sciences (IPICS), Uppsala University, Sweden.

A cost-analysis of adopting a healthful diet in a family-based obesity treatment program

OBJECTIVE

To assess dietary costs during a family-based pediatric obesity intervention.

DESIGN

Families were randomized to one of two groups. Dietary and cost data were collected from a parent or child using three 24-hour recalls: at baseline, 6 months, and 12 months.

SUBJECTS

Thirty-one families with an obese 8- to 12-year-old child entered treatment, with complete dietary data provided from 20 families.

INTERVENTION

The 20-week behavior modification intervention emphasized increasing diet nutrient-density. Families attended group and individual sessions or group sessions.

MAIN OUTCOME MEASURES

Energy intake; percent of energy from protein, fat, and carbohydrate; servings and percent servings from food groups classified by nutrient density; and daily food costs.

STATISTICAL ANALYSES PERFORMED

Mixed analyses of variance, with group as the between-subject factor, and time as the within-subject factor.

RESULTS

No significant effect of group was found in any analyses. Significant decreases in percent overweight were observed at 6 and 12 months for children (-10.0+/-8.7 and -8.0+/-10.3, respectively) (mean+/-standard deviation) and parents (-6.7+/-10.3 and -5.3+/-14.1). Energy intake for parents and children combined significantly decreased from baseline (1,881+/-462) to 6 months (1,412+/-284), and 1 year (1,338+/-444). Servings from low-nutrient-dense foods significantly decreased from baseline (34.7+/-16.2) to 6 months (16.0+/-8.6) and 1 year (18.6+/-9.2), causing a significant increase in diet nutrient density. Dietary cost did not change at 6 months, but significantly decreased from baseline to 1 year ($6.77+/-2.41 to $5.04+/-1.80). Cost per 1,000 kcal did not significantly change.

APPLICATIONS/CONCLUSIONS

Adopting a lower-energy, nutrient-dense diet did not increase dietary costs over time. Consequently, cost should not be a barrier in the adoption of a healthful diet.

Epidemiologic trends in esophageal and gastric cancer in the United States

Use of tobacco, moderate to heavy alcohol ingestion, infrequent consumption of raw fruits and vegetables, and low income accounted for more [figure: see text] than 98% of the SCE rates among both African American and white men and for 99% of the excess incidence among African Americans compared to whites in a case-control study in three areas of the United States [14]. Thus, it is likely that declines in the prevalence of smoking and drinking, especially among men, and increased intake of fresh fruits and vegetables may have contributed to the downward incidence and mortality rate trends reported for SCE. In addition, it seems plausible that obesity, GERD, and possibly reductions in H. pylori prevalence have contributed to the upward trends in ACE rates. Reductions in smoking, improved diet, and reductions in H. pylori prevalence probably have contributed to the consistent reductions observed for NGA. Contributing factors are less clear for the rising incidence rates of GCA during the 1970s and 1980s. These incidence rates have not continued to rise in recent years.

Nutrition in cancer prevention: an integrated approach

There is considerable evidence that the war on cancer is not being won. There is, however, strong evidence that a substantial fraction of cancer can be prevented by using existing nutritional knowledge. In this paper we discuss strategies for reducing cancer incidence by implementing this knowledge. The most obvious route for persuading large numbers to change their diets is by individual counseling in a health-care setting, public education campaigns and interventions at the worksite. However, such health promotion actions have met with only limited success. For efforts to change population diets to be successful, a vital component must include changes in govemment policies. Examples of the tools that need to be employed are restrictions on advertising and marketing. Effective action will likely require an economic dimension, namely the employment of taxation and subsidies, for instance, by taxing unhealthy food choices and by subsidizing fruit and vegetables.

Sodium copper chlorophyllin: in vitro digestive stability and accumulation by Caco-2 human intestinal cells

Sodium copper chlorophyllin (SCC), a mixture of water-soluble chlorophyll derivatives, is used as both a food colorant and a common dietary supplement. Although the potential antimutagenic and antioxidant properties of this commercial preparation have been demonstrated, limited information is available on its digestion and absorption by humans. Stability of SCC was examined during simulated gastric and small intestinal digestion. Three preparations were subjected to in vitro digestion: SCC in water, SCC in water + 10% corn oil, and SCC in applesauce. SCC components from raw material preparations and in digested samples were analyzed by C(18) HPLC with photodiode array detection. Cu(II)chlorin e(4), the major chlorin component of SCC, was relatively stable during simulated digestion. In contrast, greater than 90% of Cu(II)chlorin e(6) was degraded to undetermined products during digestion. Recovery of Cu(II)chlorin e(6) after digestion was increased by incorporation of SCC into applesauce, suggesting a protective role of the inclusion matrix for stabilization of labile SCC components. Accumulation of SCC derivatives was investigated by using differentiated cultures of the TC7 clone of the Caco-2 human intestinal cell line. Cellular accumulation from media containing 0.5 to 60 ppm SCC was linear with intracellular content ranging between 0.2 and 29.6 microg of total SCC per mg of cellular protein. Uptake of SCC by Caco-2 cells was significantly (p < 0.01) lower in cultures incubated at 4 degrees C than in those incubated at 37 degrees C. Although intracellular SCC was transported into both apical and basolateral compartments when Caco-2 cells were grown on inserts, apical efflux was significantly greater (p < 0.01) than basolateral efflux. Stability of Cu(II)chlorin e(4) during in vitro digestion and effective uptake by Caco-2 enterocyte-like cells support the likelihood that a portion of this SCC component or its metabolites is absorbed from the human intestine.

Eating and smoking behaviours of school children in southwestern Ontario and Charlottetown, PEI

We conducted in-class written surveys of fourth to eighth grade children's eating and smoking behaviours in southwestern Ontario (n = 870) and Charlottetown (n = 423) in order to facilitate local school boards' and health units' planning of health education initiatives. Using chi-square analysis, we examined sex, grade, provincial and rural-urban differences in behaviours. No rural-urban differences emerged. While students reported few gender differences in food group consumption, more PEI students consumed French fries, snack foods, cakes and cookies, and regular soft drinks daily. Only 60.1% (379/630) of girls and 70.0% (462/660) of boys (chi 2 = 13.8; p < 0.001) ate breakfast every day, falling to 53.2% (115/216) among eighth grade girls, and 32.9% (25/76) among students who smoked. The prevalence of smoking was 4.8% (n = 40) in Ontario and 8.5% (n = 36) in PEI (chi 2 = 6.8; p < 0.01). Compared to non-smokers, a higher proportion of students who smoked consumed snack foods and regular soft drinks daily. The results emphasize the need to promote healthy eating behaviours and anti-smoking messages among school children.

The diet-induced proinflammatory state: a cause of chronic pain and other degenerative diseases?

BACKGROUND

It is the rare physician who includes diet therapy and nutritional supplements in patient care. Perhaps this is because chiropractic and medical schools devote very few classroom hours to nutrition. It is also possible that physicians are under the misconception that a detailed biochemical understanding of each individual disease is required before nutritional interventions can be used.

OBJECTIVE

The purpose of this article is two-fold: (1) to demonstrate that chronic pain and other degenerative conditions encountered in clinical practice have similar biochemical etiologies, such as a diet-induced proinflammatory state, and (2) to outline a basic nutritional program that can be used by all practitioners.

DATA SOURCES

The data were accumulated over a period of years by reviewing contemporary articles and books and subsequently by retrieving relevant articles. Articles were also selected through MEDLINE and manual library searches.

RESULTS

The typical American diet is deficient in fruits and vegetables and contains excessive amounts of meat, refined grain products, and dessert foods. Such a diet can have numerous adverse biochemical effects, all of which create a proinflammatory state and predispose the body to degenerative diseases. It appears that an inadequate intake of fruits and vegetables can result in a suboptimal intake of antioxidants and phytochemicals and an imbalanced intake of essential fatty acids. Through different mechanisms, each nutritional alteration can promote inflammation and disease.

CONCLUSION

We can no longer view different diseases as distinct biochemical entities. Nearly all degenerative diseases have the same underlying biochemical etiology, that is, a diet-induced proinflammatory state. Although specific diseases may require specific treatments, such as adjustments for hypomobile joints, beta-blockers for hypertension, and chemotherapy for cancer, the treatment program must also include nutritional protocols to reduce the proinflammatory state.

Psychosocial factors and dietary habits associated with vegetable consumption

OBJECTIVE

We assessed scales of psychosocial factors and dietary habits related to vegetable consumption and examined associations of these scales with vegetable intake.

METHODS

Data are from 838 adults who participated in a 1997 to 1998 Washington State random digital-dial survey designed to monitor attitudes and behavior related to cancer risk and prevention. Information was collected on psychosocial factors related to vegetable consumption, vegetable-related dietary habits, demographic (participant) characteristics, and vegetable intake. Factor analyses were used to identify the underlying dimensions in the psychosocial and dietary habits scales. Analyses of variance, linear regression, and Pearson's correlations examined associations among participant characteristics, psychosocial factors, dietary habits, and vegetable consumption.

RESULTS

Factor analyses of the psychosocial scale suggested four coherent dimensions or subscales--importance of eating vegetables, health benefits, convenience and taste of raw vegetables, and taste of cooked vegetables--with good internal consistency reliability (Cronbach's alpha = 0.67-0.77). There were four subscales within the dietary habits scale--add vegetables to mixed dishes, include vegetables at lunch and dinner, eat raw vegetables, and eat salads--with fair internal consistency reliability (Cronbach's alpha = 0.37-0.61). The psychosocial factors and dietary habits were strongly correlated (summary scales Pearson's r = 0.55), and after adjustment for participant characteristics, both scales were significantly and positively associated with vegetable intake (Pearson's r = 0.45 and 0.54, respectively, for summary scales; all Ps < 0.001). Further, the scales explained between 14% and 23% of the variance in vegetable intake.

CONCLUSIONS

These scales of psychosocial factors and dietary habits related to vegetable consumption could be used to target intervention messages and evaluate intervention effects.