Diet and health: what should we eat?

The application and impact of computer-generated personalized nutrition education: a review of the literature

Computer-tailored nutrition education may be more effective than general nutrition education because messages are tailored to individual behavior, needs and beliefs of subjects. Therefore, the messages are likely to be of more personal relevance and may have stronger motivational effects. Computer-generated nutrition education has been studied for different dietary behaviors, in different target populations, and in different settings. In recent years, eight studies have been published that assessed the impact of comprehensive computer-generated nutrition interventions that were based on behavior change theory. In this article, the process of providing people with computer-tailored nutrition education is described and the studies on the impact of computer-tailored nutrition education are reviewed. The results point to the conclusion that computer-tailored nutrition education is more likely to be read, remembered, and experienced as personally relevant compared to standard materials. Furthermore, computer-tailored nutrition education also appears to have a greater impact in motivating people to change their diet, their fat intake in particular, although at present no definite conclusions can be drawn.

Increasing fruit and vegetable consumption through worksites and families in the treatwell 5-a-day study

OBJECTIVES

We report on the results of the Treatwell 5-a-Day study, a worksite intervention aimed at increasing consumption of fruits and vegetables.

METHODS

Twenty-two worksites were randomly assigned to 3 groups: (1) a minimal intervention control group, (2) a worksite intervention, and (3) a worksite-plus-family intervention. The interventions used community-organizing strategies and were structured to target multiple levels of influence, following a socioecological model. Data were collected by self-administered employee surveys before and after the intervention; the response rate was 87% (n = 1359) at baseline and 76% (n = 1306) at follow-up. A process tracking system was used to document intervention delivery.

RESULTS

After control for worksite, gender, education, occupation, race/ethnicity, and living situation, total fruit and vegetable intake increased by 19% in the worksite-plus-family group, 7% in the worksite intervention group and 0% in the control group (P = .05). These changes reflect a one half serving increase among workers in the worksite-plus-family group compared with the control group (P = .018).

CONCLUSIONS

The worksite-plus-family intervention was more successful in increasing fruit and vegetable consumption than was the worksite intervention. Worksite interventions involving family members appear to be a promising strategy for influencing workers' dietary habits.

Review article: olestra and its gastrointestinal safety

Olestra is a fat substitute made from sucrose and vegetable oil. Olestra is neither digested nor absorbed, and therefore adds no calories or fat to the diet. Because the gut is the only organ that is exposed to olestra, the potential for olestra to affect gastrointestinal structure and function, and the absorption of nutrients from the gut, has been investigated. Histological evaluations performed after long-term feeding studies have shown no indications that olestra causes injury to the gastrointestinal mucosa. Olestra is not metabolized by the colonic microflora, and has no meaningful effects on the metabolic function of these organisms. Studies of gastrointestinal transit have shown that the consumption of olestra with food does not affect gastric emptying, or small or large bowel transit times. Olestra does not affect the absorption of macronutrients, water-soluble vitamins or minerals. It causes a dose-responsive decrease in the availability of the fat-soluble vitamins A, D, E and K; however, this potentially adverse effect is offset by the addition of vitamins to olestra-containing foods. Olestra has no consistent effect on the amount of total bile acids excreted in the faeces, and therefore probably has no significant effect on bile acid absorption. The occurrence of gastrointestinal symptoms, including diarrhoea, loose stools, gas and abdominal cramping, after consumption of olestra under ordinary snacking conditions is comparable to that following consumption of triglyceride-containing snacks.

Serum antioxidant capacity is increased by consumption of strawberries, spinach, red wine or vitamin C in elderly women

It is often assumed that antioxidant nutrients contribute to the protection afforded by fruits, vegetables, and red wine against diseases of aging. However, the effect of fruit, vegetable and red wine consumption on the overall antioxidant status in human is unclear. In this study we investigated the responses in serum total antioxidant capacity following comsumption of strawberries (240 g), spinach (294 g), red wine (300 ml) or vitamin C (1250 mg) in eight elderly women. Total antioxidant capacity was determined using different methods: oxygen radical absorbance capacity (ORAC) assay, Trolox equivalent antioxidant capacity (TEAC) assay and ferric reducing ability (FRAP) assay. The results showed that the total antioxidant capacity of serum determined as ORAC, TEAC and FRAP, using the area under the curve, increased significantly by 7-25% during the 4-h period following consumption of red wine, strawberries, vitamin C or spinach. The total antioxidant capacity of urine determined as ORAC increased (P < 0.05) by 9.6, 27.5, and 44.9% for strawberries, spinach, and vitamin C, respectively, during the 24-h period following these treatments. The plasma vitamin C level after the strawberry drink, and the serum urate level after the strawberry and spinach treatments, also increased significantly. However, the increased vitamin C and urate levels could not fully account for the increased total antioxidant capacity in serum following the consumption of strawberries, spinach or red wine. We conclude that the consumption of strawberries, spinach or red wine, which are rich in antioxidant phenolic compounds, can increase the serum antioxidant capacity in humans. J. Nutr. 2383-2390, 1998

Chromosomal damage rate, aging, and diet

Chromosomal damage as measured by frequency of translocations, acentric fragments, telomere shortening, nondisjunction, chromosome loss, aneuploidy, and micronucleus formation has been shown to increase progressively with age. Using the cytokinesis-block micronucleus technique, which provides an efficient measure of chromosomal breakage and loss, we have been able to show that aging can explain at least 25% of the variation in chromosomal damage rate in lymphocytes from both males and females. We have also performed cross-sectional and placebo-controlled intervention studies to determine the relationship between the micronucleus (MN) frequency in lymphocytes and diet, and blood status for vitamins C, E, B12, and folic acid. Our studies have shown that MN frequency in the 41- to 60-year age group is significantly lower in vegetarians when compared to nonvegetarians, but the reverse was true in males aged between 20 and 40 years. This was accounted for by a deficient/low B12 status in vegetarian males; there was no difference in the MN frequency of vegetarian and nonvegetarian subjects aged between 61 and 90 years. Results from this study also showed significant negative correlations of MN frequency with folic acid and vitamin B12 but not with vitamin C or vitamin E. In separate studies on healthy men aged 50-70, we have verified the significant negative correlation between vitamin B12 status in plasma and MN frequency (r = -0.315, p = 0.013) in subjects who were not vitamin B12 deficient and observed a significant positive correlation between MN frequency and homocysteine status (r = 0.414, p = 0.0086) in those men who were not vitamin B12 and/or folate deficient. These data suggest that MN frequency is minimized when plasma B12 is above 300 pmol/L and plasma homocysteine is below 7.5 mumol/L. Double-blind placebo-controlled intervention studies conducted over four months have shown that above RDI intake of vitamin E (30 x RDI) or folic acid (10 x RDI) did not produce a significant reduction in MN frequency in men aged 50-70 years. In the latter case plasma homocysteine was reduced from a mean value of 9.33 mumol/L to 8.51 mumol/L, a level that does not correspond with minimization of MN frequency. We have also tested the hypothesis that moderate wine drinking can protect against the DNA-damaging effect of hydrogen peroxide and found that there was a strong ex vivo inhibition (> 70%) of hydrogen peroxide-induced MN frequency by plasma samples from blood collected one hour after consumption of red or white wine, as compared to plasma samples collected immediately before wine consumption (p = 0.0008). However, only samples following red wine consumption produced a significant reduction in baseline MN frequency. The above results suggest that chromosome damage can be modulated, under selected circumstances, by diverse dietary factors.

Frequent nut consumption and risk of coronary heart disease in women: prospective cohort study

OBJECTIVE

To examine the relation between nut consumption and risk of coronary heart disease in a cohort of women from the Nurses' Health Study.

DESIGN

Prospective cohort study.

SETTING

Nurses' Health Study.

SUBJECTS

86 016 women from 34 to 59 years of age without previously diagnosed coronary heart disease, stroke, or cancer at baseline in 1980.

MAIN OUTCOME MEASURES

Major coronary heart disease including non-fatal myocardial infarction and fatal coronary heart disease.

RESULTS

1255 major coronary disease events (861 cases of non-fatal myocardial infarction and 394 cases of fatal coronary heart disease) occurred during 14 years of follow up. After adjusting for age, smoking, and other known risk factors for coronary heart disease, women who ate more than five units of nuts (one unit equivalent to 1 oz of nuts) a week (frequent consumption) had a significantly lower risk of total coronary heart disease (relative risk 0.65, 95% confidence interval 0.47 to 0.89, P for trend=0.0009) than women who never ate nuts or who ate less than one unit a month (rare consumption). The magnitude of risk reduction was similar for both fatal coronary heart disease (0.61, 0.35 to 1.05, P for trend=0.007) and non-fatal myocardial infarction (0.68, 0.47 to 1.00, P for trend=0.04). Further adjustment for intakes of dietary fats, fibre, vegetables, and fruits did not alter these results. The inverse association persisted in subgroups stratified by levels of smoking,use of alcohol, use of multivitamin and vitamin E supplements, body mass index, exercise, and intake of vegetables or fruits.

CONCLUSIONS

Frequent nut consumption was associated with a reduced risk of both fatal coronary heart disease and non-fatal myocardial infarction. These data, and those from other epidemiological and clinical studies, support a role for nuts in reducing the risk of coronary heart disease.

The effects of a health promotion-health protection intervention on behavior change: the WellWorks Study

OBJECTIVES

This study assessed the effects of a 2-year integrated health promotion-health protection work-site intervention on changes in dietary habits and cigarette smoking.

METHODS

A randomized, controlled intervention study used the work site as the unit of intervention and analysis; it included 24 predominantly manufacturing work sites in Massachusetts (250-2500 workers per site). Behaviors were assessed in self-administered surveys (n = 2386; completion rates = 61% at baseline, 62% at final). Three key intervention elements targeted health behavior change: (1) joint worker-management participation in program planning and implementation, (2) consultation with management on work-site environmental changes, and (3) health education programs.

RESULTS

Significant differences between intervention and control work sites included reductions in the percentage of calories consumed as fat (2.3% vs 1.5% kcal) and increases in servings of fruit and vegetables (10% vs 4% increase). The intervention had a significant effect on fiber consumption among skilled and unskilled laborers. No significant effects were observed for smoking cessation.

CONCLUSIONS

Although the size of the effects of this intervention are modest, on a populationwide basis effects of this size could have a large impact on cancer-related and coronary heart disease end points.

Long-term dietary strawberry, spinach, or vitamin E supplementation retards the onset of age-related neuronal signal-transduction and cognitive behavioral deficits

Recent research has indicated that increased vulnerability to oxidative stress may be the major factor involved in CNS functional declines in aging and age-related neurodegenerative diseases, and that antioxidants, e.g., vitamin E, may ameliorate or prevent these declines. Present studies examined whether long-term feeding of Fischer 344 rats, beginning when the rats were 6 months of age and continuing for 8 months, with diets supplemented with a fruit or vegetable extract identified as being high in antioxidant activity, could prevent the age-related induction of receptor-mediated signal transduction deficits that might have a behavioral component. Thus, the following parameters were examined: (1) oxotremorine-enhanced striatal dopamine release (OX-K+-ERDA), (2) cerebellar beta receptor augmentation of GABA responding, (3) striatal synaptosomal 45Ca2+ clearance, (4) carbachol-stimulated GTPase activity, and (5) Morris water maze performance. The rats were given control diets or those supplemented with strawberry extracts (SE), 9.5 gm/kg dried aqueous extract (DAE), spinach (SPN 6.4 gm/kg DAE), or vitamin E (500 IU/kg). Results indicated that SPN-fed rats demonstrated the greatest retardation of age-effects on all parameters except GTPase activity, on which SE had the greatest effect, whereas SE and vitamin E showed significant but equal protection against these age-induced deficits on the other parameters. For example, OX-K+-ERDA enhancement was four times greater in the SPN group than in controls. Thus, phytochemicals present in antioxidant-rich foods such as spinach may be beneficial in retarding functional age-related CNS and cognitive behavioral deficits and, perhaps, may have some benefit in neurodegenerative disease.

Evaluation and treatment of hypertension in active individuals

Hypertension is a very common vascular disease. It is seen in adolescents, obese persons, postmenopausal women, and the elderly. A nonpharmacologic approach to treatment is a critical first step in management. The modalities include a diet low in salt and saturated fat, exercise, less than 2 ounces of alcohol daily, and abstinence from smoking. Dynamic (aerobic) exercise is effective in lowering blood pressure (BP) only if performed regularly. Weight reduction by diet must be combined with exercise if there is to be a reduction in BP. Strength training is not to be considered as an alternative to aerobic training for reducing BP. Antihypertensive mediation can be added to nonpharmacologic interventions for additional BP reduction. Beta-blockade is not a contraindication to exercise training.

Social support and readiness to make dietary changes

This article examines the relationship between reported social support and readiness to increase fruit and vegetable consumption, based on the Transtheoretical Stage of Change Model. Data were collected as part of the baseline assessments for a work site intervention study promoting increased consumption of fruits and vegetables. Among workers who did not live alone, household support was significantly higher for those of Hispanic and African American heritage than other groups, and was also higher among men, nonsmokers, and those living with adults compared to those living only with children. In multivariate analyses, coworker support was significantly associated with being in preparation compared to precontemplation/contemplation. Household support was not significantly related to readiness to change in multivariate analyses. The effectiveness of work site nutrition education interventions is likely to be enhanced by teaching participants to provide social support to coworkers and family members.

How dentition status and masticatory function affect nutrient intake

The authors examined nutrient intake in relation to the number of teeth, denture type and masticatory function among 638 men in the U.S. Department of Veterans Affairs Dental Longitudinal Study. They found that calorie-adjusted nutrient intakes decreased with progressively impaired dentition status, independently of age, smoking status and alcohol use. Intakes of fiber and most vitamins and minerals were inversely correlated with masticatory function. The findings suggest that prevention of tooth loss and prosthodontic replacement of missing teeth could improve diets of older adults.

Comparison of 4 questionnaires for assessment of fruit and vegetable intake

OBJECTIVE

This study compared fruit and vegetable assessments derived from 4 self-administered questionnaires.

METHODS

Among 102 adolescents, servings of fruits and vegetables assessed by 4 questionnaires were compared with estimates from 24-hour recalls.

RESULTS

The prevalence of consuming 5 or more servings of fruits and vegetables a day was underestimated by the questionnaires. Questionnaires asking subjects to recall their diet over the previous year were more effective in ranking subjects (r's > or = .42) than those assessing previous-day diet (r's > or = .30).

CONCLUSIONS

Brief assessments of fruit and vegetable intake are more useful for ranking subjects than for estimating prevalence of consumption of 5 or more servings per day.

The role of dietary fatty acids in lipoprotein oxidation and atherosclerosis

Although it is well established that dietary saturated fatty acid intake is an important risk factor for coronary heart disease, there remains substantial controversy regarding whether these dietary fatty acids should be replaced with either carbohydrates, monounsaturated fatty acids, polyunsaturated fatty acids or a combination of these. This review highlights recent studies evaluating the role of dietary fatty acids in atherosclerosis, with a particular emphasis on their roles in lipoprotein oxidation and other potential proatherogenic processes.

Age-related neurodegeneration and oxidative stress: putative nutritional intervention

This review describes age-related changes that occur in neuronal function and cites evidence to show that these alterations may be the result of increased sensitivity to oxidative stress (OS). Evidence is presented to show that the abilities to mitigate the OS effects and to repair the damage from OS show decline as a function of age. Results from age- and OS-sensitive tests are given; these results indicate that one of the major sites of action of OS is the membranes, especially if compromised by high amounts of sphingomyelin, and one of the major effects of OS is to further alter the calcium disregulation in aging. It is suggested that attempts to increase antioxidant protection through diets comprised of fruits and vegetables identified as being high in total antioxidant activity might prevent or reverse the deleterious OS effects on neuronal aging.

The impact of computer-tailored feedback and iterative feedback on fat, fruit, and vegetable intake

A randomized trial was conducted to study the impact of individualized computer-generated nutrition information and additional effects of iterative feedback on changes in intake of fat, fruits, and vegetables. Respondents in the experimental group received computer-generated feedback letters tailored to their dietary intake, intentions, attitudes, self-efficacy expectations, and self-rated behavior. After the first feedback letter, half of the experimental group received additional iterative feedback tailored to changes in behavior and intentions. The control group received a single general nutrition information letter in a format similar to the tailored letters. Computer-tailored feedback had a significantly greater impact on fat reduction and fruit and vegetable intake than did general information. Iterative computer-tailored feedback had an additional impact on fat intake. The results confirm that computer-generated individualized feedback can be effective in inducing recommended dietary changes and that iterative feedback can increase the longer term impact of computer-tailored nutrition education on fat reduction.

Possible explanations for the tooth loss and cardiovascular disease relationship

Several studies have shown relationships between periodontal disease and cardiovascular disease (CVD). A few studies have also shown that tooth loss may be associated with increased risk of coronary heart disease and stroke. We have reviewed the relevant literature to assess possible explanations for the reported associations between tooth loss and CVD. In particular, we considered whether the reported association between tooth loss and CVD could be explained by antecedent periodontal disease, antecedent caries, the extraction process, dietary changes following tooth loss, or confounding or bias from other sources. Since access to care and attitudes to health care may influence the decision to extract teeth, as well as cardiovascular disease risk, one needs to be cautious about confounding from behaviorally related factors. Available evidence suggests that further studies are needed to rule out that confounding is a possible explanation for the tooth loss and CVD relationship, that prior periodontal disease may not completely explain the tooth loss-CVD relationship, and that the role of diet needs to be further explored

Oxidação lipídica em alimentos e sistemas biológicos: mecanismos gerais e implicações nutricionais e patológicas

Descreve e analisa os avanços no conhecimento das reações de oxidação de lipídios em alimentos e sistemas biológicos e suas implicações sobre a qualidade dos alimentos, a nutrição e a saúde. Mecanismos, fatores e condições associadas à oxidação lipídica são analisadas em alimentos e sistemas biológicos. O problema da deterioração da coloração, da textura e dos atributos sensoriais dos alimentos são avaliados, e são discutidos diversos problemas nutricionais decorrentes da ingestão crônica de alimentos oxidados e suas implicações fisiopatológicas. Relata papel da oxidação lipídica na ocorrência de diversas doenças como aterosclerose, câncer, diabetes, estresse psicológico, infecções (HIV), intoxicações farmacológicas, deficiências nutricionais, e outros processos que envolvem a formação de radicais livres do oxigênio. Discute-se as perspectivas para a população brasileira e as estratégias de intervenção para a prevenção efetiva destes problemas.

Xenoestrogens significantly enhance risk for breast cancer during growth and adolescence

Breast cancer is one of the most common forms of cancer observed in women, and endogenous estrogen is thought to play a major role in its development. Because of this, any conditions or exposures which enhance estrogenic responses would result in an increased risk for breast cancer. The role of xenoestrogenic compounds, such as DDT, in the etiology of breast cancer is still very controversial. In the following paper we discuss recently-published observations by ourselves and others which indicate that xenoestrogens may play a significant role in the development of breast cancer. Specifically, we hypothesize that during periods of high growth rates and during breast development the sensitivity of breast cells to estrogenic compounds is sufficiently great for xenoestrogens to significantly enhance risk for breast cancer.

HPLC method for evaluation of the free radical-scavenging activity of foods by using 1,1-diphenyl-2-picrylhydrazyl

An HPLC method for evaluation of the free radical-scavenging activity of foods by using 1,1-diphenyl-2-picrylhydrazyl (DPPH) is reported. The activity was evaluated by measuring the decrease of DPPH detected at 517 nm. By using this novel method, we determined the free radical-scavenging activity of several antioxidants: ascorbic acid, alpha-tocopherol, Trolox, and cysteine. The results gave good correlation between the radical-scavenging activity determined by HPLC and by conventional colorimetry. This methodology was applied to determine the free radical-scavenging activity of 8 beverages. The activity of coffee was the highest, followed by red wine, green tea, oolong tea, black tea, rosé wine, white wine, and orange juice. The results well agree with those of previous reports. This method is expected to be useful for a simple and rapid determination of free radical-scavenging activity in colored foods, because coloring substances in foods do not interfere with the measurement.

Drug interactions with grapefruit juice. Extent, probable mechanism and clinical relevance

Concomitant intake with grapefruit juice increases the concentrations of many drugs in humans. The effect seems to be mediated mainly by suppression of the cytochrome P450 enzyme CYP3A4 in the small intestine wall. This results in a diminished first pass metabolism with higher bioavailability and increased maximal plasma concentrations of substrates of this enzyme. The effect was most pronounced in drugs with a high first pass degradation and in many cases has the clear potential to reach clinical relevance, as shown by an occasional change in drug effects or tolerability. For felodipine, nitrendipine, nisoldipine and saquinavir, the interaction was most marked with median increases of area under the curve (AUC) and/or the maximum (peak) plasma drug concentration after single-dose administration (Cmax) values exceeding 70% of respective control periods. Less pronounced, but possibly relevant, concentration increases were found for nifedipine, nimodipine, verapamil, cyclosporin, midazolam, triazolam and terfenadine. This list is not complete because many drugs have not been studied yet. The components of grapefruit juice which are the most probable causes of the interactions are psoralen derivatives, but the flavonoid naringenin may also contribute. Concomitant grapefruit juice intake does not generally decrease the variability of drug pharmacokinetic parameters. Therefore, it is recommended that patients refrain from drinking grapefruit juice when they are taking a drug that is extensively metabolised, unless a lack of interaction has already been demonstrated for the drug. It is also recommended that drugs possibly interacting with grapefruit juice should be appropriately labelled. A place for grapefruit juice as a drug-sparing agent in treatment involving expensive medicine cannot be derived from the information currently available on grapefruit juice interactions.

Fat Watch: a nationwide campaign in The Netherlands to reduce fat intake--effect evaluation

In the Netherlands, the nationwide Fat Watch campaign aiming at a reduction in fat consumption was organized from 1991 onwards. This study describes the effects of the first three consecutive campaign years on attention to fat, diet and health, attitudes, self-efficacy expectations and intentions related to dietary fat reduction, and self-rated fat intake. Data were collected each year according to the Solomon design, by telephone interviews among about 1200 consumers responsible for household purchases. Campaign awareness was high in each campaign year, but a decrease in campaign awareness was found after the first campaign in 1991. The 1991 campaign was primarily aimed at getting the attention of the Dutch public for the fat-reduction message and indeed resulted in increased attention. The second campaign year resulted in small but statistically significant positive changes in attitudes, which was the specific target of the 1992 campaign. Intention to buy low-fat food products was also significantly increased. The 1993 campaign failed to realize the targeted increases in self-efficacy among the study population, but a significant campaign effect on intentions was found. The evaluation of all three campaigns indicated that the Dutch underestimate their personal fat intake and this has been identified as an important barrier to a further reduction in fat consumption. Making subjects aware of their personal fat consumption will be given priority in future campaigns.

Effect of dietary catechin and vitamin E on aortic fatty streak accumulation in hypercholesterolemic hamsters

Male golden Syrian hamsters were fed for 16 weeks on a hypercholesterolemic diet containing, per kg, 150 g of lipids (90 g butterfat, 35 g vitamin E-stripped corn oil and 25 g fish oil), 2 g cholesterol and either 3 IU vitamin E (3 IU E), 3 IU vitamin E and 200 mg catechin hydrate (3 IU E-200 Cat) or 30 IU vitamin E (30 IU E). More fatty streaks, measured by Oil Red O staining, were deposited in aortas of hamsters fed 3 IU E than in those fed either 3 IU E-200 Cat or 30 IU E. Lipid staining increased with plasma low-density lipoprotein cholesterol (LDL-C) in all animals. At the same concentration of LDL-C, animals fed either 3 IU E-200 Cat or 30 IU E developed less fatty streaks than those fed 3 IU E. Plasma LDL-C and total cholesterol were highest in hamsters fed 3 IU E and LDL-C and total cholesterol in animals fed 3 IU-200 Cat were not different from those fed either 3 IU E or 30 IU E. This study showed the importance of circulating plasma LDL-C on atherogenesis and the inhibitory effect on this process of both dietary vitamin E and catechin.

Influences on diet, health behaviours and their outcome in select ethnocultural and religious groups

Diverse cultural components of behavior may have significant impacts on patterns of eating, drinking, and social interaction, irrespective of socioeconomic status. For example, the major world religions prescribe or proscribe specific dietary behaviors; some of these are rooted in historical or geographical origins as well as group folklore; and they have integral roles as expressions of religious piety and group cohesiveness. The literature is replete with ecological observations of between-country differences in disease trends, some of which have been associated with dietary practices. The study of distinct cultural and religious groups (especially migrants acculturating to new environments) and the extent to which they adhere to culturally-based dietary precepts, has advanced our knowledge of psychosocial influences on food habits, nutritional adequacy, and overall health. However, a relatively small proportion of culturally-based research studies conducted to date have explored cross-cultural, ethnic, or religious variables. This paper reviews some population-based differences in dietary habits and other behaviors by ethnocultural group or religious denomination; health consequences and suggestions for future research are discussed.

Vitamins E plus C and interacting conutrients required for optimal health. A critical and constructive review of epidemiology and supplementation data regarding cardiovascular disease and cancer

Antioxidants are crucial components of fruit/vegetable rich diets preventing cardiovascular disease (CVD) and cancer: plasma vitamins C, E, carotenoids from diet correlate prevalence of CVD and cancer inversely, low levels predict an increased risk of individuals which is potentiated by combined inadequacy (e.g., vitamins C + E, C + carotene, A + carotene); self-prescribed rectification of vitamins C and E at adequacy of other micronutrients reduce forthcoming CVD, of vitamins A, C, E, carotene and conutrients also cancer; randomized exclusive supplementation of beta-carotene +/- vitamin A or E lack benefits except prostate cancer reduction by vitamin E, and overall cancer reduction by selenium; randomized intervention with synchronous rectification of vitamins A + C + E + B + minerals reduces CVD and counteracts precancerous lesions; high vitamin E supplements reveal potentials in secondary CVD prevention. Plasma values desirable for primary prevention: > or = 30 mumol/l lipid-standardized vitamin E (alpha-tocopherol/cholesterol > or = 5.0 mumol/mmol); > or = 50 mumol/l vitamin C aiming at vitamin C/vitamin E ratio > 1.3-1.5; > or = 0.4 mumol/l beta- (> or = 0.5 mumol/l alpha+ beta-) carotene.

CONCLUSIONS

In CVD vitamin E acts as first risk discriminator, vitamin C as second one; optimal health requires synchronously optimized vitamins C + E, A, carotenoids and vegetable conutrients.

Nutrition education interventions in a community setting: 2 Dutch examples

This article presents the results of two studies among participants of two Dutch nutrition education interventions, i.e. a self-help program and a living room group session. Both interventions aim to reduce fat intake in the general population and were developed as part of the Dutch community health project 'Healthy Bergeyk'. The objectives of the studies were to assess number of participants, participant characteristics, use of the self-help program, participant satisfaction and self-reported effects. Telephone interviews and written questionnaires were completed by inhabitants after participating in the interventions. The results are encouraging and the interventions seem to be useful as part of community projects.

Dietary fat, genes, and human health

These studies show that a macronutrient like dietary fat plays an important role in gene expression. In the cases presented here, dietary fat regulates gene expression leading to changes in carbohydrate and lipid metabolism. The interesting outcome of these studies is the finding that the molecular targets for dietary fat action did not converge with the principal targets for hormonal regulation of gene transcription, like hormone receptors. Instead, PUFA-RF targets elements that play key ancillary roles in gene transcription. This is important because it shows how PUFA can interfere with hormone regulation of a specific gene without having generalized effect on overall hormonal control, i.e. PUFA effects are promoter-specific. How PUFA-RF interferes with gene transcription will require the isolation and characterization of PUFA-RF along with the tissue-specific factors targeted by PUFA-RF. A different story emerges when fatty acids activate PPAR. Based on the studies presented here and elsewhere, long chain-highly unsaturated fatty acids (like 20:5,n-3 and 22:6, n-3) or high levels of fat activate PPAR. PPAR directly activates genes like AOX, but also inhibits transcription of genes like S14, FAS, apolipoprotein CIII, transferrin. For S14, the mechanism of inhibition involves sequestration of RXR, a critical factor for T3 receptor binding to DNA. Thus, PPAR can have generalized effects on T3 action or on other nuclear receptors, like vit. D (VDR) and retinoic acid (RAR) receptors, that require RXR for action. For apolipoprotein CIII and transferrin, PPAR/RXR heterodimers compete for HNF-4 binding sites (DR + 1). In addition to HNF-4, COUP-TF, ARP-1 and RXR all bind the DR + 1 type motif. These factors are important for tissue-specific regulation of gene transcription. PPAR can potentially interfere with the transcription of multiple genes through disruption of nuclear receptor signaling leading to changes in phenotype. Clearly, more studies are required to assess the role PPAR plays in the fatty acid regulation of gene transcription and its contribution to chronic disease. Finally, it is clear that dietary fat has the potential to affect gene expression through multiple pathways. Depending on the gene examined, PUFA might augment or abrogate gene transcription which leads to specific phenotypic changes altering metabolism, differentiation or cell growth. These effects can be beneficial to the organism, such as the n-3 PUFA-mediated suppression of serum triglycerides or detrimental, like the saturated and n-6 PUFA-mediated promotion of insulin resistance. How such effects contribute to the onset or progression of specific neoplasia is unclear. However, studies in metabolism might provide important clues for this connection.

Healthy traditional Mediterranean diet: an expression of culture, history, and lifestyle

The term Mediterranean diet refers to dietary patterns found in olive-growing areas of the Mediterranean region and described in the 1960s and beyond. There are several variants of the Mediterranean diet, but some common components can be identified: high monounsaturated/saturated fat ratio; ethanol consumption at moderate levels and mainly in the form of wine; high consumption of vegetables, fruits, legumes, and grains; moderate consumption of milk and dairy products, mostly in the form of cheese; and low consumption of meat and meat products. Growing evidence demonstrates that the Mediterranean diet is beneficial to health; the evidence is stronger for coronary heart disease, but it also applies to some forms of cancer. Results from recent investigations provide a strong biomedical foundation for the beneficial effects of the Mediterranean diet.

Diet and gene expression in the intestine

Gene expression is central to the pathogenesis of many disorders. An ability to alter the expression of genes would, if their relationship to disease processes were fully understood, constitute a new modality of treatment. This review examines the evidence that nutritional factors can regulate genes in the gastrointestinal epithelium and it discusses the physiological relevance of such alterations in gene expression. Dietary regulation of the genes expressed by the epithelium confers three fundamental advantages for mammals. It enables the epithelium to adapt to the luminal environment to digest and absorb food better; it provides the means whereby mother's milk can influence the development of the gastrointestinal tract; when the proteins expressed by the epithelium act on the immune system, it constitutes a signalling mechanism from the intestinal lumen to the body's defences. Each of these mechanisms is amenable to manipulation for therapeutic purposes.

Behavioral research contributions and needs in cancer prevention and control: dietary change

This paper summarizes key behavioral research contributions to the promotion of healthful diets and identifies the outstanding behavioral research needs that could lead to positive dietary changes in the United States. Nutrition plays an important role in the initiation, promotion, and progression of cancer. Dietary guidelines for health promotion and cancer prevention recommend diets that are lower in fat and higher in fiber, fruits, and vegetables. Behavioral research on dietary change has become more rigorous and sophisticated in the past decade, with noteworthy contributions in four areas: behavioral research within clinical trials, self-help or minimal contact intervention strategies, school nutrition programs and services, and advances in the development of measures. Work in progress includes large-scale randomized intervention trials, with the majority of funding for studies to increase fruit and vegetable consumption. There are many needs for further research. Six priority areas for behavioral research are identified and discussed: (1) determinants of dietary behavior and change processes; (2) policy, environmental, and organizational interventions; (3) studies of dietary change and exercise and interventions with persons at high risk for diet-related cancers; (4) methodological research; (5) research on diffusion and dissemination; and (6) systematic behavioral research on dietary change in clinical trials. A concerted research effort in the area of dietary change has great potential benefits for cancer prevention and control and for public health in general.

Population nutrient intake approaches dietary recommendations: 1991 to 1995 Framingham Nutrition Studies

OBJECTIVE

To estimate population nutrient intake levels and to assess adherence to current dietary recommendations for health promotion and disease prevention.

DESIGN

Cross-sectional analysis of nutrient intake estimated from 3-day food records. Median macronutrient and micronutrient intake levels for men, women, and the total population are reported along with the proportions of men and women who achieved intakes compatible with nutrient goals defined by published guidelines.

SETTING

Adult participants (2,520: 1,375 women and 1,145 men) in the Framingham Offspring-Spouse Study surveyed between 1991 and 1995.

STATISTICAL ANALYSES

chi 2 Analyses were used to test for gender differences in the proportions of persons who had intakes that met nutrient guidelines.

RESULTS

Population intake levels of certain key nutrients, including total and saturated fat, appear to be approaching recommended levels. High proportions of the Framingham population (70% or more) met current recommendations for intakes of protein, polyunsaturated and monounsaturated fat, cholesterol, alcohol, vitamins C and B-12, and folacin. About half or fewer met guidelines for carbohydrate; total and saturated fat; fiber; beta carotene; vitamins A, E, and B-6; calcium; and sodium. Important gender differences in the proportion of those meeting nutrient guidelines were observed for 12 of the 18 nutrients examined, including carbohydrate; total, saturated, and monounsaturated fat; cholesterol; fiber; sodium; calcium; and several vitamins.

CONCLUSIONS

Although progress has been made toward achieving population adherence to preventive nutrition recommendations, large proportions of adults fall short of guidelines for some key nutrients. Differences in adherence rates between men and women suggest areas for gender-specific, targeted nutrition messages and behavioral interventions.

Effect of a diet high in vegetables, fruit, and nuts on serum lipids

We assessed the effect of a diet high in leafy and green vegetables, fruit, and nuts on serum lipid risk factors for cardiovascular disease. Ten healthy volunteers (seven men and three women aged 33 +/- 4 years [mean +/- SEM]; body mass index, 23 +/- 1 kg/m2) consumed their habitual diet (control diet, 29% +/- 2% fat calories) and a diet consisting largely of leafy and other low-calorie vegetables, fruit, and nuts (vegetable diet, 25% +/- 3% fat calories) for two 2-week periods in a randomized crossover design. After 2 weeks on the vegetable diet, lipid risk factors for cardiovascular disease were significantly reduced by comparison with the control diet (low-density lipoprotein [LDL] cholesterol, 33% +/- 4%, P < .001; ratio of total to high-density lipoprotein [HDL] cholesterol, 21% +/- 4%, P < .001; apolipoprotein [apo] B:A-I, 23% +/- 2%, P < .001; and lipoprotein (a) [Lp(a)], 24% +/- 9%, P = .031). The reduction in apo B was related to increased intakes of soluble fiber (r = .84, P = .003) and vegetable protein (r = -.65, P = .041). On the vegetable compared with the control diet, the reduction in total serum cholesterol was 34% to 49% greater than would be predicted by differences in dietary fat and cholesterol. A diet consisting largely of low-calorie vegetables and fruit and nuts markedly reduced lipid risk factors for cardiovascular disease. Several aspects of such diets, which may have been consumed early in human evolution, have implications for cardiovascular disease prevention.

Stable behaviors associated with adults' 10-year change in body mass index and likelihood of gain at the waist

OBJECTIVES

The purpose of this study was to identify behaviors associated with change in body mass index or with weight gain at the waist.

METHODS

A cohort of 79236 White, non-Hispanic, healthy adults was questioned in 1982 and 1992 about diet and 10 physical activities. Estimates were made of the mean effects of stable behaviors on 10-year change in body mass index and on odds ratios for gain at the waist.

RESULTS

Ten-year changes in body mass index was associated positively with meat consumption and smoking cessation and inversely with vegetable consumption, vitamin E supplementation, continued smoking, and some vigorous activities (e.g., jogging/running). Women's body mass index decreased with walking 4 or more hours per week and with regular alcohol intake, but these behaviors had a smaller effect on men's body mass index. weight gain was inversely associated with high vegetable consumption, walking 4 or more hours per week, and jogging/running 1 to 3 hours per week but not with less demanding physical activities.

CONCLUSIONS

Simple derivation of behaviors associated with weight loss or reduced abdominal obesity may enhance programs designed to prevent obesity and chronic diseases.

Social class differences in women's fat and fibre consumption: a cross-national study

This study focuses on social class variation in the intake of fat and fibre in Maastricht, Liège and Aachen, based on food frequency questionnaires of 849 women from nuclear families with schoolgoing children. In Maastricht and Liège higher-middle class women consumed less fat than working class women, while in Aachen no class difference was apparent. The intake of fibre was highest among the higher-middle class women, although this tendency was not significant in Aachen. Analysis of food groups that contribute to the intake of fat and fibre revealed that not all food groups showed this pattern. Higher-middle class women consumed less bread, less potatoes and more cheese than working class women. Moreover, they chose more often high-fat cheese and fats. Yet, working class women consumed more meat, milk and fats, and less grain, fruit and vegetables. In general, social class variations in fat and fibre intake were uniform across the cities, although in Aachen class differences were small or absent. In conclusion, these results suggest that the diet of higher-middle class women is more in accordance with the dietary recommendations regarding fat and fibre than the diet of working class women.

Dietary sucrose and starch affect dysplastic characteristics in carcinogen-induced aberrant crypt foci in rat colon

To study whether dietary carbohydrates affect dysplasia in aberrant crypt foci (ACF), rats treated with 1,2-dimethilhydrazine (DMH) were fed for three months with diets containing 46% sucrose or corn starch. The number of ACF/colon in the two dietary groups was similar (P = 0.58), but ACF were smaller in the starch than in sucrose group (P < 0.05). ACF in the starch group also showed less severe goblet cell dysplasia, more sulphomucins and less sialomucins than in the sucrose group (P < 0.05), indicating that corn starch protects against colon carcinogenesis while sucrose in the diet is detrimental, promoting the dysplasia of preneoplastic lesions like ACF.

How can components of common foods affect cancer risk?

Strong epidemiological evidence implicates diet in a substantial proportion of cancer cases. Nutritionists largely agree on the attributes of a healthy diet for cancer prevention (and also for cardiovascular health). Researchers are now studying specific food components that can actively suppress the processes involved in carcinogenesis. The most potent of these could be used directly for chemoprevention in high-risk individuals and might even have potential in cancer therapy.

Nutrient intake patterns, body mass index, and vitamin levels in patients with rheumatoid arthritis

OBJECTIVE

To assess nutrient intakes and vitamin levels in 79 patients with rheumatoid arthritis participating in a trial and to determine whether changes in body mass index were associated with changes in disease activity.

METHODS

This study evaluated baseline vitamin levels, 1-day dietary intakes, and weight every 3 months for 1 year. Linear regression analysis was used to evaluate the relationship of time to body mass index. Analysis of covariance was used to determine if body mass index, time, or treatment had an effect on disease activity.

RESULTS

Deficient vitamin levels and poor nutrient intake patterns were prevalent in the study population. Changes in body mass index over time did not correlate with changes in disease activity.

CONCLUSIONS

Rheumatoid arthritis patients are at high risk of obesity, abnormal vitamin levels, and poor nutrient intakes. Changes in body mass index failed to correlate with changes in disease activity.

What demographers can learn from fruit fly actuarial models and biology

Historically demographers have viewed the results of actuarial studies of nonhuman species, particularly those on invertebrates such as fruit flies, as largely irrelevant to investigations on human populations. In this paper I present life table data from large scale studies on the Mediterranean fruit fly, and show that they provide important insights into fundamental aspects of mortality relevant to human populations: the trajectory of mortality at older ages, sex mortality differentials, the concept of maximal life span, and demographic heterogeneity and selection. An overriding theme of the paper is the need for demographers to acquire a heightened awareness of new developments in biology including areas such as evolutionary ecology, experimental demography, and molecular medicine.

Estrogenic and antiproliferative properties of genistein and other flavonoids in human breast cancer cells in vitro

Experimental and epidemiologic studies support the view that soyfoods prevent cancer as well as diseases and symptoms associated with estrogen deficiency. Recent research suggests that the isoflavonoid genistein, a phytoestrogen found in abundance in soyfoods, may be one of the principal molecular components responsible for these health benefits. In this study we investigated the effects of a broad physiologically relevant concentration range of genistein on estrogen receptor (ER) binding, induction of the estrogen-regulated antigen pS2, and cell proliferation rate in ER(+) and ER(-) human breast cancer cells grown in vitro. Dose response to genistein was compared with that of estradiol, tamoxifen, and several other structurally similar iso- and bioflavonoids (e.g., equol, kaempferol, and quercetin). Our results revealed that genistein has potent estrogen agonist and cell growth-inhibitory actions over a physiologically achievable concentration range (10 nM-20 microM). Other flavonoids over the same concentration range were good estrogen agonists and poor cell growth inhibitors (equol) or poor estrogen agonists and potent growth inhibitors (kaempferol and quercetin). The growth-inhibitory actions of flavonoids were distinctly different from those of triphenyl antiestrogens like tamoxifen. In summary, our results reveal that genistein is unique among the flavonoids tested, in that it has potent estrogen agonist and cell growth-inhibitory actions over a physiologically relevant concentration range.

Effect of a high or a low fat diet on cardiovascular risk factors in male and female runners

Dietary fat may be associated with coronary heart disease (CHD). Studies suggest that restricting fat intake may compromise endurance performance and that increasing fat intake may improve endurance performance. We studied the effects of varying dietary fat intake on CHD risk factors in runners. Twelve male and 13 female runners increased fat from 16% to 30% of daily calories (4 wk each). Of this group, six males and six females increased fat to 42% of daily calories (4 wk). Physiological and lipoprotein risk factors were measured after each diet. Results were analyzed by repeated measures ANOVA. Increasing dietary fat from 16% to 42% of daily calories did not change adiposity, weight, heart rate, blood pressure, serum triglycerides, total cholesterol, LDL cholesterol. Apolipoprotein B, or the Apo A1/Apo B ratio. Compared with those eating higher fat, subjects eating 16% fat had lower HDL cholesterol (50 +/- 3 vs 62 +/- 3 mg.dl-1, P < 0.0001) and Apolipoprotein A1 (111 +/- 6 v. 134 +/- 6 mg/dl, P < 0.0005) and a higher TC/HDL-C ratio (4.05 +/- 0.27 vs 3.42 +/- 0.24, P < 0.0005). Runners who increased fat intake to 42% further raised HDL cholesterol (64 +/- 6 to 69 +/- 5 mg.dl-1, P < 0.04) without adversely affecting other lipoproteins. In conclusion, a 42% fat diet maintained favorable CHD risk factors in female and male runners whereas a 16% fat diet lowered Apo A1 and HDL-C and raised the TC/HDL-C ratio.