Variation in fruit and vegetable consumption among adults in Britain. An analysis from the dietary and nutritional survey of British adults

OBJECTIVES: Using a national representative sample to examine variation in fruit and vegetable consumption among adults in the UK, with particular reference to consumers with high and low reported intakes. DESIGN: National representative dietary survey using 7-d weighed diet records of men and women aged 16-64 y living in private households in the UK in 1986-1987. SETTING: The UK. SUBJECTS: 1087 men and 1110 women. The sample was selected by a multi-stage random probability design. The response was 70%. Subjects with low energy intake were subsequently excluded. MAIN OUTCOME MEASURES: Food group, nutrient intake, physiological measures socio-economic, demographic and behavioural characteristics. RESULTS: Consumption of fruit and vegetables was estimated. The sample was divided by sex into four quarter groups according to fruit and vegetable consumption. There were significant similarities between quarter groups in fruit and vegetable and other food intake, nutrient intake, physiological measures, and socioeconomic, demographic and behavioural variable. The lowest consumers of fruit and vegetables had a mean intake of 738 g/week (men) and 630 g/week (women), equivalent to 1.3 and 1.1 portion/d, respectively. Conversely, the mean intake of both men women with the highest consumption was 3137 g/week (5.6 portions day). There were more than twice as many adults in the age group 16-24 located in Q1 than in Q4. The Manual social class and those in receipt of benefits were negatively associated with fruit and vegetable consumption. Smokers were significantly associated with low fruit and vegetable intake. Being married was associated with increased fruit and vegetable intake and being single or divorced/separated was associated with low fruit and vegetable intake. Eating home grown produce was associated with high intake. Consumers who lived in London or the South-East were associated with higher fruit and vegetable intake. CONCLUSIONS: The analysis draws attention to the wide variation in reported fruit and vegetable consumption among British adults. High consumers merit further investigation to elucidate practical strategies for increasing fruit and vegetable consumption. Strategies to increase consumption should be targeted at groups most likely to include low consumers of fruits and vegetables. SPONSORSHIP: London School of Hygiene and Tropical Medicine.     

Dietary intake of vegetables and fruits among adults in five regions of Spain. EPIC Group of Spain. European Prospective Investigation into Cancer and Nutrition

OBJECTIVE: To assess the consumption of vegetables and fruits (V&F) in adults from five regions in Spain according to sex, age and educational level. DESIGN: Cross-sectional study within the members of the EPIC cohort in Spain. SETTING: Three regions of the north of Spain (Asturias, Guipúzcoa and Navarra) and two regions of the south of Spain (Granada and Murcia). SUBJECTS: 41448 healthy volunteers (15365 men, 25813 women), aged 29-69 y. INTERVENTIONS: Information on habitual diet during the previous year was collected by means of a computerised version of a diet history questionnaire. RESULTS: Among men, the mean daily consumption of vegetables and of fruits was 273.7 g (3.4 servings) and 348.3 g (4.4 servings) respectively. Among women, the corresponding vegetables and fruit intakes per day were 244.4g (3.1 servings) and 349.4g (4.4 servings). The total V&F intake tended to increase with age and educational level. Overall, 74% of subjects consumed 400 g/d (5 servings) of vegetables and fruit. CONCLUSIONS: Consumption of vegetables and fruits in healthy adults in Spain is considerably higher than in most European countries and the United States; this complies with what is considered to be the Mediterranean diet. Despite some regional differences, there were no clearly differentiated patterns of V&F intake between southern and northern regions within Spain.     

Encouraging the consumption of fruit and vegetables by older Australians: an experiential study

OBJECTIVE: To explore perceptions of dietary recommendations for fruit and vegetables, and barriers and opportunities for increasing consumption. DESIGN: Qualitative study with an experiential component. SETTING: Older adults' households. PARTICIPANTS: Six focus groups with 38 Australian adults aged 50 to 64 years who reported low vegetable consumption. INTERVENTION: Week 1: focus group including demonstration of recommended fruit and vegetable servings; week 2: delivery of a week's supply of fruit and vegetables and recipes; week 3: follow-up focus group. VARIABLES MEASURED: Perceptions of a healthful diet, fruit and vegetable recommendations, barriers to consumption, and reactions to the food delivery and recipes. ANALYSIS: Qualitative, thematic analysis. RESULTS: Participants were unfamiliar with serving recommendations. Barriers to consumption were as follows: perceptions that vegetables are eaten only with evening meals, preference for eating meat, believing that recommended quantities were too big, and a lack of preparation time. The delivery had a positive impact on some (especially low fruit consumers), for whom the availability of appealing fruit served as a prompt for consumption. CONCLUSIONS AND IMPLICATIONS: Possible strategies for enabling consumers to achieve adequate fruit and vegetable consumption are education about the recommended number and size of servings and distribution of fruit and vegetables relative to meat and carbohydrates, encouragement to spread fruit and vegetable consumption over the day, and promoting the appealing sensory attributes of fruit and vegetables.     

Effects of enhanced consumption of fruit and vegetables on plasma antioxidant status and oxidative resistance of LDL in smokers supplemented with fish oil

OBJECTIVE: To determine whether consumption of five portions of fruit and vegetables per day reduces the enhancement of oxidative stress induced by consumption of fish oil. SUBJECTS: A total of 18 free-living healthy smoking volunteers, aged 18-63 y, were recruited by posters and e-mail in The University of Reading, and by leaflets in local shops. DESIGN: A prospective study. SETTING: Hugh Sinclair Unit of Human Nutrition, School of Food Biosciences, The University of Reading, Whiteknights PO Box 226, Reading RG6 6AP, UK. INTERVENTION: All subjects consumed a daily supplement of 4 x 1 g fish oil capsules for 9 weeks. After 3 weeks, they consumed an additional five portions of fruits and vegetables per day, and then they returned to their normal diet for the last 3 weeks of the study. Fasting blood samples were taken at the ends of weeks 0, 3, 6 and 9. RESULTS: The plasma concentrations of ascorbic acid, lutein, beta-cryptoxanthin, alpha-carotene and beta-carotene all significantly increased when fruit and vegetable intake was enhanced (P<0.05). Plasma concentrations of alpha-tocopherol, retinol and uric acid did not change significantly during the period of increased fruit and vegetable consumption. Plasma oxidative stability, assessed by the oxygen radical absorbance capacity (ORAC) assay, also increased from weeks 3-6 (P<0.001) but not in association with increases in measured antioxidants. Lag phase before oxidation of low-density lipoprotein (LDL) significantly decreased in the first 3 weeks of the study, reflecting the incorporation of EPA and DHA into LDL (P<0.0001). Subsequent enhanced fruit and vegetable consumption significantly reduced the susceptibility of LDL to oxidation (P<0.005). CONCLUSION: Fish oil reduced the oxidative stability of plasma and LDL, but the effects were partially offset by the increased consumption of fruit and vegetables.     

Fruits and vegetables increase plasma carotenoids and vitamins and decrease homocysteine in humans

Observational epidemiologic studies have shown that a high consumption of fruits and vegetables is associated with a decreased risk of chronic diseases. Little is known about the bioavailability of constituents from vegetables and fruits and the effect of these constituents on markers for disease risk. Currently, the recommendation is to increase intake of a mix of fruits and vegetables ("five a day"). We investigated the effect of this recommendation on plasma carotenoids, vitamins and homocysteine concentrations in a 4-wk dietary controlled, parallel intervention study. Male and female volunteers (n = 47) were allocated randomly to either a daily 500-g fruit and vegetable ("high") diet or a 100-g fruit and vegetable ("low") diet. Analyzed total carotenoid, vitamin C and folate concentrations of the daily high diet were 13.3 mg, 173 mg and 228.1 microg, respectively. The daily low diet contained 2.9 mg carotenoids, 65 mg vitamin C and 131.1 microg folate. Differences in final plasma levels between the high and low group were as follows: lutein, 46% [95% confidence interval (CI) 28-64]; beta-cryptoxanthin, 128% (98-159); lycopene, 22% (8-37); alpha-carotene, 121% (94-149); beta-carotene, 45% (28-62); and vitamin C, 64% (51-77) (P < 0.05). The high group had an 11% (-18 to -4) lower final plasma homocysteine and a 15% (0.8-30) higher plasma folate concentration compared with the low group (P < 0.05). This is the first trial to show that a mix of fruits and vegetables, with a moderate folate content, decreases plasma homocysteine concentrations in humans.     

Longitudinal trends in consumption of vegetables and fruit in Finnish children in an atherosclerosis prevention study (STRIP)

OBJECTIVE: To assess prospectively the consumption of fruit and vegetables and its' correlation to the parental consumption in boys and girls taking part in an atherosclerosis prevention study (Special Turku Coronary Risk Factor Intervention Project for Children (STRIP) study). HYPOTHESIS: Nutrition counselling focused on cardiovascular health effects vegetable and fruit consumption. DESIGN: A prospective, randomised, clinical trial. SUBJECTS: Children were recruited to the STRIP study between 1989 and 1992. At the age of 7 months, children were randomised to the intervention (n = 540) or the control group (n = 522) and were followed up until the age of 11 years. INTERVENTION: Families in the intervention group have, since randomisation, received biannual individualised dietary counselling aimed at reduction of cardiovascular risk factors, especially saturated fat intake. Food records were used to assess fruit and vegetable consumption of children and parents. RESULTS: The percentage of total energy intake provided by fruit and vegetables decreased when the children grew older (P for age <0.001). The 1- to 10-year-old intervention boys consumed more vegetables (mean difference 3.18 g/day; CI 1.48-4.86; P < 0.001) and fruit (mean difference 10.1 g/day; CI 5.28-14.94; P < 0.001) than did the control. Mother's consumption correlated with the consumption of their daughters and sons, whereas father's consumption correlated only with the consumption of their sons. CONCLUSIONS: Finnish children taking part in the atherosclerosis prevention study had a remarkably low fruit and vegetable consumption, which furthermore decreased with age. The children's consumption correlated with the parental consumption, except between boys and mothers. A slight intervention effect was present only among boys.     

The effect of an increased intake of vegetables and fruit on weight loss, blood pressure and antioxidant defense in subjects with sleep related breathing disorders

OBJECTIVE: To assess the effect of an increased consumption of vegetables and fruit on body weight, risk factors for cardiovascular disease (CVD) and antioxidant defense in obese patients with sleep-related breathing disorders (SRBD). DESIGN: Randomized, controlled trial of an intervention to increase the intake of vegetables to 400 g/day and fruit to 300 g/day. Dietary intake was calculated from a food frequency questionnaire. Antioxidant status was assessed with the ferric-reducing/antioxidant power (FRAP) assay. Plasma carotenoids were biomarkers for the intake of vegetables and fruit. SETTING: A hospital clinic preventing risk factors for CVD. SUBJECTS: Subjects were 103 men and 35 women with a body mass index of 36.7+/-5.8 kg/m(2) of which 57 (86%) in the control and 68 (94%) in the intervention group completed the study. INTERVENTION: Group-based behavioral program during 3 months. RESULTS: The mean between group differences in body weight was -2.0% (95% CI -3.6, -0.5), P<0.0001. The mean between group difference in systolic and diastolic blood pressure (BP) was -7.1 mm Hg (95% CI: -11.6, -2.6), P=0.0022 and -3.9 mm Hg (95% CI: -7.0, -0.9), P=0.0120, respectively. The mean change in daily intake of vegetables and fruit was 12 g (95% CI: -33, 57) and -4 g (95% CI: -79, 71) versus 245 g (95% CI: 194, 296) and 248 g (95% CI: 176, 320) in the control and intervention groups, respectively. This was reflected in higher concentrations of alpha-carotene and beta-carotene. No change in FRAP was seen. In a multiple regression analysis the change in intake of vegetables was a significant contributor (R(adj)(2)=0.073 (95% CI: 0.019, 0.214)) to the change in weight. CONCLUSION: Targeted dietary advice to increase the intake of vegetables and fruit among subjects with SRBD contributed to weight reduction and reduced systolic and diastolic BP, but had no effect on antioxidant defense measured with FRAP.     

Psychosocial predictors of increases in fruit and vegetable consumption

OBJECTIVES: To examine psychosocial predictors of changes in fruit and vegetable consumption. METHODS: Baseline psychosocial variables were used to explain differences in changes in consumption in 83 healthy women with children after they received free fruit and vegetables for one month. RESULTS: One-month changes in fruit consumption (mean 144; SE 16 g/day) were positively associated with perceived costs and perceived health benefits for the children, and negatively associated with perceived behavioral control. Changes in vegetable consumption (68 (11) g/day) were positively related with the intention to eat at least 200 g of vegetables and taste preferences of the children. CONCLUSIONS: Fruit and vegetable consumption may be encouraged by influencing the above variables.     

Dietary approaches for weight loss with increased intakes of fruit, vegetables and dairy products

Aim:  To assess the effectiveness of specific advice for increasing fruit, vegetable and dairy intake in free-living men participating in a weight loss study.
Methods:  Subjects were randomised to one of two 12-week weight loss diets, either the WELL with daily targets of four serves of fruit, four serves of vegetables and three serves of dairy or a low fat diet (LF) with general advice to increase fruit and vegetable intake. Three-day food group diaries and a food frequency questionnaire assessed intake.
Results:  Fifty-four overweight/obese male adults completed the study (WELL, n = 27; LF, n = 27; body mass index (mean ± standard deviation), 30.4 ± 2.5 kg/m²; age, 47.7 ± 9.5 years). There was no difference in mean weight change between groups (WELL, −4.8 ± 3.3 kg; LF, −4.6 ± 3.1 kg). Subjects on the WELL diet had greater (mean difference ± standard error) fruit (0.7 ± 0.2 serves/day), vegetable (1.2 ± 0.2 serves/day) and dairy (1.1 ± 0.1 serves/day) intakes than the LF group (measured by the food group diaries) (all P  < 0.01). The WELL group reached the daily target for fruit from week 1 (4.7 ± 1.4 serves/day), vegetables by week 6 (4.1 ± 1.5 serves/day) and for dairy by week 8 (3.0 ± 0.8 serves/day).
Conclusions:  Providing specific dietary targets to men for weight loss appears to promote greater consumption of fruit, vegetable and dairy foods than providing general dietary advice. Meeting dietary targets appears to require different adjustment periods depending on the food type.     

Assessment of fruit and vegetable intake among the population of junior high school students from Oleśnica

The aim of this study was to assess fruit and vegetable intake among the population of junior high school students. 113 students from Junior High School No. 2 in Ole?nica participated in the research. In order to assess the intake of fruit and vegetables, the method of food frequency questionnaire was used. It was stated that vegetables appearing most frequently in the diet of girls were: tomatoes, carrots, cucumbers and fresh vegetable salads, and in the meals of boys were: tomatoes, fresh vegetable salads, cucumbers and vegetable salads. Boys and girls declared that the most often consumed fruits were: apples, oranges, mandarins and bananas. The mean daily total consumption of fruit and vegetables by the junior high school students was 358.5 g/day. Compared with current dietary recommendations, intakes of fruit and vegetables were too low.     

An approach to the development of food-based dietary guidelines for Ireland

The aim of the present study was to analyse the different food and nutrient intakes of the adult Irish population from the lowest and highest quartiles of intake for total fat (%energy) dietary fibre (g/MJ) and fruit and vegetables (g/day). Data on Irish adults (n = 715) from the Irish National Nutrition Survey conducted in 1989 were used for the analyses and showed that the average diet is low in dietary fibre, with fruit and vegetables being only half the recommended level of 400 g. Comparisons of people with low or high intakes (from lowest and highest quartiles) of total fat (%energy), dietary fibre (g/MJ) and fruit and vegetables (g/day) show patterns of food intake differing in both the percentage of consumers and in the mean intakes among consumers only. This analysis provides data which may be useful as a first step towards the development of food-based dietary guidelines for Ireland. In particular, the low intake of fruit and vegetables in the adult Irish population deserves special attention.     

Guidelines for the intake of vegetables and fruit: the Mediterranean approach

Various studies have demonstrated that the nutrient and non-nutrient substances present in vegetables and fruit (V&F) are most likely to be responsible for the beneficial effect of the increased V&F consumption. Urged by scientific evidence, current dietary guidelines strongly recommend the consumption of V&F in substantial amounts. In a recent paper (Brit. J. Nutr. 2000; 84, 549-556) V&F availability in 10 European countries was compared with the WHO recommendations (minimum combined V&F intake of about 400 g/day/person), as well as with guidelines of a minimum daily intake of three portions of vegetables (approx. 250 g/person) and two portions of fruit (approx. 150 g/person). All countries, excluding Greece, had a vegetable intake below the recommended minimum. Moreover, in all countries, the percentages of low vegetable consumers were significantly higher than those of low fruit consumers, suggesting that there is considerable room for improvement in the intake of vegetables, an important source of antioxidants. Wild edible greens are among the vegetables commonly consumed in Greece. These greens have a high flavonoid content, which in several cases substantially exceeds the respective values in foods and beverages, such as onions, black tea and red wine (Food Chemistry 2000; 70, 319-323). The high flavonoid content of edible wild greens requires consideration of their role in contemporary diet, as a possible mean for increasing vegetable consumption.     

Increasing fruits and vegetables in midlife women: a feasibility study

The positive link between bone health and fruit/vegetable consumption has been attributed to the lower renal acid load of a diet high in alkaline-forming fruit/vegetables. Other important dietary determinants of bone health include micronutrients and bioactives found in fruit/vegetables. We hypothesized that increased intake of fruit/vegetables to 9 or more servings a day would lower net endogenous acid production (NEAP) significantly (~20 mEq/d) and increase urine pH (0.5 pH units). This 8-week feasibility study investigated if 21 midlife women (age, 40-65 years) currently consuming 5 or less servings a day of fruit/vegetables could increase their intake to 9 or more servings a day to substantially lower NEAP and include specific vegetables daily. Three-day diet diaries were completed at baseline and the end of the study and assessed for NEAP (estimated) and number of servings from all food groups. Urine pH dipsticks were provided for the participants to assess and record their fasting urine pH daily (second void). Seventy-six percent of women achieved the study aim, which was to increase to 9 or more servings of fruit/vegetables for at least 5 d/wk. There was a reduction in the number of bread/cereal servings. Net endogenous acid production (estimated) was reduced significantly, with a mean urine pH increase of 0.68 pH units (95% confidence interval, 0.46-1.14); however, daily urine pH measures showed high variability. This study demonstrated that a group of midlife women can change their diet for 8 weeks by significantly increasing fruit/vegetable servings and include specific “bone friendly” vegetables daily, resulting in a significant decrease in estimated dietary NEAP and an increase in urine pH.     

The global burden of disease attributable to low consumption of fruit and vegetables: implications for the global strategy on diet

OBJECTIVE: We estimated the global burden of disease attributable to low consumption of fruit and vegetables, an increasingly recognized risk factor for cardiovascular disease and cancer, and compared its impact with that of other major risk factors for disease. METHODS: The burden of disease attributable to suboptimal intake of fruit and vegetables was estimated using information on fruit and vegetable consumption in the population, and on its association with six health outcomes (ischaemic heart disease, stroke, stomach, oesophageal, colorectal and lung cancer). Data from both sources were stratified by sex, age and by 14 geographical regions. FINDINGS: The total worldwide mortality currently attributable to inadequate consumption of fruit and vegetables is estimated to be up to 2.635 million deaths per year. Increasing individual fruit and vegetable consumption to up to 600 g per day (the baseline of choice) could reduce the total worldwide burden of disease by 1.8%, and reduce the burden of ischaemic heart disease and ischaemic stroke by 31% and 19% respectively. For stomach, oesophageal, lung and colorectal cancer, the potential reductions were 19%, 20%, 12% and 2%, respectively. CONCLUSION: This study shows the potentially large impact that increasing fruit and vegetable intake could have in reducing many noncommunicable diseases. It highlights the need for much greater emphasis on dietary risk factors in public health policy in order to tackle the rise in noncommunicable diseases worldwide, and suggests that the proposed intersectoral WHO/FAO fruit and vegetable promotion initiative is a crucial component in any global diet strategy.     

Six carotenoids in plasma used to assess recommended intake of fruits and vegetables in a controlled feeding study

BACKGROUND: There is a need for objective and universally applicable biomarkers for the intake of foods believed to affect human health. OBJECTIVE: The purpose of this feeding study was to test whether plasma concentrations of carotenoids could be used to distinguish recommended consumption of mixed fruits and vegetables (five a day) from the current national intake of fruits and vegetables (two a day). DESIGN: A strict crossover design was chosen to correct for observed interindividual variations in carotenoid response. A total of 40 healthy subjects were included in the study. After 1 week run-in period with no fruits and vegetables in the diet, one group was given two portions (300 g) of fruits and vegetables daily, while another group was given five portions (750 g) for 14 days. Following a 2 week wash-out period and 1 week run-in, the regimens were switched between the groups. Fruits and vegetables were combined to match a typical Norwegian diet. RESULTS: Enhanced intake from two to five portions of mixed fruits and vegetables increased plasma concentrations of alpha-carotene (P=0.033) and lutein (P=0.051) in a crossover analysis. Analysis of data in the parallel part of the study revealed differences between the high and low intake for plasma concentrations of alpha-carotene (P=0.013) and beta-carotene (P=0.016). A trend was also evident for plasma concentrations of lycopene (P=0.057) and lutein (P=0.076) in the parallel analysis. No effect of high vs low intake of fruits and vegetables was observed for plasma concentrations of beta-cryptoxanthin, zeaxanthin, cholesterol and triacylglycerols. CONCLUSION: The study indicates that plasma concentration of alpha-carotene, beta-carotene and lutein may be used to assess changes of fruit and vegetable intake corresponding to an increase from the present national intake in Norway to the recommended amount of five portions of fruits and vegetables daily. SPONSORSHIP: Norwegian Research Council, National Nutrition Council, Throne Holst Foundation for Nutrition Research and Freia Chokoladefabriks Medisinske Fond.     

An investigation into the bioaccessibility of potassium in unprocessed fruits and vegetables

Epidemiological studies and clinical trials have consistently shown an inverse association between potassium intake and blood pressure. As a means of raising potassium intake within the UK population, an increase in the consumption of fruits and vegetables is strongly advocated. The aim of this study was to determine the bioaccessibility of potassium in these foods. A 10-day crossover feeding trial was performed on 11 healthy volunteers. For 5 days a diet providing most of the potassium in the form of unprocessed fruits and vegetables was followed by a diet in which the potassium was believed to be almost wholly bioaccessible, being derived from animal foods and fruit juices. The potassium and sodium of the diets and the urine were determined by chemical analysis: 96.3% of the potassium in the ‘high bioaccessible diet’ was recovered in the urine, compared with 76.8% from the diet rich in fruits and vegetables. This difference is attributed to the cellular structure of plant foods. The relatively poor bioaccessibility of potassium diminishes the perceived nutritive value of these foods with regard to potassium intake.     

Spinach and tomato consumption increases lymphocyte DNA resistance to oxidative stress but this is not related to cell carotenoid concentrations

Summary Background The increased consumption of fruit and vegetables has been linked to protection against different chronic diseases, but the dietary constituents responsible for this association have not been clearly identified. Aim of the study We evaluated the effect of spinach and spinach+tomato puree consumption on cell DNA resistance to an oxidative stress. Methods To this aim, in a dietary controlled intervention study, 9 healthy female volunteers consumed a basal diet low in carotenoids (< 600 μg/day) enriched with daily portions (150 g) of spinach (providing about 9 mg lutein, 0.6 mg zeaxanthin, 4 mg β-carotene) for 3 weeks (from day 0 to day 21) followed by a 2 week wash-out period (basal diet) and finally another 3 weeks (from day 35 to day 56) of diet enriched with daily portions of spinach (150 g) + tomato puree (25 g, providing about 7 mg lycopene, 0.3 mg β-carotene). At the beginning and the end of each period of vegetable intake, blood samples were collected for lymphocyte separation. Carotenoid concentrations of lymphocytes were determined by HPLC and DNA damage was evaluated by the comet assay following an ex vivo treatment with H₂O₂. Results During the first period of spinach consumption, lymphocyte lutein concentration did not increase significantly (from 1.6 to 2.2 μmol/10¹² cells) while lycopene and β-carotene concentrations decreased significantly (from 1.0 to 0.1 μmol/10¹² cells, P < 0.001, and from 2.2 to 1.2 μmol/10¹² cells, P < 0.05, respectively). Lutein and lycopene concentrations increased after spinach+tomato puree consumption (from 1.2 to 3.5 μmol/10¹² cells, P < 0.01, and from 0.1 to 0.7 μmol/10¹² cells, P < 0.05, respectively). The increase may be attributed to the addition of tomato puree to spinach; however, the different concentrations of carotenoids in lymphocytes registered at the beginning of the two intervention periods may have affected the results. DNA resistance to H₂O₂ insult increased significantly after both the enriched diets (P < 0.01); however, no “additive effect” was seen after spinach + tomato puree consumption. In the spinach + tomato intervention period an inverse correlation was observed between lymphocyte lycopene concentration and DNA damage, but this seems not able to explain the protection observed. Conclusions The consumption of carotenoid-rich foods even for a short period of time gives protection against oxidative stress. The results obtained seem to suggest that this protective role is not specifically related to carotenoids. However they may contribute together with other substances present in vegetables to lymphocyte resistance to oxidative damage. Received: 20 September 2001, Accepted: 18 February 2002     

A Nitrate-Rich Vegetable Intervention Elevates Plasma Nitrate and Nitrite Concentrations and Reduces Blood Pressure in Healthy Young Adults

BackgroundEmerging evidence suggests that increasing dietary nitrate intake may be an effective approach to reduce blood pressure. Beetroot juice is often used to supplement dietary nitrate, whereas nitrate intake levels from habitual diet are low. An increase in the habitual intake of nitrate-rich vegetables may represent an alternative to nitrate supplementation. However, the effectiveness and acceptability of a nitrate–rich-vegetables diet remain to be established.ObjectiveThe aim was to investigate the effect and feasibility of two different intervention strategies to increase dietary nitrate intake, on plasma nitrate/nitrite concentrations and blood pressure.DesignA randomized, crossover trial was used.ParticipantsParticipants were healthy men and women (both n=15; age: 24±6 years) from the Netherlands.InterventionParticipants were instructed to consume ∼400 mg nitrate at lunch, provided through nitrate-rich vegetables and dietary counseling, or beetroot juice supplementation. Both interventions lasted 1 week, with 1-week washout (January to April 2017).Main outcomePlasma nitrate and nitrite concentrations and resting systolic and diastolic blood pressure were measured in an overnight fasted state (before and after intervention) and ∼2.5 hours after lunch (before and throughout intervention on day 1, 4, and 7).Statistical analysisTwo-factor (time × treatment) repeated-measures analyses of variance were performed.ResultsMean plasma nitrate concentrations increased with both interventions, with a larger increase in beetroot juice vs nitrate-rich vegetables, both in a fasted state and ∼2.5 hours after lunch (day 1, beetroot juice: 2.31±0.56 mg/dL [373±90 μmol/L] vs nitrate-rich vegetables: 1.71±0.83 mg/dL [277±134 μmol/L]; P<0.001). Likewise, mean plasma nitrite concentrations increased with both interventions, but were higher after lunch in beetroot juice than in nitrate-rich vegetables (day 1: 2.58±1.52 μg/dL [560±331 nmol/L] vs 2.15±1.21 μg/dL [468±263 nmol/L]; P=0.020). Fasting mean systolic and diastolic blood pressure did not change, but mean systolic and diastolic blood pressure assessed ∼2.5 hours after lunch were significantly reduced throughout both intervention periods (P<0.05), with no differences between beetroot juice and nitrate-rich vegetables (day 1, systolic blood pressure: –5.1±9.5 mm Hg and diastolic blood pressure: –5.3±8.9 mm Hg).ConclusionShort-term consumption of dietary nitrate in the form of nitrate-rich vegetables represents an effective means to increase plasma nitrate and nitrite concentrations, and reduces blood pressure to the same extent as beetroot juice supplementation.     

Effect of increasing fruit and vegetable intake by dietary intervention on nutritional biomarkers and attitudes to dietary change: a randomised trial

Purpose

Low fruit and vegetable consumption is linked with an increased risk of death from vascular disease and cancer. The benefit of eating fruits and vegetables is attributed in part to antioxidants, vitamins and phytochemicals. Whether increasing intake impacts on markers of disease remains to be established. This study investigates whether increasing daily intake of fruits, vegetables and juices from low (approx. 3 portions), to high intakes (approx. 8 portions) impacts on nutritional and clinical biomarkers. Barriers to achieving the recommended fruit and vegetable intakes are also investigated.

Method

In a randomised clinical trial, the participants [19 men and 26 women (39–58 years)] with low reported fruit, juice and vegetable intake (<3 portions/day) were randomised to consume either their usual diet or a diet supplemented with an additional 480 g of fruit and vegetables and fruit juice (300 ml) daily for 12 weeks. Nutritional biomarkers (vitamin C, carotenoids, B vitamins), antioxidant capacity and genomic stability were measured pre-intervention, at 4-, 8- and 12 weeks throughout the intervention. Samples were also taken post-intervention after a 6-week washout period. Glucose, homocysteine, lipids, blood pressure, weight and arterial stiffness were also measured. Intake of fruit, fruit juice and vegetables was reassessed 12 months after conducting the study and a questionnaire was developed to identify barriers to healthy eating.

Results

Intake increased significantly in the intervention group compared to controls, achieving 8.4 portions/day after 12 weeks. Plasma vitamin C (35%), folate (15%) and certain carotenoids [α-carotene (50%) and β-carotene (70%) and lutein/zeaxanthin (70%)] were significantly increased (P < 0.05) in the intervention group. There were no significant changes in antioxidant capacity, DNA damage and markers of vascular health. Barriers to achieving recommended intakes of fruits and vegetables measured 12 months after the intervention period were amount, inconvenience and cost.

Conclusion

While increasing fruit, juice and vegetable consumption increases circulating level of beneficial nutrients in healthy subjects, a 12-week intervention was not associated with effects on antioxidant status or lymphocyte DNA damage.

Trial registration

This trial was registered at Controlled-Trials.com; registration ISRCTN71368072.

     

Fruit and vegetable consumption among adults--United States, 2005

A diet high in fruits and vegetables is associated with decreased risk for chronic diseases. In addition, because fruits and vegetables have low energy density (i.e., few calories relative to volume), eating them as part of a reduced-calorie diet can be beneficial for weight management. Healthy People 2010 health objectives include increasing to 75% the percentage of persons aged >/=2 years who eat at least two daily servings of fruit (objective 19-5) and increasing to 50% the proportion of persons aged >/=2 years who eat at least three daily servings of vegetables, with at least one third being dark green or orange vegetables (objective 19-6). To assess the level of fruit and vegetable consumption among adults by state and demographic characteristics, data from the 2005 Behavioral Risk Factor Surveillance System (BRFSS) were analyzed. This report describes the results of that analysis, which indicated that 32.6% of adults consumed fruit two or more times per day and 27.2% ate vegetables three or more times per day. The results underscore the need for continued interventions that encourage greater fruit and vegetable consumption among U.S. adults.