Systematic review and meta-analysis of school-based interventions to improve daily fruit and vegetable intake in children aged 5 to 12 y

BACKGROUND

To our knowledge, no reviews have assessed the impact of a range of multi- and single-component school-based programs on daily fruit and vegetable intake by using a meta-analysis.

OBJECTIVE

The aim of this study was to quantify the impact of school-based interventions on fruit and vegetable intake in children aged 5-12 y.

DESIGN

A systematic literature review was carried out to identify randomized and nonrandomized controlled trials that were based in primary schools and designed to increase portions of daily fruit and vegetable intake. MEDLINE, Cochrane libraries, EMBASE, PsycINFO, and Educational Information Centre were searched from 1985 to 2009. Data were extracted, and mean effect sizes were calculated by using random effects models.

RESULTS

A total of 27 school-based programs involving 26,361 children were identified that met the inclusion criteria and assessed the daily weight of fruit and vegetable intake combined, fruit intake only, or vegetable intake only, and 21 studies were used in meta-analyses. The results of the meta-analyses indicated an improvement of 0.25 portions (95% CI: 0.06, 0.43 portions) of fruit and vegetable daily intake if fruit juice was excluded and an improvement of 0.32 portions (95% CI: 0.14, 0.50 portions) if fruit juice was included. Improvement was mainly due to increases in fruit consumption but not in vegetable consumption. The results of the meta-analyses for fruit (excluding juice) and vegetables separately indicated an improvement of 0.24 portions (95% CI: 0.05, 0.43 portions) and 0.07 portions (95% CI: -0.03, 0.16 portions), respectively.

CONCLUSIONS

School-based interventions moderately improve fruit intake but have minimal impact on vegetable intake. Additional studies are needed to address the barriers for success in changing dietary behavior, particularly in relation to vegetables.

Barcoding the major Mediterranean leguminous crops by combining universal chloroplast and nuclear DNA sequence targets

The ability to discriminate all species is the ultimate target in barcoding. The Mediterranean basin is a center of origin for legumes and thus they have played a key role in feeding the Mediterranean population. It is also a region with important protected designation of origin and protected geographical indication legumes that provide income in rural areas. We evaluated the use of two chloroplast regions, trnL and rpoC1, and a nuclear internal transcriber region, ITS2, for their efficiency to barcode the main Mediterranean leguminous crops. Twenty-five legume species were studied. Plant material of pasture and legumes was obtained from the Greek GenBank and the Fodder Crops and Pastures Institute (National Agricultural Research Foundation). DNA was extracted with the Qiagen DNeasy plant mini-kit and PCR amplification was performed using the Kapa Taq DNA polymerase using primers amplifying the chloroplast trnL and rpoC1 regions or the nuclear region ITS2. PCR products were sequenced and the sequences were aligned using CLUSTAL W. Species identification based on the sequence similarity approach was performed using the GenBank database. In order to evaluate intraspecific and interspecific divergence in legumes we used Molecular Evolutionary Genetics Analysis 5 and for pairwise Kimura 2-parameter distance calculations for all 3 DNA regions (2 chloroplast regions, trnL and rpoC1, and the nuclear region ITS2). Four tree-based methods (neighbor joining and maximum parsimony, maximum likelihood, and Bayesian inference analyses) were used to exhibit the molecular identification results to represent differences as an uprooted dendrogram. Additionally, the sequence character-based method was used with DnaSP and the information from each site was treated as a character to distinguish the species from one another. The DNA regions trnL and ITS2 successfully (100%) discriminated the Mediterranean crop legume species used, while rpoC1 identified only 72% of them. Furthermore, the use of the trnL region enabled the discrimination of even very closely related species, like Phaseolus lunatus and P. coccineus or Vicia faba subsp major with V. faba subsp minor, which are so closely related that even in NCBI they were both referred as Phaseolus vulgaris and V. faba, respectively. We conclude that trnL and ITS2 are efficient DNA barcoding target regions in order to discriminate Mediterranean leguminous crops and provide a reliable and efficient tool for the scientific, agricultural and industrial community.

The biochemical and functional food properties of the bowman-birk inhibitor

The Bowman-Birk inhibitor (BBI) is a small water-soluble protein present in soybean and almost all monocotyledonous and dicotyledonous seeds. The molecular size of BBI ranges from 1,513 Da to about 20,000 Da. BBI is to seeds what alpha(1)-antitrypsin is to humans. Soy-based food products rich in BBI include soybean grits, soymilk, oilcake, soybean isolate, and soybean protein concentrate. BBI is stable within the pH range encountered in most foods, can withstand boiling water temperature for 10 min, resistant to the pH range and proteolytic enzymes of the gastrointestinal tract, bioavailable, and not allergenic. BBI reduces the proteolytic activities of trypsin, chymotrypsin, elastase, cathepsin G, and chymase, serine protease-dependent matrix metalloproteinases, urokinase protein activator, mitogen activated protein kinase, and PI3 kinase, and upregulates connexin 43 (Cx43) expression. Several studies have demonstrated the efficacy of BBI against tumor cells in vitro, animal models, and human phase IIa clinical trials. FDA considers BBI as a drug. In 1999, FDA allowed a health claim on food labels stating that a daily diet containing 25 grams of soy protein, also low in saturated fat and cholesterol, may reduce the risk of heart disease [corrected] This review highlights the biochemical and functional food properties of the Bowman-Birk inhibitor.

Whole-food sources of vitamin A more effectively inhibit female rat sexual maturation, mammary gland development, and mammary carcinogenesis than retinyl palmitate

Previous work using an adolescent rat model for breast cancer showed increased tumor occurrence in rats fed a chemopreventive dose of vitamin A. Preclinical models for nutrient-cancer interactions utilizing defined diets do not replicate the complexity of the human diet and may be inadequate to investigate food patterns associated with reduced cancer risk in humans. To evaluate this concept, the effects of vitamin A on sexual maturation, mammary gland development, and sensitivity to carcinogenesis were determined in the context of a human food-based diet (whole food diet). At 20 d of age (p20), female rats received either a whole-food diet with adequate levels of vitamin A, a diet with a 5.5-fold increase in vitamin A from fruits and vegetables (S diet), or a diet with a 6.2-fold increase in vitamin A provided as retinyl palmitate (RP diet). To determine the effect of dietary intervention on pubertal mammary gland development, the dietary intervention period was restricted to postnatal d 21-63. Rats were injected with 50 mg 1-methyl-1-nitrosourea/kg body weight at d 66. Compared with adolescent rats that consumed the Ad diet, consumption of S and RP diets reduced mammary cancer multiplicity (relative risk approximately 0.7, P < or = 0.002), which was associated with a reduction in alveolar gland development. The S diet suppressed the onset of sexual maturation (P < 0.001) and inhibited markers of mammary alveologenesis more than the RP diet. These data demonstrate that the amount and source of vitamin A consumed by adolescent female rats can influence the onset of puberty, mammary gland alveolar development, and breast cancer risk and highlight the relevance of utilizing whole-food diets to evaluate the role of dietary factors in cancer prevention.

Diffusion and dissemination of evidence-based dietary strategies for the prevention of cancer

OBJECTIVE

The purpose was to determine what strategies have been evaluated to disseminate cancer control interventions that promote the uptake of adult healthy diet?

METHODS

A systematic review was conducted. Studies were identified by searching MEDLINE, PREMEDLINE, Cancer LIT, EMBASE/Excerpta Medica, PsycINFO, CINAHL, the Cochrane Database of Systematic Reviews, and reference lists and by contacting technical experts. English-language primary studies were selected if they evaluated the dissemination of healthy diet interventions in individuals, healthcare providers, or institutions. Studies of children or adolescents only were excluded.

RESULTS

One hundred one articles were retrieved for full text screening. Nine reports of seven distinct studies were included; four were randomized trials, one was a cohort design and three were descriptive studies. Six studies were rated as methodologically weak, and one was rated as moderate. Studies were not meta-analyzed because of heterogeneity, low methodological quality, and incomplete data reporting. No beneficial dissemination strategies were found except one that looks promising, the use of peer educators in the worksite, which led to a short-term increase in fruit and vegetable intake.

CONCLUSIONS AND IMPLICATIONS

Overall, the quality of the evidence is not strong and is primarily descriptive rather than evaluative. No clear conclusions can be drawn from these data. Controlled studies are needed to evaluate dissemination strategies, and to compare dissemination and diffusion strategies with different messages and different target audiences.

Energy from fat is associated with obesity in U.S. men: results from the Prostate Cancer Prevention Trial

BACKGROUND

Diets high in fat have been proposed as one cause of obesity, primarily because fat is more energy-dense than other macronutrients. However, the literature on fat consumption and human obesity is inconclusive. This research examines associations between dietary fat intake and obesity in men participating in the Prostate Cancer Prevention Trial.

METHODS

Data in this cross-sectional study are from 15,266 men (55-79 years) who completed questionnaires on usual diet, physical activity, and health-related characteristics. Height and weight were collected by clinic personnel. Obesity was defined as body mass index (BMI) greater than or equal to 30 kg/m2.

RESULTS

In this healthy cohort, 23.3% were obese. Younger age, a sedentary lifestyle, lower education, and black race were positively associated with obesity (all P < 0.001). Using two statistical approaches, both total energy and energy from fat, but not total energy from other macronutrients, increased linearly and significantly with increasing BMI. Mean fat intake increased from 691 kcal (31.4% energy) among normal-BMI men to 797 kcal (34.3% energy) among the obese (P for trend <0.001). After controlling for demographic and health-related characteristics in regression models, BMI increased by 0.53 and 0.14 kg/m(2) for every 500 kcal of fat and total energy consumed, respectively. Energy underreporting, based on estimated basal metabolic rate and physical activity, was fourfold higher among obese compared to normal-weight men.

CONCLUSIONS

In this large cohort of healthy older men, energy from fat was associated with obesity, suggesting that high-fat dietary patterns are contributing to the high rates of obesity in U.S. men.

Perceptions and practices of self-defined current vegetarian, former vegetarian, and nonvegetarian women

OBJECTIVE

To assess the diversity of vegetarians' dietary practices and how they change over time, and to explore perceptions of meat and dairy products among vegetarians, former vegetarians, and nonvegetarians.

DESIGN

Cross-sectional survey; qualitative interviews with a subsample.

SUBJECTS/SETTING

Ninety self-defined current vegetarian, 35 former vegetarian and 68 nonvegetarian women in Vancouver, British Columbia. A subsample of 15 subjects completed qualitative interviews.

STATISTICAL ANALYSIS PERFORMED

Group comparisons using 1-way analysis of variance with post-hoc testing for continuous variables, chi2 for categorical variables.

RESULTS

Of 90 current vegetarians, 51 and 14 reported occasional use of fish or chicken respectively. Fifty-six vegetarians, including 4 of 6 vegans, reported that their diets had become more restrictive over time, and 48 planned additional changes, most frequently a reduction in dairy product use. Reasons cited by former vegetarians for resuming omnivorous diets included: not feeling healthy, concern about their nutritional status, a change in living situation, or missing the taste of meat. Perceptions of meat and dairy products differed significantly by dietary pattern: nonvegetarians and former vegetarians were more likely than current vegetarians to agree with statements inferring positive attributes (eg, nutrient content). In contrast, more current and former vegetarians than nonvegetarians agreed with statements inferring negative attributes (eg, presence of contaminants).

APPLICATIONS/CONCLUSIONS

Dietitians who counsel women need to be aware of the heterogeneity of dietary practices and beliefs regarding use of animal products to provide advice appropriate to each individual. At a broader level, addressing women's food safety and animal welfare concerns will likely require collaboration among food industry and government, health, and consumer agencies.