Vegetables and fruit provide a significant part of human nutrition, as they are important sources of nutrients, dietary fibre, and phytochemicals. However, it is uncertain whether the risk of certain chronic diseases can be reduced by increased consumption of vegetables or fruit by the general public, and what strength of evidence has to be allocated to such an association. Therefore, a comprehensive analysis of the studies available in the literature and the respective study results has been performed and evaluated regarding obesity, type 2 diabetes mellitus, hypertension, coronary heart disease (CHD), stroke, cancer, chronic inflammatory bowel disease (IBD), rheumatoid arthritis (RA), chronic obstructive pulmonary disease (COPD), asthma, osteoporosis, eye diseases, and dementia. For judgement, the strength of evidence for a risk association, the level of evidence, and the number of studies were considered, the quality of the studies and their estimated relevance based on study design and size. For hypertension, CHD, and stroke, there is convincing evidence that increasing the consumption of vegetables and fruit reduces the risk of disease. There is probable evidence that the risk of cancer in general is inversely associated with the consumption of vegetables and fruit. In addition, there is possible evidence that an increased consumption of vegetables and fruit may prevent body weight gain. As overweight is the most important risk factor for type 2 diabetes mellitus, an increased consumption of vegetables and fruit therefore might indirectly reduces the incidence of type 2 diabetes mellitus. Independent of overweight, there is probable evidence that there is no influence of increased consumption on the risk of type 2 diabetes mellitus. There is possible evidence that increasing the consumption of vegetables and fruit lowers the risk of certain eye diseases, dementia and the risk of osteoporosis. Likewise, current data on asthma, COPD, and RA indicate that an increase in vegetable and fruit consumption may contribute to the prevention of these diseases. For IBD, glaucoma, and diabetic retinopathy, there was insufficient evidence regarding an association with the consumption of vegetables and fruit. This critical review on the associations between the intake of vegetables and fruit and the risk of several chronic diseases shows that a high daily intake of these foods promotes health. Therefore, from a scientific point of view, national campaigns to increase vegetable and fruit consumption are justified. The promotion of vegetable and fruit consumption by nutrition and health policies is a preferable strategy to decrease the burden of several chronic diseases in Western societies.

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Critical review: vegetables and fruit in the prevention of chronic diseases

Obesity has recently emerged as a major global health problem. According to World Health Organization estimates, ≈1.6 billion adults worldwide were overweight (body mass index [BMI] ≥25 kg/m2) and at least 400 million were obese (BMI ≥30 kg/m2) in 2005, numbers that are expected to reach 2.3 billion and 700 million, respectively, by 2015. In the United States, the percentage of overweight and obese adults increased markedly from 47% and 15% in 1976 to 1980 to >66% and 33% in 2005 to 2006, with the greatest proportion of increase seen among non-Hispanic black and Mexican American women.1,2 The implications of excess body weight are far-reaching. Epidemiological studies indicate that overweight and obesity are important risk factors for type 2 diabetes mellitus (T2DM), cardiovascular disease, cancer, and premature death.3 In the United States, healthcare expenditures attributable to overweight and obesity are estimated to be $147 billion or 9.1% of total healthcare costs per year.4 Such excess costs could have serious repercussions for resource-poor countries, which must manage the dual burdens of chronic and infectious disease.

In the setting of a pandemic of obesity and related chronic diseases, the American Heart Association recently released a scientific statement recommending reductions in added-sugar intake to no more than 100 to 150 kcal/d for most Americans.5 The statement identified sugar-sweetened beverages (SSBs) as the primary source of added sugars in the American diet.6 Although it has long been suspected that SSBs contribute at least in part to the obesity epidemic, only in recent years have large epidemiological studies been able to substantiate the relationship between SSB consumption and long-term weight gain, T2DM, and cardiovascular risk. It is thought that SSBs contribute to weight gain because of their high added-sugar content, low satiety, and potential incomplete compensation for total …

Sugar-Sweetened Beverages, Obesity, Type 2 Diabetes Mellitus, and Cardiovascular Disease Risk

Food and Agricultural Organization of the United Nations PA N I S F I A T G u id e in e s o n fo o d fo r tific atio n w th m ic r o n u tr ie n ts Interest in micronutrient malnutrition has increased greatly over the last few years. One of the main reasons is the realization that micronutrient malnutrition contributes substantially to the global burden of disease. Furthermore, although micronutrient malnutrition is more frequent and severe in the developing world and among disadvantaged populations, it also represents a public health problem in some industrialized countries. Measures to correct micronutrient deficiencies aim at ensuring consumption of a balanced diet that is adequate in every nutrient. Unfortunately, this is far from being achieved everywhere since it requires universal access to adequate food and appropriate dietary habits. Food fortification has the dual advantage of being able to deliver nutrients to large segments of the population without requiring radical changes in food consumption patterns.

Guidelines on food fortification with micronutrients

Cardiovascular disease (CVD) is the leading cause of death and disability worldwide. Raised blood pressure (BP), cholesterol and smoking, are the major risk factors. Among these, raised BP is the most important cause, accounting for 62% of strokes and 49% of coronary heart disease. Importantly, the risk is throughout the range of BP, starting at systolic 115 mm Hg. There is strong evidence that our current consumption of salt is the major factor increasing BP and thereby CVD. Furthermore, a high salt diet may have direct harmful effects independent of its effect on BP, for example, increasing the risk of stroke, left ventricular hypertrophy and renal disease. Increasing evidence also suggests that salt intake is related to obesity through soft drink consumption, associated with renal stones and osteoporosis and is probably a major cause of stomach cancer. In most developed countries, a reduction in salt intake can be achieved by a gradual and sustained reduction in the amount of salt added to food by the food industry. In other countries where most of the salt consumed comes from salt added during cooking or from sauces, a public health campaign is needed to encourage consumers to use less salt. Several countries have already reduced salt intake, for example, Japan (1960–1970), Finland (1975 onwards) and now the United Kingdom. The challenge is to spread this out to all other countries. A modest reduction in population salt intake worldwide will result in a major improvement in public health.

A comprehensive review on salt and health and current experience of worldwide salt reduction programmes.

This review covers current knowledge of selenium in the environment, dietary intakes, metabolism and status, functions in the body, thyroid hormone metabolism, antioxidant defense systems and oxidative metabolism, and the immune system. Selenium toxicity and links between deficiency and Keshan disease and Kashin-Beck disease are described. The relationships between selenium intake/status and various health outcomes, in particular gastrointestinal and prostate cancer, cardiovascular disease, diabetes, and male fertility, are reviewed, and recent developments in genetics of selenoproteins are outlined. The rationale behind current dietary reference intakes of selenium is explained, and examples of differences between countries and/or expert bodies are given. Throughout the review, gaps in knowledge and research requirements are identified. More research is needed to improve our understanding of selenium metabolism and requirements for optimal health. Functions of the majority of the selenoproteins await characterization, the mechanism of absorption has yet to be identified, measures of status need to be developed, and effects of genotype on metabolism require further investigation. The relationships between selenium intake/status and health, or risk of disease, are complex but require elucidation to inform clinical practice, to refine dietary recommendations, and to develop effective public health policies.

Selenium in human health and disease.

SPECIFIC AIMTo determine the effect of a deficiency of the nutritionally essential trace element selenium (Se) in mice infected with influenza virus on lung pathology, viral titers, and the host im...

Selenium deficiency increases the pathology of an influenza virus infection.

Dietary strategies to prevent and treat osteoporosis focus on increased intake of calcium and vitamin D. Modification of whole dietary patterns and sodium reduction may also be effective. We examined the effects of two dietary patterns and three sodium levels on bone and calcium metabolism in a randomized feeding study. A total of 186 adults, aged 23-76 y, participated. After a 2-wk run-in period, participants were assigned randomly to diets containing three levels of sodium (50, 100 and 150 mmol/d) to be consumed for 30 d in random order. Serum osteocalcin (OC), C-terminal telopeptide of type I collagen (CTX), fasting serum parathyroid hormone (PTH), urinary sodium, potassium, calcium and cAMP were measured at baseline and at the end of each sodium period. The Dietary Approaches to Stop Hypertension (DASH) diet reduced serum OC by 8-11% and CTX by 16-18% (both P < 0.001). Urinary calcium excretion did not differ between subjects that consumed the DASH and control diets. Reducing sodium from the high to the low level significantly decreased serum OC 0.6 microg/L in subjects that consumed the DASH diet, fasting serum PTH 2.66 ng/L in control subjects and urinary calcium 0.5 mmol/24 h in both groups. There were no consistent effects of the diets or sodium levels on urinary cAMP. In conclusion, the DASH diet significantly reduced bone turnover, which if sustained may improve bone mineral status. A reduced sodium intake reduced calcium excretion in both diet groups and serum OC in the DASH group. The DASH diet and reduced sodium intake may have complementary, beneficial effects on bone health.

The DASH Diet and Sodium Reduction Improve Markers of Bone Turnover and Calcium Metabolism in Adults

Iron bioavailability in infants from an infant cereal fortified with ferric pyrophosphate or ferrous fumarate.

OBJECTIVE To propose a correction for the hemoglobin (Hb) increase induced by altitude-associated hypoxia. DESIGN Part of a national study of nutrition and health of preschool children (0-59 months), based on a stratified, probabilistic, cluster sample. SETTING Coastal and Andean regions of Ecuador, comprising about 97% of the population, living at altitudes ranging from sea level to 3400 m. SUBJECTS Subsample of 469 girls and boys, 6-59 months old, with normal iron (Fe) status parameters, i.e serum ferritin > or = 10 micrograms/l, transferrin saturation > or = 12%, zinc protoporphyrin < or = 2.8 micrograms/g Hb. RESULTS Exponential regression curves are adapted through the Hb values of the children, grouped by altitude ranges, and through the data reported by Hurtado in 1945 for male adults. From these exponential curves, correction factors for Hb are derived for altitudes ranging from sea level to 3400 m. CONCLUSION The striking parallelism between the hypoxia-induced hemoglobin increase with altitude in young children (girls and boys) and that in male adults strongly suggests that the proposed correction factors for Hb are applicable for all ages and possibly both genders, at least in the Andes.

Altitude correction for hemoglobin.

We compared growth of infants whose mothers either did or did not receive docosahexaenoic acid (DHA) supplements during pregnancy and lactation. At 21 weeks' gestation, 144 women were enrolled into a randomized, double-blind clinical trial receiving: (1) a basic supplement consisting of vitamins and minerals (BS), or (2) BS plus 4.5 g fructooligosaccharide (BSF), or (3) BSF plus fish oil DHA (200 mg) until the end of the third month of lactation. Infants' length, weight and head circumference were measured at birth and at 1, 3 and 21 months. A total of 51 mothers/infants were lost to follow-up by the third month and 24 at 21 months. The two groups not receiving DHA were combined into a control group. Analysis with mixed models adjusted for confounding factors showed a significant time dependent effect for the DHA group on the development of the body mass index (BMI) (P=0.037), and of weight (P=0.046), but no effect on the development of length (P=0.537), or of head circumference (P=0.267). At 21 months, weight of the DHA group was lower by -601 g (95% CI -171; -1030 g) and BMI was lower by -0.76 kg/m(2) (95% CI -0.07; -1.46) compared to controls. The results indicate that DHA taken by pregnant and lactating mothers may reduce BMI in late infancy.

Denis Barclay

Papers

Selenium deficiency increases the pathology of an influenza virus infection.

The DASH Diet and Sodium Reduction Improve Markers of Bone Turnover and Calcium Metabolism in Adults

Iron bioavailability in infants from an infant cereal fortified with ferric pyrophosphate or ferrous fumarate.

Altitude correction for hemoglobin.

Does maternal docosahexaenoic acid supplementation during pregnancy and lactation lower BMI in late infancy