Nutrition, health and schoolchildren
Article first published online: 11 AUG 2011
© 2011 The Authors. Journal compilation © 2011 British Nutrition Foundation
Volume 36, Issue 3, pages 295–355, September 2011
How to Cite
Weichselbaum, E. and Buttriss, J. (2011), Nutrition, health and schoolchildren. Nutrition Bulletin, 36: 295–355. doi: 10.1111/j.1467-3010.2011.01910.x
- Issue published online: 11 AUG 2011
- Article first published online: 11 AUG 2011
- nutritional requirements;
- overweight and obesity;
- physical activity;
- school food standard
- 1Nutritional requirements of schoolchildren
- 2Findings of the National Diet and Nutrition Surveys
- 3Physical activity in schoolchildren
- 4Nutrition, physical activity and health in childhood
- ○ 4.1 Overweight and obesity
- ○ 4.2 Cardiovascular risk factors
- ○ 4.3 Iron deficiency anaemia
- ○ 4.4 Oral health
- ○ 4.5 Bone development
- ○ 4.6 Food allergy and intolerance
- ○ 4.7 Mental health
- 5Factors affecting food choice
- 6Food provision in school
- 7Food in the curriculum
- 8Promoting healthy lifestyles in children
- • Acknowledgements
- • References
Healthy eating and being physically active are particularly important for children and adolescents. This is because their nutrition and lifestyle influence their wellbeing, growth and development. The nutritional requirements of children and adolescents are high in relation to their size because of the demands for growth, in addition to requirements for body maintenance and physical activity. Data from the National Diet and Nutrition Surveys (NDNS) show that the contribution of protein to food energy intake has increased between 1997 and 2008/2009 in both boys and girls aged 4-to-18-years. The contribution of fat to food energy intake has decreased in boys and girls aged 4-to-10-years, and in boys aged 11-to-18-years; saturated fatty acid intakes have decreased in boys and girls of both age groups. A decrease in the contribution of non-milk extrinsic sugars to food energy has been found in the younger age group, whereas it has hardly changed in the older age group. The most recent NDNS data (Year 1 of the NDNS Rolling Programme) on micronutrient intake showed that low intakes of almost all minerals and vitamin A in boys and girls in the older age group, and also of riboflavin and folate in girls in the older age group were evident. In the younger age group, low intake of zinc was evident in boys and girls. Data on micronutrient status is as yet only available from the 1997 NDNS. There was some evidence of poor status of riboflavin, thiamin, vitamin C, folate, vitamin D and iron. A comparison of data from the Low Income Diet and Nutrition Survey (2003–2005) and the 1997 NDNS showed that children from low-income families tended to have higher intakes of whole milk; fat spreads; meat and processed meats; and non-diet soft drinks compared with children from the general population. Intakes of wholemeal bread; buns, cakes and pastries; semi-skimmed and skimmed milk; vegetables; fruit and fruit juices; and diet soft drinks were lower in children from low-income families.
Physical activity has a major impact on health at all stages of life. In children and young people physical activity is particularly important to maintain energy balance and therefore a healthy bodyweight, for bone and muscoskeletal development, for reducing the risk of diabetes and hypertension, and for numerous psychological and social aspects. There is concern that many children spend too much time engaged or sedentary activity and not enough time being active. In the UK, it is recommended that children undertake at least 60 minutes of moderate to vigorous intensity physical activity every day, and vigorous activities, including those that strengthen muscle and bone, should be incorporated at least three times a week. Children and young people should also minimise the amount of time spent being sedentary (sitting) for extended periods.
Data from the 2008 Health Survey for England suggested that 32% of boys and 24% of girls aged 2-to-15-years met the previous target to be active for 60 minutes each day. However, as only out-of-school activity was assessed, this is likely to be an underestimation of actual activity. Physical activity levels in girls dropped with age, whereas in boys no clear patterns were observed. The average reported time spent doing sedentary activities (excluding sleeping or school time) was 3.4 hours on weekdays and 4.1 hours on weekend days. The Scottish National Health Survey 2009 found that 69–72% of boys and 56–60% of girls in Scotland met the previous 60 minute-per-day recommendation. The large differences between England and Scotland can in large part be explained by the use of a revised questionnaire in the latest Health Survey for England. The Welsh Health Survey 2009 reported that 47% of boys and 29% of girls were physically active for at least an hour a day, whereas research in Northern Ireland has indicated that only 15% of 8-to-12-year-olds take part in 60 minutes of activity, which ‘made them out of breath or hot and sweaty’ everyday. In England, children and young people, in particular girls, from some ethnic groups (Black African, Indian, Chinese, Pakistani, Bangladeshi) had lower activity levels compared with the general population.
Trends in overweight and obesity in children and adolescents have become increasingly worrying. Data from the Health Surveys for England showed that rates of overweight and obesity have increased over the past 15 years, the overall increase being mainly due to increasing obesity rates. In Scotland, overweight and obesity levels in girls aged 2-to-15-years and boys aged 2-to-6-years have not changed considerably between 1998 and 2009, whereas more boys aged 7-to-15-years were overweight or obese in 2009 compared with 1998. For Wales and Northern Ireland, no data showing long-term trends of overweight and obesity are available.
Overweight and obesity are associated with an increased risk of various conditions in adulthood, but consequences of overweight and obesity are already observed in children. Obese children have been shown to already have many of the changes associated with vascular disease in adults, including insulin resistance, high blood pressure and elevated levels of blood cholesterol. Considered previously to be a disease of adults, in the last decade, type 2 diabetes mellitus has become a far more common occurrence in children and adolescents. In addition, multiple studies have suggested that childhood overweight and obesity track into adulthood. Evidence shows that there seems to be no single dietary or lifestyle factor that leads to overweight and obesity, but a variety of different, often interlinked factors, exist.
Oral health has clearly improved since the 1970s. Data from the Children's Dental Health Surveys show that in 1973, 12-year-olds had an average of 5 decayed, missing and filled teeth (DMFT), and in 2003, this had fallen to less than one DMFT. Fifteen-year-olds had an average of around 8 DMFT in 1973 and 1.5 DMFT in 2003. The highest proportion of children with dental decay was found in Northern Ireland, followed by Wales, and the lowest proportion was found in England (no information for Scotland available). The decrease in dental decay since the 1970s is mainly due to fluoridation of water and toothpaste and generally improved oral hygiene, although nutrition plays a role as well.
A sufficient supply of calcium and vitamin D, as well as being physically active, is important for healthy bone development. However, data from the most recent NDNS show that 11% of girls aged 11-to-18-years and 6% of boys of this age group have calcium intakes below the Lower Reference Nutrient Intake, suggesting insufficient intakes. Data from the 1997 NDNS found that more than 1 in 10 (13%) 11-to-18-years-olds had low vitamin D status (no newer status data available as yet).
Estimates of the prevalence of food allergy in the UK vary, but have been suggested to be around 5–8% in children, the incidence of perceived food allergies and intolerances usually being considerably greater than the actual prevalence. It has been suggested that avoidance of certain allergens at an early age may decrease the risk of food allergy, although not all experts share this view, some suggesting that there are critical periods in early life when exposure triggers normal immune system tolerance.
It has been suggested that diet affects mental health, including cognitive function and depression, although there is limited evidence. The best-studied factor, in relation to cognitive function, is breakfast consumption. There is some evidence that eating breakfast may improve cognitive function, but inconsistencies and shortcomings of many studies do not allow firm conclusions to be drawn. There is conflicting evidence on the effect of fish oils on cognitive function.
One way to improve dietary habits of schoolchildren is via food provided in schools. Standards for school food are available in all UK countries. In England, food-based standards for school lunches were introduced in 2006, followed by food-based standards for food other than school lunches in 2007. Finally, nutrient-based standards were implemented in primary schools in 2008 and in secondary schools and special schools in 2009. A survey found that, compared with 2005, caterers in English primary schools now provide a healthier lunch that meets food-based and most nutrient-based standards, with substantial increases in fruit and vegetable consumption (60% on average), and a 32% decrease in sodium intake, although improvements still need to be made for some nutrients (e.g. iron and zinc). The Scottish government has also set out nutrient standards for school lunches, and food and drink standards for school lunches and for school food and drinks other than school lunches. The regulations came into effect in August 2008 for primary schools and in August 2009 for secondary schools. In Wales, minimum food-based standards apply to primary and secondary schools. More stringent food-based standards for school lunches and other food and drinks served at school, as well as nutrient-based standards for school lunches, are outlined in the Appetite for Life Action Plan, but are not compulsory. In Northern Ireland, new food-based standards for school lunches were introduced and made compulsory from September 2007, and in 2008 were extended to include all other foods and drinks served at school. Nutrient-based standards for school lunches are not in place in Northern Ireland.
Nutritional standards for packed lunches prepared at home have not been set, and research in England has shown that the composition of these lunches is less favourable than lunch provided at school. Ways of improving the quality of packed lunches have been investigated, with only limited success. Other schemes, such as fruit and vegetable schemes and breakfast clubs, have also been initiated with the aim to improve the dietary habits of schoolchildren. Furthermore, each UK country has the study of food and nutrition incorporated into the school curriculum. Examples of other projects aiming to improve children's health include Change4Life and SmallSteps4Life; the Healthy Schools initiative; Food and Fitness in Wales; Healthy Eating, Active Living in Scotland; Investing for Health in Northern Ireland; MEND; Let's Get Cooking; and Food Dudes.