Presentation on theme: "Teenage diets, nutrition and health"— Presentation transcript:
1Teenage diets, nutrition and health British Nutrition FoundationThis Presentation outlines some key messages for older children and young people that you teach – can be useful for classroom teaching.
2Teenagers (12-18 years) Nutritional requirements Dietary recommendationsMacronutrientsMicronutrientsEnergy balancePhysical activityDiet and cognitive abilityDiet and behaviourEating disordersSummary - key issuesOutlineThis is an outline of what this presentation will cover.Nutritional requirementsDietary recommendations (The eatwell plate)Macronutrient intakes (Carbohydrate, fat)Micronutrient intakes (esp. iron and calcium)Energy balancePhysical activityDiet and behaviourEating disordersSummary - key issues
3Nutritional requirements Growth and development are rapid.Onset of puberty - characterised by a spurt in physical growth (height and weight).Considerable gain in muscle and bone mass.Changes in body composition, e.g. increased deposition of fat in girls.Energy and nutrient requirements at their highest.Nutritional requirementsGrowth and development are rapid during the teenage years.A growth spurt usually begins around the age of 10 in girls, and 12 in boys – adding an average of 23cm to height and kg in weight (boys and girls).Body composition also changes during puberty – in boys the proportion of fat declines from an average of 15% to about 10%. In girls the proportion increases from 15% to around 20%.Extra energy and nutrients are therefore required to support growth and development.Energy and nutrient needs are at their absolute highest.
4A healthy diet is important for teenagers Eating a healthy, balanced diet can:promote wellbeing by improving mood, energy and self-esteem to help reduce anxiety and stress;boost concentration and performance;reduce the risk of ill-health now and in the future, e.g. obesity, heart disease, cancer, and type 2 diabetes;increase productivity/attainment and reduce days off sick.A healthy, varied diet is important to us all, but also particularly crucial for teenagers because they are growing rapidly. Eating habits established during this time is likely to track into adulthood.
5The eatwell plateUK’s official food selection guide, sets out the proportion and types of food which makes up a healthy, varied diet. Applies to everyone from the age of two, so of course this is also appropriate for teenagers.
6Dietary recommendations Teenagers should consume a variety of foods from each of the four main food groups:Bread, rice, potatoes, pasta and other starchy foods (33%)Fruit and vegetables (33%)The eatwell plateThe eatwell plate model applies to all healthy adults and children over 2 years.It gives a visual representation of how different foods contribute towards a healthy balanced diet and helps us to achieve the right balance of nutrients in the diet.Teenagers should consume a variety of foods from each of the 4 main food groups.Meat, fish, eggs, beans and other non-dairy sources of protein (12%)Milk and dairy foods (15%)
7Macronutrients- average intakes (Scottish NDNS and Survey of Sugar Intake data)MacronutrientRecommended intake(% food energy)Boys average intakeGirls average intakeFat35%35.4%35.9%of which saturates11%14.2%14.3%Carbohydrate50%51.6%51.1%of which added sugars (NMES)16.7%16.4%Macronutrient intakesThis table shows Dietary Reference Values (DRVs) for fat, saturates, carbohydrate and sugars intake (as a percentage of food energy) and the average intake for boys and girls (all ages). These figures are very similar for younger and older children, including teenagers.Average intakes of total fat for both boys and girls are close to the adult benchmark of 35% of food energy. However, average intakes of saturates are higher than the recommended 11% of food energy.Total carbohydrate intake is close to the adult benchmark of 50% of food energy. However, intakes of added sugars (NMES, non-milk extrinsic sugars) are higher than the recommended 11% of food energy in both boys and girls.The main sources of NMES in children’s diets were carbonated soft drinks and chocolate confectionery, with the proportion provided by drinks increasing with age e.g. soft drinks provided 42% of NMES intake in boys aged years.
8What about dietary fibre? NDNS survey found average dietary fibre (NSP) intakes to be low in teenagers:- Boys (11-14 years) 11.6 g/day(15-18 years) 13.3 g/day- Girls (11–14 years) 10.2 g/day(15-18 years) 10.6 g/dayReference values:- 15 g/day (11-14 years)- 18 g/day (15 years or above)Dietary fibre/Non-starch polysaccharides (NSP)Dietary fibre (NSP) is important for gut health, soluble types can also enhance heart health by reducing blood cholesterol.The NDNS survey found dietary fibre (as NSP, non-starch polysaccharide) intakes to be low in teenagers.The reference value (GDA) for children aged years is 15 g/day. The reference value for children aged 15 and over and adults is 18 g/day.
9Micronutrients- percentage of older children and teenagers with intakes below the LRNIVitaminBoys11-14 yrsGirls15-18 yrsVitamin A8%20%13%12%Riboflavin (B2)6%22%21%Folate1%3%0%4%Vitamin intakesThis table shows the proportions of older children and teenagers with vitamin intakes below the LRNI (Lower Reference Nutrient Intake).Average intakes of most vitamins were found to be adequate in older children and teenagers, with the exception of vitamin A and riboflavin (B2). Low intakes of riboflavin (B2) were found, particularly in girls. Folate intakes were also below the LRNI in a small proportion of older girls.Source: National Diet and Nutrition Survey 2003
10Micronutrients- percentage of older children and teenagers with intakes below the LRNIMineralBoys11-14 yrsGirls15-18 yrsIron3%44%48%Calcium13%24%9%19%Magnesium28%51%11%53%Potassium10%15%38%Zinc14%37%Mineral intakesThis table shows the proportions of older children and teenagers with mineral intakes below the LRNI (Lower Reference Nutrient Intake).In older children and teenagers, a substantial proportion, particularly girls, have low intakes of a number of minerals, including iron, calcium, magnesium, potassium and zinc.Of particular concern is that 44% of year old girls and 48% of year old girls have iron intakes below the LRNI.15% of older girls and 12% of older boys reported not drinking milk, which is a major source of calcium in the UK diet.Source: National Diet and Nutrition Survey 2003
11What about salt?NDNS survey results - average salt intakes above recommendations in teenagers:- Boys (11-14 years) 6.75 g/day(15-18 years) 8.25 g/day- Girls (11-18 years) 5.75 g/day(excluding salt added in cooking or at the table)Recommended maximum daily salt intake:- 11 years and over: up to 6 g/day.Salt intakesThe NDNS survey found salt intakes to be above the recommended level in teenagers. This does not include salt added in cooking or at the table, so actual intakes are likely to be higher.This is concerning as dietary habits in childhood and adolescence often track into adulthood, and too much salt in the diet can contribute towards high blood pressure in later life.
12Teenagers and iron Teenagers have increased iron requirements. Girls need more iron than boys to replace menstrual losses (RNI: boys 11.3 g/day, girls 14.8 g/day).Low iron intakes (< LRNI) in 44% of girls (11-14 years) and 48% of girls (15-18 years).9% of girls (15-18 years) were found to have poor iron status (Hb < 12g/dl).Lack of iron leads to an increased risk of iron deficiency anaemia and associated health consequences.Teenagers who follow a vegetarian diet or restrict food intake (e.g. to lose weight) particularly at risk.Teenagers and ironTeenagers have increased iron requirements for growth and muscle development.Low iron intakes and poor iron status in teenage girls is concerning due to the risk of developing iron deficiency anaemia.It is common for teenage girls to follow a vegetarian diet or try to restrict their food intake e.g. to lose weight, which puts them particularly at risk of poor iron status.
13Iron absorptionGood sources: meat (especially lean red meat), liver and offal, green leafy vegetables, pulses (beans, lentils), dried fruit, nuts and seeds, bread and fortified breakfast cereals.Iron from meat sources (haem iron) is readily absorbed by the body.Vitamin C helps the body to absorb iron from other sources (non-haem iron).Iron absorptionNote that since the 1950s in the UK, all wheat flours (except wholemeal) have been fortified with iron by law.Vitamin C helps the body to absorb iron from other sources (non-haem iron).Having a glass of fruit juice or eating fruit and vegetables at mealtimes can help the absorption of non-haem iron.
14Teenagers and calcium Teenagers have high calcium requirements. Around 50% of the adult skeleton is formed during the teenage years (RNI - boys 1000 mg/day, girls 800 mg/day).Low calcium intakes (< LRNI) found in 24% of year-old girls and 19% of year-old girls.A lack of calcium may have consequences for future bone health e.g. increased risk of osteoporosis.Teenagers and calciumDuring puberty, the total amount of calcium deposited (as bone) per day is greater than at any other time in life. Therefore, total calcium needs are greatest during adolescence.Teenagers have high calcium requirements due to rapid increase in bone mass during teenage years.Absorption of calcium is also greater during adolescence than in childhood and adulthood, due to hormonal changes.Achieving an adequate calcium intake is important for optimising bone mass and therefore it is of concern that many adolescents have inadequate calcium intakes.Good sources of calcium include milk and dairy products, green leafy vegetables, fish containing soft bones (e.g. canned sardines), pulses and bread (white and brown wheat flour is fortified with calcium).The bioavailability of calcium from foods varies e.g. the bioavailability of calcium from milk is around 30% (i.e. only 30% of the calcium from milk is absorbed by the body), compared with 5% from spinach.
15Teenagers and energy balance Levels of overweight and obesity are increasing: 35% of teenagers (12-15 years) are classified as overweight or obese (Scottish Health Survey 2009).Teenagers, especially girls, often try to control their weight by adopting very low energy diets or smoking.Restricted diets may lead to nutrient deficiencies and other health consequences.Teenagers of unhealthy weight may need guidance on lifestyle changes to help them achieve a healthy weight.Teenagers - energy balanceAlthough it is important for teenagers to obtain sufficient energy and nutrients, some eat more than they need and so become overweight, especially if they are inactive.Teenagers, especially girls, often try to control their weight e.g. by adopting very low energy diets or smoking.Restricted diets (e.g. excluding whole food groups) can lead to nutrient deficiencies and other health consequences.The short-term consequences of obesity in teenagers include psychological problems (e.g. low self esteem, bullying), increased cardiovascular risk factors, diabetes and asthma.The long-term consequences include persistence of obesity and CVD risk factors into adult life and premature death.The majority of obese adolescents will remain obese into adulthood.
16Teenagers – physical activity Physical activity through life is important for maintaining energy balance and overall health.At least 60 mins of moderate-intensity physical activity each day is recommended.Include activities that improve bone health, muscle strength and flexibility at least twice per week.68% of boys and 41% of girls (13-15 year-olds) achieve the recommended 60 mins per day (Scottish Health Survey 2005).Teenagers – physical activityDuring adolescence, physical activity can be particularly beneficial in terms of social interaction and wellbeing, self-esteem and confidence, as well as helping to maintain energy balance. High impact physical activity is particularly important as it can help to increase bone mass.Maintaining physical activity throughout the teenage years also helps to reduce the risk of chronic diseases in later life, such as CVD and type 2 diabetes.At least twice a week, activities that improve bone health, muscle strength and flexibility should be included, e.g. running, cycling or swimming.Teenage boys tend to be more active than teenage girls, and it is common to see a decline in physical activity levels from around 13 years of age, which is more marked in girls.
17Diet and cognitive ability Food eaten at school can make up a substantial proportion of the diet and have a significant effect on functions such as learning, memory, information processing and mood.Cognition represents a complex multidimensional set of abilities and cognitive performance is affected by many influencing factors.Nutritional effects are difficult to measure.Bellisle F (2004) Effects of diet on behaviour and cognition in children Br J Nutr 92 Suppl 2: SStevenson J (2006) Dietary influences on cognitive development and behaviour in children Proct Nutr Soc 65(4):361-5.
18GlycaemiaThe brain appears to be sensitive to short-term fluctuations of glucose supply and therefore it might be beneficial to maintain glycaemia at adequate levels to optimise cognition.Glycaemia is the level of blood glucose.
19Eating breakfastStarting each day with breakfast will supply energy to the brain & body.Eating breakfast leads to improved energy and concentration levels throughout the morning.Breakfast consumption may improve cognitive function related to performance in school.Other benefits of breakfast include better nutrient intakes and weight control.Other benefits:Evidence suggests that eating breakfast may improve cognitive function related to performance in school, e.g. memory, test grades and school attendance.People who eat breakfast tend to have a better nutrient intake.Having breakfast helps control weight. Skipping breakfast makes it more likely to snack on foods which are high in saturated fat or sugar before lunch.Hoyland A et al. (2009) A systematic review of the effect of breakfast on the cognitive performance of children and adolescents Nutr Res Rev 22(2):
20Fluids and hydrationEven mild dehydration (1-2%) can lead to headaches, irritability and loss of concentration. This level is not enough to cause feelings of thirst.The recommendation is to drink 6-8 glasses/day (1.2 litres) to prevent dehydration. People need to drink more when the weather is hot or when they have been active.All drinks count in terms of fluid intake but those without sugar are best between meals.You can re-hydrate using water in all its forms including plain water, carbonated drinks, juices and hot drinks.We will look at hydration in the next section…
21Diet and IQBrain health depends on optimal intakes of nutrients from the diet.Much speculation about the importance of long chain omega-3 fatty acids to behavioural and cognitive development, including IQ.Supplementation studies show the best outcome observed in children with learning disabilities.Current recommendation is one portion of oily fish (140g) per week.Long-chain omega-3 fatty acids can also improve heart health.The intake of long-chain omega-3 fatty acids is through the current recommendation of oily fish (1 portion per week).It is important not to eat too much oily fish (esp. for women of childbearing age) because it may lead to the accumulation of pollutants in the body, and this is particularly harmful to the developing nervous system of the unborn foetus.Willatts P. (2002) Long chain polyunsaturated fatty acids improve cognitive development J Fam Health Care 12(6 suppl):5.
22Diet and mood/behaviour There are a number of foods that have a pharmacological effect in the body which affects mood:* caffeine;* vaso-active amines, such as histamine;* tryptophan and serotonin.There is evidence to suggest that poor vitamin and mineral status may be associated with poor educational attainment and antisocial behaviour.Caffeine is a stimulant.Histamine may increase the risk of migraines and panic attacks. Foods high in histamine include cheese, alcoholic drinks and condiments, such as fish sauce, ketchup, vinegars.Tryptophan is an essential amino acid, and a precursor for serotonin, the sleep-inducing hormone.
23Food additives and hyperactivity The Southampton study suggested that consumption of mixes of certain artificial food colours and the preservative sodium benzoate could be linked to increased hyperactivity in some children. The colours are:sunset yellow FCF (E110)quinoline yellow (E104)carmoisine (E122)allura red (E129)tartrazine (E102)ponceau 4R (E124)An EU-wide mandatory warning must be put on any food and drink (except drinks with more than 1.2% alcohol) that contains any of the six colours.The Southampton study on food additives and ADAH demonstrated a strong association between consumption of mixes of certain artificial food colours and the preservative sodium benzoate and increased hyperactivity in some children (3 year-olds).These colours are used in a wide range of foods including some soft drinks, sweets, cakes and ice cream. These colours are used in a wide range of foods including some soft drinks, sweets, cakes and ice cream.The Food Standards Agency has introduced a voluntary ban on the use of these six colours in the UK, and wants manufacturers to phase out their use by the end of 2009.An European Union-wide mandatory warning must be put on any food and drink (except drinks with more than 1.2% alcohol) that contains any of the six colours. The label must carry the warning ‘may have an adverse effect on activity and attention in children’. This became mandatory across the European Union from 20 July 2010.Sugar is often blamed for hyperactive behaviour but there is no convincing evidence.Bateman B et al. 2007
24Eating disordersDefined as: an eating pattern that becomes harmful to health.Can affect anyone but most likely young women.It is estimated that there are 1 million people affected in the UK, with the majority being 12 to 25 year-old women.Trigger is multi-factorial and often linked to emotions.New evidence to suggest genetic makeup may have a small impact.Various symptoms and severity.Related to feelings of boredum, anxiety, anger, loneliness, shame or sadness. Often a combination of many factors, events, feelings or pressures e.g. low self-esteem, family relationships, sexual or emotional abuse.Anyone can develop an eating disorder, regardless of age, sex or background. Most likely to be affected tend to be young women, particularly between the ages of 12-25, but it is also important to note that men are less likely to seek help compared with women. Research has shown that genetic make-up may have a small impact. Attitude of other family members towards food can have an impact.Where there are high academic expectations, family issues or social pressures, the sufferer may focus on food and eating as a way of coping.
25Anorexia NervosaDefined as: the refusal to eat enough to maintain a normal body weight.Sufferers have the impression that they are overweight and often picture themselves as being fat even though they are already underweight.If it occurs before puberty, anorexia may lead to stunted growth. In teenage girls and young women, menstrual abnormalities may occur including amenorrhoea (the cessation of periods), which can pose a significant risk to bone health.Other physical symptoms include: constipation, stomach pains; dry, patchy skin; low body temperature and loss of hair.People who develop anorexia have often been compliant and obedient children. They would be less likely to become angry than their brothers or sisters and would have been eager to please. They have often hidden their inner feelings and anxieties. They may fear failure and have an overwhelming desire to please and care for others. They are committed to achieving high standards set - or that they assume have been set - by parents or teachers, whereas often these high standards are self-imposed.Anorexia represents an attempt to demonstrate independence through control over food and eating. It is also very difficult for many people to understand that although food is an important issue, an eating disorder is actually all about feelings and emotions.Many families also find that the person with an eating disorder becomes the centre of attention which can seriously affect relationships between brothers and sisters, parents, relatives and carers.
26Anorexia Nervosa Impact on mental health: intense fear of gaining weight and obsessive interest in what others are eating;distorted perception of body shape or weight;denial of the existence of a problem;changes in personality and mood swings;becoming aware of an ‘inner voice’ that challenges views on eating and exercise.Impact on behaviour:rigid or obsessive behaviour with eating, mood swings;restlessness and hyperactivity;wearing big baggy clothes;vomiting.Rigid or obsessive behaviour attached to eating, mood swings, e.g. cutting food into tiny pieces.Also:The long-term effects of anorexiaThe long-term effects of anorexia on the body and mind can be alarming and severe. Women with anorexia tend to find it more difficult to become pregnant and may develop infertility in the long term. Fortunately, many of these effects can be reduced - once the body receives proper and regular nourishment. For both men and women there is a high likelihood of developing osteoporosis.Anorexia and familyMany families also find that the person with an eating disorder becomes the centre of attention which can seriously affect relationships between brothers and sisters, parents, relatives and carers.
27Bulimia NervosaSufferers are obsessed with the fear of gaining weight and undergo a recurring pattern of binge eating, which is usually followed by self-induced vomiting.People with bulimia often feel a lack of self-control and have an excessive concern with their body weight and shape.Sufferers may also use large quantities of laxatives, slimming pills or strenuous exercise to control their weight.Many bulimics have poor dental health due to regular vomiting; vomit is acidic and can erode teeth in a characteristic way.The foods eaten tend to be high in carbohydrate and fat.
28Bulimia Nervosa Impact on mental health uncontrollable urges to eat vast amounts of food;an obsession with food, or feeling ‘out of control’ with food;distorted perception of body weight and shape;emotional behaviour and mood swings;anxiety and depression; low self-esteem, shame and guilt;Impact on behaviourdisappearing to the toilet after meals to vomit food eaten;excessive use of laxatives, diuretics or enemas;frequent periods of fasting;excessive exercise;secrecy and reluctance to socialise;shoplifting for food;abnormal amounts of money spent on food;food disappearing unexpectedly or being secretly hoarded.Long-term effects of bulimiaIn extreme cases can lead to heart failure.An imbalance or dangerously low levels of the essential minerals in the body can significantly/fatally affect the working of vital internal organs.Other dangers of bulimia include rupture of the stomach, choking, and erosion of tooth enamel, painful swallowing and drying up of salivary glands.Laxative abuse can lead to serious bowel problems.
29Other eating disorders Binge Eating Disorder (BED);complusive overeating;eating disorders in sport;‘Orthorexic’;‘Drunkorexic’.Visit for further information.Binge Eating Disorder: similar to Bulimia Nervosa, people with BED binge uncontrollably, but do not purge. The binges are often triggered by some serious upset, and may take place in secret.complusive overeating: eat at times when you are not hungry. People with compulsive eating are often overweight, if not obese. They may use their weight or appearance as a shield they can hide behind to avoid social interaction, others hide behind a happy or jolly façade to avoid confronting their problems. Sufferers often have great shame at being unable to control the compulsion to eat. Compulsive overeating is a serious condition and needs professional support to ensure long term recovery.eating disorders in sport: ‘female athlete triads’ characterised by eating disorders, poor bone health and the absence of periods.‘Orthorexic’: not a recgonised medical term, people who are termed as orthorexic only eat certain ‘healthy foods’ and cut out certainly food groups completely for ‘health’‘Drunkorexic’: not a recgonised medical term either, displacing food calories for alcohol
30Teenagers - key issues Nutritional requirements Dietary recommendationsMacronutrientsMicronutrientsEnergy balancePhysical activityDiet and cognitive abilityDiet and behaviourEating disordersKey issuesRapid growth and development – energy and nutrient requirements at their highest.Average intakes of saturated fat, added sugars and salt are above recommendations. Low fibre intakes.Inadequate average intakes of some vitamins and minerals (Low iron intakes in teenage girls is particularly concerning due to the risk of developing iron deficiency anaemia. Low calcium intakes also concerning as an adequate calcium intake in adolescence is important for optimising bone mass and future bone health.)Increasing prevalence of obesity – lack of physical activity.Restriction of food intake to control weight or adoption of vegetarian diet (girls in particular) – can lead to inadequate nutrient intakes.30
31Teenagers - dietary improvements needed More fruit and vegetables, pulses, wholegrain foods.More milk and diary foods.More iron-rich foods.More oily fish.Less foods high in saturated fat and added sugars.Less salt.Dietary improvements needed – hopefully can be supported by new Scottish Dietary TargetsThese dietary improvements are in line with following a healthy, balanced diet, as depicted in The eatwell plate model.More fruit and vegetables, pulses, wholegrain foods (5 A DAY, micronutrients, dietary fibre)More milk and diary foods (calcium, zinc, riboflavin, vitamin A)More iron-rich foods (e.g. lean meat, pulses, dried fruit, fortified bread and breakfast cereals)More oily fish (long-chain omega-3 fatty acids, vitamin D)Less foods high in saturates and added sugars (e.g. biscuits, cakes, pastries, confectionery, soft drinks)Less salt (e.g. from salty snacks, processed foods, salt added at table)31
32For more information visit www.nutrition.org.uk www.foodafactoflife.org.uk