ADOLESCENT NUTRITION

Dr.Fatemeh Famouri

Pediatric Gastroenterologist

ADOLESCENCE

It is the time between the onset of puberty and adulthood (11- 17 years old)

Boys grow about 8 inches, gain about 45 pounds and increase their lean body mass. Girls grow about 6 inches, gain about 35 pounds and increase their body fat.

Growth through adolescence is hormone driven. Growth spurts for girls

begin between ages 10.5 and 11 years with a peak in the rate of growth at around age 12.

Considerable gain in muscle and bone mass

DEFINITION

• Early adolescence: 10 -15 years;• Mid adolescence: 15-17;• Late adolescence : 17-21, but variable.

differences between genders becomes apparent females: higher fat

percentage males: more lean body

mass

Adolescence is an uncomfortable time for the teen who is concerned with body image or body changes or athletic activities.

Low nutrient snacks are a large part of the diet and adequate amounts of fruits and vegetables are missing.

Factors that determine food selection and consumption include the desire to behealthy, fitness goals, amount of discretionary income, social practices and peers.

• improved nutrition in adolescence,particularly in girls, is the reduced risk of osteoporosis in older age.

• stunting becomes a permanent consequence of past malnutrition rather than being a sign of present malnutrition.

• If there is indeed catch-up growth in height, adolescence can provide a final chance for intervention to promote additional growth,with potential benefit in terms of physical work capacity and for girls, of diminished obstetric risk .

Linear growth may be limited by multiple simultaneous nutrient deficiencies in many populations,

which could explain that interventions with specific individual nutrients (eg, vitamin A, iron, zinc)

increased pre-pregnancy weight and body stores of nutrients, thus contributing to improved future pregnancy and lactation outcome,

improved iron status with reduced risk of anaemia in pregnancy, low birth weight, maternal morbidity and mortality, and with enhanced work productivity and perhaps linear growth;

improved folate status, with reduced risk of neural tube defects in the newborn and megaloblastic anaemia in pregnancy.

Small girls are likely to become small women who are more likely to have small babies, particularly if at a young age

The overall nutritional status is better assessed with anthropometry, in adolescence as well as at other stages of the life cycle. Anthropometry is the single most inexpensive, non-invasive and universally applicable method of assessing body composition, size and proportions

Iodine deficiency disorders Iodine deficiency disorders were widely

prevalent in most populations Neuromotor and cognitive impairments of

variable degrees Iodine deficiency is recognized as the most

common cause of preventable mental retardation in the world.

ZINC

Evidence from supplementation trials suggests that marginal zinc nutriture may also limit skeletal growth

zinc supplementation increased accretion of fat-free mass and enhanced linear growth in those that were stunted at baseline

Figure 18.4

CALCIUM ½ of peak bone mass

accumulates in adolescence

AI for calcium = 1,300 mg for ages 9–18 years Inadequate calcium intake

can lead to low peak bone mass and is a risk factor for osteoporosis

TEENAGERS 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 11-14 year-old girls and 19% of 15-18 year-old girls.

A lack of calcium may have consequences for future bone health e.g. increased risk of osteoporosis.

IRON

Additional iron supports muscle growth and increased blood volume Adolescent females need iron to support

menstruation RDA for iron

Females aged 14–18 years = 15 milligrams Males aged 14–18 years = 11 milligrams

Iron deficiency is common in adolescence, especially among individuals who limit intake of enriched grains, lean meats, and legumes

IRON ABSORPTION Good 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 (heme iron) is readily absorbed by the body.

Vitamin C helps the body to absorb iron from other sources (non-heme iron).

A 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;

• best 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.

NUTRIENT NEEDS OF ADOLESCENTS Growth not age should be ultimate indicator of nutrient needs. Energy needs are greater during adolescence than at any other time of life

with exception of pregnancy & lactation. Energy & Proteins RDAsMales Age (yrs) Kcal/kg Kcal/day Proteins g/kg Proteins

gm/day 11-14 55 2500 1.0 4515-18 45 3000 0.9 59FemalesAge (yrs) Kcal/kg Kcal/day Proteins g/kg Proteins

gm/day 11-14 47 2200 1.0 4615-18 40 2200 0.9 44 Vitamins & Minerals Higher vitamins and minerals needs. Three nutrients of importance i.e. vitamin A, iron and calcium. AI for calcium 1300 mg/day, for iron is 11 mg/day (boys) and 15 mg/day

(girls). Improving fruit & vegetable intake will help in obtaining adequate vitamin A.

DIETARY RECOMMENDATIONS

Teenagers should consume a variety of foods from each of the four main food groups:

Fruit and vegetables (33%)

Bread, rice, potatoes, pasta and other starchy

foods (33%)

Milk and dairy foods (15%)

Meat, fish, eggs, beans and other non-dairy

sources of protein (12%)

FOOD GUIDE PYRAMID

serving sizes can help you control the amount of calories, fat, saturated fat, cholesterol, sugar or sodium in your diet.

Grains, Bread, Cereal and Pasta form the Base Fruits and Vegetables Lean Meat and Fish, Beans, Eggs Dairy Products Fats and Sweets

MACRONUTRIENTS

MacronutrientRecommended intake (% food energy)

Boys average intake

(% food energy)

Girls average intake

(% food energy)

Fat35%35.4%35.9%

of which saturates

11%14.2%14.3%

Carbohydrate50%51.6%51.1%

of which added sugars (NMES)

11%16.7%16.4%

-average intakes (Scottish NDNS and Survey of Sugar Intake

data)

WHAT ABOUT DIETARY FIBER?

average dietary fibre 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/day

Reference values:- 15 g/day (11-14 years)- 18 g/day (15 years or above)

WHAT 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.

TEENAGERS 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 – 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

DIET 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.

Stevenson J (2006) Dietary influences on cognitive development and behaviour in children Proct Nutr Soc

65(4):361-5.

Bellisle F (2004) Effects of diet on behaviour and cognition in children Br J Nutr 92 Suppl 2: S227-32.

GLYCEMIA

The brain appears to be sensitive to short-term fluctuations of glucose supply and therefore it

might be beneficial to maintain glycemia at adequate levels to optimise cognition.

EATING BREAKFAST

Starting 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.

Improvement of memory

Other benefits of breakfast include better nutrient intakes and weight control.

•Even 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.

FLUIDS AND HYDRATION

DIET AND IQ Brain 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.

DIET 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.

FOOD 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.

Bateman B et al. 2007

EATING HABITS irregular eating habits snacks generally provide ¼ of daily energy

intake more fast food: less fruits, vegetables, milk food choices are often dictated by peers

WHAT DO BOYS AND GIRLS WANT?

boysys usually want to gain muscle and

get tallerGirls usually want to

control their weight

FOR GIRLS SOME ADDITION OF FAT IS NATURAL

Need at least 17% body fat for normal periods

Diet is a four letter word

Improve eating habits and activity – but don’t starve or over exercise

BOYS MATURE LATER

Growth spurt up to 2 years later than girls

Full muscle mass doesn’t develop until one year after full height achieved

Excess calories and protein won’t speed things up

MAKE EVERY DRINK COUNT

Cut the soft drinks

Drink 3-4 cups of milk Drink at least 4 more

cups of water or juice

(watch the juice – it has calories)

DURING A SPORTS EVENT

Drink at least 2 cups of water before event

Continue to drink 4 ounces every half hour

Cool, not cold, water is best

Replace two cups of fluid for every pound lost

EAT AT LEAST 5 SERVINGS OF FRUITS AND VEGETABLES

Lots of vitamins and minerals with few calories

More fiber so you feel full

Portion size – palm of girl’s hand

EAT MORE WHOLE GRAIN BREADS AND CEREALS

Won’t cause weight gain if don’t eat too much

Depending on body size, will need 6-11 servings

Portion size – the palm of a girl’s hand

GET ENOUGH PROTEIN BUT NOT TOO MUCH

Get protein from lean meat, fish and poultry

Portion size – palm of girl’s hand

Protein also comes from dairy foods, dried beans and peas, peanut butter, nuts, seeds, soy foods

Limit low nutrient foods with lots of fat, sugar and sodium

Make fast food a special occasion choose grilled or broiled

meat, fish or poultry choose side salads,

baked potatoes choose milk, water or

juice

DISORDERED EATING

Disordered eating patterns are more prevalent in adolescent females than males May be linked with poor body image or low self-

esteem Teens often adopt unhealthy habits such as

Skipping meals Using food substitutes Taking diet pills or nutritional supplements Purging through vomiting, laxatives, or diuretics

Eating family meals promotes healthy eating patterns

ANOREXIA NERVOSA

Refusal to maintain body weight over a minimal normal weight.

Intense fear of gaining weight or becoming fat, even though underweight.

Denial of low body weight.

In females, absence of at least 3 consecutive menstrual cycles.

.

ANOREXIA NERVOSA:CLINICAL & LABORATORY FINDINGS

LANUGO and EDEMA of the skin, bradycardia and hypotension, constipation, normochromic anemia and leukopenia, hyponatremia, hypoglycemia, low hormonal levels (estrogen or testosterone, LSH, FSH) but normal TSH and increased cortisol

SKELETAL CHANGE: OSTEOPENIA

ANOREXIA NERVOSASIGNS OF MALNUTRITION :

Easy pinching in the posterior region of the arms, due to to loss of fat

Hollowing temporal muscles

Wasting of the tigh muscles

Easily plucked hairs

MEMO: the laboratory signs of malnutrition are HYPOALBUMINEMIA and HYPOPREALBUMINEMIA

TREATMENT FOR ANOREXIA NERVOSA

Close supervision Individual and family counseling Self-acceptance Time and patience Nutrition therapy

BULIMIA NERVOSA

Characterized episodes of binge eating alternating with purging

Female to male ratio 10:1

Some genetic factors may be involved, but and above all cultural attitudes toward standards of physical attractiveness

3 modalities are the most frequent:Self induced vomiting via “fingers” or ipecacAbuse laxatives (e.g. bisacodyl, cascara or senna)Misuse diuretics

In addition to diuretics also diet pills (containing ephedrine)

BULIMIA NERVOSA: COMPLICATIONS

Oral: loss of enamel of the anterior teeth and dental caries

GI tract: frequent vomiting can induce GE-reflux (occasionally tears in the esophagus). The abuse of laxatives can lead to constipation due to damage of the myo-enteric plexus

Abnormalities of the electrolytes: Metabolic alkalosis due to frequent vomiting HYPOKALEMIA present in 5% of the patients

BULIMIA NERVOSA: TREATMENT

Replenish potassium losses

Eventually I.V. fluids and lytes

Monitor lytes frequently

and, of course

Refer for psychiatric or psychologic counseling

TREATMENT FOR BULIMIA

Eating only at mealtime Portion control Close supervision after eating Psychological counseling

OBESITY:HEALTH CONSEQUENCES

Cardiovascular disease risk Type 2 diabetes (epidemic) Hypertension Orthopedic Sleep apnea Gall bladder

disease/steatohepatitis Psychosocial problems

BODY MASS INDEX

Weight in kg divided by height in m2

NORMAL BMI : 18 to 24 years of ageBMI < 18 : suspect malnutrition

BMI 24 to 30 : overweightBMI 30 to 40 : obesity

BMI above 40 = morbid obesity

OBESITY TREATMENTS

Caloric restrictions: restrict fats to less than 30% of the total caloric intake

Modification of lifestyle and exercise: A walk of 1 mile (1.5 m) burns 100 Kcal

Walk 2 - 3- or even 4 miles, 4 or 5x weekly, and add some resistance exercise 2 or 3 times weekly (all under some supervision).

The dietary variations: the high protein low carbohydrate (only 20 grams of CHO/day)

FINAL COMMENTS

The recipe for effective weight loss is a combination of: Motivation

Physical activity Caloric restriction

And all this with a lifelong adherenceBUT

MEMO: Prevention of weight gain is the first step EVEN IN CHILDREN