Week 10 - Nutrition for Special Groups

Infants (newborn to ~1 year) – why is the first year nutritionally important?

A time of rapid growth and development that must be supported with good nutrition | A healthy infant's weight doubles by ~5 months and triples by 1 year

Infant growth charts – how are they used and what is normal?

Weight and height percentile charts (weight-for-age, length/height-for-age) are used to track growth | Healthy babies are born at a variety of weights and track along a fairly standard growth trajectory | Tracking along a low or high percentile isn't necessarily a problem as long as weight and height track along similar percentiles

Infant growth charts – what raises concern?

Height tracking along a high percentile while weight tracks along a low percentile | A child moving across percentiles (e.g., following the 50th percentile then dropping away to the 10th)

What should be considered when interpreting WHO growth charts?

The population used to create the normative data, including factors such as ethnicity and whether infants were breastfed or formula-fed.

Energy requirements – infant vs adult (per day and per kg)

Per day: infant ~1,800–2,000 kJ vs adult ~8,700 kJ – adults need more in total because they are larger | Per kg: infant ~420–450 kJ/kg vs adult ~170 kJ/kg – infants have much higher needs relative to body size, especially in the first few months

Energy-yielding nutrient percentages – breast milk vs adult diet

Breast milk: ~6% protein, 55% fat, 39% carbohydrate | Adult (midpoints of acceptable ranges): ~20% protein, 25% fat, 55% carbohydrate | Adult acceptable ranges: protein 15–25%, fat 20–35%, carbohydrate 45–65%

Why do infants need a high proportion of fat (and still some carbohydrate)?

High energy needs per kg and a small capacity to consume food, so they need an energy-dense diet | Less active than adults so need less carbohydrate, but still need some for brain development

Protein in breast milk – why is the proportion low, and what is notable?

Protein is important for growth and development, but too much stresses the infant's liver and kidneys | Much of the protein in breast milk is alpha-lactalbumin, which is easily digested | Infants fed concentrated formula or other fluids can receive excess protein

Australian Dietary Guidelines Guideline 4 – what does it say and why?

Encourage and support breastfeeding | Strong health benefits for both mother and child; good outcomes are also possible with formula, but breastfeeding is encouraged as the first option wherever possible

NHMRC Infant Feeding Guidelines (2013) – key statement

Breastfeeding is the healthiest start for infants | Published 2013; to be reviewed as the Australian Dietary Guidelines are reviewed

Breastfeeding – infection, allergy and 'sterile' benefits for the infant

Breast milk contains immune substances that protect against infection: colostrum, antibodies, bifidus factors (antibacterial protection) and lactahedrin (antiviral) | The immune substances are protective against atopic disease (allergies) | Breast milk is sterile, so there is no risk of passing on germs through the milk

Breastfeeding – chronic disease and cognitive benefits for the infant (NHMRC 2013)

Protects against some chronic diseases: type 1 and 2 diabetes, coeliac disease, inflammatory bowel disease, CVD, obesity | Some studies show improved cognitive development | Caveat: the differences between breastfed and formula-fed infants may be narrowing, and the cognitive benefit may be less relevant, as formulas and feeding practices improve

Breastfeeding – benefits for the mother

NHMRC 2013: reduced risk of ovarian cancer, breast cancer and type 2 diabetes | 2019 National Breastfeeding Strategy adds: hyperlipidaemia, hypertension, cardiovascular disease and maternal depression

According to the 2019 Australian National Breastfeeding Strategy, what risks are increased in infants who are not breastfed?

Sudden infant death syndrome (SIDS); respiratory and gastrointestinal infections; acute ear infection; asthma; type 1 and type 2 diabetes; overweight and obesity; leukaemia; and compromised biome.

What societal impacts are reduced by breastfeeding according to the 2019 Strategy?

Costs on the health system, environmental impact and socioeconomic stress.

Older hospital feeding practice (when the lecturer was born) and its limitation

Babies were taken to a nursery so mothers could rest and brought to mothers at scheduled 3–4 hourly intervals; sometimes given formula in between if nurses thought it would give the mother a break | All babies were fed the same thing on the same schedule rather than according to each baby's cues

Current approach to infant feeding – responsive feeding

Mothers are encouraged to stay close to their babies, learn their cues and feed when the baby indicates hunger | A young baby feeds roughly every 2–4 hours (could be 1–2 hourly or have longer gaps); a feed takes ~20–45 minutes; no definite preferred schedule, and strict schedules are no longer recommended | No specific volume of breast milk is prescribed as long as the baby is growing and gaining weight normally

Formula-company gift bags in hospitals – what changed and why?

Used to include nappies, dummies, formula samples and bottles | No longer allowed, to prevent formula companies advertising to mothers at this influential time

Current practice for supporting breastfeeding

Support mothers to establish breastfeeding; turn to formula only if there is a need or strong preference | Breastfeeding is natural but doesn't automatically happen easily – most mothers find it difficult and need support to persevere through the early days | Some mothers feel discouraged, think something is wrong with them or their milk supply, and stop unnecessarily or prematurely

What principle should guide infant-feeding decisions?

Every mother has the right to make her own feeding decisions, and decisions should be informed and supported.

What does the lecture say about Australian advertising of infant formula?

The lecture states that Australian law does not allow advertising of formula for infants on television; follow-on formula for toddlers may be advertised.

WHO/UNICEF Baby-Friendly Hospital Initiative (2018) and the Ten Steps

Protects, promotes and supports breastfeeding in facilities providing maternity and newborn services by implementing the Ten Steps to Successful Breastfeeding | The steps are strategies that increase the likelihood mothers start and continue breastfeeding | Lecturer: you don't need to memorise every detail – just understand that several strategies are used

NHMRC 2013 – breastfeeding recommendations (exclusive breastfeeding and beyond)

Encourage, support and promote exclusive breastfeeding to around 6 months | Exclusive = breast milk only: no formula, water, other liquids or food | Then continue breastfeeding while introducing solid foods until 12 months and beyond, for as long as mother and child desire | Any breastfeeding is beneficial to infant and mother – a mother who can't exclusively breastfeed is encouraged to breastfeed to whatever extent she can

2010 Australian National Infant Feeding Survey – breastfeeding figures

96% initiated breastfeeding | Still receiving some breast milk: ~69% at 4 months and 60% at 6 months | Exclusively breastfed: ~39% to 3 months, only 15% to 5 months

What are examples of absolute or important contraindications to breastfeeding mentioned in the lecture?

A small number of physical issues, such as surgery; some medicines, such as chemotherapy or radioactive substances; illicit substance and alcohol use; and some illnesses, such as untreated tuberculosis or untreated HIV.

Aboriginal & Torres Strait Islander infants – breastfeeding initiation and Brown et al. (2018)

Some research shows lower initiation in some Aboriginal & Torres Strait Islander populations (~83%); no national data | Brown et al. 2018 (344 women, South Australia): 86% initiated; 54% breastfeeding at 12 weeks | Women in remote areas were more likely to be breastfeeding at 12 weeks than women in Adelaide (OR 2.6, 95% CI 1.5–4.7)

Brown et al. (2018) – survey limitation

Questions (e.g., 'How did you feed your baby at the start?', 'Are you still breastfeeding baby?') could not distinguish exclusive breastfeeding from mixed breast milk and formula feeding, except in the first few days after birth

Brown et al. (2018) – reasons for switching to formula, and how the lecturer interprets the top reason

Not enough milk/baby not gaining weight 48% | Mastitis/breasts too sore 17% | Attachment or feeding issues 12% | Mother's choice/prefer formula 10% | Stress/exhaustion 6%; baby stopped/preferred bottle 6% | Maternal ill health 5%; too hard/time-consuming 5% | All others <5% (too busy/other children, drinking/smoking, work/childcare, baby feeding too often/too long, biting, not enough support/shame, baby readmitted to hospital) | Lecturer: 'not enough milk' often reflects poor support to establish breastfeeding rather than a physiological problem

Australian National Breastfeeding Strategy 2019 and beyond (COAG Health Council) – vision

Create an enabling and empowering environment that protects, promotes, supports and values breastfeeding as the biological and social norm for infant and young-child feeding | Overall focus: enable and empower mothers to breastfeed

What is the first objective of the Australian National Breastfeeding Strategy?

Increase exclusive breastfeeding to around 6 months (up to 40% by 2022 and 50% by 2025), particularly in priority and vulnerable populations; continue breastfeeding with complementary foods until 12 months and beyond as mother and child desire.

Australian National Breastfeeding Strategy – other objectives

Enable mothers, fathers/partners and other caregivers to access evidence-based, culturally safe breastfeeding education, support and clinical care | Increase breastfeeding-friendly settings (baby-friendly health services, workplaces, early childhood education and care, public spaces) | Strengthen regulation of marketing of infant formula and breast milk substitutes | Increase the proportion of health professionals receiving adequate, evidence-based breastfeeding training free from commercial influence | Raise community awareness of the significance of breastfeeding and the risks of not breastfeeding

Formula (NHMRC 2013) – what is recommended when an infant is not (fully) breastfed?

Commercial cow's-milk-based infant formula as an alternative to breast milk until 12 months, prepared as directed | Specialty formulas only for specific medical, cultural or religious reasons – most infants don't need them

Energy-yielding nutrient percentages – infant formula vs cow's milk

Infant formula: ~9% protein, 49% fat, 42% carbohydrate – a suitable alternative to breast milk if prepared according to instructions | Cow's milk: ~20% protein, 51% fat, 29% carbohydrate – too much protein and too little carbohydrate to be an infant's main milk | (Breast milk for comparison: ~6% / 55% / 39%)

Infants – NHMRC advice on other fluids

Exclusively breastfed infants need no additional fluids up to 6 months | Over 6 months or not exclusively breastfed: tap water is preferred, boiled and cooled until 12 months | Other beverages are not recommended

Introducing solid foods (NHMRC 2013) – when and why?

At around 6 months, when infants are physiologically and developmentally ready | They need more nutrients (e.g., iron) than breast milk/formula alone can provide | They need exposure to new textures, tastes and modes of feeding (e.g., drinking from a cup)

Signs of readiness for solids around 6 months – and how has timing changed?

Can sit up, has a strong choking reflex, can hold food and bring it to the mouth | Solids used to be introduced at ~4 months; now recommended at ~6 months

Breastfeeding, timing of solids and childhood obesity

Systematic reviews of observational studies: breastfeeding is associated with reduced risk of obesity in childhood | Breastfed children are more likely to be introduced to solids later than formula-fed children | Delaying solids is associated with lower prevalence of obesity in early and later childhood

Children (~1–10 years in this lecture) – growth and appetite regulation

Growth slows at ~1 year, so appetite usually decreases | Children generally spontaneously adjust food intake to coincide with growth patterns and hunger/satiety | Overweight children are more likely to eat in response to external cues than hunger and satiety signals

Children – recommended feeding approach

Offer a range of healthy foods and let children decide how much to eat | Encouraging children to eat when not hungry may encourage behaviours that lead to over-consumption

Why are children at increased risk of iron deficiency?

Transition to adult foods and cow's milk (low in iron; heavy milk intake can dull appetite for other foods) | Fluctuating appetites | Fussy food preferences

Children and iron – why is it important, and what can poor iron status cause?

Important for normal brain growth and development – directly involved in neurotransmitter synthesis | Poor iron status can cause behaviour change, attention issues and impaired learning and memory

Children and iron – Australian Health Survey 2011–12, main sources and vegetarian diets

~7% of boys and ~12% of girls aged 4–8 did not meet the EAR for iron | Main contributors to iron intake: fortified cereal products, meat and meat dishes | Vegetarian children can meet requirements, but the diet needs to be very high quality – usually fortified foods are needed

What are the general 'Healthy, Happy Mealtimes' tips?

Honour children's preferences; be realistic with quantities; role model; encourage learning through participation; use repeated exposure; avoid power struggles; and provide smart snacks.

Healthy, Happy Mealtimes – what the tips mean

Be realistic: parents often over-estimate how much children need; intake varies day to day | Role model: children learn by seeing others eat a wide range of foods | Participation: involve children in food preparation | Repeated exposure: children may need to try foods multiple times before they learn to like them | Avoid power struggles: no rigid rules like forcing certain foods or finishing the plate | Smart snacking: a series of small meals and snacks across the day, with snacks mostly high quality

How can discretionary foods be introduced in children's diets according to the lecture?

One approach is to delay exposure as long as possible; another is to include them as part of the normal diet and teach children to include them healthily without excess.

Vegetables for 4–8-year-olds – AGHE recommendation vs actual intake (Australian Health Survey 2011–12)

AGHE recommends 4.5 serves/day of vegetables/legumes/beans – ambitious, since many adults don't manage it | Median intake: 1.6 serves (boys), 1.3 serves (girls) | 0% of boys and girls aged 4–8 met the 4.5-serve recommendation | Lecturer's question: is the recommendation wrong, or is a lot more work needed to improve children's intakes?

How does the WHO define adolescence?

The period from 10 to 19 years of age, between the onset of puberty and adulthood.

Adolescents – what affects nutritional status, and why is it an important time?

Nutritional status is affected by rapid growth and biological, emotional, social and cognitive change | Desire for independence may make eating behaviour health-compromising or health-promoting | A time of great influence – potential to shape future health behaviours

Adolescent growth spurt – timing, duration and typical growth

Typically begins at age 10–11 in females and 12–13 in males | Lasts ~2.5 years | Males typically grow 20 cm and gain 20 kg; females grow 15 cm and gain 16 kg

Adolescent growth – what changes, and how does it compare with other life stages?

Height, weight, bone mass, muscle mass and blood volume increase; heart, brain, lungs, liver and kidneys increase in size | Growth rate is second only to infancy | Adolescents grow in height first, then catch-up weight gain occurs

Adolescents – when is adult height reached? (menarche)

Females: usually ~1 year after menarche (when periods commence) | Menarche ranges from 11–14 years between populations, mean 12.6 years; age of menarche has decreased over the last century | Males: usually by ~17 years, with great individual variability

Adolescent energy requirements (EER) by age

Age 12: 7,400–11,600 kJ/day | Age 16: 8,900–14,700 kJ/day | Age 18: 9,400–15,600 kJ/day | Higher during growth phases but highly variable at any age depending on activity levels

What nutrition behaviour should adolescents develop as growth slows?

Healthy eating behaviours that can continue when their growth rate slows, rather than relying on energy-dense foods.

Adolescents' vegetable intake – Australian Health Survey 2011–12

Most adolescents are not eating the recommended amounts of vegetables

Adolescence and peak bone mass

Almost half of adult peak bone mass is accrued during adolescence; by age 18 more than 90% of adult skeletal mass has formed | Calcium intake throughout childhood and adolescence is important to optimise bone density before it starts to decline | Slide graph: bone mass rises through puberty to a peak in early adulthood, then declines; the women's curve is lower and falls after menopause

Calcium absorption in adolescence

Females: absorption is highest around menarche and during early adolescence | Males: ~4 times more calcium is absorbed in early adolescence than in early adulthood

Calcium – Australian Health Survey 2011–12 (14–18-year-olds)

71% of males and 90% of females aged 14–18 did not meet the EAR for calcium

Why are adolescent calcium intakes low? Barr (2007)

10-year follow-up of 45 healthy girls (mean starting age 10.5 years) | Girls with higher 'dieting scores' had lower total and dairy calcium intakes at baseline | Girls preoccupied with body shape excluded dairy foods, perceiving them as 'fattening' | Study done in 2007 – it would be interesting to see if perceptions have changed

Why are adolescent calcium intakes low? Replacing milk with other drinks

Adolescents tend to reduce milk consumption in favour of drinks such as soft drinks and juice – which can explain low calcium intakes in males too

Adolescents and iron – Australian Health Survey 2011–12

40% of females aged 14–18 did not meet the EAR for iron | Adolescents often experiment with ways of eating such as vegetarian diets; if not supported to implement them well, iron intake can be compromised

Disordered eating in adolescents – dieting as a risk factor

Dieting is the single most important risk factor for developing an eating disorder | Girls who diet moderately are 5 times more likely, and those who diet severely 18 times more likely, to develop an eating disorder than those who don't diet | Both males and females are affected

Why should changes in adolescent eating behaviour not be dismissed as normal teenage behaviour?

They may indicate disordered eating; early intervention is important to support recovery.

Older adults – heterogeneity, chronological vs physiological age

Older adults are a heterogeneous group; functional status is more important than chronological age | Chronological age = age in years since birth | Physiological age = age estimated from physiological health | People of the same chronological age can look and function as older or younger

Ageing – physiological changes that can compromise dietary intake

Taste and smell decline (also affected by disease and medications) → reduced appetite and enjoyment of food | Oral health: declines in oral musculature, dentition and oral secretions affect the capacity and experience of eating | Appetite and thirst: hunger, satiety and thirst-regulation cues weaken, reducing the physiological drive to meet nutritional requirements

Ageing – which nutrient requirements increase, and why?

Increased requirements for protein, calcium and vitamin D | Why: harder to maintain nitrogen balance; GI changes (decreased gastric acid, intrinsic factor and pepsin; altered bowel flora/permeability) affect absorption of B vitamins, folate, iron, zinc, magnesium and calcium; medications can affect absorption

Ageing – energy needs and the need for nutrient-dense foods

Energy requirements decrease (less active, lower muscle mass) | But requirements for some nutrients increase, so older adults need nutrient-dense foods | Exception: iron – women need less once menstruation ceases

Protein RDI by age (men and women)

Men: 0.84 g/kg at 31–50 and 51–70; 1.07 g/kg over 71 | Women: 0.75 g/kg at 31–50 and 51–70; 0.94 g/kg over 71

Calcium RDI by age (men and women)

Men: 1,000 mg/day at 31–50, 51–70 and over 71 | Women: 1,000 mg/day at 31–50 and 51–70; 1,300 mg/day over 71

What are the vitamin D AIs for ages 31-50, 51-70 and over 71?

5 micrograms/day; 10 micrograms/day; and 15 micrograms/day, respectively.

Iron RDI by age (men and women)

Men: 8 mg/day at 31–50, 51–70 and over 71 | Women: 18 mg/day at 31–50; 8 mg/day at 51–70 and over 71 (requirement falls after menstruation ceases)

Ageing – body composition changes and contributing factors

Bone and muscle are lost while body fat increases | Contributors: hormonal changes (decreased androgens and growth hormone), reduced activity, poor nutrition, smoking

Sarcopenia – what is it, what are its effects and how is it minimised?

Loss of skeletal muscle mass, strength and quality | Reduces strength and balance, lowers metabolic rate and increases the potential for falls | Minimise with adequate protein, adequate energy and exercise (especially weight-bearing/strength-building)

Sarcopenia – thigh cross-section comparison

20-year-old woman's thigh is dense with muscle; 64-year-old woman's thigh has lost muscle and gained fat, despite similar external size | These changes may be largely preventable or slowed with strength-building activity and a quality diet

Older adults – how do AGHE food-group recommendations change with age, and why?

Generally decrease across the food groups as energy requirements fall | The milk, yoghurt and cheese group is the exception – higher serves in some older age groups to meet increased calcium and protein needs (and to some extent vitamin D) | Challenge: ageing's physiological effects can make this intake hard to achieve – smaller portions that are rich in nutrients may help

AGHE – the five food groups

Vegetables and legumes/beans | Fruit | Grain foods (cereal foods, mostly wholegrain/high-fibre varieties) | Lean meats and alternatives (lean meats, poultry, fish, eggs, tofu, nuts and seeds, legumes/beans) | Milk, yoghurt, cheese and alternatives (mostly reduced-fat)