Anthropometry

Dr.Nishan Silva (MBBS)

Anthropometry

• Nutritional care • Body mass index • Basal metabolic rate • Recommended Daily allowances • Physical Measurements • Energy expenditure

The Nutrition Care Process

• Identifying and meeting a person’s nutrient and nutrition education needs. Five steps: 1.

Assess

Assessment of nutritional status 2.

Analyze

Analyze assessment data to determine nutrient requirements 3.

Develop

Develop a nutrition care plan to meet patient’s nutrient and

education

needs.

4.

Implement :

Implement care plan 5.

Evaluate :

Evaluate effectiveness of care plan: ongoing follow-up, reassessment, and modification of care plan.

Assessing Nutritional Status

• Historical Information • Physical Examination • Anthropometric Data • Laboratory Analyses

CLINICAL ASSESSMENT

Good nutritional history should be obtained General clinical examination, with special attention to organs like hair, angles of the mouth, gums, nails, skin, eyes, tongue, muscles, bones, & thyroid gland.

Detection of relevant signs helps in establishing the nutritional diagnosis

Anthropometric Data – physical measurement of the body anthropos = human metric = measure • Indirect assessment of body composition and development • Used in Nutrition Assessment: – Measures using height and weight – Measures of body composition (fat vs. lean tissue) – Functional Measures

Indices

• W/A: combined measurement: – NO individual diagnosis but trend assessment – For growth monitoring and FU • W/H indicates degree of wasting – Individual diagnosis – Community diagnosis – Sensitive to change • H/A indicates linear growth retardation – not sensitive to change – slow progress – Community diagnosis

Body Mass Index

Nutritional Indices in Adults

•

The international standard for assessing body size in adults is the body mass index (BMI).

•

BMI is computed using the following formula: BMI = Weight (kg)/ Height (m ² )

•

Evidence shows that high BMI (obesity level) is associated with type 2 diabetes & high risk of cardiovascular morbidity & mortality

Measures Using Height and Weight

BMI Body Mass Index

wt (kg) ht (m)

2 or wt (lb) X 705 ht (inches) 2

International classification of BMI

Measurements

Example

• Height – 1.96 m (6 ft 5 in) • Weight – 125 kg (276 lb; 9 st 10 lb) • BMI –

32.55 kg/m 2

•Still … BMI –

32.55 kg/m2

Run 100m

in 10.8 s!!!!

Measures Using Height and Weight

Cons:

BMI can misclassify up to one out of four people.

– Does not account for fat distribution – Doesn’t account for LBM - may misclassify frail/sedentary or very muscular people

Other anthropometric Measurements

•

Mid-arm circumference

•

Skin fold thickness

•

Head circumference

•

Hip/waist ratio

•

Head/chest ratio

Measuring weight - Video

Measuring weight

Measuring weight

Measuring Height - video

Stadiometer Infantometer

Measuring Length - video

Circumferences - video

Skin fold thickness - video

Skin fold thickness - video

Growth percentile charts

Growth charts

What is normal growth?

When can you call it abnormal?

When does it tends to change?

Drawbacks?

ADVANTAGES OF ANTHROPOMETRY

• • • • •

Objective with high specificity & sensitivity Measures many variables of nutritional significance (Ht, Wt, MAC, HC, skin fold thickness, waist & hip ratio & BMI).

Readings are numerical & gradable on standard growth charts Readings are reproducible. Non-expensive & need minimal training

Limitations of Anthropometry



Inter-observers errors in measurement



Limited nutritional diagnosis



Problems with reference standards, i.e. local versus international standards.



Arbitrary statistical cut-off levels for what considered as abnormal values.

Energy Expenditure

Humans oxidise (metabolise) carbohydrate, protein, fat (and alcohol) to produce Energy.

Energy is used to….

• To maintain body functions - to breathe, to keep the heart beating, to keep the body warm and all the other functions that keep the body alive.

• For physical activity - for active movement - muscle contraction.

• For growth and repair, which require new tissues to be made

Measurement…

• Energy can be measured in either joules or calories • 1 kcal = 4.184 kj • The average daily energy intake in the UK is 10250kJ (2450 kcal) for men and 7030kJ (1680 kcal) for women. • The energy in the diet is provided by carbohydrate,protein, fat and alcohol.

A gram of…..

• carbohydrate (starch or sugar) provides 16kJ (3.75 kcal) • protein provides 17kJ (4 kcal) • fat provides 37kJ (9 kcal) • alcohol provides 29kJ (7 kcal)

Energy Expenditure…

The energy expenditure (EE) of a man or woman over a whole day is often divided into different components, which can be individually determined.

These are: Basal metabolic rate (BMR), Diet induced Thermogenesis (DIT), Physical activity (PA)

Calculating total energy expenditure

Basal Metabolic Rate (BMR)

• is the amount of daily energy expended by humans (and other animals) at rest.

• Rest is defined as existing in a neutrally temperate environment while in the post absorptive state .

BMR

• Basal metabolism is usually by far the largest component of total caloric expenditure. • Basal metabolic rate is usually expressed in terms of daily rates of energy expenditure. (kcal/day) • The primary organ responsible for regulating metabolism is the hypothalamus .

• The basal metabolic rate varies between individuals.

Energy Expenditure at Rest

• Basal Metabolic Rate – BMR is rate of energy expenditure fasted, rested and supine conditions in thermoneutral environment – Resting metabolic rate (RMR) is rate of energy expenditure when at rest but not basal – BMR proportional to BSA, after age 20 reduces 2% & 3% per decade in women and men, respectively

Factors effecting BMR

• Regular exercise – Keeps BMR elevated at rest • Muscle mass – More muscles – more BMR • Diet – Severe calorie restriction reduces BMR • Food type – Proteins increase BMR

Factors effecting BMR

• Hormones – Thyroxine • Stress – Increases BMR • Age – Reduces BMR • Gender – Males higher • Body temperature – Elevates BMR • ? What happens to BMR in an infection / inflammation?

Dietary reference intakes (DRI)

• • • •

Recommended Dietary Allowance (RDA

)

Adequate Intake (AI) Tolerable Upper Intake Level (UL) Estimated Average Requirement (EAR)

Recommended Daily Allowances

Recommended Dietary Allowance (RDA) • It is the average daily level of intake sufficient to meet the nutrient requirements of nearly all (97%-98%) healthy people.