Topic 7: Adult Years

Question 1

What are the priorities for nutrition in adult years?

Answer 1

maintain body homeostasis,
optimize general health and wellbeing and
prevent the onset of dietary-related chronic diseases.

Question 2

What are the physiological characteristics of the adult years?

Answer 2

The adult years are characterized by the completion of sexual and reproductive development, attainment of both full genetic size, and a state of tissue maintenance. Body tissues are in a state of flux, with some tissues undergoing a greater rate of turnover. Protein breakdown eventually exceeds protein synthesis and one observes a gradual decline of body tissues.

Question 3

What variables impact body composition?

Answer 3

sex
age
genetic predisposition
level of physical activity
nutrient intake

Question 4

How much water makes up a female and male’s body weight?

Answer 4

The percentage of water is generally higher in males than in females because of the proportionally greater muscle mass (75–80% water) in men and a smaller amount of adipose tissue (8–10% water).

Question 5

What are the two methods used to determine body fat percentage?

Answer 5

• non-invasively by measuring skinfold thickness at various points around the body, such as tricep, suprailiac, pectoral, and thigh.
  direct methods such as bioelectrical impedance analysis and DEXA scans [5].

Question 6

What diseases are overweight and obese individuals more susceptible to?

Answer 6

non-insulin-dependent diabetes mellitus, coronary heart disease, hypertension, gall bladder disease, and some types of cancers.

Question 7

What is the calculation for BMI?

Answer 7

[weight (kg)/ height (m)2]

Question 8

What are the BMI classifications for obesity?

Answer 8

Class I obese: 30.00-34.99
Class II obese: 35.00-39.99
Class III obese: >40

Question 9

What is the BMI classification for overweight?

Answer 9

25-29.99

Question 10

What is the BMI classification for normal weight?

Answer 10

18.5-24.99

Question 11

What is the BMI classification for underweight?

Answer 11

<18.50

Question 12

What did the 2011-12 AHS survey reveal about the prevalence of obesity and overweight?

Answer 12

• 63% of adult Australians were overweight or obese (35% overweight and 28% obese).
• more men (70%) were overweight or obese compared with women (56%)

Question 13

Explain waist circumference (WC) in comparison to BMI.

Answer 13

Waist circumference is a good indicator of total body fat and is also a useful predictor of visceral fat. Compared to BMI, waist circumference is a better predictor of cardiovascular risk, type 2 diabetes in women, and metabolic syndrome.

Question 14

What is the UL for WC in men and women and what diseases are they associated with?

Answer 14

A WC > 80cm in women and >94cm in men is indicative of a body fat distribution around the abdomen and is associated with an increased risk of developing diseases such as type 2 diabetes, cardiovascular disease and hypertension.

Question 15

What did the 2011-12 AHS survey reveal about WC statistics?

Answer 15

• 60.3% of men and 66.6% of women had WC measurements above recommendations.
• The average waist circumference for men was 97.9cm and for women, it was 87.7cm.
• The proportion of men and women with WC levels above recommendations increased with age [3].
• In Aboriginal and Torres Strait Islander people over 18 years of age, 61.5% of men and 81.2% of women had WC measurements above recommendations [10].

Question 16

What is energy expenditure (EE) comprised of?

Answer 16

• basal metabolic rate (BMR)
• physical activity
• the thermic effect of food (TEF) and facultative thermogenesis.

Question 17

How can TEE be calculated?

Answer 17

Total energy expenditure (TEE) can be estimated by calculating BMR using prediction equations and multiplying this BMR by the appropriate level of activity.

e.g. Male, 25 years old, 75 kg, very sedentary

BMR = 0.063 × 75 + 2.896 = 7.6 MJ/day

BMR × 1.3 (activity factor) = 9.9 MJ/day

Question 18

Where is calcium found in the body and when does it start accumulating?

Answer 18

The majority of calcium (99%) in the body is found in the skeleton. The daily accumulation of calcium in skeleton commences in infancy and peaks during adolescence, but continues until the age of 30–35 years.

Question 19

What does negative calcium balance refer to?

Answer 19

This is where calcium losses via urine, faeces or skin exceed calcium intake. In this situation calcium skeletal reserves will be utilised to maintain plasma calcium levels which will compromise the ability to attain optimum peak bone density.

Question 20

What role does menopause play in calcium depletion?

Answer 20

Beyond the reproductive system, lack of oestrogen has an impact on two major body systems: the skeletal and cardiovascular systems. Postmenopausal reduction in oestrogen leads to increased activity of bone dissolving osteoclasts and diminished activity of bone building osteoblasts. The end result is a decrease in bone density and a greater incidence of bone fractures.
There is an increase in requirement for calcium for women after menopause (1300 mg/day), but the similar increased requirement for men does not occur until approximately 70 years

Question 21

Explain the role of vitamin D and the active form

Answer 21

Plays an important role in calcium homeostasis. Calcitriol, synthesized in the kidneys is considered the active form of vitamin D and functions like a steroid hormone. Calcitriol induces the production of proteins involved in calcium absorption in the small intestine and is proposed to be involved in the parathyroid hormone stimulation of calcium and phosphorus reabsorption in the distal renal tubule.

Question 22

Define hypertension and what it is a risk factor for

Answer 22

Hypertension (defined as having a blood pressure reading of greater than 140mmHg for systolic blood pressure and or 90mmHg for diastolic blood pressure) is a major risk factor for cardiovascular disease, increasing the risk by two to four times. Blood pressure is known to rise with age in developed countries on high and relatively high sodium intakes.

Question 23

What is the NRV for sodium?

Answer 23

The NRV recommendations advocate a general reduction in salt intake to less than 1600mg sodium per day (approximately 2/3 teaspoon of salt) for the general population.

Question 24

The reduction in estrogen that occurs after menopause reduces bone mineral density.
This is in part due to the increased activity of particular cells that break bone down. These cells are?

Answer 24

Osteoclasts

Question 25

Why is dietary fibre important?

Answer 25

Diets high in dietary fibre can reduce the incidence of constipation, diverticular disease and colon cancer. In addition, high fibre foods are high in bulk and have a low energy density, both of which can minimise weight gain.