What are the reasons why people make the food choices they eat?
- Personal preference
- Ethnic heritage or tradition
- social interaction
- Availability, convenience and economy
- Positive & negative associations
- Emotional comfort
- Body weight & image
- Nutrition & health benefits
What is a Nutrient?
a substance that provides nourishment essential for the maintenance of life and for growth
What are the six classes of nutrients found in foods?
Inorganic: Minerals & Water
Organic: Carbohydrates, Lipids (fats), Proteins & Vitamins
What is an essential nutrient?
An essential nutrient is a nutrient required for normal physiological function that cannot be synthesized by the body, and thus must be obtained from a dietary source. Essential fatty acids are fatty acids that humans and other animals must ingest because the body requires them for good health but cannot synthesize them.
Which nutrients yield energy and how much energy do they yield per gram?
Carbohydrate - 17kJ
Protein - 17kJ
Fat - 37kJ
Alcohol - 29kJ
What are the NRV?
Nutrient Reference Values (NRV)
Acceptable Macronutrient Distribution Range (AMDR) represents the range of intakes for energy nutrients that provide adequate energy and nutrients and reduce risk of chronic disease.
- 45–65 % kilojoules from carbohydrate
- 20–35 % kilojoules from fat
- 15–25 % kilojoules from protein
What is Estimated Average Requirements (EAR)?
A daily nutrient level estimated to meet the requirements of half the healthy individuals in a particular life stage and gender group
What is the Recommended Dietary Intake (RDI)?
The average daily dietary intake level that is sufficient to meet the nutrient requirements of nearly all (97–98%) healthy individuals in a particular life stage and gender group
What is Adequate Intake?
– The average daily nutrient intake level based on observed or experimentally-determined approximations
– used when an RDI cannot be determined
What is Estimated Energy Requirements?
The average dietary energy intake that is predicted to maintain energy balance in a healthy adult of defined age, gender, weight, height and level of physical activity, consistent with good health
What is Upper Level of Intake?
The highest average daily nutrient intake level likely to pose no adverse health effects to almost all individuals in the general population
What is the Science of Nutrition? Describe the types of research studies and methods used.
• Study of the nutrients and other substances in foods and the body’s handling of them
• Types of studies include:
– Epidemiological studies include cross-sectional, case-control and cohort designs
– Laboratory-based studies include animal studies and laboratory based in vitro studies
– Human intervention or clinical trials
Name the three macronutrients?
Proteins, Fats & Carbohydrates
If a person’s estimated energy requirement is 8000 kJ per day, how many grams of fat would you recommend they consume to be within the AMDR?
– AMDR for fat is 20-35 %
– 1 gram of fat = 37 kJ
8000 x 20/100 = 1600 kJ / 37 = 43 g
8000 x 35/100 = 2800 kJ / 37 = 76 g
What is Digestion?
What is absorption?
- Digestion = the process by which food is broken down into absorbable units
- Absorption = the uptake of nutrients by the cells of the small intestine for transport into either the blood or the lymph
The gastrointestinal tract is divided into many parts. How long is each part and in total?
- Mouth to Oesophagus (25cm)
- Stomach (25cm; 2L holding capacity)
- Small Intestine: - duodenum (30cm) - jejunum (2.5m) - ileum (4m)
- Large Intestine (2.5m)
What is the Pathway of Digestion of Food Components?
- Mouth - oesophagus
- Stomach - gastric juice breaks down proteins
- Pancreas - pancreatic juices carbs, fats & proteins
- Liver - produces/makes bile
- Gallbladder - stores bile
- Small Intestine - intestinal juice breaks down carbs, fats & proteins
What is dietary Fibre? What are two types and how are they different?
Dietary Fibre: provide structure in plants, are very diverse and cannot be broken down by human enzymes.
- Soluble fibres - found in fruits & vegetables, viscous & can be digested by intestinal bacteria; this process is also known as 'ferment ability'
- Insoluble fibres - found in grains & vegetables, non-viscous & partially digested by intestinal bacteria.
The nutrient reference values for Australia & New Zealand recommend eating how much fibre per day for men and women?
Men: 30 g/day
Women: 25 g/day