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Flashcards in Nutrition Deck (11)
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1

COMPONENTS OF FOOD

- Nutrients→ organic molecules (carbs, proteins, lipids) water, vitamins and minerals the body needs for development and growth, repair and maintenance of structures and physiological processes

2 types of nutrients;
- Macronutrients→ needed in large amounts in diet (in gram amounts)
- Micronutrients→ needed in small amounts in diet (in mg or less)

2

Macronutrients

Carbohydrates (sugars, starches and fibre)
Lipids (fats and oils)
Proteins
Water

3

Micronutrients

Vitamins
Minerals

4

Essential Nutrients

Nutrients that can’t be produced by body (vitamins, minerals, essential fatty acids and amino acids)

5

CARBOHYDRATES

Composed of carbon, hydrogen and oxygen; 3 types
- Monosaccharides→ single sugar molecules (glucose, fructose, galactose)
- Disaccharides→ 2 sugar molecules joined together (e.g. lactose (the sugar in milk) = glucose + galactose)
- Polysaccharides→ chains of sugar molecules (e.g. plant starches)

- Principally derived from plant products; grains, fruit and veg
- Principal function of carbs→ source of glucose to be used to generate energy (ATP) in cells
- Some forms of polysaccharide (e.g. cellulose plant fibres) can’t be digested; serve as dietary fibre function

6

PROTEINS

- Proteins→ chains of amino acids (20 different amino acids found in proteins)
- Some amino acids; synthesised from carbon skeletons derived from other metabolic pathways
- Some are essential amino acids (histidine, lysine etc) and can’t be synthesised by humans; must be included in diet
- Need to include essential acids in diet as complete proteins contain essential amino acids at levels needed (eggs, milk, meat etc) but some plant proteins are missing 1 or more essential acids
- Major sources of protein in diet→ meat, fish, dairy, eggs, nuts and legumes

7

LIPIDS (FATS AND OILS)

- Composed of Carbon, Hydrogen and Oxygen
Most important in nutrition are:
- Fatty Acids→ long chain of carbons flanked by hydrogens
- Triglycerides→ 3 fatty acids linked to glycerol

- Saturated fats→ Carbon in chains of fatty acids joined together exclusively by single bonds
- Mono or polyunsaturated fats→ Carbon in fatty acids chained joined by combination of single or double bonds
- Domestic animal fats→ rich in saturated but poor in unsaturated
- Plants often rich in polyunsaturated

8

ESSENTIAL FATTY ACIDS

- Naturally occurring unsaturated fats fall into 3 groups; based on where in the carbon chain the first double appears (e.g. n-3, n-6 or n-9)
- Humans can’t synthesize certain n-3 and n-6 fatty acids (required for body)

9

WATER

- Beverages are major source of water but so are foods (e.g. fruit and veg)
- Body can produce small amount of water but can’t meet its total requirements
- Can last several weeks without eating but going 3-4 days without water will kill you

10

VITAMINS

- Vitamin→ essential carbon-containing compound required in small amounts in diet
- Generally can’t be synthesised by body- some exceptions; some can be synthesised inside body
- Vit D→ synthesized from cholesterol and sunlight
- Vit K and some B→ synthesised by intestinal bacteria
- 2 types of vitamins
Water soluble→ B group and Vit C
Fat soluble→ Vit A, D, E and K

Vitamins regulate and support many chemical reactions in body; in reactions they aren't consumed but may be reversibly modified

11

MINERALS

- Chemical elements required in diet; all are essential nutrients
- Functions→ support and regulation of chemical reactions in body (e.g. as components of proteins such as iron in haemoglobin)
- Major minerals→ minerals whose required intake is 100 mg or more/day (e.g sodium, calcium, magnesium)
- Trace minerals→ minerals whose required intake is less than 100 mg/day (iron, zinc, iodine, copper)
- Important to not exceed daily intakes; excess levels can be toxic