Nutrients – Functions and Food Sources

Foods contain various chemical compounds, called ‘nutrients’, that are necessary in certain quantities for good health. For each nutrient, you’ll have to know their function and food source.  When listing food sources, be as specific as possible.


Function: involved in the growth, repair, and maintenance of body tissues; used to produce antibodies, enzymes and hormones, so they help with immunity and function.
Food Sources: eggs, fish, meat, poultry, milk and milk products, soy, nuts, seeds, legumes


Function: the body’s main, preferred energy source.
Food Sources: breads, grains, fruit, starchy vegetables, milk, honey
Other: Carbohydrates are have a glycaemic index (GI), which refers to the speed at which the carbohydrate is digested, and thus the insulin required to digest it. High GI foods are digested quickly and can put a strain on insulin production, making high GI diets a risk factor for developing diabetes mellitus.


Function: insoluble fibre digests and removes body wastes; soluble fibre delays glucose absorption and lowers cholesterol levels in the blood.
Food Source: fruit and vegetable skins, dried beans, lentils, seeds, wholegrains, wheat and oat bran.
Other: fibre is a carbohydrate; there are two types of fibre, soluble and insoluble fibre.


Function: the body’s concentrated energy source; provides insulation; stores fat-soluble vitamins (A, D, E, K)
Other: there are four types of fat: polyunsaturated, monounsaturated, saturated and trans fats.

 – Polyunsaturated fats

Function: provides omega-3 and omega-6 fatty acids.  Omega-3 helps blood circulation, and omega-6 maintains a healthy immune system and regulates blood pressure and clotting.
Food sources: fish (tuna, salmon), vegetable oils (safflower, sunflower, corn and soy oils), nuts (walnuts, Brazil nuts), seeds.

 – Monounsaturated fats

Function: lower levels of low-density lipoprotein in the blood, reducing build-up of plaque in blood vessels.
Food sources: avocado, nuts (peanuts, hazelnuts, cashews, almonds), canola oil, olive oil.

 – Saturated fats

Function: increase levels of low-density lipoprotein.
Food sources: fatty cuts of meat, full cream milk, cheese, butter, coconut milk, fried takeaway chips.

 – Trans fats

Function: increases levels of low-density lipoprotein and decreases levels of high-density lipoprotein.
Food sources: hydrogenated margarines, baked or fried processed goods (e.g. commercial pastries).


Function: aids digestion and movement of waste materials; helps absorb and transport nutrients.
Food Source:
fruit (watermelon), vegetables (iceberg lettuce, cucumber), soup

Vitamin D

Function: aids in absorption of calcium and phosphorus for bone health
Food Source:
butter, cream, salmon, liver, kidney (mainly absorbed from sunlight rather than food)


Function: ossifies and strengthens bones and teeth to achieve peak bone mass; plays a role in nerve transmission
Food Source:
milk and milk products, green leafy vegetables (kale, broccoli, bok choy)


Function: works with calcium to ossify bones and teeth
Food Source:
milk, meat, eggs, beans, lentils, nuts, grains


Function: regulates blood pressure and volume; helps with nerve transmission and muscle contraction
Food Source:
processed meats (ham, salami), cheese, potato chips