2. definition
• Lipids are organic substances that are greasy and insoluble in water
but soluble in organic solvents such as alcohol and ether.
• Lipids have the same elements as carbohydrates (carbon, hydrogen
and oxygen) but lipids contain a higher proportion of hydrogen.
• Fats are lipids that are solid at room temperature while oils are lipids
that are liquid at room temperature.
• Fatty acids are structural units of most lipids that can be saturated or
unsaturated, according to relative number of hydrogen atoms they
contain.
3. Sources of lipids
• Saturated: butter, cream, fat on meat, chicken skin, processed meats,
cheese, full cream milk and milk products
• Monounsaturated: oils( sunflower, canola, olive), nuts, peanut butter,
avacado, mayonnaise, margarine
• Polyunsaturated: seeds (pumpkin, sunflower, flax) fish (sardines,
mackerel, salmon)
• Trans – fats : processed foods (biscuits, pies, pastries)
4. Functions of lipids
• Extra energy not needed by the body at present is stored in the fat
cells (adipose tissues) for later use. Lipids are a concentrated source
of energy.
• Lipids transport flat-soluble substances in and out of cells.
• Lipids form part of bile, steroid hormones and vitamin D
• Essential fatty acids are needed for healthy skin and normal growth in
children and form part of retinal and brain tissue.
• Lipids contain vitamin A, D, and E and are needed for absorption of
insoluble vitamins A, D, E and K
5. Cont.
• Fats slow down the emptying of the stomach and therefore
contribute to a feeling of fullness.
• Fat enhances the flavour and texture of food
• The fat layer under skin act as insulation and helps maintain a
constant body temperature
• Lipids in the skin act as natural lubricants, protecting and maintaining
the conditions of skin and hair
• Body fat around the internal organs acts as a protective cushion,
especially for the kidneys, intestines and mammary glands.
