What causes free radical damage?
- UV exposure
- smoking
- alcohol
- exercise
- metabolism
- pollution
- saturated fat
What are the 3 main compounds/sources of antioxidant activity?
- vitamins
- minerals
- polyphenols
How do antioxidants work to protect cells from free radicals?
Stabilize free radicals by donating/accepting an electron
How do free radicals cause damage?
Lipids - create lipid radicals
DNA and RNA - alter DNA and RNA causing absence/excess of specific proteins
Protein - alter proteins to impair cell function or cause an inflammatory response
ALL lead to cell damage, diabetes and ageing
What are the 3 endogenous antioxidants?
- superoxide dismutase
- catalase
- glutathione peroxidase
What are the exogenous antioxidants?
Provided from dietary sources: Vitamins A, C, E Selenium Iron Zinc Copper Manganese Polyphenols
What is ORAC?
Oxygen radical absorbance capacity - measures the antioxidant content in foods
What conditions are caused by free radical damage in the body?
CVD T2DM cataracts macular degeneration alzheimers cancer
What is Vitamin A made up of?
Retinol, B-carotene and a-carotene
What protective roles does vitamin A provide?
Protects
- cell membranes
- LDL from oxidation and plaque formation
- skin and eyes from UV damage
- viral/bacterial lung infection
What dietary sources does retinol come from?
Animal products
- liver
- kidneys
- dairy (full fat)
- fortified margarine
- oily fish
What dietary sources do carotenoids come from?
Vegetables - yellow, dark green, red, orange
What are 2 other carotenoid antioxidants & what dietary sources are they found in?
Lycopene (red - watermelon, tomato, red citrus)
Lutein (yellow/orange and green veg)
What can lycopene possibly prevent?
Prostate cancer
What can lutein prevent?
protects eyes & skin from UV damage and may prevent cataract development (eye protection)
What is the role of vitamin E?
Prevents free radical oxidation of PUFA membranes - important in lung and muscle cells, prevents LDL plaque formation
What is a-tocopherol?
Vitamin E
What are sources of vitamin E/a-tocopherol?
- nuts
- oils - palm oil, soybean oil, margarine
- breads and cereals
- dairy (cheddar cheese)
- meat, chicken, fish
What is the role of vitamin C?
- prevents LDL oxidation
- prevents WBC damage
- protects muscle cells from oxidation
What are dietary sources of vitamin C?
blackcurrent, guava, citrus, kiwi
What is the RDI of vitamin C?
45mg/day
What is B-carotene?
A carotenoid
Inactive form of vitamin A - converted to retinol to increase bioavailability
