Class Notes (806,814)
Canada (492,451)
Nutrition (877)
NUTR 1010 (437)

Week 8.docx

3 Pages
Unlock Document

University of Guelph
NUTR 1010
Jess Haines

Week 8 – Antioxidants th October 24 , 2012 What Are Antioxidants? - Chemicals that prevent oxidation Oxidation: - Molecules are a physical unit of an element; they consist of atoms; all atoms are unique; all atoms have a nucleus (positively charged) and it is surrounded by electrons (negatively charged); the opposite attractions keep them together. - During metabolism (the process by which our bodies break down and build up molecules), atoms may lose electrons; this loss is called oxidation because it is usually fueled by oxygen; atoms can also gain electrons during this (called reduction); the loss and exchange of electrons usually results in an equal exchange (exchange reaction) - It happens because we use hydrogen and oxygen to generate energy (ATP) *Results in the formation of free radicals Free Radicals Superoxide (0 -2 Hydroxyl Radicals (OH) Nitric oxide (NO) - Can be caused from environmental exposure: o Exposure to toxic substances: tobacco, asbestos, pollution o Sun exposure o Radiation exposure - They are dangerous because they are “luring” paired electrons away from their stable atoms; creating more free radicals. - They form within the lipid layer of the cell membrane; when the lipid molecules are destroyed, they do not repel water and they cannot regulate fluids in ad out of the cell - Can also damage LDL’s, proteins and DNA. Can cause: cancer, heart disease, diabetes, arthritis, cataracts, kidney disease, Alzheimer’s, Parkinson’s Antioxidants: chemicals that decrease the adverse effects of free radicals by: - Donate their electrons without creating more free radicals. - Have complex enzyme systems that convert free radicals into less harmful substances. Major Antioxidants Vitamin E Vitamin C Vitamin A Selenium Vitamin Review - minerals that are essential for us to eat (our bodies can’t make them) - Can be fat or water soluble. VITAMIN E AKA alpha-tocopherol - fat saleable vitamin (non polar); absorb it better when you eat it raw - absorbed in the intestines with fat in micelles - transport in the blood via lipoproteins - your body stores vitamin e in the adipose tissue (body fat) - an antioxidant - works in lipid environments; donates free radicals Some fatty acids are oxidated more easily than others; poly unsaturated fats. This is why: saturated fat/trans have a longer shelf life; old fish smells bad, frying in oil with high heat can smell bad. PUFA The more pufa you eat the more vitamin e you need to eat; lucky foods that contain pufa also contain vitamin E; oils, avocado, nuts, seeds, soy products. Vitamin E is destroyed by light; exposure to oxygen, metals, ultraviolet light and high temperatures; heating veggies destroys the vitamin E. Toxicity Uncommon and only happens with supplements; not with food; doses would have to be huge, over 800 mg according to RDA); would cause nausea, and upset stomach. Deficiency Acute deficiency is rare because our bodies store vitamin E; puts people at risk for cardio vascular disease; causes erythrocyte hemolysis – rupturing of blood cells; impaired vision, speech, movement and leg cramp. 27-41% of Americans have low vitamin E levels. REVIEW Water soluble vitamins are: polar molecules Molecules are oxidized when they steal electrons? False; their molecules are stolen. Vitamin E is an antioxidant in: cell membranes, lipoproteins. 3 food sources of vitamin E: avocado, soy, nuts and seeds, vegetable oils (margarine, salad dressing), green leafy vegetables (spinach, broccoli) VITAMIN C Ascorbic acid: a water soluble vitamin; can be carried freely in the blood; not stored in the body; should be eaten regularly. - Most animals make their own vitamin c out of glucose; except monkeys, apes, guinea pigs and fruit bats and humans. - We don’t have the right enzymes to do It.; explains why animals do not need to eat fruits and vegetables. Purpose: - It is a major water soluble water antioxidant (works in watery areas of our body or extracellular fluid). - Donates its electrons to free radicals - It recharges vitamin E by giving it electrons; can be recycled.
More Less

Related notes for NUTR 1010

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.