Chapter 8 Flashcards
Define free radicals and discuss how they can damage our cells.
Free radicals contain unpaired electrons They can destabilize other molecules and damage cells
Describe how antioxidants protect our cells from the oxidative damage caused by free radicals.
Antioxidants stabilize free radicals 1. Antioxidants work independently by donating their electrons or hydrogen atoms to free radicals to stabilize them. 2. Antioxidant minerals act as cofactors, substances required to activate enzymes so that they can do their work.
Which mineral discussed in class has the most significant antioxidant properties?
Selenium
List three antioxidant vitamins. Which of these has the strongest antioxidant function?
A
C
E
Identify diseases linked to free radical damage.
CancerHeart disease
Type 2 Diabetes
ArthritisCataracts
Kidney disease
Alzheimer’s disease
Parkinson’s disease
Identify risk factors that increase likelihood of free radical formation.
Smoking,
Obisity,
Inactivity
UV radiation
What is the RDA for Vitamin C?
Men - 90 mg
Women - 75 mg
Add 35 mg per day day for smokers
the Upper intake level 2000 mg per day
Describe the relationship between antioxidant nutrients and our risk for cancer.
Within the body, antioxidants act as a defense against the damaging effects of free radicals. Free radicals are unstable, so they can damage cells, proteins and other genetic materials, such as DNA, thus leading to many health-related problems. Enzymes, which are proteins within the body, are known to contain antioxidants, as do nutrients such as vitamins A, C and E, selenium and beta carotene. During some studies, these nutrients have been given to patients to explore the relationship between antioxidants and cancer.
What is beta carotene?
A precursur to Vitamin A
In the class of phytochemicals called carotenoids
A provitamin
Provitamins are inactive forms of vitamins that must be converted to active forms in the body.
Beta-carotene is the precursor of retinol, the active form of Vitamin A.
Functions of beta-carotene
Even before it is converted to vitamin A, beta-carotene is a weak antioxidant that protects cell membranes and LDLsOther carotenoids include alpha-carotene, lycopene, lutein, and zeaxanthin. These carotenoids also help protect the body from free radicals.
Carotenoids in general are known to
Support the immune systemProtect skin and eyes from damage by UV light
Carotene is the substance in carrots, pumpkins and sweet potatoes that colors them orange and is the most common form of carotene in plants.
What is the RDA for vitamin C for men and women, smokers and non-smokers?
Recommended intake
RDA = 90 mg/day for men; 75 mg/day for women
Smokers need an extra 35 mg/day
What is the UL for vitamin C?
2000 mg/day
Where is Vitamin E found?
Vegetable oils, nuts, seeds, wheat germ, soybeans
What is a pro-vitamin?
Provitamins are inactive forms of vitamins that must be converted to active forms in the body.
Beta-carotene is the precursor of retinol, the active form of Vitamin A.
What food groups are important for cancer prevention?
Vegetables, fruits, fiber, phytochemicals
Soy based foods, and (contain progesterens)
Omega-3 Fatty Acids
List vitamins and minerals that have antioxidant properties. Describe their functions and best food sources.
Vitamin E
Vitamin C
Beta-carotene
Vitamin A
Selenium
Where is Vitamin A found?
Obtained from animal sources (liver, eggs) and, as the precursor beta-carotene, plant sources (dark green, orange, and deep yellow fruits and vegetables)
Where is Vitamin C found?
Fresh fruits and vegetablesCooking at high temperature for long periods of time and excessive exposure to oxygen (such as when there is only a little orange juice left in a large carton) destroys vitamin C
Where is selenium found?
High sources include organ meats, pork, seafood, nuts, whole wheat, brown rice
List three antioxidant vitamins. Which of these has the strongest antioxidant function?
Vitamin A,E,C
The most active form of vitamin E in food and supplements is alpha-tocopherol
Discuss how consuming nutrients with antioxidant properties can reduce our risk for cardiovascular disease.
We have learned that vitamin E, vitamin A, and other plant chemicals (phytochemicals) protect LDL. Why would protecting “bad” cholesterol be a good thing? LDL needs to be protected because once the LDL has suffered damage from free radicals it is even more likely to “stick” to artery walls and form heart attack and stroke promoting plaques.
Without adequate amounts of antioxidants, free radicals travel throughout the body, damaging cells. This cellular damage leads to the development of cardiovascular disease.
What are the deficiency diseases for vitamins C?
Scurvy: is the most common vitamin C deficiency diseaseSymptoms of scurvy include bleeding gums, loose teeth, weakness
What are the deficiency diseases for vitamins E?
Vitamin E deficiencies are uncommon. However, results from NHANES III suggest 27-41% of Americans may be low in vitamin E and, as a result, have increased risk for cardiovascular disease (from LDL not being protected).Vitamin E deficiency can result in erythrocyte hemolysis and anemia
What if you don’t consume enough vitamin A?
Night blindness is the most common disease of vitamin A deficiency.
What if you consume too much vitamin E?
Vitamin E toxicity is uncommon. However, one study found no benefit and hinted at potential harm from megadose supplements of vitamin E. This finding has not been confirmed by additional studies.Vitamin E can interfere with anticoagulant medications (aspirin and Coumadin) and cause uncontrollable bleedingLong term use in some people can cause hemorrhagic stroke
What if you consume too much vitamin C?
Megadoses of vitamin C can cause nausea, diarrhea, nosebleeds, and abdominal crampsIf a person has hemochromatosis or preexisting kidney disease, excess Vitamin C can be harmful.
What if you consume too much vitamin A?
Vitamin A is highly toxic, especially from supplements.Birth defects and permanent damage to the liver and eyes can result.
What if you consume too much selenium?
Selenium toxicity (brittle hair, nails, skin rashes) can result from supplements.
What is a megadose?
Although there is no clear-cut explanation of what exactly constitutes a vitamin megadose, according to Harvard University Medical School, it is generally a vitamin intake many times higher than the recommended amount. You can safely take some nutrients in high amounts, but do not exceed the IOM’s guidelines, as taking too much of some nutrients can cause toxicity and health problems.
Describe low grade inflammation and how it relates to heart disease
Researchers are now recognizing low-grade inflammation in its central role in insulin resistance, diabetes, and cardiovascular disease. Understanding the underlying causes of inflammation will help guide prevention and treatment guidelines.
