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Unformatted text preview: Nutri Sci 132 Chapter 12 21:57 Introduction Phytonutrients Called phytochemicals Non nutrient components of plant foods that have physiological effects on humans Lower cholesterol, reduce the risk of cancer, lower blood pressure Not technically nutrients Not essential in the diet If failed to consume, we dont develop deficiencies Low intake over a period of time can increase your likelihood of cancer or heart disease An Ecological Perspective Fundamental cell function becomes deranged without them, resulting in cancer and other disease Plant Foods and Cancer 2/3 of cancers can be attributed to the environment most of these 2/3 of cancer are due to smoking not smoking is the biggest single thing you can do to reduce your risk of cancer second thing you can do to reduce risk of cancer is eat a diet rich in fruits and vegetables Fruits and Vegetables 128/156 studies shows that fruits and vegetables protect against cancer eating fruits and vegetables can cut your cancer risk in half Protective list of fruits and vegetables Lettuce, leafy greens, onions, carrots, cabbage family, citrus, broccoli, potatoes, raw and fresh fruits and vegetables Nutrients as Protective Mechanism Vitamin A as Protective Factor Retinol has a role in cell differentiation, which is the process by which newly formed cells mature Retinol is protective against cancer in cell culture studies Retinol deficiency in animals get more cancer Blood levels of retinol are not correlated with cancer risk in humans Vitamin A Precursors as Protective Factor Produce contains beta-carotene which is a precursor of retinol Beta-carotene hypothesis Beta carotene protects against cancer without conversion to retinol beta carotene is a powerful anti-oxidant and blood levels of beta carotene correlate with cancer risk Anti-Oxidant Hypothesis Anti-oxidant compounds such as beta carotene protect the body from oxidative damage that could lead to cancer Oxidative damage is caused by free radical oxygen, an oxygen atom with an unpaired electron Oxidative damage of DNA can lead to cancer Anti-oxidants quench free radicals React with the free radical and donate an electron They stop the oxidative rampage The antioxidant blocks the DNA damage, preventing cancer Vitamin C and E are powerful antioxidants Carotenoids Less than 1/3 of the US vitamin A intake comes from carotenoids 500 carotenoids to be found in nature only half a dozen are used as a precursor to retinol (beta carotene is the significant source) yellow and orange fruits and vegetables are excellent sources of beta carotene example of carotenoid is lutein and lycopene found in highest concentration in the blood...
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- Fall '09