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Diet and Heart Disease

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McGill University
CHEM 181
David Harpp

World of Chem: Food January 31 Diet and Heart Disease Diet and Heart Disease Simple version: eat small portions of not highly processed foods, eat fruits and vegetables, and exercise. Coronary heart disease is the leading cause of death in North America, both in men and women. 3 servings of fruits and vegetables per person per day on average. Risk Factors Low birth weight Being male (more men die of heart disease than women) Hypertension Obesity Smoking bigger heart disease risk than lung cancer. (inhale carbon monoxide, which displaces oxygen from haemoglobin so you are in a low oxygen supply situation) Diabetes Stress put in a situation you dont want to be in Microbes: viruses and bacteria o Can take up residence in coronary arteries and impair work of the heart o Cause inflammation o Bleeding gums opening into blood stream bacteria may infect coronary arteries this way. Homocysteine: manufactured in the body from methionine, an amino acid. o Methionine homocysteine broken down and excreted in the form of various metabolites, with the help of B vitamins B vitamins break down homocysteine o Dr. Kilmer McCully 1969 noticed those with high levels of homocysteine in the blood were more likely to develop heart disease. Injected homocysteine into rabbits and triggered heart diease. o 1992: 14,000 male physicians studied. Those whose blood levels of homocysteine were in the top 5% had a heart attack risk three times greater than in subjects with the lowest levels. Only a risk factor does not prove cause and effect. o Typical range of homocysteine: Men 8-12 micromol/L Women 6-10 micromol/L Risk begins at 11 micromol/L o How do you reduce homocysteine? Fruits and vegetables contain the B vitamins that are co-factors in the enzymes that break down homocysteine Spinach: high in folic acid World of Chem: Food January 31 Diet and Heart Disease Processed foods such as cereal vitamin B and folic acid fortified Supplements Regular dose (the dose that reduces homocysteine levels): 400 mcg folic acid; 3 mcg vitamin B-12; 3 mg vitamin B-6. o Does reducing homocysteine reduce the risk of heart attacks? Heart Outcomes Project Evaluation (HOPE) after 5 years homocysteine reduced 25% with 2.5 mg folic acid, 50 mg vitamin B-6 and 1 mg vitamin B-12. No benefit in terms of heart attacks. Homocysteine is NOT a cause; its a parallel factor. High triglycerides fat in the blood o The more of it, the greater the risk of heart disease. Cholesterol o Just one of the risk factors! o Is found only in animal products; no vegetable or grain product contains cholesterol o White powder o Is a steroid: a multi-ring compound o Is critical to life used in the synthesis of cell membranes, used as raw material for synthesis of numerous compounds. The body can make it (made in the liver), unlike vitamins, which the body cannot make. o Why are we concerned about cholesterol? Because high levels in the blood are a risk factor for heart disease Same situation with homocysteine but is it causative? o Not a vitamin; a vitamin is something the body needs but cannot manufacture. Cholesterol is something the body can make. Epidemiological studies Look at large populations and disease patterns Framingham study disease and cholesterol. 1948. o High blood cholesterol was associated with high risk of heart disease. o Town is homogeneous in social structure. Not a great variation in genetics. Want to ensure there are as few variables as possible when trying to study one variable. 7 country study: cholesterol and coronary heart disease: as average cholesterol rises, so does risk of heart disease. o Epidemiological evidence not causative yet. Familial hypercholesterolemia: a genetic disease very rare where the liver produces huge excesses of cholesterol. Very high risk of heart disease. o Most will die when theyre teenagers. Mona Lisa theory that she suffered from this.World of Chem: Food January 31 Diet and Heart Disease High cholesterol predisposes to heart disease. But half of all people who have heart attacks have normal cholesterol levels! o Thus cholesterol is not the only factor! Anatomy Coronary arteries stem out from the aorta. These arteries supply oxygenated blood to the heart. Impairment in flow of blood in coronary arteries, heart muscle is affected. Heart attack: cutting off flow of blood through coronary artery; causes cells to die. Atherosclerosis hardening of the arteries deposits. Deposits build up in endothelium the wall of the artery. Cant scrape off from the inside of the artery. Oxidized cholesterol when cholesterol that builds up inside the deposit oxidizes. This is a foreign substance that must be eliminated; macrophages (white blood cells) try to get rid of the cholesterol. This causes inflammation at the area, which can cause the deposit to burst open. o Thus antioxidant vitamins o Results with the use of antioxidants have been inconsistent in reducing the risk of CHD. Inflammation: a response of body tissues to injury or irritation; characterize
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