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Understanding Nutrition Chapter 18 Diet and Health By A. Fellah, Ph.D. Nutrition and Chronic Diseases Lifestyle factors that influence disease development: Diet Physical inactivity. Tobacco use. Alcohol and drug abuse. Overweight. Irresponsible sexual behavior. Some risk factors such as diet and physical activity, are modifiable, meaning that they can be changed; others, such as genetics, age and gender, cannot be changed. Ten Leading Causes of Illness and Death in U.S. Diet influences the development of several chronic diseases—notably, heart disease, some types of cancer, stroke, and diabetes. These four conditions account for about two-thirds of the nation’s 2 million deaths each year. Diet/Lifestyle Risk Factors and Chronic Diseases The same risk factor can affect many chronic diseases. Notice, for example, how many diseases have been linked to a high-fat diet. A particular disease, such as atherosclerosis, may have several risk factor. Risk Factors for Chronic Diseases Synergistic: multiple factors operating together in such a way that their combined effects are greater than the sum of their individual effects. Many of these conditions are themselves risk factors for other chronic diseases. For example, a person with diabetes is likely to develop atherosclerosis and hypertension. These two conditions, in turn, worsen each other. Notice how all of these chronic diseases are linked to obesity. Heart Disease and Strokes Cardiovascular disease is the leading cause of death around the world today. It accounts for 1 million deaths in the US and costs ~260 billions yearly. Coronary heart disease (CHD): the most common form of cardiovascular disease, usually involves: Atherosclerosis: accumulation of lipids and other materials in the arteries. Hypertension: is high blood pressure. Each makes the other worse. Read the glossary on page 605 How Atherosclerosis Develops Plaques Develop: Atherosclerosis begins with the accumulation of soft fatty streaks along the inner arterial walls. These fatty streaks usually gradually enlarge and become hardened with minerals, forming plaques. Plaques stiffen arteries and narrow passage through them. Blood Clots Form: Platelets are small, disc-shaped bodies in the blood, important in blood clot formation. Clots normally form and dissolve in blood all the time. In atherosclerosis, clots form faster than they dissolve because the platelets respond to plaques. The action of platelets is under the control of eicosanoids. Eicosanoids: 20-C omega-6 & omega-3 fatty acids, each helps to regulate: • • • • • Blood pressure Blood clot formation. Blood vessel contractions. Immune response. Nerve impulse transmissions. Blood Flow Diminishes: Plaques and blood clots restrict blood flow. The loss of blood flow to the area supplied by the blocked artery robs the tissue of oxygen and nutrients, and die. Blood Pressure Rises: The heart must create enough pressure to push blood through the circulatory system. When arteries are narrowed by plaques, clots, or both, blood flow is restricted, and the heart must then generate more pressure to deliver blood to tissues. Risk Factors for Cardiovascular Disease Major risk factors for CHD: High blood cholesterol. Hypertension. Diabetes (insulin) Obesity. Physical response. Smoking. Insulin resistance: the condition of which a normal amount of insulin produces a subnormal effect; a metabolic consequence of obesity. Metabolic syndrome: a combination of four risk factors-insulin, hypertension, abnormal blood cholesterol, and obesity-that greatly increase a person’s risk of developing coronary heart disease; also called Syndrome X or insulin resistance syndrome. High Blood Cholesterol:: Cholesterol is carried by several lipoproteins, chief among them LDL and HDL. High LDL and low HDL indicate correlate directly with heart attack. The higher the LDL, the greater the risk of CHD. Hypertension: Chronic high blood pressure frequently accompanied atherosclerosis, diabetes, and obesity. The higher the blood pressure above normal the greater the risk of heart disease. Diabetes: Blood vessels become blocked and circulation diminishes. Atherosclerosis progresses rapidly. Associated with high LDL, high triglycerides, low HDL, hypertension, and obesity. Smoking: Low HDL associated with cigarette smoking. It deprived the heart of oxygen and damages platelets. In general men have higher blood cholesterol and a greater risk of CHD than women. Cardiovascular disease occurs ~10 to 12 years later in women than in men HDL and LDL Compared Risk factors for cardiovascular disease. An LDL-to-HDL ratio > 5 indicates a risk for men, and a ratio > 4.5 indicates a risk for women Recommendations for Reducing Cardiovascular Disease Risk Cholesterol Screening: Measuring total cholesterol, LDL, HDL, and triglycerides. Population Goals: Maintain a healthy body weight and limit intake of saturated fat, total fat, and dietary cholesterol. Control Weight: Aim for a healthy weight. With weight loss, heart disease risk factors improve: blood pressure, blood cholesterol, and TG. Reduce Fat, Especially Saturated fat: AHA recommends fat intake of less than 30% of daily kcalories. Choose a diet that is low in sat. fat and cholesterol and moderate in total fat. Diets to Reduce High LDL Dietary Factors Protecting Against CHD Read also table 18-2 page 609 Hypertension Affect 50 million people in US, > 1/3 of adult population. Blood Pressure Regulation: The Arteries: The heart is pushing the blood into arteries to ensure its circulation through the whole system. Peripheral resistance: resistance to the flow of blood caused by the reduced diameter of the vessels at the extremities of the body-the smallest arteries and capillaries. Blood Volume contributes to blood pressure. The Kidneys: depend on blood pressure to help them filter waste out of the blood into the urine. Another determining factor is the volume of fluid in the circulatory system, which depends in turn on the number of dissolved particles in that fluid. (1) Pumping pressure from the heart forces blood into the arteries. (2) Fluid cannot cross the thick wall of the arteries. (3) Capillary walls are very thin and porous, allowing fluids and small substances such as ions, glucose, and amino acids to easily cross, primarily by the process of diffusion. (4) Blood proteins and red blood cells that remain become more concentrated. Blood presume decreases. (5) Blood is now so concentrated that it attracts fluid back into the capillary. Small molecules (waste products) accompany the fluid. The pressure that draws fluid back into the vein is osmotic pressure. How Hypertension Develops When blood flow to the kidneys is reduced, the kidneys expanding blood volume and constricting peripheral blood vessels, result in high blood pressure. Obesity: more of extra capillaries through which the blood must be pumped. Insulin Resistance: high blood insulin signals kidneys to retain sodium. Hypertension is 2—3 times in people with type 2 diabetes. Consequence of Hypertension: Stain on the heart’s pump until it gradually fails (heart failure). Risk Factors for Hypertension Smoking. High blood lipids. Diabetes. Gender. Age. Heredity Obesity. Race. Recommendations for Reducing Hypertension Risk Weight Control: aim for a healthy weight. Increase physical Activity. Alcohol: if you drink alcoholic beverages, do so in moderation. Sodium/Salt Intake: choose and prepare foods with less salt. Cancer Diseases that result from the unchecked growth of malignant tumors. It is not a single disorder. There are many cancers, that is, many different kinds of malignancies. Carinogens: substances or agents that are capable of causing cancer. Antipromoters: factors that oppose the development of cancer. Read glossary, page 616 Steps in the development of cancer. Antioxidants, other substances in food, and the body’s protective mechanisms may repair damage to cells and halt the progression of cancer. Repair of Cellular Damage Promotion of Cancer Progression of Cancer Tumor Formation: 1 of 3 How cancer develops? Tumor Formation: 2 of 3 Tumor Formation: 3 of 3 Food Sources of Antioxidants Vegetables rich in fiber, phytochemicals, and the antioxidant nutrients (betacarotene, vitamin C, and vitamin E) help to protect against cancer. Recommendation for Reducing Cancer Risk Choose a diet rich in a variety of plant-based food. Maintain a health weight and be physically active. Drink alcohol in moderation. Select food low in fat and salt. Prepare and store foods safely. Do not smoke or use tobacco in any form. Diabetes Mellitus Ranks 6th among the leading causes of death. It is a chronic disorder characterized by high blood glucose and either insufficient or ineffective insulin. Type I Diabetes: less common, the pancreas can not synthesize insulin. (5-10% of all diagnosis) Insulin dependent diabetes mellitus. Type 2 Diabetes: predominant form It develops in people over 40 years old, seen in obese children Cells are less sensitive to insulin. Blood glucose rises high which stimulate pancreatic cells to make insulin, exhausting these cells and reducing their ability to function. Obesity-Diabetes Cycle Complication of Diabetes In both types, glucose fails to gain entry into the cells and consequently accumulates in the blood. Diseases of the Large Blood Vessels: Atherosclerosis tends to develop early, progress rapidly, and be more severe in people with diabetes. Diseases of the Small Blood Vessels: Microangiopathies are disorders of the small blood vessels. Loss of kidney function and retinal degeneration. Disease of the Nerves: Gangrene is the death of tissue due to deficient blood supply. Consequences of Diabetes Nutrition and Immunity Regardless of where a person enters the spiral, malnutrition, illness, and weakened immunity interact to compromise and worsen malnutrition. Disease and malnutrition create a synergistic downward spiral that must be broken for recovery to occur. Human Immunodeficiency Virus (HIV) The virus that causes AIDS. The infection progresses to become an immune system disorder that leaves its victims defenseless against numerous infection. Opportunistic infections: infections from microorganisms that normally do not cause disease in the general population but can cause great harm in people once their immune systems are compromised. Wasting syndrome: an involuntary loss of more than 10% of body weight , common in AIDS and cancer. Summary Heart disease, strokes, cancers and diabetes are leading causes of death in the United States. Reducing fat intake, saturated fat intake and cholesterol intake can reduce risk. Regular physical exercise and cessation of smoking are also important in reducing risk. Obesity and hypertension have a direct relationship to cardiovascular disease. Weight control is the most effective treatment of hypertension. Summary Alcohol and heavily salted and smoked foods may initiate cancer development. Fiber and antioxidant nutrients and nonnutrients serve as antipromoters that protect against the development of cancer. It is wise to eat foods that contain these nutrients. Diabetes mellitus characterized by high blood glucose with insufficient or ineffective insulin. Summary Coordination of diet, insulin injections, and physical activity all help to control blood glucose. There are many significant complications with diabetes. Nutrition plays a key role in keeping people healthy and reducing the risk of chronic diseases. Nutrition interventions can help prevent malnutrition and minimize wasting that occurs with the progression of AIDS