4. digestive system Insulin produced by the pancreas is a key regulator of the body's metabolism . It works in the following way: (1) During and immediately after a meal the process of digestion breaks down carbohydrates into glucose and proteins into amino acids . (2) Right after the meal, glucose and amino acids are absorbed directly into the bloodstream , and blood glucose levels rise sharply. (3) The rise in blood glucose levels signals important cells in the pancreas , called beta cells , to secrete insulin , which pours into the bloodstream. Within 10 minutes after a meal , insulin rises to its peak level. (4) Insulin enables glucose and amino acids to enter cells in the body , particularly muscle and liver cells . Here, insulin and other hormones direct whether these nutrients will be burned for energy or stored for future use . (5) When insulin levels are high, the liver stops producing glucose and stores it in other forms until the body needs it again. (6) As blood glucose levels reach their peak, the pancreas reduces the production of insulin. (7) About 2 to 4 hours after a meal , both blood glucose and insulin are at low levels, with insulin being slightly higher. Small intestine
5. Type 2 diabetes is the most common form of diabetes, accounting for 90% of cases. The disease mechanisms in type 2 diabetes are not wholly known, but some experts suggest that it may involve the following three stages in most patients: (1) The first stage in type 2 diabetes is the condition called insulin resistance . Although insulin can attach normally to receptors on liver and muscle cells, certain mechanisms prevent insulin from moving glucose (blood sugar) into these cells where it can be used. (2) Over time, the pancreas becomes unable to produce enough insulin to overcome resistance. In type 2 diabetes, the initial effect of this stage is usually an abnormal rise in blood sugar right after a meal. This effect is now believed to be particularly damaging to the body . (3) Eventually, the cycle of elevated glucose further impairs and possibly destroys beta cells, thereby stopping insulin production completely and causing full-blown diabetes.
8. The body makes all the cholesterol it needs. In other words, you do not need to add any in your diet . Dietary cholesterol comes from animals , such as meat, dairy products, eggs and animal fats . Too much cholesterol can cause serious health problems. There are two main types of cholesterol. The “ bad cholesterol” or LDL , may create serious health problems if your body has persistent high levels of LDL or total cholesterol. The “good cholesterol” is HDL . Low HDL levels may be partially improved if you exercise , avoid smoking , lose weight and eat a healthier diet high in fruits and vegetables and low in simple carbohydrates . Saturated fats raise cholesterol levels more than anything else in your diet. They include all fats from meat and skinned poultry , palm-kernel oil , coconut oil and fats from dairy products . On the other hand, helpful fats include peanut oil , olive oil , canola oil , safflower oil , corn oil and fish, such as tuna 鮪 , salmon, trout 鱒 and mackerel 鯖 . What should I eat? Five or more servings per day of fruits and vegetables, legumes (beans, peas), whole-grains (wheat bread), lean meats (avoid red meat) and poultry (chicken) without the skin. In addition, you should limit milk products and use fat-free or low-fat milk . Your diet should include at least two servings per week of baked or grilled fish. Cooking should be done with canola, corn, olive, safflower or soybean oils. What should I limit in my diet? Fatty or red meat that is not trimmed, whole milk and ice cream, excessive amounts of butter, egg yolks or cheese, organ meats such as kidney, brain or liver, saturated oils such as coconut or palm oil and fried food.
