Cholesterol

Cholesterol is a member of the lipid family. Lipids are fats and fat-like substances that appear in plants and animals. Cholesterol is an essential nutrient that the body acquires partially through diet, as well as through the liver’s manufacture of it. Despite its reputation, cholesterol is an essential lipid that repairs cell membranes, manufactures vitamin D, and creates hormones.

Several types of lipids exist. The three most prominent are: low density lipoproteins (LDL), high density lipoproteins (HDL), and triglycerides.

• LDL
  
  LDL carries approximately 75% of the blood’s cholesterol to your body’s cells. In most cases, LDL is harmless. However, if it collects on arterial walls, plaque can form and cause damage. LDL may also lower your body’s level of nitric oxide, which normally allows blood to freely flow. When this happens, your arterial walls may constrict and reduce blood flow, resulting in a condition called atherosclerosis (hardening of the arteries). Artherosclerosis is often a precursor to coronary artery disease.
  
  

  Low levels of LDL are important to your health.

• HDL
  
  HDL rids the artery walls of cholesterol and returns it to the liver. Your HDL level should be high (above 45 mg/dl). This will help prevent narrowing of your arteries, and thus prevent heart attacks.

  
  

• Triglycerides
  
  High levels of triglycerides are often associated with obesity and diabetes. They are a combination of fat molecules and cholesterol that may harm the heart by partnering with LDL to form dense packets of more-dangerous LDL. Triglycerides may cause blood clot formation, leading to heart attack.
  

A cholesterol reading of over 200 mg/dl is considered too high, and thus unhealthy. More than half of American adults have readings over 200, compared with only 7% of Asian adults. The American lifestyle of a high-fat, low-fiber diet is a risk factor for high cholesterol levels. Obesity and lack of exercise also contribute to high cholesterol levels.

In general, women have higher cholesterol levels than men, especially between the ages of 20 to 34 and after menopause. Women should pay special attention to their HDL levels. Studies show that women with total cholesterol over 200 and HDL below 50 had a higher death rate than women with HDL above 50.

To evaluate your cholesterol, your doctor will measure your HDL and total cholesterol levels. LDL is difficult to measure on its own, but your doctor will be able to calculate it.

Several medical groups suggest that you should get your cholesterol measured periodically starting at age 20. In the 12 hours before your reading, you should not exercise, and not eat or drink anything other than water.

If you register a normal cholesterol level, you may not need to be re-tested for 5 years, unless you undergo a lifestyle change during that time. People with high cholesterol should be monitored every two to six months.

Home tests and public location tests are also available. These tests generally measure total cholesterol only, without separating results into good and bad lipids.

Proton nuclear magnetic resonance (NMR) spectroscopy may be the future of cholesterol testing. This test can detect radio signals sent by LDL and HDL particles, and may be the most accurate predictor of cholesterol and heart disease available.

You can help maintain healthy cholesterol levels by exercising regularly and adhering to a cholesterol reduced diet recommended by the American Heart Association.

• Most cholesterol-lowering diets stress high fiber and fresh fruits and vegetables while avoiding saturated fats, such as those found in animal products, and transfatty acids, typically found in commercial baked goods and fast foods.
  
• People with active lifestyles are 45% less likely to develop coronary heart disease than sedentary people
  

Drug therapy is available to improve cholesterol levels by complementing healthy lifestyle changes if those changes fail to reduce cholesterol levels sufficiently. People with LDL levels greater than 190 mg/dl are most likely to receive medication from their physicians. However, people with family histories of heart disease will be given medication if their LDL levels are lower.

Statins, resins, and probucol are three types of drugs that aim to lower LDL levels. Fibrates and niacin target LDL as well as lower triglycerides and increase HDL. If you need to severely lower your cholesterol, your doctor may recommend a combination of drugs.

• Statins are especially effective in lowering LDL levels. They raise HDL levels as well, but not to as great a degree as other drugs. Statins are taken once or twice a day, depending on the type prescribed. Side effects may include stomach discomfort, muscle aches, drowsiness, and nausea.
  
• Niacin, or vitamin B3, reduces triglyceride levels and raises HDL better than any other anti-cholesterol drug. Incidentally, it is also the least expensive cholesterol-lowering drug. Its side effects are usually more intolerable than those of other drugs. Side effects include flushing in the face and neck, headache, and dizziness. The longer you take the drugs, the more tolerant you become to the side effects.
  
• Resins work by binding bile, a substance made by the liver. They decrease LDL levels with no great risk. Generally, they are used in powder form, but are also available as chewable bars. Side effects include gas, heartburn, and constipation. Vitamin supplements may be necessary if you take resins for an extended period because they deprive the body of vitamins A, D, E, and K.
  
• Fibrates effectively lower triglyceride levels and increase HDL for people who cannot tolerate the side effects of niacin.
  
• Probucol can lower LDL levels by 10 to 15 percent. On the other hand, it also lowers HDL levels 20 to 30 percent. People with genetic disorders that cause high cholesterol typically use probucol. Side effects include bloating, diarrhea, and nausea.