Cholesterol is a vital component of normal cell function, but too much of it can lead to serious problems such as heart disease. Luckily, measuring cholesterol levels is as simple as a blood test and a fasting lipid profile gives the most complete assessment of your cholesterol health. A fast before testing means avoiding not only food and beverages, but also medications because they can also affect cholesterol results.
Types of Cholesterol
Cholesterol circulates throughout the bloodstream carried by lipoproteins. The two most important types of cholesterol are low-density lipoprotein, or LDL, and high-density lipoprotein, HDL, cholesterol. Both play different roles in handling cholesterol in the body; while LDL helps deposits cholesterol onto artery walls, HDL helps remove it from these areas and take it to liver for removal. Levels of total cholesterol are comprised of both LDL and HDL, but how much of each is important to distinguish. Triglycerides are a lipid also measured during cholesterol testing because high levels often correlate with high LDL levels.
Medication and Cholesterol Testing
To obtain a total lipid profile --which provides levels of HDL, LDL, total cholesterol and triglycerides-- a fast is required to get accurate results. Total cholesterol and HDL testing don't require a fast, but levels of triglycerides and LDL are impacted without a preceding fast. Fasting requires consuming no food and beverage, as well as not taking medications for nine to 12 hours before testing; only drinking water is permitted. Anabolic steroids, beta blockers, oral contraceptives, vitamin D and epinephrine are all known to affect cholesterol levels. For the most accurate results, it's best not only to avoid these specific medications, but all medications before cholesterol testing.
Other Factors
While total cholesterol and HDL are not affected by food, beverages and medication, levels can be affected by stress. Physical or psychological stress can give inaccurately lower cholesterol readings. Acute illnesses such as an infection, stroke or heart attack can also produce lower cholesterol results. According to Harvard Health Publications, unusually low cholesterol levels are sometimes the first signs of cancer. Pregnancy also can produce inaccurate cholesterol readings -- usually too high.
Recommendations
The National Cholesterol Education Program recommends that every adult get a fasting lipid profile every five years. More frequent cholesterol testing may be recommended by your doctor if you have other risk factors for heart disease. Risk factors include cigarette smoking, previous heart attack, being a man older than 45 or a woman older than 55, high blood pressure, diabetes and a family history of heart disease.
