Questions and Answers on Cholesterol and Health with NHLBI Nutritionist Janet de Jesus, M.S., R.D.

Q: What is the difference between dietary cholesterol and cholesterol levels in the body?

Cholesterol in the body is a waxy, fat-like substance found in cell walls that comes from two sources: the body and the food we eat.  The body, especially the liver, makes all the cholesterol it needs, and this is used to make essential substances like hormones and bile acids. Dietary cholesterol is found in foods from animal sources, such as meats, liver and other organ meats, dairy foods, egg yolks, and shellfish.  Cholesterol circulates in the blood throughout the body. Your liver produces more cholesterol when you eat a diet high in saturated and trans fats.  Blood cholesterol includes LDL cholesterol, which is also referred to as “bad” cholesterol, and HDL cholesterol, which is referred to as “good” cholesterol.  Too much LDL cholesterol in the blood can combine with other substances in the blood and stick to the walls of your arteries, forming plaque which is a culprit in narrowing the arteries and leading to heart disease.

Q: What affects blood cholesterol levels?

• Heredity:  High blood cholesterol can run in families. 
• Age:  Blood cholesterol begins to rise around age 20. 
• Being overweight:  Weight loss can lower LDL cholesterol levels. 
• Physical inactivity:  Increasing physical activity can lower LDL cholesterol and raise HDL cholesterol.
• Diet:  Saturated and trans fats raise blood LDL cholesterol levels

Q: Does too much cholesterol from foods cause health problems?

The 2013 American College of Cardiology/American Heart Association Guideline on Lifestyle Management to Reduce Cardiovascular Risk concluded that there was not enough evidence across a broad range of dietary cholesterol intake to make a recommendation regarding dietary cholesterol for treatment of high levels of LDL cholesterol.  The guideline was based on a comprehensive review of meta-analyses and systematic reviews from 1990 to 2009.  Further research is needed to understand the effects of dietary cholesterol on heart disease and to better differentiate these potential effects from other dietary factors, such as saturated and trans fats.  More importantly, carefully controlled randomized trials are needed that test reductions in dietary cholesterol intake which more closely parallel the amounts currently consumed in the U.S.  Until that research is conducted, consumption of dietary cholesterol should be limited.

Q: What other components of the diet affect blood cholesterol levels?

Importantly, most foods that are high in dietary cholesterol such as high fat meat and dairy products are also high in saturated fat. Saturated and trans fats raise blood LDL cholesterol and high levels of these fats have been associated with higher risk of heart disease.  The ACC/AHA Panel also recommended replacing saturated and trans fats with unsaturated vegetable sources, such as olive or canola oil, to lower blood LDL cholesterol levels. Saturated fats are found in fatty cuts of meat, poultry with skin, whole-milk dairy foods, lard, butter, and coconut and palm oils.  Trans fats are found in some bakery products and stick margarines. 

Additional Resources:

Information on the Development of the 2015 Dietary Guidelines for Americans: www.health.gov//dietaryguidelines/2015.asp#resources

High Blood Cholesterol: What You Need to Know: http://www.nhlbi.nih.gov/health/resources/heart/heart-cholesterol-hbc-what-html

Medline Plus Cholesterol  Information: http://www.nlm.nih.gov/medlineplus/cholesterol.html