There are many things that can affect your cholesterol level. The most important things are what you eat and your genes.

• What you eat: Eating a lot of saturated fats and trans fats is likely to increase the amount of cholesterol in your blood.¹ Researchers aren't sure how this happens.² Trans fats are found in hard margarine and have the same effect on your body as saturated fats. See A guide to fats in food.
• Your genes: Some people seem to be able to eat lots of fatty food without getting abnormal levels of lipids in their blood. But other people have to be very careful about what they eat. This difference may be caused by differences in their genes (the basic material in all cells that controls how cells grow and behave). Differences in genes may affect how much cholesterol your body makes and how it handles the fat in the food you eat.
• Lack of exercise: Not getting regular exercise can increase triglycerides and reduce good cholesterol. See More about cholesterol and triglycerides.
• Being overweight: Putting on weight can have the same effect on cholesterol as not exercising.
• Getting older: Cholesterol tends to rise as we get older.
• Drinking alcohol to excess: Drinking a lot of alcohol on a regular basis can increase your cholesterol and triglycerides.
• Severe lipid disorders: Some lipid disorders are inherited, which means that faulty genes are inherited from one or both parents. People with one of these disorders have high levels of lipids and are more likely to have heart or circulation problems, even when they are quite young. These types of lipid disorders are rare. To learn more, see Inherited lipid disorders.

This information is for educational use only, and is not a substitute for prompt professional medical advice. Readers should always consult a physician or other professional for advice and treatment. ©BMJ Publishing Group Limited 2008. All rights reserved.