This information is for people with heart disease. It tells you about eating a healthy diet, a treatment used to lower cholesterol. It is based on the best and most up-to-date research.
Does it work?
Yes. If you have heart disease and you eat a healthy diet there's a good chance that your blood cholesterol will fall.
You are also likely to reduce your risk of having a heart attack or a stroke.
What is it?
There are lots of different things you can do to make your diet more healthy. One of the diets we know works to lower cholesterol is called the Mediterranean diet.
The Mediterranean diet is traditionally eaten by people who live around the Mediterranean in countries like Greece, Italy, and Spain. It is rich in olive oil, grains, fruits, nuts, vegetables, and fish. It is low in meat (especially red and processed meat), dairy products, and alcohol, although some red wine is usually consumed with meals.
Other things you can do to make your diet more healthy include cutting down on fat, especially saturated fats, and eating more oily fish such as mackerel and salmon. To learn more about which fats are more or less healthy, see A guide to fats in food.
How can it help?
In one good-quality study, people with heart disease who switched to the Mediterranean diet were less likely to have another heart attack or stroke, and less likely to die from heart disease.  The risk of having a heart attack fell by 70 percent among people who spent just more than two years on the diet.
There's less evidence about the benefits of a low-fat diet or eating more oily fish. But the research does suggest a low-fat diet can lower your cholesterol . Eating more oily fish, if you've already had a heart attack, may help you live longer. But the research is unclear.   Read more about oily fish for people with heart disease.
How does it work?
Scientists aren’t exactly sure why a Mediterranean-style diet is healthy. It may be because the main fats in this diet come from olive oil rather than from animal fats. Olive oil is healthier than the saturated fats and trans fats that are found in meat and meat products, butter, lard, cakes, biscuits, coconut oil, and palm oil. Saturated fats and trans fats can increase the amount of LDL cholesterol in the blood, which can clog the arteries and lead to high blood pressure and heart disease. So replacing saturated fats and trans fats with olive oil could help to keep the blood healthy.
Oily fish contain omega-3 fatty acids, which may help make the blood less sticky and reduce the chances of a clot forming. Nuts and seeds are also high in monounsaturated fats and polyunsaturated fats, both of which may have health benefits. Some scientists think that it’s not one element of the Mediterranean diet that makes it healthy, but a combination of the foods together.