Eating less saturated fats in favour of more polyunsaturated fats reduces the risk of heart attacks and other serious problems from heart disease, a new review of studies reports. This is the first review to confirm that changing your diet in this way can cut your risk of heart attacks, although experts have long thought that cutting down on saturated fats improves heart health.
What do we know already?
Coronary heart disease is the most common cause of death for adults in the UK. You get this disease when the arteries that carry blood to your heart become narrowed with fatty deposits. If an artery becomes blocked, this can lead to a heart attack.
We don't know exactly why fatty deposits build up in some people's arteries. But we do know that some things can increase your risk, such as smoking and not taking much exercise. Another key risk factor is eating a lot of saturated fats, which are plentiful in meat, butter, cream, and other dairy products. These fats boost the level of 'bad' cholesterol in your blood, and it's this cholesterol that creates the fatty deposits in your arteries.
To reduce the risk of heart problems, doctors often recommend swapping saturated fats for a healthier kind called polyunsaturated fats, which are found in vegetable oils and fatty fish, such as salmon. Instead of increasing levels of 'bad' cholesterol, these fats can help lower it.
However, not much good-quality research has shown that this dietary approach actually reduces the risk of heart attacks and other serious problems from heart disease. There are also concerns that eating a diet high in polyunsaturated fats might ultimately increase a person's risk of heart problems, and some experts have recommended getting only 5 percent to 10 percent of your total energy from these fats.
In the new review, the researchers addressed these concerns and gaps in the research by looking closely at the best studies on replacing saturated fats with polyunsaturated fats. They also did a meta-analysis, which means they pooled the results of the studies to see what conclusions they could draw from this larger body of research. In all of these studies, people were randomly assigned to replace saturated fats with polyunsaturated fats in their diet, or to make no change. They were then compared over time.