Are foods more important than fats for lowering cholesterol?

By Sophie Ramsey

BMJ Group News

What do we know already?

People with high cholesterol are often advised to cut back on unhealthy fats. This means eating less butter, cheese, meat, baked goods, and other sources of saturated and trans fats. Studies show this can lower the amount of bad (LDL) cholesterol in their blood, reducing their risk of a heart attack or stroke.

However, out in the real world - beyond the strict dietary controls of a study - such advice often falls short of reaching these goals, and people instead rely on medicines, such as statins, to lower their cholesterol.

In the new study, researchers wondered whether different dietary advice might be more effective. Instead of focusing on fats, they looked at adding cholesterol-lowering foods to people’s diets.

The researchers put together a ‘dietary portfolio’ of four groups of foods shown to lower LDL cholesterol:

• Foods rich in oats, barley, and psyllium (such as oat bran cereal and bread)
• Soya milk, tofu, and other sources of soya protein
• Nuts, including peanuts and tree nuts (such as walnuts and almonds)
• Margarine enriched with plant substances called sterols.

They recruited 351 people with high cholesterol who were not currently taking cholesterol-lowering medicines. Over six months, some participants had two counselling sessions on how to follow a low-fat diet that was high in whole grains, fruits, and vegetables but avoided the portfolio foods. The rest of the participants had either two or seven counselling sessions on adding the portfolio foods to their diet.

What does the new study say?

After six months, people advised to eat the portfolio foods had a larger drop in LDL cholesterol than those in the low-fat group.

On average, participants who had two counselling sessions on the portfolio foods had a 13.1 percent decrease in LDL cholesterol, and those who had seven sessions had a 13.8 percent drop. By comparison, people who were advised to eat the low-fat diet had only a 3 percent drop.

The researchers also found that the more closely people adhered to the portfolio diet, the lower their LDL cholesterol.

The drop in cholesterol levels with the portfolio foods was only about half that achieved in studies on statins, say the researchers. Even so, this could translate into an 11 percent lower risk of heart disease over 10 years, they estimate. These estimates would need to be tested in long-term studies.

How reliable is the research?

This was a good-quality study with compelling findings.

However, it’s worth noting that most participants had fairly healthy diets to begin with. This could mean that people with poorer eating habits would see an even larger drop in LDL cholesterol after having advice on the portfolio diet. But it might also mean that the people in the study were quite motivated to manage and improve their health, suggesting that the dietary advice might not have as much of an impact on less health-conscious individuals.