Cholesterol lowered with soy, fibre, nut diet

People who ate soy, nuts and certain fibres were able to lower their cholesterol more than those who ate a diet low in saturated fat, Canadian researchers say.

People who ate soy, nuts and certain fibres were able to lower their cholesterol more than those who ate a diet low in saturated fat, Canadian researchers say.

Doctors are concerned about high levels of LDL because it can build up on the walls of arteries and increase the risk of heart disease and stroke.

Diet changes have been shown to reduce "bad" cholesterol levels to the same degree as medications in shorter-term studies.

A study detailed in Wednesday's issue of the Journal of the American Medical Association showed promising results in a longer trial done under "real-world" conditions.

"In conclusion, this study indicated the potential value of using recognized cholesterol-lowering foods in combination," Dr. David Jenkins, who works at St. Michael's Hospital and the University of Toronto, and his co-authors wrote.

"We believe this approach has clinical application."

By combining foods that are known to have cholesterol-lowering properties, participants lowered their so-called bad cholesterol, or LDL, by more than 13 per cent.

In comparison, those in the control group who ate a low-fat diet alone lowered their cholesterol by three per cent, researchers found.

Both groups were asked to eat a combination of foods with cholesterol lowering properties, known as a dietary portfolio.

The diet included:

  • Soy proteins such as soy milk and tofu.
  • Viscous or "sticky" fibres from oats, barley and psyllium.
  • Nuts, including tree nuts and peanuts.
  • Plant sterols in margarine.

The study included 351 men and postmenopausal women in Quebec City, Toronto, Winnipeg  and Vancouver.

They were randomly assigned to the cholesterol-lowering or a low-fat diet.

Within the cholesterol-lowering group, researchers also compared two levels of diet advice — two visits with a dietitian over the six-month study period or seven visits in that time.

The dietitian reviewed participants' records of what they ate for seven days and suggested improvements.

The control group did not receive any diet advice during the six-month study period.

"A meaningful 13 per cent [LDL] reduction can be obtained after only two clinic visits," the researchers said. 

2 diet sessions suffice

The fact that only two visits with a dietitian were needed is encouraging, Jenkins said,  because it is a "great burden off the medical system if people are equipped to look after themselves. Doctors can do a better job if there are fewer patients to see."

The goal of the study was to look at the effect of dietary advice in "real-world conditions," researchers said.

All participants had their weight measured, blood pressure taken and blood drawn for cholesterol checks.

A limitation of the study included the high overall dropout rate of 22.6 per cent, which the researchers said is common for such intense diet studies.

Because the diet was complex, researchers couldn't tell which foods made a difference in lowering cholesterol.

The Canadian Institutes of Health Research was the main funder of the study. Loblaw, Solae and Unilever also provided funding and some of the foods used in the study but played no role in how the study was designed or conducted.