Eating certain foods can help people lower their cholesterol levels, even without the aid of medication, a new study finds.
In the study, published in the Journal of the American Medical Association, patients who started out with high or borderline high LDL, or bad cholesterol, levels (anything above 158 mg/dL) were able to lower their LDL by 14% over six months by sticking with a diet rich in cholesterol-lowering foods.
That diet cut participants' LDL three times more than a standard low-fat diet.
So what foods were effective against artery-clogging fat? According to study leader Dr. David Jenkins, chair of nutrition, metabolism and vascular biology at the University of Toronto, there are four pillars of a cholesterol-lowering diet: plant oils or sterols such as margarine; viscous fibers including oats, barley and psyllium; nuts; and soy.
For most people, Jenkins says, it wouldn't require that much effort to boost consumption of these foods enough to achieve a cholesterol-reducing effect. In fact, he says, it would be sufficient to substitute oat bran or psyllium cereal in the morning in place of your regular breakfast, and to try soy milk products instead of dairy.
The six-month study was the first to look at the potential impact of a real-world diet on cholesterol levels. Rather than providing their 345 participants with foods to eat, researchers counseled them on how to shop for and incorporate more cholesterol-lowering products into their diet on their own. (The only food given to the study participants was plant sterol-based margarine, which was not permitted to be sold in Canada, the site of the study, at the time.) One group of participants received two nutritional counseling sessions of 40-60 mins. each, while another group received a more intensive schedule of seven sessions over six months. The control group got advice on how to eat a low saturated fat diet.
At the end of the six months, the two intervention groups showed an average 25 mg/dL drop in their LDL levels, compared with an 8 mg/dL decline in the low-fat-diet group. Both groups that received counseling on cholesterol-lowering diets showed similar reductions, suggesting that people were able to change their diets after just two sessions of instruction.
"The results show that we do have something worthwhile to add to the dietary formula," says Jenkins.
He notes that the majority of people in the study were recruited through advertisements, which may have targeted people with a pre-existing interest in lowering their cholesterol levels, so they might have been particularly keen on adopting the necessary dietary changes to keep their lipid levels in check.
Jenkins suggests that the results could be even more impressive among people who aren't paying much attention to their diet at all and may therefore have more to gain. "The implication from our point of view is that if we take the couch potato, and they were to bite the bullet and adopt these changes, they could do much better in terms of reducing their cholesterol," he says.
How much more tofu and oat bran would it take to make a difference? Based on an average 2,000-calorie daily diet, Jenkins said the study participants were instructed to aim for 2 g of plant sterol, nearly 20 g of fiber, and 40 g each of soy and nut products daily.
Only about 40% of the volunteers reached this target, but Jenkins says anyone can easily start adding some of these foods into their diet gradually. "To eat more oats, for example, change your breakfast cereal and try some desserts made of oat bran with fruits and nuts," he says. He acknowledges that boosting soy intake could be a little more difficult, particularly among westerners who still aren't accustomed to the protein that's such a staple of Asian diets.
But the effort may be worth it, especially for those who aren't eager to start popping pills to lower their cholesterol, Jenkins says. In the first study his team did on these foods, in 2003, they showed that in a lab setting, when participants were provided with the adequate amounts of fiber, nuts, soy and plant sterols, they were able to lower their LDL levels by nearly 30% — with the reductions associated with early cholesterol-lowering statin drugs.
Jenkins says his next step is to follow-up with his diet-study patients to see whether the change in their eating habits translates to cleaner arteries and therefore to fewer heart events. He plans to conduct imaging studies of the major arteries to document any changes the diet may have on blood vessels.
In the meantime, he says, "I don't think it's that difficult" to switch to a more powerful cholesterol-lowering diet. "You don't have to hold your nose, but just change as much as you can and look for substitutes for high-fat foods that often fill the gap very, very well."