A diet based around plants, nuts and high-fiber grains lowered "bad" cholesterol more than a low-saturated-fat diet that was also vegetarian, researchers reported on Tuesday.
And the drop in low-density lipoprotein, or LDL cholesterol, was big enough that dietary changes could be an alternative to statin medications for many people, they said.
"There's no question that statins have made a major difference in terms of cardiovascular disease control," said study author Dr. David Jenkins, from the University of Toronto. But at least for now, he added, "we can only get so far with statins."
One in four adults age 45 and older in the U.S. takes the cholesterol-lowering drugs.
Jenkins and his colleagues wanted to see how big an effect a diet based on the pillars of lower cholesterol could have on LDL numbers without statins.
They randomly split 351 Canadians with high cholesterol into three groups. One group got nutrition counseling promoting a low-saturated-fat diet for six months.
In the other two groups, dietitians helped participants fit more cholesterol-lowering foods, including soy milk, tofu, nuts, oats, peas and beans, into a healthy diet — meeting with some of them twice during the study, and with others seven times. All the diets were vegetarian.
After six months, people on the low-saturated-fat diet saw a drop in LDL cholesterol of 8 milligrams per deciliter (mg/dL), on average, according to findings in the Journal of the American Medical Association.
That compared to 24 mg/dL and 26 mg/dL decreases in participants on the cholesterol-lowering diets. (The average starting LDL was about 170 mg/dL. A number 160 mg/dL and above is considered high.)
That drop is "really a lot," said Dr. Yunsheng Ma, a nutrition and heart disease researcher from the University of Massachusetts Medical School in Worcester, who was not involved in the new study.
Volunteers in the cholesterol-lowering group were encouraged to consume about a gram of plant sterols in an enriched margarine per 1,000 calories of food they ate, as well as about 10 grams of fiber in the form of oats, barley and psyllium, 22.5 grams of soy protein and 22.5 grams of nuts, per 1,000 calories.
"A lot of people rely on the medication, but diet is really powerful actually," he told Reuters Health. "People ignore that. They think if they're on statins, they can do anything they want, they can eat the high-fat foods because the statins are going to take care of that."
One in five of the participants dropped out before the full six months, and even those that didn't had a hard time sticking closely to the diet plans — but many still saw cholesterol benefits.
The researchers had everyone in the study who was taking statins go off the medication for the diet intervention. Jenkins said the question of how diet and statins could lower LDL in tandem is for future research.
But for those who like the idea of changing their diet instead of going on medications, this is a reasonable option, he said. Others who aren't interested in adjusting their eating habits might be better suited to sticking with statins, Jenkins added.
"If you want to sit on the couch with the six pack and the wings and watch other people exercise and you're quite determined not to do anything other than that, then we've got a medication for you," he said.
For other people, genetics or very high cholesterol may mean that diet isn't enough to get LDL down to a healthy level without statins, said Dr. Joan Sabate, head of nutrition at Loma Linda University in California.
Jenkins said that doctors should encourage their patients with high cholesterol to try diet changes, if they're interested. A couple of visits to a nutritionist might be enough for motivated patients to make the switch to a plant-based, higher-fiber diet, he added.
"The diet only is enough for the majority of the people that have a not-so-good lifestyle," Sabate, who was not involved in the new research, told Reuters Health. "By changing the diet and their lifestyle they can establish good control of their cholesterol."