Though low-fat diets have long been advocated for lowering High Cholesterol levels, a study published Monday points up the importance of replacing fatty foods with nutritious fare - not fat-free cookies and chips.

In a comparison of two Low fat diets - one plant-based and one packed with the convenience foods typical of the American diet - researchers found that the plant-based menu lead to greater reductions in study participants’ LDL cholesterol, the “bad” form of cholesterol linked to cardiovascular disease.

After four weeks, the 59 men and women who followed the vegetarian-style diet saw their total cholesterol fall by an average of 18 points (that is, milligrams per deciliter of blood) and their LDL drop by 14. That compared with 9 and 7 points, respectively, among 61 adults on the comparison diet.

According to the researchers, the findings underscore what experts now generally believe about traditional dietary advice for cutting cholesterol: the directive to go low-fat was overly simplistic.

It’s thought that the advice led many people to opt for reduced-fat processed foods, but not the fruits, vegetables and whole grains that can help lower cholesterol, according to lead study author Dr. Christopher D. Gardner of Stanford University in California.

The simple avoid-fat message, he noted in an interview with Reuters Health, has been changing in recent years to instead advise people on what foods to favor - including fruits, vegetables, beans, nuts and whole grains.

And these latest findings support that move, Gardner and his colleagues report in the March 3rd issue of the Annals of Internal Medicine.

Their study included 120 adults between the ages of 30 and 65 who had mildly elevated LDL cholesterol. The two diets that participants were randomly assigned to follow were both low in total fat - 30 percent of daily calories - and saturated fat, which was limited to 10 percent of calories. The diets were also equal in their amounts of cholesterol, protein and carbohydrates.

Where they differed was in the food choices. One diet was made up of large daily doses of whole grains like oats and brown rice, along with vegetables, soy protein, fruit, beans and nuts. The saturated fat was provided by modest amounts of butter, eggs and cheese.

The other diet, according to Gardner, was meant to emulate what the typical American might eat when cutting fat: foods like skinless chicken, potatoes, low-fat cheese and reduced-fat snack foods.

As mentioned, the vegetarian-style group showed total and LDL cholesterol declines that were twice that of the other group after four weeks.

The benefits were not universal, as the researchers found great variation from person to person in each group. Some people saw large declines in their cholesterol levels, while a small number in each group showed increases. Overall, however, the plant-based plan met with greater success.

The secret of the plant-based diet, Gardner said, does not come down to any single food component. Instead, the benefit likely stems from the combination of natural cholesterol-fighters found in such foods, including fiber and so-called plant sterols - cholesterol-lowering compounds that are now being added to some margarines and juices expressly for that purpose.

But people need not go totally vegetarian to get a cholesterol benefit, according to Gardner, who noted that simply avoiding meat does not make a diet healthy. Instead, it’s the inclusion of produce, beans, whole grains and nuts that seems key.

“What we’re talking about is moving toward a plant-based diet,” Gardner said.

The study serves up an “important reminder that diet, in addition to drugs, can play a role in achieving cholesterol targets,” according to an editorial published with the report

The findings should give an “injection of new enthusiasm” for using diet to treat High cholesterol, write Dr. David J.A. Jenkins and colleagues at the University of Toronto in Canada.

As far as the palatability of the diets used in the study, Gardner noted that some people in the vegetarian group were initially skittish about such “weird” items as soy burgers and vegetarian burritos - but just as many people in the conventional-diet group were at first “disappointed” with their assignment.

In the end, he said, both groups gave generally high ratings to their diets.

SOURCE: Annals of Internal Medicine, May 3, 2005.