Study shows cholesterol-lowering power of dietitian visits

March 4, 2008

Worried about your cholesterol? You may want to schedule a few appointments with a registered dietitian, to get some sound advice about how to shape up your eating habits, according to a new national study led by University of Michigan Health System researchers.

Not only are you likely to lower your cholesterol levels, you may be able to avoid having to take cholesterol medication, or having to increase your dose if you’re already taking one. And you’ll probably lose weight in the process, which also helps your heart.

The new results, published in the February issue of the Journal of the American Dietetic Association, are based on data from 377 patients with high cholesterol who were counseled by 52 registered dietitians at 24 sites in 11 states.

In the group of 175 patients who started the study with triglycerides less than 400 milligrams per deciliter of blood (mg/dL), and who had their cholesterol measured before they changed or added medication, 44.6 percent either reduced their levels of “bad” cholesterol by at least 15 percent, or reached their cholesterol goal.

The results reflect progress in approximately eight months, after three or more appointments with a dietitian. But the results add further evidence that medical nutrition therapy, as it is called, can make a big difference in a patient’s life.

All of the R.D.s in the study based their advice to their patients on the latest research-based evidence about eating habits and cholesterol levels available at the time of the study: the American Dietetic Association’s 1998 Medical Nutrition Therapy Hyperlipidemia Protocol.

Since that time, the ADA has updated the clinical guideline based on new research, which means that patients who see an R.D. today may have even more success.

The study was funded by the ADA and its Clinical Nutrition Management Dietetic Practice Group, and based on a framework developed for a pilot project carried out in Michigan by the Michigan Dietetic Association and led by U-M cardiovascular dietitians.

“Everyone knows that nutrition is important for cholesterol management, and that a registered dietitian is the professional most thoroughly trained to help patients choose foods wisely,” says lead author Kathy Rhodes, Ph.D., R.D., manager of Nutrition Services with the U-M Cardiovascular Medicine program at Domino’s Farms and the U-M Cardiovascular Center. “But this is the first national study to show what happens when high-risk patients work with R.D.s to follow nutrition guidelines grounded in the best evidence.”

Key nutrition issues in the 1998 guidelines used in the study include reducing saturated and trans fat and increasing “healthy” fats such as olive oil; increasing soluble and insoluble fiber; eating fish twice a week; increasing fruits and vegetables; regular exercise and healthy weight management. Information about food-label reading and dining out was also included.

Called the Lipid Management Nutrition Outcomes Project or LMNOP, the national study was launched by Rhodes and her U-M colleagues Melvyn Rubenfire, M.D., and Martha Weintraub, MPH, R.D., after the successful completion of the Michigan-wide pilot project. Rubenfire, Weintraub and Christina Biesemeier, M.S., R.D., FADA, of Vanderbilt University are co-authors of the new study.

The study gives us an important “real world” picture of what happens when R.D.s try to implement evidence-based nutrition guidelines in daily practice, Rhodes notes.

Some commercial health insurance plans are beginning to cover appointments with registered dietitians, but many still do not. Only dietitian visits for diabetes or kidney disease are covered by Medicare. It is important for people to check their specific health insurance plan to see whether nutrition is covered, Rhodes says. But even if individuals need to pay for the appointments out of their own pocket, they may find that an R.D.’s advice will pay off in the long run, she says.

To get uniform data, the researchers brought lead R.D.s from each state to U-M for training on the cholesterol and nutrition guidelines, and on the data collection practices used in the study. R.D.s at Veterans Affairs hospitals got their training by phone conferencing. R.D.s then returned to their own practices, trained their colleagues and implemented the ADA guidelines.

The study included only patients between the ages of 25 and 70 years who had high cholesterol levels, or triglyceride levels over 200 mg/dL, and who met other inclusion criteria including no recent changes in their cholesterol medication status. Neither the R.D.s nor their patients were paid to participate in the study.

The “real world” aspect of this study included the disappointing finding that many patients dropped out of nutrition counseling after one or two visits, when three or four sessions with an R.D. is recommended to make and sustain truly effective changes in eating habits. Lack of insurance coverage was a major factor in this dropout rate.

Patients whose doctors changed their cholesterol medication status, either by starting them on a drug for the first time, or increasing their dose before assessing the effect of diet change, were not included in the analysis. But for the 219 patients who didn’t have any change in their medication status, the impact of the R.D. counseling became apparent in the first year after the initial visit.

“Although some patients may already be eating a relatively healthy diet, medical nutrition therapy can increase patient’s knowledge of ‘cardioprotective foods’ and assist them in individualizing the guidelines to fit their preferences and lifestyle,” says Weintraub. A significant number of patients reduced the fat in their diets to less than 30 percent of calories, as recommended for a heart health. Many participants also lost weight and/or increased the number of days each week on which they exercised for 30 minutes or more.

“Often, we see heart patients who are on multiple cholesterol medications but have never seen a dietitian. And even when a patient with high cholesterol does get to see an R.D., their care team may not allow enough time to see how effective diet is before they add additional treatment,” says Rhodes. “We hope that this demonstration of how well cholesterol can be lowered without medication or increases in medication will be very useful for patients and physicians, and perhaps insurers too.”

Source: University of Michigan Health System