Obese children with high cholesterol who followed a strict vegan diet with little added fat in a small Cleveland Clinic study showed significant improvements in both weight and heart disease risk factors in only a month, according to research released Thursday.
The children, ages 9 to 18, were mostly white and middle class, and volunteered to try one of two healthy eating plans. Two groups of 14 children were randomly assigned, along with a parent, to eat either a plant-based, no fat-added diet (PB) or the American Heart Association (AHA) diet, which is similar but permits non-whole grains, low-fat dairy, selected plant oils, and lean meat and fish in moderation.
After a month, the children in both groups had lost weight and seen improvement in myeloperoxidase (MPO), a blood test that measures inflammation related to heart disease risk. The kids eating the vegan diet, however, also showed significant improvements in systolic blood pressure, body mass index, total cholesterol, total low density lipoprotein (LDL, long referred to as "bad cholesterol"), c-reactive protein (another marker of inflammation), and insulin levels compared to their baseline.
The study, published online today in the Journal of Pediatrics, was too small to allow a head-to-head comparison of the two diets, but the results are "suggestive," of an added benefit both for weight and heart health on the stricter vegan diet, said Dr. Michael Macknin, the study's lead author and a pediatrician at the Clinic.
"It was exciting to see," Macknin said. "If they can eat like this, the hope is that they can grow into adults who do not have the risk factors for cardiovascular disease. What this is is hope for the future."
He believes the study provides a good reason to look further into vegan, no-added-fat and plant-based diets as a prescription for preventing future health problems for overweight and obese children and adolescents.
Vegetarian diets have long been supported for heart health in adults, but have been little studied in children, primarily because health concerns such as high blood pressure, cholesterol and inflammation were once unheard of in kids. Now, with obesity affecting nearly 18 percent of children aged 6-11 years and 21 percent of adolescents, high cholesterol, high blood pressure and prediabetes have become common.
All the children in the study had high cholesterol, a risk factor for heart disease, heart attacks and stroke.
"We know that cardiovascular disease begins in childhood, so the concern is that the high cholesterol may put them at risk for subsequent heart attack," Macknin said. "We'd like to lower it now to prevent the risk later on. That's one of the joys of being a pediatrician: You actually have a chance to prevent disease rather than treat it."
The main drawback of the vegan diet used in the study is how difficult it may be for some families to follow -- not being able to easily shop for food that met the PB diet was the only significant complaint of people in the study.
That being said, the families that participated didn't feel the food was bland, boring or unappetizing, found it easy to stay on the diet and find options at restaurants, and were satisfied with what they had to eat, Macknin said.
"Which I thought was -- unscientifically -- surprising," Macknin said. "I was amazed that they found it as acceptable as they did. Part of that could be that they we took a highly motivated group that volunteered."
It may also have had something to do with the short length of the study, a limitation that jumped out at Lisa Cimperman, a registered dietitian at University Hospitals Case Medical Center.
"It's only four weeks," she said. "That's when I start thinking -- how doable is this long-term? The true test of any change in eating pattern is how easy it is to stick with it over time."
Macknin isn't sure if the families maintained the diets, but he's pretty sure they relaxed some of the requirements as soon as they could. "It was rigorous -- they didn't add oils and we discouraged them from even adding nuts and avocados," he said.
Being able to stick to a diet this strict over the long haul is probably its biggest drawback, Macknin said. But, he added, "I'm confident that we've changed eating patterns. They know how to eat well now. They took cooking classes. They learned how to read labels, so they know how to pick out healthy foods. I'm quite confident it changed their overall eating patterns."
Cimperman said vegan diets for kids are "absolutely possible to do" but recommends that any parent considering it sit down with a doctor or nutrition expert first to plan out a healthy diet. Cimperman and Macknin said it's important to pay attention to levels of particular nutrients such as vitamin B-12, vitamin D, calcium, iron and omega-3 fats, in vegetarian or vegan diets.
"Overall, we know that plant-based diets are beneficial for chronic diseases like heart disease, diabetes and obesity," Cimperman said. "So it's a pretty rational jump to think that maybe these diets would be helpful to children who are obese."
It would take some significant changes in our eating and shopping habits and in our overall food culture to support a shift toward a more plant-based diet, Macknin acknowledges.
"The average American teenager has one fruit and one vegetable a day, and a lot of the vegetables are French fries," he said. "So it would be a big change for most people. For this to become increasingly popular it would involve a different way of thinking about how we eat."
While the participants said that the cost of the diet was not problematic, fresh fruits and vegetables and plant-based foods can be more expensive and more difficult for people shopping on a fixed or lower income to buy.
But, Macknin said, if you're cutting meat and dairy out of your diet, you're likely saving money that way. And, said Cimperman, a low-cost vegan or plant-based diet can require a lot of coupon-cutting, planning, and searching for the best prices and markets, but it may save a lot of costs down the road.
"It can take a lot of time to plan these diets, but the upshot is that no one has time to be sick, either," she said. "So you can either decide to take the time in up front with your nutrition and exercise habits, or you put the time in on the back end with health problems."
She also wants people to know that if you can't cut out all animal products, just making small changes in your diet can help.
"We know for sure that simply increasing your intake of plant-based foods and cutting back on animal-based foods, particularly high-fat foods, is enormously beneficial," she said. "You can take small steps to get a little closer to this eating pattern. Any progress is better than none."