Weighing the Cost of Weight Loss
Nutrition Science Professor Explores Nutritional Complications of Bariatric Surgery
Nana Gletsu-Miller, assistant professor of nutrition science, asks if people who opt for bariatric surgery are "trading one set of problems for another." (Photo by Steven Yang)
Bariatric surgery has become a popular weight-loss option — more than 200,000 surgeries were performed in the U.S. in 2011.
"There are not many other proven programs for people who have 100 or more pounds to lose," says Nana Gletsu-Miller, assistant professor of nutrition science. "And the surgery works. In a month people lose about 10 percent of their body weight and 25 percent over six months. It takes one to two years to realize normal body weight."
Bariatric surgery makes the stomach smaller and allows food to bypass part of the small intestine and to go directly to the lower intestine. The operation fools the patient into feeling full with less food than before the surgery when the stomach was its original size. Although patients are absorbing less fat and losing weight, thus reducing serious health risks such as heart disease, diabetes and stroke, the surgery has drawbacks. Nutrients are not absorbed as well in the lower intestine, and because patients are eating less, fewer essential nutrients and vitamins are available in the body.
Gletsu-Miller's research studies the impact of weight-loss surgery on overall health. She wondered, "Are these patients trading one set of problems for another?"
"With the weight loss, patients often feel so good after surgery they stop going to their doctors for follow-up and monitoring. Over time we see nutritional deficiencies," she explains. "Patients lack iron, vitamin D, some B vitamins, zinc and copper resulting in a range of issues including fatigue, anemia, hair loss or neurological problems."
Surgery itself only helps with weight loss for a year or two. Outcomes of Gletsu-Miller's work include helping postsurgical patients maintain weight loss over the long term while encouraging better nutritional health. "It is fascinating to study. We know obesity leads to cancer and heart disease, but why? What are the molecular reasons? The best way to study these things is to study people who lose weight."
Part of the work, she adds, is to share data with Purdue collaborators Kolapo Ajuwon, assistant professor of animal sciences, and Kee Hong-Kim, assistant professor of food science. Both researchers study the mechanisms that link excess body fat and diseases such as diabetes, heart disease, cancer and metabolic syndrome. "We supply biological samples, and they look at the molecular basis," Gletsu-Miller says. "This population allows us to make observations from human samples we analyze in the laboratory, as opposed to taking information from the lab to humans. We can use our understanding of what is going on to help others.
"These patients develop nutritional problems we haven't seen in this country in decades. We do see them in underdeveloped or developing countries. So, what we find using research with bariatric surgery patients, especially related to iron, copper and zinc deficiencies, can be applied to other populations who are at risk."
Educating postsurgery patients on the nutritional risks remains a key to optimal health, Gletsu-Miller says. "Patients should get routine nutritional check-ups after surgery, and always continue to take vitamins and minerals. It is important to be aware of symptoms and to not ignore them."