Cardiovascular and Metabolic Health are Focus of Arciero’s Research

Associate Professor of Exercise Science Paul Arciero has received a $100,000 grant from Experimental and Applied Sciences Inc. (EAS) to support new research into the effects of diet and exercise on cardiovascular and metabolic health in overweight, middle-aged men and women. He’s hoping to discover how a low-carbohydrate diet alone - or in combination with resistance and cardiovascular exercise - affects levels of body fat and mass, and ultimately, heart health.

Arciero is using the grant to pursue a new line of inquiry into his continuing research on the effects of food intake and exercise on health. He earlier completed a study (also supported by EAS) that considered the effects of diet and exercise on resting metabolism, blood lipids, body composition, and muscle strength. “The current study is slightly more sophisticated because it is more invasive,” he explained. His new research will compare the effects of a low-carbohydrate diet with a diet of moderate levels of carbohydrate consumption combined with aerobic and resistance exercise on important blood markers of metabolic and cardiovascular health.

A key question of his research concerns the effects of low versus moderate carbohydrate consumption. He recruited 33 healthy, moderately overweight (those with a Body Mass Index of 27 or more) men and women between the ages of 35 and 65 and assigned them to three groups. The first group is following a diet that contains 25 percent carbohydrates and that includes Carb Sense (a low-carbohydrate food supplement manufactured by EAS, a leading nutritional supplement company). The first group also performs high intensity aerobic exercise three days a week and weight-training three days per week. The second group is using a diet plan featuring moderate carbohydrate levels (totaling 55 percent) and is following the same exercise program; while the third group is using just the low-carbohydrate Carb Sense diet and no structured exercise.

Arciero's goal is to show specific results relating to the use of low-carbohydrate supplements combined with a program of resistance and cardiovascular exercise, and contrast those results with the groups involved in either the low-carbohydrate diet alone or the moderate carbohydrate diet combined with a similar exercise program. All participants are required to consume six meals daily, three of which are in the form of a meal replacement bar or liquid. These contain either low (25 percent) or moderate (55 percent) levels of carbohydrates.

Carbohydrates are increasingly being targeted as contributing to overweight and obesity among people of all ages. Many scientists believe that people consume too many highly refined carbohydrates, said Arciero. These include such items as white flour, potatoes, white rice, white pasta and all bread products. According to Arciero, this view represents “a real paradigm shift with regard to the federal Department of Agriculture’s well-known food pyramid, established in 1992,” which emphasizes carbohydrate intake over fats and protein.

The diet supplement Arciero is using is low in refined carbohydrates. He’s contrasting use of this supplement with a diet that includes moderate complex/unrefined carbohydrate consumption. Diets for those using Carb Sense in his study consist of 55 percent protein consumption, 25 percent carbohydrate consumption, and 20 percent fat consumption. Study participants not taking Carb Sense have diets consisting of 55 percent carbohydrates, 25 percent protein, and 20 percent fat. Both groups may have unrestricted consumption of vegetables, with emphasis on those with darker colors - green, orange, and yellow - that are known to be more nutritious.

To gauge the effectiveness of the study, all participants are having regular blood draws to test for glucose, insulin, and other markers of vascular health. Body composition also is being analyzed.

“There are essentially two ways to lose weight and body fat: increase energy expenditure and/or decrease energy intake,” says Arciero. There are less data, however, on the influence of both exercise and different macronutrients on body composition and risk factors affecting cardiovascular health.

According to a May 8, 2003 story in USA Today, approximately 65 percent of Americans weigh too much, putting them at greater risk of heart disease, diabetes, arthritis, and most types of cancer. “This country needs to make major changes involving all aspects of society - business, schools, institutions, the public, and the government,” according to experts quoted in the story.

Arciero hopes his study will shed more light on “Metabolic Syndrome X,” a collection of risk factors including high blood sugar (diabetes), hypertension, elevated LDL (the so-called “bad” cholesterol), low HDL (known as “good” cholesterol), and high triglycerides. These are known contributors to heart disease. Says Arciero, “A combination of healthy exercise and diet is critical to dealing with Syndrome X.”

Blood analysis of study participants checks for two key metabolic markers: high levels of C-reactive proteins (CRP) and Angiotensis II (Ang-II), two proven risk factors for predicting future cardiovascular events. CRP is a marker of inflammation of the body’s blood vessels and is elevated in insulin-resistant individuals. Its presence decreases in response to improved insulin sensitivity. Ang-II is typically elevated in obese people and is a contributor to Syndrome X. This is the first time that a scientific study has looked at the effects of diet and exercise on the presence of these markers.

In addition to CRP and Ang-II, Arciero is looking at such metabolic and hormonal variables as plasma glucose, insulin, and leptin (by having participants take regular oral glucose tolerance tests); cholesterol; blood pressure, resting heart rate, and peripheral blood flow; and blood clotting factors.

Now about halfway through the three-month study, Arciero anticipates that all participants will show reduced body weight and an improved lipid profile. He’s also hoping to show that all groups will experience increased insulin sensitivity, and lower CRP and Ang-II levels. “We hope to get a better idea of the bio-chemical markers of cardiovascular disease and metabolic health. The comprehensive blood analysis will helps us learn what is responsible for improvements in this area,” Arciero said.

The EAS grant supports the work of five research technicians: Heather Wood
’01; and Meghan Everett, Roger Martin-Pressman, and Michael Ormsbee, all Class of ’02; and Gordon Cogan ’02, currently at Cornell University. Four research assistants also are funded: Lauren Swicky ’03; and Liza Gorman, Jason Santamore, and Jeff Martin, all Class of ’04. In addition, the services of a registered dietician and nurse are funded with grant support, as is processing of all blood work of the participants.

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