Statin Therapy Depresses Fat Metabolism in Older Individuals

Abstract

Objective: Statins (3-hydroxy-3-methylglutaryl coenzyme A [HMG CoA] reductase inhibitors) reduce blood lipoproteins and reduce the risk of cardiovascular events. However, they may reduce fat metabolism. This study tested the hypothesis that total body fat oxidation is reduced by statins in older subjects and the reduction is not due to substrate availability.

Methods: A total of 14 elderly patients (71 ± 6 years) on statin therapy were compared with 14 matched elderly controls (75 ± 7 years). Subjects were tested for respiratory exchange ratio (RER) during both maximal and submaximal sustained (70% Vo_2max) exercise to voluntary exhaustion. Blood samples were drawn for lipoprotein analysis and substrate availability.

Results: RER was significantly higher in subjects taking statins during both the max and submax tests, indicating reduced fat oxidation. Blood lipoprotein levels after a fast were not different between the statin and control groups. Levels of glucose, lactate, or triglyceride were not different between groups; however, free fatty acid levels were elevated by exercise in the statin group. Fat oxidation was significantly reduced in older subjects taking statin drugs that were not associated with diet, exercise, and fitness, which were matched between groups, nor availability of fat from the blood, which was higher in the statin group.

Conclusion: Although statin therapy normalizes blood lipoproteins, it reduced fat metabolism in older individuals, which cannot be a result of lower availability from blood.

Key words::

• aging
• fat oxidation
• oxygen consumption
• respiratory exchange ratio
• blood lipoproteins

ACKNOWLEDGMENTS

Partial funding was received from the Office of Naval Research, Naval Sea Systems Command, the Center for Research and Education in Special Environments, and the Mark Diamond Research Fund. We recognize the technical support of Siritorn Yingrengreung, Maria Brady, Eric Stimson, Mike Fletcher, Dean Marky, Dr. Paul Wallace, Michael Rickard, Derek Farkas, Emily Grieco, and Krista Macy. We thank the Department of Exercise and Nutrition Sciences for their partial support of A. Limprasertkul and Kaleida Health for assisting with blood analysis.

Fig. 1. Respiratory exchange ratio (RER) is plotted as a function of oxygen consumption expressed per unit body weight determined during the Vo_2max test. The (•) represents statin group and the (○) represents control group. The * indicates that the statin group is significantly different from the control group (p ≤ 0.05).

Fig. 2. Respiratory exchange ratio (RER) is plotted as a function of exercise time in the submaximal test. The (•) represents the control group and the (○) represents the statin group. The * indicates that the statin group is significantly different from the control group (p ≤ 0.05).

Table 1. Physical Characteristics of the Control and Statin Groups*

Table 2. Dietary Intake and Analysis for the Control and Statin Groups*

Table 3. Fasting Levels of Blood Lipids (mg/dL) for the Control and Statin Groups*

Table 4. Free Fatty Acid (μM) Measured Pre-Exercise and Postexercise during the Vo_2max and Submaximal Tests in the Control and Statin Groups*

Notes

This paper was presented at the American Nutritional Society at Experimental Biology, Washington DC, 2009.

The authors have no financial interest in this work or with a commercial sponsor.