Submitted to: Journal of Nutritional Biochemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/8/2007
Publication Date: 1/10/2008
Citation: Diaz, M., Watkins, B., Li, Y., Anderson, R.A., Campbell, W. 2008. Chromium picolinate and conjugated linoleic acid do not synergistically influence diet- and exercise-induced changes in body composition and health indexes in overweight women. Journal of Nutritional Biochemistry. 19:61-68. Interpretive Summary: The prevalence of overweight and obesity has increased all across the nation. Excess body fat substantially increases the risk of morbidity from many metabolic and cardiovascular diseases, including hypertension, dyslipidemia, type 2 diabetes mellitus, coronary heart disease, and stroke. Many people use dietary supplements to hopefully achieve weight loss or enhance diet and exercise-induced weight loss. Chromium picolinate (CP) and conjugated linoleic acid (CLA) are two supplements promoted for use in weight control. In this study 35 women were asked to reduce normal caloric intake by 500 kcal per day and take either a supplement containing the two weight loss products or a placebo for 12 weeks. There were no additional effects of consuming the two weight loss products after 12 weeks on weight or clinical measurements. This work should be of interest to the scientific and medical communities as well as the large numbers of people consuming supplements to lose weight.
Technical Abstract: Objective: This study assessed the effects of combined chromium picolinate (CP) and conjugated linoleic acid (CLA) supplementation on energy-restriction and exercise-induced changes in body composition, glucose metabolism, lipid-lipoprotein profile, and blood pressure in overweight, pre-menopausal women. Design: For 12 wk, 35 women (age 36±1 y (mean±SEM); BMI 28.0±0.5 kg/m2) were counseled to consume a 500 kcal/d energy deficit diet and perform 30 min of moderate-intensity walking or jogging 5 d/wk. The women were randomly assigned to ingest either CP-CLA (400 µg Cr, 1.8 g CLA in 2.4 g tonalin oil, n=19) or placebo (<0.1 µg Cr, 2.4 g canola oil, n=16). Results: Compared to baseline, urinary Cr excretion increased 22-fold, plasma fatty acid 18:2 (c9,t11) content increased 79%, and 18:2 (t10,c12) became detectable in CP-CLA, and were unchanged in Placebo. Over time, VO2 maximum increased 8.3±3.1% (CP-CLA 1.9±1.3; Placebo 3.8±1.5 mL O2•kg-1•min-1), body weight decreased 3.5±0.5% (CP-CLA -2.6±0.5; Placebo -2.5±0.5 kg) and fat mass decreased 8.9±1.3% (CP-CLA -2.7±0.5, Placebo -2.4±0.5 kg), with no differences in responses between groups. Fasting blood hemoglobin A1c, plasma glucose and insulin, a homeostatic assessment of insulin resistance (HOMA-IR), serum total cholesterol (CHOL), HDL, LDL, triacylglycerol (TG), CHOL/HDL ratio, TG/HDL ratio, and sitting systolic and diastolic blood pressures were not changed over time or influenced by CP-CLA. Conclusion: The use of a combined chromium picolinate and conjugated linoleic acid supplement for three months does not affect diet and exercise-induced changes in weight, body composition, and indexes of metabolic and cardiovascular health in young, overweight women.