Effect of sucrose on inflammatory markers in overweight humans

Nutrition Research Newsletter, Sept, 2005 by L. Sorensen, A. Raben, S. Stender, A. Astrup

A biological marker of inflammation, C-reactive protein (CRP), has been shown in several prospective, nested, case-control studies to be associated with an increased risk of myocardial infarction, stroke, sudden death from cardiac causes, and peripheral arterial disease. Moreover, CRP and LDL-cholesterol concentrations measured at baseline in 27,939 apparently healthy women were found to be independent risk factors for the first cardiovascular event at 8-year follow-up.

The importance of CRP as a predictor of coronary heart disease is not clear, because different studies have provided varying results. In the present randomized, controlled trial researchers tested the hypothesis that overweight men and women who increase their intake of sugar-sweetened drinks and foods experience an increase in the inflammatory serum markers CRP and haptoglobin and a decrease in transferrin compared with a control group that consumed similar amounts of artificially sweetened beverages and foods. The study had a parallel design with two intervention groups. For 10 weeks one group received supplemental drinks and foods containing sucrose, and the other group received similar drinks and foods containing artificial sweeteners. Forty-two healthy, overweight subjects were included, and 41 (6 men and 35 women) completed the study.

During the 10-week intervention the subjects consumed a specific minimum amount of either sucrose-sweetened or artificially sweetened foods and drinks daily. The subjects were assigned to three different levels of intake according to their initial body weight: level 1, 2, or 3 corresponding to 60 kg to 75 kg, 75 kg to 90 kg, and >90 kg, respectively. The minimum intake of the experimental diet was regulated by the sucrose intake and corresponded to a sucrose intake of 125 g/d (level 1), 150 g/d (level 2), and 175 g/d (level 3). The artificial sweetener content of the intervention diet was 54% aspartame, 23% cyclamate, 22% acesulfame K, and 1% saccharin.

In the present study the sucrose diet produced a nonsignificant 6% increase and the sweetener diet produced a 26% decrease in CRP concentrations. It was found that the median CRP concentration for the lowest quintile of dietary glycemic load was significantly lower than the CRP concentration for the highest quintile. This result remained after adjusting for several confounders such as age, BMI, history of hypertension, high cholesterol or diabetes mellitus, and lifestyle factors. The sucrose diet increased concentrations of haptoglobin, and changes in haptoglobin concentrations were positively associated with changes in sucrose intake. This finding could indicate increased inflammation in the sucrose group and decreased inflammation in the artificial sweetener group. However, changes in haptoglobin concentrations were positively correlated with changes in energy intake, which suggests that haptoglobin may respond to the body's energy flux rather than to the sucrose intake. However, it is not possible to reach a firm conclusion on this aspect because of the close covariation between energy and sucrose intakes.

Transferrin is a negative acute-phase protein, and a drop in transferrin concentrations therefore reflects increased inflammation. It was therefore contrary to the researchers' expectations that transferrin increased in the sucrose group and decreased in the sweetener group. Changes in transferrin concentrations were also positively associated with changes in energy intake, which could indicate that transferrin responds to the body's energy flux. Adjusting for changes in energy intake did not eliminate the difference between the two groups, in either haptoglobin or transferrin, although the differences became less significant. In conclusion, this study shows that, apart from causing weight gain and increasing blood pressure, a high consumption of sugar-sweetened drinks and foods may increase inflammatory activity in overweight subjects. This finding was independent of weight changes. The relative changes in inflammatory markers in the present study were small. Even though the between-group differences in haptoglobin and transferrin were statistically significant, it is doubtful that these differences are biologically important.

L. Sorensen, A. Raben, S. Stender, A. Astrup. Effect of sucrose on inflammatory markers in overweight humans. AJCN; 82(2):421-427 (August 2005) [Correspondence: L. B. Sorensen, Department of Human Nutrition, Centre for Advanced Food Studies, Royal Veterinary and Agricultural University, Rolighedsvej 30, DK-1958 Frederiksberg C, Denmark. E-mail: lbs@kvl.dk]