Cardiovascular responses to the ingestion of sugary drinks using a randomised cross-over study design: does glucose attenuate the blood pressure-elevating effect of fructose?

Abstract

Overconsumption of sugar-sweetened beverages has been implicated in the pathogenesis of CVD. The objective of the present study was to elucidate acute haemodynamic and microcirculatory responses to the ingestion of sugary drinks made from sucrose, glucose or fructose at concentrations similar to those often found in commercial soft drinks. In a randomised cross-over study design, twelve young healthy human subjects (seven men) ingested 500 ml tap water in which was dissolved 60 g of either sucrose, glucose or fructose, or an amount of fructose equivalent to that present in sucrose (i.e. 30 g fructose). Continuous cardiovascular monitoring was performed for 30 min before and at 60 min after ingestion of sugary drinks, and measurements included beat-to-beat blood pressure (BP) and impedance cardiography. Additionally, microvascular endothelial function testing was performed after iontophoresis of acetylcholine and sodium nitroprusside using laser Doppler flowmetry. Ingestion of fructose (60 or 30 g) increased diastolic and mean BP to a greater extent than the ingestion of 60 g of either glucose or sucrose (P, 0·05). Ingestion of sucrose and glucose increased cardiac output (CO; P,0·05), index of contractility (P,0·05) and stroke volume (P, 0·05), but reduced total peripheral resistance (TPR; P,0·05), which contrasts with the tendency of fructose (60 and 30 g) to increase resistance. Microvascular endothelial function did not differ in response to the ingestion of various sugary drinks. In conclusion, ingestion of fructose, but not sucrose, increases BP in healthy human subjects. Although sucrose comprises glucose and fructose, its changes in TPR and CO are more related to glucose than to fructose.

Cardiovascular responses to sugary drinks in humans: galactose presents milder cardiac effects than glucose or fructose

“…The interpretation of this study's data is, however, limited for several reasons: (1) a higher baseline value was observed for fructose (118-121 mmHg) than for glucose and galactose (111-114 mm Hg), which could hence contribute to the inability to demonstrate an increase in BP after fructose ingestion, (2) all of their subjects experienced watery diarrhoea after ingestion of fructose (1 g/kg), most of them within 40-60 min post-drink, (3) the consumption of a large distilled water preload (>1 L) 2 h before the sugary drinks may also be an interfering factor in the cardiovascular responses after the sugary drinks and (4) BP was monitored by discontinuous oscillometric method and measured only once every hour. In the current study, in which we performed continuous beat-by-beat measurement of BP in response to the sugary drinks, we are able to confirm the BP-elevating effects of fructose observed in two previous studies in our laboratory using a similar experimental protocol and sugar load (60 g in 0.5 L water) [16,17], namely a greater and sustained increase over at least 90 min in both SBP and DBP after fructose than after glucose ingestion. In these latter studies, glucose led to marginal or no increase in BP similar to that observed in the present studies after glucose and galactose.…”

“…Moreover, based upon our previous observations [16,21] that SBP tended to increase by a few mmHg over 1-2 h after a 0.5 L water load, our findings here of a small gradual increase in BP after glucose or galactose ingestion could be largely attributed to the water-load component of the sugar drinks rather than an effect of these sugars per se. Overall, in previous studies from our laboratory [16,17] and in the present study, the BP response to fructose was found to be significantly greater than that after glucose by 3-4 mmHg. Furthermore, no differences are observed here between galactose and glucose in BP, whether SBP, DBP or MBP, and unexpectedly the ingestion of galactose, compared to glucose ingestion, resulted in a lesser effect with marginal impact on HR, SV and CO.…”

“…By contrast, it has repeatedly been demonstrated that the ingestion of glucose and fructose drinks is characterized by specific haemodynamic responses in healthy young [16,17] and older people [18]. Unlike drinking glucose, which decreases total peripheral resistance by an insulin-mediated release of nitric oxide accompanied by a metabolic vasodilation leading to an increase in cardiac output (CO), thereby resulting in little or no change in blood pressure (BP), the ingestion of fructose elicits a significant increase in BP that results from a more modest increase in CO but without a decrease in TPR [16,17].…”

“…By contrast, it has repeatedly been demonstrated that the ingestion of glucose and fructose drinks is characterized by specific haemodynamic responses in healthy young [16,17] and older people [18]. Unlike drinking glucose, which decreases total peripheral resistance by an insulin-mediated release of nitric oxide accompanied by a metabolic vasodilation leading to an increase in cardiac output (CO), thereby resulting in little or no change in blood pressure (BP), the ingestion of fructose elicits a significant increase in BP that results from a more modest increase in CO but without a decrease in TPR [16,17]. These differential BP responses to glucose and fructose ingestion have been attributed to their differential effects on insulin secretion [17], and to the well-known effect of insulin not only in enhancing sympathetic activation of cardiac contractility (hence contributing to the increased CO) [19], but also in stimulating peripheral vasodilatation and hence decreasing TPR [20].…”

“…Unlike drinking glucose, which decreases total peripheral resistance by an insulin-mediated release of nitric oxide accompanied by a metabolic vasodilation leading to an increase in cardiac output (CO), thereby resulting in little or no change in blood pressure (BP), the ingestion of fructose elicits a significant increase in BP that results from a more modest increase in CO but without a decrease in TPR [16,17]. These differential BP responses to glucose and fructose ingestion have been attributed to their differential effects on insulin secretion [17], and to the well-known effect of insulin not only in enhancing sympathetic activation of cardiac contractility (hence contributing to the increased CO) [19], but also in stimulating peripheral vasodilatation and hence decreasing TPR [20]. In this context, the question arises as to whether ingestion of galactose, which like fructose has only a mild stimulatory effect on insulin release [12][13][14][15], would also lead to higher BP.…”