Fructose substitution offers little impact on fasting blood glucose, insulin, triglycerides
Individuals with impaired glucose tolerance or type 2 diabetes (T2D) may benefit from the substitution of fructose for glucose or sucrose in food or beverages, suggests a systematic review and meta-analysis.
Researchers searched Medline, Embase, the Cochrane Library, the WHO International Clinical Trials Registry Platform Search Portal and clinicaltrials.gov until 26 April 2016 to review the evidence for a reduction in fasting glycaemic and insulinaemic markers after chronic, isoenergetic replacement of glucose or sucrose in foods or beverages by fructose.
Included were randomized controlled trials of isoenergetic replacement of glucose, sucrose or both by fructose in adults or children with or without diabetes. The trials lasted ≥2 weeks and measured fasting blood glucose (FBG). Main outcome measures included FBG and insulin, fasting triglycerides, blood lipoproteins and glycated haemoglobin (HbA1c) and body weight.
There were 14 comparison arms from 11 trials, involving 277 patients, included in the meta-analysis. The length of the studies varied from 2 to 10 weeks (mean 28 days), while doses of fructose were between 40 and 150 g/day (mean 68 g/day).
In some subgroups, substituting fructose led to significantly but only slightly lowered FBG (−0.14 mmol/L; 95 percent CI, −0.24 to −0.036 mmol/L), HbA1c (‒10 g/L; ‒12.90 to ‒7.10 g/L impaired glucose tolerance; ‒6 g/L; ‒8.47; ‒3.53 g/L normoglycaemia), triglycerides (‒0.08 mmol/L; ‒0.14 to ‒0.02 mmol/L) and body weight (‒1.40 kg; ‒2.07 to ‒0.74 kg).
No effect was seen on fasting blood insulin or blood lipids, according to researchers, adding that high-quality studies in individuals with impaired glucose tolerance or T2D are warranted.