The effects of apples and apple juice on acute plasma uric acid production and satiety: a randomised controlled trial

Abstract

Background: It has been suggested that fructose from natural sources including fruit and fruit juice behaves differently in the body than added fructose from processed foods. Furthermore, there is inconclusive evidence regarding whether whole fruit and fruit juice differ in their ability to satiate, and their effects on appetite post consumption.

Methods: We conducted a randomised controlled crossover trial, with 64 healthy young adults. The three arms of the study included the consumption of whole Royal Gala apples, 100 % New Zealand apple juice, or a control beverage of glucose or fructose in solution. Mean change in acute uric acid concentration and incremental area under the curve were measured at baseline, and then 30 and 60 minutes post food consumption. Satiety ratings from apple and apple juice were measured using visual analogue scales at baseline, 30 and 60 minutes post consumption.

Results: We observed a significant difference in plasma uric acid concentration for all three foods at 30-60 minutes, except the glucose monosaccharide beverage. No significant difference existed between the uric acid increase from apples (P=0.286) or apple juice (P=0.132) and the fructose beverage. However, the apple juice and fructose beverages displayed a greater rate of increase than whole apples. Some measures of appetite were significantly different between the solid and liquid foods during the first 30 minutes, with whole apple more satiating than apple juice.

Conclusions: Fructose control, whole apple and apple juice displayed the same plasma uric acid raising potential. These findings suggest the body treats fructose as fructose, independent of the food source. Whole apples were more satiating than apple juice, providing evidence for the consumption of whole fruit to be encouraged over fruit juice.