The Facts on Fructose

Despite sugar being in the news frequently, confusion remains about different sugar types and their metabolism in the body. The term ‘sugars’ includes glucose, fructose, lactose and sucrose, but fructose stands out due to claims that it may have specific detrimental health effects. This article will consider questions about fructose, providing answers supported by high-quality, peer-reviewed research.

Which foods contain fructose?

All fruits naturally contain sugars, including fructose. The total amount of fructose in a portion of fruit varies from 1-6 g for citrus fruits, around 7 g for pineapple, and 3-10 g for apples and pears depending on the variety. The fructose content of fruit juices reflects the composition of whole fruit. For example, 100 ml of orange juice contains 2.4 g fructose, while 100 g of whole orange contains 2.2 g of fructose.

What contributes the most fructose to the diet?

Dietary surveys from the UK, France and New Zealand suggest that daily fructose intakes are around 20 to 40 g, compared with 50 to 70 g in the USA. A significant source of fructose in the UK and France is whole fruit, followed by soft drinks containing sucrose (50% fructose). In general, 100% fruit juice contributes very little fructose to the diet. A 200 ml glass of 100% orange juice would provide 5 g of fructose daily, but average fruit juice intakes in Europe are less than 100ml per day.

Does fructose consumption affect disease risk?

There does not seem to be an association between fructose intake and conditions such as high blood pressure or diabetes. In fact, several studies on moderate fructose intakes (<50 g per day) have reported statistically lower blood glucose levels, markers of abnormal blood glucose control, diastolic blood pressure and reduced diabetes risk.

There’s slightly more evidence for negative effects on blood lipids, but only when fructose intake is much higher than habitual intakes. In general, studies of modest fructose intakes find neutral or positive effects of fructose on health markers.

Is there an association between fructose intake and body weight?

Studies considering the impact of fructose on body composition have not found any consistent evidence of harm when participants remain in energy balance (energy in = energy out) and fructose comes from natural sources, e.g., fruit or 100% fruit juice. In contrast, moderate amounts of fructose are associated with reduced risk of overweight and the impacts of fructose and glucose are the same under conditions of overfeeding, suggesting that excess calories are more important than sugar type.