It seems all sugar is not created equal. Research suggests that a high intake of fructose is associated with increased weight gain and metabolic problems such as insulin resistance (pre diabetes), high blood lipids and high blood pressure. While fructose is fruit sugar, this is no mandate to avoid fruit. In fruit and vegetables, fructose doesn’t pose an issue as it comes with nutrients and fibre. The issue with fructose comes with high intakes and from foods that give little nutritional value.
While just about every single cell in our bodies uses glucose for energy, fructose can only be processed in the liver. Some of the end products of this is the formation of triglycerides (a type of fat) uric acid and free radicals – all of which can have negative effects in the body.
When released into the blood stream triglycerides can contribute towards the build up of fatty plaques in the arteries, gradually narrowing the arteries and reducing blood flow. Over time this can lead to stroke and heart attack. In the liver, triglycerides can build up and impair liver function. Uric acid can turn off the production of a substance which helps prevent our arteries from damage and free radicals cause oxidative damage to our cells.1 It is thought this is the reason why a high intake of fructose is linked to metabolic problems.
It’s not all bad news. Fructose does have some positives however. Research suggests that some fructose before a meal can help reduce appetite when eaten before a meal, and fructose has a lower glycemic index than other sugars.
A moderate intake of fructose doesn’t seem to be harmful – an intake of less than 50g/day or at ~10% of energy, research has shown that fructose has no negative effects on lipid and glucose control and an intake of less than 100g/day does not influence body weight.2
Fructose is a part of table sugar, found in high fructose corn syrup and many processed foods and beverages. The key is to reduce overall sugar intake – and keep your sugar intake to sources that provide good nutrition as well.
1: Rizkalla, S Is Fructose Bad For You? Harvard University Health Blog – accessed here
2.Rizkalla, S. (2010) “Health Implications of Fructose Consumption: A Review of Recent Data – A Review of Recent Data” by Salwa Nutrition and Metabolism, volume 7 2010 – via Web MD see here for article