Fructose

Fructose is a sugar that does not require digestion and absorbs quickly in the stomach and upper intestine, causing a powerful stimulant to insulin, similar to pure glucose 1. However, its fructose component has a mild insulin-inhibiting effect, providing sugar energy more gradually than starch and avoiding the glucose-insulin-hypoglycemia stress reaction 1. Fructose is found in fruits, which contain approximately the same ratio of fructose and glucose as white sugar, half fructose and half glucose 2. In contrast, other sources of carbohydrates like grains, beans, starches, bread, pasta, and potatoes are almost all glucose and devoid of fructose 2.

Fructose has several beneficial effects, including enhancing the production of carbon dioxide, which is integral for delivering oxygen to tissues and supporting oxidative energy 3. It can also be used for oxidative energy when glucose cannot, and is excellent at restoring liver glycogen 3. Additionally, fructose has been shown to be cytoprotective against cyanide and can protect liver cells in a low oxygen environment 7. Fructose has also been used in diabetics for decades as a small supplement to help bring down their blood sugar, and is effective in hypoglycemia because it helps to regulate insulin production and slowly turns into glucose 6.

The universally negative view of fructose appears to be an outgrowth of the draconian view of cholesterol, and fructose is actually the most effective carbohydrate for supporting oxidative mitochondrial metabolism 7. In contrast, glucose has been shown to increase the generation of reactive oxygen species and inflammatory markers, while fructose has been shown to lower serum phosphate and decrease its absorption from the intestine 5.