Fructose

What is fructose?

Fructose is a low glycemic simple sugar (monosaccharide) used by the body as a source of energy and is one of the three most important blood sugars along with glucose and galactose. Fructose is a naturally occurring sweet sugar (twice as sweet as sucrose). Fructose is found naturally in combination with sucrose or glucose in honey, fruits mainly melons and berries, root vegetable such as sweet potatoes, beets, onions and parsnips. Sucrose is a disaccharide consisting of glucose and fructose and fructose can also be derived from sucrose by digestion. The low glycemic index of fructose can be attributed to its structure (5-member hemiketal ring) and lengthy and unique metabolic pathway that involves multi-step enzymatic process in the liver.

However fructose when given alone in pure form increases blood glucose levels in a similar amount of glucose. Pure crystalline fructose has a fruity aroma and tastes similar to cane sugar.

GULT-5 transporter is required for the absorption of fructose in the body; in case of its deficiency excess fructose is carried in to the lower intestine and acts as a nutrient for existing gut flora. This results in fructose malabsorption, bloating, loose stools, excessive flatulence and even diarrhea depending on the amounts consumed and other factors. Excess consumption of fructose is been related to obesity (central obesity), elevated triglycerides and LDL cholesterol levels that can ultimately cause metabolic syndrome. Unlike glucose fructose is processed in the liver, when amount of fructose exceeds the limit of the liver to process it, the excess of it is converted to fat and transported in the blood stream as triglycerides. Moreover the excess consumption can be due to the fact that the calorie from fructose does not make a person feel satisfied. This is a possible reason why fructose is related to weight gain. Dietary fructose is often avoided if plasma triglyceride levels are a risk factor for cardiovascular diseases.

High fructose added in the processed products is due to the easy accessibility and inexpensive high fructose corn syrup. Studies show that high fructose corn syrup has similar properties to sucrose and have essential identical physiological effects. Fructose also chelates minerals like copper, zinc and chromium in the blood. Since these micronutrients are present in small quantities, chelating effects may lead to deficiency disorders, immune system impairment, fructose intolerance or even insulin resistance (a major factor for type-2 diabetes).

These effects of fructose doesn’t happen with consumed in normal amounts in natural form that is fruits and vegetables, but the problem occurs when the consumption exceeds the limit which body can handle.

Submitted on January 16, 2014