Foods rich in fructose
Fructose is a very widespread monosaccharide in free form in fruit, honey and vegetables. Carrots, figs, plums, peppers, courgettes, bananas and apples are particularly rich in it. Many sugary drinks, soft drinks, sweets and industrial products enriched with fructose-glucose syrups are also abundant in fructose.
In addition to its free form, fructose in foods can also be associated with other sugars or fructose molecules:
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when combined with a glucose molecule, it gives rise to sucrose, which represents the white crystalline disaccharide extracted from beet or sugar cane commonly used as "table sugar"; specific enzymes located in the brush border provide for the digestion of sucrose, separating fructose from glucose, which are then absorbed in free form;
- if polymerized in long chains through β-2,1 bonds, it forms inulin, a component of the soluble fiber which is NOT digestible for man but still useful for the functioning of the intestine (thanks to the PREBIOTIC function against Bifidobacteria physiological). Fiber, therefore, does not represent a bioavailable source of fructose.
Functions and metabolism
Fructose is a sugar which, at low blood concentrations, boasts a certain "independence" from insulin, the anabolic hormone essential for the transport of glucose, amino acids and many other molecules from the blood into tissues (with the exception of the nervous one and a few others).
