Carbohydrates

Classification

Carbohydrates are classified based on the length and complexity of their Molecular Chains:

• Monosaccharides — basic units that cannot be further hydrolyzed. The main ones: Glucose (universal cellular fuel), Fructose (found in fruits and honey), Galactose (found in the lactose in milk).
• Disaccharides — two monosaccharides linked by a glycosidic bond. Sucrose (glucose + fructose), lactose (glucose + galactose), maltose (glucose + glucose).
• Oligosaccharides — short chains of 3–10 units. These include fructooligosaccharides (FOS) and galactooligosaccharides (GOS), which act as prebiotics in the colon.
• Polysaccharides — long chains consisting of hundreds or thousands of units. They can be digestible (starch, glycogen) or indigestible (dietary fiber).

Biological Functions

The primary function of carbohydrates is to provide Energy: glucose is the preferred substrate for ATP production through Glycolysis and the Krebs cycle. Under normal conditions, the Brain uses almost exclusively Glucose as an energy source, consuming about 120 g per day.

In the Muscles and Liver, Glucose in excess of immediate needs is stored as Glycogen —an energy reserve that can be readily mobilized during physical exercise or fasting.

Carbohydrates also perform Structural functions: they are components of Nucleic Acids (Ribose in RNA, Deoxyribose in DNA), membrane Glycoproteins, and structures such as Hyaluronic Acid — a Polysaccharide found in the extracellular matrix of Connective Tissues.

Glycemic Index and Glycemic Load

Not all carbohydrates have the same effect on blood sugar levels.The Glycemic Index (GI) measures the rate at which a carbohydrate-containing food raises blood glucose levels compared to pure glucose (reference value: 100).

High-GI foods (Refined Flours, simple Sugars) cause rapid spikes in blood Sugar levels followed by equally rapid drops. Low-GI foods (Legumes, Whole Grains, Vegetables) ensure a more gradual release of Glucose, with documented benefits for satiety control and Metabolic Management.

In the nutraceutical field, the selection of slow-release carbohydrates — waxy corn starch, low-DE maltodextrin, and isomaltulose — is important in the formulation of sports supplements for maintaining performance during prolonged exercise.

Dietary Fiber: The Non-Caloric Carbohydrate

Dietary fiber is the component of plant-based carbohydrates that resists enzymatic digestion in the small intestine. It reaches the colon intact, where it is fermented by the gut microbiome. It is classified as:

• Soluble Fiber (Pectin, Beta-glucans, Inulin, Psyllium) — forms a viscous gel in the intestine, slows the absorption of glucose and cholesterol, and promotes a feeling of fullness
• Insoluble Fiber (Cellulose, Hemicellulose, Lignin) — increases stool bulk, accelerates intestinal transit, and supports regularity

Fermentable soluble fiber—particularly inulin and FOS—serves as the nutritional substrate for intestinal probiotics: this is the mechanism of action underlying the term “prebiotics.” This connection makes fiber a key ingredient in the formulation of supplements for microbiome health.

Approved EFSA Claims

• Oat beta-glucans contribute to the maintenance of normal blood cholesterol levels
• Consumption of foods containing beta-glucans contributes to a reduction in the postprandial glycemic response
• Wheat fiber (arabinoxylan) helps increase stool bulk
• Consuming pectin with a meal helps reduce the postprandial rise in blood glucose

A high intake of dietary fiber in individuals who are not accustomed to it can cause bloating, flatulence, and bowel irregularities. Increasing dietary fiber intake should be done gradually and accompanied by adequate hydration. In cases of irritable bowel syndrome or gastrointestinal disorders, it is necessary to consult a doctor or dietitian before significantly altering fiber intake with specific supplements.

Always remember that it is important to consult a healthcare professional before starting any new supplement or treatment.