The present invention provides nutritional supplements consisting of an alginate hydrogel with sub-saturating amounts of calcium ions and comprising an aqueous solution comprising active ingredients, selected from sugars, complex carbohydrates, electrolytes, caffeine, and amino acids. The nutritional supplements allow for intake of carbohydrates without causing oral pH lowering and risk of dental caries, and without causing gastrointestinal discomfort while maintaining a high rate of intestinal uptake and oxidation of carbohydrates.
