Table 4 Contraindicated excipients in HFI patients

Elderberry syrup

Flowers and elderberry fruits contain sugars, including mainly fructose and glucose with less sucrose [29].

Fructose

Monosaccharide. It is metabolised through aldolase B, the deficient enzyme in HFI.

Honey

Natural sweetener with 75% carbohydrates, of which fructose is the main sugar (38%). It also contains glucose (31%) and maltose or sucrose (< 5%)

Invert sugar

A mixture of glucose and fructose in equal parts.

Isomaltitol, isomalt

A mixture of polyalcohols: sorbitol ≤ 6%, mannitol ≤ 3%, maltitol and glucose-mannitol. The disaccharides are hydrolysed in the intestine in small quantities (approximately 10%), and the sorbitol released is only partially absorbed; the rest is degraded by the gut microbiota [23].

Maltitol, maltitol syrup, Lycasin, hydrogenated glucose syrup

Polyalcohol: glucose-sorbitol disaccharide. Glucose and sorbitol are hydrolysed in the intestine (approximately 40%), but the sorbitol released is only partially absorbed; the rest is degraded by gut microbiota [23].

Raspberry syrup

Concentrated raspberry syrup contains fructose.

Sorbitol, sorbitol syrup

Polyalcohol. The 25% absorbed in the intestinal tract is converted into fructose by sorbitol dehydrogenase.

Sorbitol esters

Esters are hydrolysed to fatty acids and sorbitol anhydrides in the gastrointestinal tract (the proportion will depend on the type of ester, vehicle, etc.) [30, 31].

Sucrose, sugar, saccharose, simple syrup (oral)

Fructose and glucose disaccharide. In the small intestine, the linkage is hydrolysed by glucosidase, and the released fructose is absorbed.

Sucrose esters

Esters are hydrolysed at a proportion of 70–80% in the human gastrointestinal tract, releasing sucrose [32].

Thyme syrup

Syrup with an unknown composition.