We reach the end of a cone and often find ourselves with a tense stomach. Simple impression, perhaps triggered by feelings of guilt? Not exactly, at least sometimes, because some ice creams really swell more, and there’s not just one reason: it actually depends on what’s inside, and above all on the amount of air.
The air you don’t see: the overrun
The first factor is the least intuitive. Industrial ice creams contain a variable amount of air incorporated during processing, measured as a percentage of the so-called overrun: an overrun of 100% means that half of the final volume is composed of air bubbles. Precisely on the topic in question, we can mention the American FDA, which regulates ice cream pursuant to 21 CFR 135.110. According to these regulations, part of the “Standards of Identity” for foods, ice cream must contain at least 10 percent milk fat, no less than 1.6 pounds total solids per gallon, at least 20 percent milk solids, and weigh at least 4.5 pounds per gallon. These requirements effectively set a ceiling on overrun: adding too much air would cause the weight to drop below the legal threshold. Premium ice cream typically has an overrun of less than 30%, while cheap ice cream often exceeds 80%.
When we eat high overrun ice cream we are physically ingesting more air, which ends up straight in the stomach and contributes to the typical feeling of bloating, especially if eaten quickly. Be careful, this is not bacterial fermentation, but a mechanical aspect, in which it takes longer to expel the air trapped in the abdomen. Homemade ice creams and industrial premiums, which are denser, tend to swell less for this very reason.
Lactose: the main problem
For most people, lactose is the real culprit. Lactose intolerance has a global prevalence estimated at around 57% with instrumental methods, while the real prevalence exceeds 65%. The absence of lactase (enzyme produced by the human intestine responsible for the digestion of lactose) determines an excessive osmotic load in the small intestine and the fermentation of lactose by the bacterial flora, with consequent production of short-chain fatty acids and gas, responsible for abdominal pain, bloating and flatulence.
In practice, those who do not produce enough lactase poorly digest the lactose present in milk and cream. The unabsorbed lactose reaches the colon, where bacteria ferment it, producing hydrogen, methane and carbon dioxide. The result is swelling, cramps and in some cases diarrhea, with intensity proportional to the quantity consumed and the degree of individual intolerance.
Not all flavors contain the same amount of lactose. For example, sorbet fruit ice creams, water-based flavors and those prepared with vegetable milk are free of it. On the contrary, flavors such as stracciatella, cream, panna cotta and hazelnut, rich in whole milk and cream, have a significantly higher lactose content than, for example, a lemon sorbet. The difference is not marginal and explains why the same person tolerates certain tastes well and feels bad with others.
Sugars: not all the same for the intestine
The quantity and type of sugars affect differently. Common sucrose is generally well absorbed, more problematic are FODMAPs, the fermentable carbohydrates that the intestine struggles to absorb. These include fructose when it is present in quantities greater than glucose, a frequent condition in industrial syrups and in some natural fruit flavourings. The small intestine has limited transporters for fructose: when more fructose arrives than it can handle, the excess reaches the colon, where bacteria ferment it, producing gas.
Flavors with glucose-fructose syrup, mango, apple and pear among the ingredients may be more problematic for those with a FODMAP sensitivity than flavors with simple sugar and classic flavors such as vanilla and dark chocolate.
Sweeteners: the case of sorbitol and other polyols
“Sugar-free”, “light” and/or diabetic ice creams often contain polyol sweeteners, such as sorbitol, xylitol, maltitol and erythritol, which are partially absorbed in the small intestine; the unabsorbed portion reaches the colon where it is fermented, with laxative and swelling effects. The study published on Gastroenterology by Hyams and colleagues, still cited today in the sector literature, is one of the classic references: the majority of subjects experienced mild gastrointestinal disorders (gas and bloating) after 10 grams of sorbitol and serious symptoms (cramps, diarrhoea) after 20 grams. The source is available on PubMed. A systematic review published in Advances in Nutrition in 2017 (Lenhart & Chey) further confirmed that polyols, consumed in even moderate quantities, produce gastrointestinal effects in a significant portion of the population, with individual variability linked to the composition of the intestinal microbiota. The study can be consulted on PubMed Central.
What to do in practice
Post-freeze swelling therefore has distinct causes which can be divided as follows:
Often, as mentioned at the beginning, swelling is caused by a combination of the aforementioned factors.
If you have recurring problems, move towards water-based sorbets and ice creams prepared with vegetable milk, read the label under sweeteners and try to choose flavors with simple sugar and few additives
