Brazzein ice cream roughly halved glucose spikes in 101 adults with fatty liver disease

We would expect any recipe without sucrose to lower the glucose rise after a 100-gram dessert ^[5]. A spike about half the size of the sugar version's ^[6] is the expected direction. What the trial has to show is how much of that drop comes from brazzein.

The researchers point out that sugar also gives ice cream its bulk and viscosity ^[12]. A sugar-free recipe has to make that up with other ingredients, and ScienceAlert reports that filler ingredients used with brazzein produced something very similar to the real thing ^[17]. Those other ingredients were in every brazzein serving the participants ate ^[7]. In their conclusion the team gives the credit to the whole recipe, not to the protein alone: "From a clinical nutrition perspective, the present findings indicate that the tested sucrose-free brazzein-containing formulations may warrant further investigation as potential sugar-substitution options for patients with MASLD, including those with type 2 diabetes," the researchers wrote ^[9].

The nearest the trial gets to testing a single ingredient is its third arm, which added the fibre inulin to brazzein ^[5]. That version also produced a spike about half the size of the sugar one's, much the same as brazzein without inulin ^[6]. ScienceAlert's account does not give the glucose values or the time window in which they were measured.

For a question about one serving, the design is a good one. The team, from Russia's Federal Research Center of Nutrition, Biotechnology and Food Safety, enrolled 101 adults with MASLD ^[3]. They ran a randomized, double-blind crossover ^[4], published in Clinical Nutrition ESPEN ^[1]. Each participant ate all three ice creams on separate days ^[5]. ScienceAlert notes that blood sugar responds to things as ordinary as who you eat with and how you eat ^[16]. In a crossover each person is compared with themselves ^[4]. That removes the differences between people, though not the differences between one day and the next.

Earlier work in mice suggested brazzein could replace sugar while keeping the sweetness ^[19]. This trial takes that idea into people, for one serving. In our view it is good evidence that a sugar-free brazzein ice cream lowers the immediate glucose rise in adults with MASLD. As evidence about brazzein itself, it is still thin. The authors' case for substitution rests on adherence, and we think that case holds for any sugar-free dessert people will keep eating, whatever sweetener is in it. "Extensive restriction of these products in the diet is often unrealistic and may lead to poor adherence to dietary recommendations," they wrote ^[13].