CIC bioGUNE research finds the propensity to consume sugar in a genetic anomaly

Recent research has found that individuals with a genetic abnormality in the digestion process eat less cakes, sweets and chocolate, which could be crucial in assisting the general population to reduce sugar consumption.

The international study, published in the journal Gastroenterology, reveals that genetic alterations in the sucrase-isomaltase (SI) gene are linked to consumption and preference for foods high in sucrose.

An international team of scientists has found that mice lacking the sucrase-isomaltase (SI) gene have a reduced intake and preference for sucrose in the diet, a rapidly developing tendency linked to an inability to regulate appetite hormones. This has been confirmed in large population-based cohorts, which have shown that people with genetic defects in sucrose digestion consume less cakes, pastries, candy and chocolate, and prefer foods less as their sucrose content increases.

The work provides new genetic insights into dietary preferences and opens up the possibility of targeting the SI gene to selectively reduce sucrose intake at the population level.

The study was led by Dr Peter Aldiss, now at the University of Nottingham Medical School, together with co-lead authors Ikerbasque Research Professor Mauro D’Amato from CIC bioGUNE – a BRTA member – and LUM University, and Dr Mette K Andersen from the Novo Nordisk Foundation Centre for Basic Metabolism Research.

The group of specialists began studying feeding behaviours in mice without the SI gene, experiencing a rapid decrease in intake and an inclination towards sucrose. This was corroborated in two large population groups including 6,000 people in Greenland and 134,766 in the UK Biobank.

The team adopted a nutrigenetic approach to understand how genetic variation in the SI gene impacts sucrose intake and preference in humans. Surprisingly, individuals in Greenland with a complete inability to digest sucrose consumed significantly less sucrose-rich foods, while people in the UK with a defective and partially functional SI gene showed less preference for these foods.

Dr Aldiss says: ‘Excess calories from sugar are a proven contributor to obesity and type 2 diabetes. In the UK, we consume between 9% and 12% of our dietary intake in free sugars, such as sucrose, and 79% of the population consume up to 3 sugary snacks a day. Our study suggests that genetic variation in our ability to digest sucrose may impact not only how much we eat, but also how much we like sugary foods, thus opening up the possibility of targeting the SI gene to selectively reduce sucrose consumption at a population level.’

‘We continue to expand our understanding of the relevance of sucrase-isomaltase to people’s health, as we had previously shown that defective forms of this gene also affect the risk of irritable bowel syndrome (a common functional disorder affecting up to 10% of the population) and the response to its dietary treatment with carbohydrate-reducing diets,’ highlights Prof D’Amato.

In the future, understanding how defects in the SI gene act to reduce intake and preference for sucrose in the diet will facilitate the development of new therapies to help reduce sucrose consumption at the population level and improve digestive and metabolic health, the authors concluded.