- Consumption of moderate amounts of specific types of sugar can double the production of fat in the liver.
- This in turn can lead to the development of fatty liver disease and type 2 diabetes.
- A recent study found that sucrose promotes fat synthesis slightly more than the same amount of fructose.
New research provides further evidence of the dangers of sugar intake and suggests that the intake of even moderate amounts of the substance may lead to a change in a person’s metabolism.
Researchers at the Medical University of Graz, Austria, and the University of Zurich and the University Hospital of Zurich, Switzerland, recently shared their findings in theJournal of Hepatology.
Some sugars are natural ingredients of fruits and vegetables. However, many of the processed foods we eat contain added sugars – sugars that the manufacturers add to food and beverages to enhance their taste or improve the appearance and texture of the food.
The high sugar intake has been linked to numerous health problems including type 2 diabetes, obesity, cardiovascular disease and cancer.
In 2015, the World Health Organization (WHO) advised people not to eat more than 5% of their daily calories from added sugar. For a diet of 2000 calories per day, this would amount to 100 calories or 6 teaspoons or about 25 grams (g) of added sugar.
In 2015, market research firm Euromonitor reported that the average person in the United States consumes more than 126 grams of sugar per day.
Meanwhile, the average person in the UK consumed 93.2 g.
Switzerland did not make the list of the ten best countries whose citizens consume the most sugar. Yet in 2015, the average person there consumed 76.1 g per day.
Authors of the study were interested in finding out what happens when people consume moderate amounts of added sugar.
For their work, which they performed between 2013 and 2016, they recruited 94 healthy male volunteers. The participants were 18-30 years old and had a body mass index below 24 kg / m2, which is considered a moderate weight.
The researchers selected participants under a certain weight to reduce the chance of recruiting people who may have already had an increased liver fat content.
Men who already drank sugary drinks daily or recorded more than 3 hours of physical activity per week were also excluded.
The researchers explained that they did not study women because there is evidence for divergent metabolic effects of fructose on male and female subjects. ‘
Indeed, a 2008 study reported that fructose ‘noticeably blunted’ causes metabolic effects on young female participants compared to males.
The researchers initially made the participants remember sugar-sweetened drinks for 4 weeks. The participants then started drinking sugary drinks with fructose, sucrose or glucose three times a day. A total of 80 g of each type of sugar was consumed daily.
A fourth group of participants was asked to continue the abstinence with sugary drinks.
To investigate how beverages with added sugar affected the individuals, the researchers used spores, these are substances that can be followed as it moves through the body.
Overall, the researchers found that the participants did not consume more calories than before the study. The authors assume that drinking sweet drinks increases the satiety of the participants, causing them to eat fewer calories from other sources.
The researchers also reported that although the participants consumed the same number of calories, their overall health had an effect on sugary drinks in their diet.
The participants who drank beverage sweetened with fructose had twice as high the production of fat as those who drank beverage sweetened with glucose, and those who did not remember sugar-sweetened drinks.
“This was still the case more than 12 hours after the last meal or sugar consumption,” says study leader, Dr Philipp Gerber from the Department of Endocrinology, Diabetology and Clinical Nutrition at the University of Zurich.
Fat that builds up in the liver leads to serious health issues, such as type 2 diabetes and non-alcoholic fatty liver.
A particularly surprising finding by the researchers was that sucrose, or table sugar – the form of sugar that most people consume – promotes fat synthesis slightly more than the same amount of fructose. So far, most scientists have believed that fructose is more likely to cause such changes.
Dr Gerber notes that the typical Swiss do not follow the WHO advice to limit their daily sugar consumption to 25 g. “Our results are a critical step in investigating the harmful effects of added sugars and will be very important for future dietary recommendations,” he says.
The scientists also note some limitations to their research.
They say that they had ‘little control’ over the compliance of the study participants and that they did not know their ‘gut ability’. In other words, if you do not know the participants’ individual tolerance to fructose, it can lead to variation in the results.