The sweetener aspartame reduces body fat, but could be harmful to the heart and brain

A study conducted on mice has found that prolonged intake of sweeteners can have a detrimental impact on the function of these organs, even at low doses

The results obtained by CIC biomaGUNE and the Biogipuzkoa Health Research Institute suggest that current consumption guidelines should be revised

A study by CIC biomaGUNE and IIS Biogipuzkoa conducted on mice has found that prolonged consumption of sweeteners can have harmful effects on the function of various organs. Artificial sweeteners are widely used to reduce sugar intake and control body weight. Although these substances were initially thought to be beneficial to health, in recent years there has been growing concern that they may have adverse effects on cell and organ metabolism in the long term.

One of the most ubiquitous sweeteners, aspartame, is widely used in sweets, diet drinks, baked goods, chewing gum, etc. It produces a sweetness 200 times greater than sucrose, so it has a relatively low caloric value. Numerous studies have investigated the effects of aspartame; however, until now, its long-term metabolic and behavioural effects were unknown.

A study conducted by researcher Irati Aiestaran Zelaia, under the direction of Ikerbasque professors Jesús Ruiz Cabello, from CIC biomaGUNE, and Ian J. Holt, from IIS Biogipuzkoa, has evaluated the effects of long-term aspartame consumption in mice, exposing them for one year to a dose equivalent to one-sixth of the maximum daily intake recommended for humans.

The study concluded that ‘aspartame does indeed reduce fat deposits (by 20%) in mice, but it does so at the cost of mild cardiac hypertrophy and decreased cognitive performance,’ the research team said. These findings indicate that ‘while this sweetener may help achieve weight loss in mice, this is accompanied by pathophysiological changes in the heart and, possibly, in the brain,’ they add.

Very low doses

The daily dose of aspartame used in the study was 7 mg per kg of body weight in human equivalent units. “This dose is well below the maximum dose recommended by the World Health Organisation and the EMA (European Medicines Agency) and FDA (Food and Drug Administration, USA), which is 50 mg/kg per day. This highlights the importance of the results obtained in the study,” they point out. The study shows that prolonged exposure to artificial sweeteners can have a detrimental impact on organ function, even at low doses, suggesting that current consumption guidelines need to be critically reviewed.

This study, which examined the effects of aspartame intake over a whole year for the first time, helps to fill important gaps in knowledge about the consequences of long-term consumption and provides crucial information on the chronic effects of intake levels achievable through a normal diet. In fact, researchers at CIC biomaGUNE and IIS Biogipuzkoa point out that in the study ‘we have observed effects that had not been described until now, probably due to the difficulty and duration of the study’.

It should be noted that these results are supported by “a large amount of data of all kinds — functional imaging (magnetic resonance imaging), molecular imaging (positron emission tomography), spectroscopy in the brain and liver, cognitive tests, temperature, amount of food and drink, etc.—which have helped to elucidate the effects it produces in mice and will serve as a basis for reinforcing and expanding the conclusions of this study.”

The study is part of a series of investigations in which “we are observing how nutrient modulation affects organ function in health and disease, and in this case we set out to determine the physiological impact of aspartame on the heart and brain of mice, as well as the effects on fat levels and body weight, to compare them with other types of sugars and sweeteners,” they conclude.