Sugar-rich diets have a negative impact on health, but not only because of the relationship between sugar consumption and obesity, but for a different reason. A study led by the MRC London Institute of Medical Sciences (UK) and the Kiel University (Germany) has found that the lower survival of fruit flies fed a diet rich in sugar It is not the result of your diabetic-type metabolic problems.
The findings, published in the journal Cell Metabolism, suggest that premature death from excess sugar is related to the accumulation of a natural waste product, uric acid.
We all know that consuming too much sugar is not healthy. Increases our risk of developing metabolic disorders, such as obesity and diabetes, and can shorten our life expectancy by several years. And although this reduction in life expectancy is believed to be caused by metabolic defects, the new study reveals which may not be the case.
“Like humans, flies fed a high sugar diet show many characteristics of metabolic disease, for example, become resistant to grease and insulin, ”says Helena Cochemé, principal investigator of the study. “Obesity and diabetes are known to increase mortality in humans, so it has been added that this is how excess sugar is detrimental to the survival of flies.”
However, as salt, sugar also causes dehydration. In fact, thirst is an early symptom of blood sugar and diabetes. «Water is vital to our healthBut its importance is often overlooked in metabolic studies. Therefore, we were surprised that flies fed a high sugar diet did not show a reduction in their life expectancy by providing them with drinking water, although they still had the typical metabolic defects associated with a high content of sugar in the diet ».
For this reason, the team decided to focus in the kidney system of the fly. They showed that excess sugar in the diet made flies accumulate uric acid. Uric acid is a final product of the decomposition of the purines, which are important building blocks in our DNA.
But uric acid is also prone to crystallize, leading to kidney stones in the fly. Researchers could prevent these stones, either by diluting their formation with drinking water or blocking uric acid production with a medicine. This in turn protects against the shortened survival associated with a high sugar diet.
So, Does this mean we can eat all the sugary treats we want, as long as we drink plenty of water?
“Unfortunately not,” says Cochemé. “Sugar-fed flies can live longer when we give them access to water, but they are still not healthy. And in humans, for example, the obesity increases the risk of heart disease».
However, he adds, “Our study suggests that Disruption of the purine pathway is the limiting factor for survival in flies fed high sugar content. This means that premature death Sugar is not necessarily a direct consequence of obesity itself. “
To understand the impact of sugars in the diet on human health, the collaborators of the Kiel University explored the influence of diet on healthy volunteers. “Surprisingly, like flies, we found that dietary sugar intake in humans was associated with worse kidney function and higher levels of purine in the blood “, says the professor Christoph Kaleta, co-author of the study.
Uric acid accumulation is a direct cause of kidney stones in humans, as well as gout, a way of inflammatory arthritis. Uric acid levels also tend to increase with age and can predict the onset of metabolic diseases such as diabetes. “It will be very interesting to explore how our fly results translate into humans and whether the purine pathway also contributes to regulating human survival,” concludes Cochemé.
“There is substantial evidence that what we eat influences our life expectancy and our risk for age-related diseases. By focusing on the path of purines, our group hopes to find new therapeutic targets and strategies that promote healthy aging ».