Artificial sweeteners, which duplicated the sweet taste of sugar without the calories, emerged as an alternative to added sugar, which is deservedly considered as a public health hazard in view of its well established links in causing weight gain, diabetes and heart disease. This strategy is so successful that, in a survey conducted between 2009 and 2011, 25.1% of children and 41.4% of adults in the US reported consuming these products, a marked increase compared with its use two decades before. Furthermore, the industry is poised to have a 5% annual growth.

An extensive number of brands worldwide contain these food additives, especially ultra-processed foods such as artificially sweetened beverages, some snacks and low calorie ready-to-go meals and dairy products. Besides, artificial sweeteners are also directly used by consumers as table top sweeteners instead of sugar. The main types of these include saccharin, sucralose, aspartame, acesulfame-K, and stevia, and are considered to be neutral from the health point of view, as they are presumed to be inert and calorie free.

The safety of artificial sweeteners is debatable and study findings remain divided about their role in the cause of various diseases. But in the absence of strong evidence linking it directly with negative health outcomes and lack of  a clear mechanism demonstrating how “metabolically inert” substances can affect human metabolism, consumption of these products is still widely endorsed by clinicians and dietitians for adults, although a more cautious approach has been lately recommended for children.

However,  evidence has emerged which strongly questions the neutral health credentials of artificial sweeteners in a study published in the highly respected British Medical Journal, involving close to 100,000 adults in France, who regularly consume artificial sweeteners predominantly as soft drinks with no added sugar or table top sweeteners. These subjects were followed for an average of nine years. In this large scale, prospective study of French adults, artificial sweeteners (especially aspartame, acesulfame potassium and sucralose) were associated with an increased risk of heart disease and stroke. In a parallel study looking into how a seemingly metabolically inert product such as artificial sweeteners can cause these diseases has found scientific evidence pointing to the human gut microbiome as the likely link to transmit the adverse impact of these chemicals to our bodies. Similarly, other “modern” food additives such as dietary emulsifiers, food preservatives and colorants have been suggested to impact the gut microbiome.

The human gastrointestinal tract harbours trillions of microorganisms that play a critical role in multiple aspects of the functioning of our bodies. There is increasing evidence that disharmony with our gut microbiome may have a role in triggering off many diseases including heart disease and cancer. But, interestingly, the assemblage of microorganisms varies between individuals, leading to differences in how we respond to a particular diet.  Artificial sweeteners appear to modify our gut microbes in a way that mirrors the metabolic perturbations as those caused by regular sugar consumption thereby accounting for its negative impact on health.

The findings indicate that these food additives, consumed daily by millions of people and present in thousands of foods and beverages, should not be considered a healthy and safe alternative to sugar, in line with the current position of several health agencies. These results should not be interpreted as calling for the consumption of sugar, which is strongly linked to cardiometabolic diseases.