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food for thought

Last week, the World Health Organization released a new guideline on non-sugar sweeteners (NSS), warning against their use for weight loss or for preventing unhealthy weight gain.

Based on a comprehensive evidence review, the organization concluded that NSS offered no long-term benefit for reducing body fat in adults and children.

What’s more, the findings suggested that consuming these sweeteners over the long-term could have unwanted health effects.

Here’s a rundown of the WHO guideline, plus tips for reducing sweeteners in your diet.

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What are non-sugar sweeteners?

NSS, also called high-intensity sweeteners, low- or no-calorie sweeteners, non-nutritive sweeteners and sugar substitutes, are found in thousands of pre-packaged foods and beverages and many are also sold as tabletop sweeteners.

This group of sweeteners includes synthetically made chemicals (e.g., aspartame, sucralose, acesulfame potassium, saccharin, cyclamates) as well as natural extracts (e.g., stevia, monk fruit, sugar alcohols) which may or may not be chemically modified.

Because they impart a sweet taste without the calories of free sugars, they’re typically marketed for weight control. They are also used to help manage blood sugar levels.

What the evidence showed

To develop the new guideline, a panel of international experts reviewed 238 studies, including randomized controlled trials and observational studies, that were conducted in adults, children and pregnant women.

These studies investigated the relationship between NSS and the risk of overweight and obesity, dental caries, type 2 diabetes, cardiovascular disease, death from cardiovascular disease, chronic kidney disease, cancer and cancer death.

Evidence from randomized controlled trials, most of which lasted three months or less, showed that, overall, adults with higher intakes of NSS (versus less or none) had lower body weights. However, these effects were observed only in trials that compared intakes of NSS to free sugars, meaning that weight loss may have been due, in part, to a reduction in calorie intake.

Results from longer-term trials, lasting six to 18 months, did not suggest that consuming NSS led to weight loss.

Evidence from observational studies that followed adults for up to 10 years found that higher intakes of NSS were linked to an increased risk of obesity. Higher intakes from diet drinks and tabletop sweeteners were also associated with a greater risk of type 2 diabetes.

The findings from observational studies also suggested that higher intakes of NSS were tied to a heightened risk of cardiovascular disease, stroke and hypertension.

Evidence from studies conducted in children and pregnant women was more limited than that for adults.

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The WHO’s bottom line

Based on these findings, the WHO recommends that children and adults, including pregnant women, not use NSS as a means of weight control or reducing the risk of diet-related chronic disease.

The evidence doesn’t demonstrate that doing so produces these benefits over the long-term.

The WHO’s recommendation is not intended for people with diabetes as the included studies did not assess the use of NSS for managing blood glucose.

The new guideline is considered “conditional” meaning that the overall certainty of the evidence is low. It’s possible, for example, that people with higher intakes of NSS may have used them to control existing overweight or elevated blood sugar.

The guideline is intended for government health organizations who may consider WHO’s recommendation when developing public health policies around NSS.

How non-sugar sweeteners may harm

There are proposed ways in which NSS could cause the negative health effects seen in observational studies.

Experimental research conducted in rodents, and confirmed in humans, showed that certain artificial sweeteners altered the composition of the gut microbiome in a direction that lead to glucose intolerance.

Studies in rodents have also demonstrated that zero-calorie sweeteners don’t activate the brain’s reward centre, which regulates energy intake and appetite, the same way sugar does. When sweetness and calories are mismatched, the brain is tricked, leading to increased food consumption.

The regular consumption of NNS may also promote a preference for intensely sweet foods.

Reduce sweetness in your diet

It’s wise to limit your intake of added sweeteners of any kind.

Replace artificially-sweetened and sugar-sweetened soft drinks with water or unsweetened flavoured carbonated water.

Replace flavoured yogurt with plain yogurt; sweeten it with fresh fruit. If you desire something sweet after a meal, satisfy your craving with naturally sweet fruit.

Train your taste buds to prefer a less sweet taste. Gradually reduce the amount of sweetener you add to coffee, tea, oatmeal and other foods. Once you’re used to a lower level of sweetness, cut back some more.

Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan. Follow her on Twitter @LeslieBeckRD