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As a Canadian dietitian who works and lives in the United States, I like to keep up with health policy in both countries. So, I was quite interested to see that Health Canada, the governmental agency responsible for public health, is charting a new course when it comes to dietary advice, particularly in the area of sugar substitutes. It’s a track that sharply diverges from the one the United States is on.

In a significant departure from the past as well as from the U.S. approach, Canada’s new food and dietary guidelines, released this year, say zero-calorie or low-calorie sugar substitutes are neither necessary nor helpful. “Sugar substitutes do not need to be consumed to reduce the intake of free sugars,” the guidelines say, adding that, because “there are no well-established health benefits associated with the intake of sweeteners, nutritious foods and beverages that are unsweetened should be promoted instead.”

In contrast, the 2015-2020 Dietary Guidelines for Americans (DGAs), issued by the U.S. Agriculture and Health and Human Services departments, suggest sugar substitutes may have a place in helping people consume fewer calories, at least in the short term, though “questions remain about their effectiveness as a long-term weight management strategy.” The guidelines neither encourage nor discourage their usage.

The differences may seem subtle, but dietary guidelines in each country shape what is served at public institutions such as schools and influence the recommendations made by health-care professionals. Language matters. But before we try to explain the difference in advice, let’s have a quick primer on sugar substitutes.

What are sugar substitutes?

Sugar substitutes include many categories, such as high-intensity sweeteners that are at least 100 times as sweet as sugar. They can be “artificial,” such as aspartame and saccharin, or “natural,” such as stevia and monk fruit. They can contain a negligible number of calories or be classified as low-calorie sweeteners, such as sugar alcohols.

In much of the research and in most policy documents, sugar substitutes are often discussed as a single category rather than a heterogenous group of compounds. This makes it challenging to know whether certain types are preferable.

Most concern seems to focus on artificial sweeteners. Six are approved by the U.S. Food and Drug Administration as ingredients in foods and drinks and as table sweeteners people can add themselves. The most ubiquitous is aspartame (sold as brand names NutraSweet or Equal), which is found in more than 6,000 food products, followed by sucralose (Splenda), acesulfame K (Sweet One or Sunett) and saccharin (Sweet’N Low or Sugar Twin), and the lesser-known neotame and advantame. You’ll find artificial sweeteners in a range of foods and drinks, including light yogurt, diet sodas, protein bars and chewing gum as well as baked goods and frozen desserts. Carbonated drinks are the top source of artificial sweeteners in the American diet.

What does the research say?

Research suggests that stevia and monk fruit, the natural sugar substitutes, are safe for human consumption, though it’s not clear that they lead to weight loss. There has been conflicting research, however, about the safety of artificial sweeteners. Some studies have suggested that artificial sweeteners could increase the risk of Type 2 diabetes, heart disease, kidney disease and cancer, and may have a negative influence on the microbiome and mental health.

For example, research based on data from 37,716 men from the Health Professional’s Follow-up study and 80,647 women from the Nurses’ Health study published in Circulation last month found that consuming artificially sweetened beverages is associated with a greater risk of death as well as death from heart disease. The risk was found specifically for women consuming four or more servings of artificially sweetened beverages a day. The authors say this finding needs to be confirmed by future research, but it does raise questions about whether artificial sweeteners are necessary — or should be recommended at all.

As for the U.S. contention that sugar substitutes might help people cut back on calories and sugar to improve their health or lose weight — that seems doubtful.

A review by the nonprofit research foundation Cochrane, conducted for the World Health Organization, examined 56 studies into the effects of sugar substitutes on health. It found that there is no evidence sugar substitutes provide any benefit — and that they may even have some risks.

An analysis of U.S. dietary intake from 2003 to 2004 shows that people tend to add artificial sweeteners to their diets rather than using them to replace sugary foods and beverages.

The same seems to be true for children. This month, research published in the Pediatric Obesity journal revealed that in U.S. children, drinking artificially sweetened beverages is associated with consuming more calories and sugar.

Why the difference in advice?

U.S. and Canadian health officials are looking at the same research and have populations with similar health issues. So why the difference in guidelines regarding sugar substitutes?

The new Canadian approach seems to be that if a food or beverage doesn’t have a demonstrated health benefit, it doesn’t belong in your diet. Their 2019 guidelines suggest that people’s taste buds will adapt to less-sweet tastes when they reduce their consumption of sweetened foods and beverages — and using high-intensity sweeteners delays that process.

This is a marked change from Canada’s last dietary guidelines, released in 2007, which advised the general population to consume sugar substitutes in moderation and cut back on them if they noticed any digestive symptoms such as gas and bloating.

The new Canadian recommendations may seem tougher, but I see them as being clearer and something for people to aspire to. (Canada’s latest Food Guide takes a stand on several other divisive nutrition issues. For example, it promotes whole grains as the only grains to put on your plate, while the U.S. guideline is that at least half your grains be whole grains.) The U.S. view seems to be focused on encouraging health behaviors that are thought to be more achievable.

Alice H. Lichtenstein, a professor of nutrition science and policy at Tufts University and member of the 2015-2020 DGA committee, seems skeptical of an all-or-nothing approach to sugar substitutes. She expressed her stance in an editorial in Circulation, responding to the study that said consuming artificially sweetened beverages is associated with a greater risk of death. “To a certain extent, as a community, we can take the high road about beverage recommendations: Drink water (or flavored water) in place of [sugar-sweetened beverages]. However, continuing this simple approach would be disingenuous because we know that it has not worked well in the past and there is little reason to expect that it will work well in the future.”

Over email, Lichtenstein said: “For some people, I suspect the use of high-intensity sweeteners is helpful in avoiding excess energy intake. For others, it might not be helpful.”

A 2018 advisory from the American Heart Association also takes a more middle-ground approach to sugar substitutes than Canada’s, stating that they can play a role in helping people to reduce the amount of sugar-sweetened beverages they’re drinking. The advisory also says that beverages containing low-calorie sweeteners could be especially useful for people who are used to sweetness and find water unappealing at first.

For insight, I turned to Marion Nestle, a renowned American author and professor emerita of nutrition, food studies and public health at New York University. She said over email: “What we know about artificial sweeteners is for sure that they are not necessary. On a population basis, they do not seem to help people lose weight, but they may help some individuals. So, both approaches are valid. Personally, I follow a food rule not to eat anything artificial, so these sweeteners are off my dietary radar.”

When I asked what she thought was the reasoning behind the differing approaches to sugar substitutes taken by the U.S. and Canadian governments, she responded, “One can only speculate that the lobbying for artificial sweeteners worked better in the U.S. than in Canada.”

Whatever the reason for the disparate approaches, I found one hint that the viewpoint in the United States might be changing. Last month, the American Diabetes Association released a Nutrition Consensus Report that recommends that water replace sugar-sweetened beverages. If sugar substitutes are used, the report says, people should receive nutrition counseling to help them avoid replacing the calories and carbohydrates with food.

The authors also note that any proposed advantages to sugar substitutes haven’t been proven, and that there could be potential adverse effects, such as impacts on hunger, confusion around calorie intake and the possibility that use of sugar substitutes could be replacing healthier options.

Could the United States be slowly shifting its guidance around sugar substitutes, including artificial sweeteners? The approaching 2020-2025 DGAs will let us know.

Christy Brissette is a registered dietitian, nutrition writer, TV contributor and president of 80TwentyNutrition.com. Follow her on Twitter @80twentyrule.