Sugar Substitutes: Helpful or Harmful?
Since the 1980s there has been an explosion of sugar substitutes in the marketplace. These artificial or highly refined “natural” compounds are used frequently in beverages and processed foods to lower total calories (so-called “diet” foods and beverages) or decrease added sugar (as in “sugar-free” or “low-sugar” products). The number of products available for use at the table or in cooking and baking at home has also increased. While these compounds are touted as calorie-cutting weight loss aids and an option to people with diabetes looking for sweet choices while sticking to their diet, questions about efficacy and safety have dogged them from the start.
Non-Sugar Sweeteners: If a beverage or food tastes sweet but says it is low-calorie or sugar-free, chances are it contains a sugar substitute. “Sugar substitutes as a group are referred to by many names: artificial sweeteners, non-sugar sweeteners, low-calorie sweeteners, non-nutritive sweeteners, or high-intensity sweeteners,” says Alice H. Lichtenstein, DSc, director of the Cardiovascular Nutrition Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging. A separate category of sugar substitute is sugar alcohols (see Box for more information). “Although they are frequently referred to (and studied) as a single entity, the wide variety of compounds used as sugar substitutes are actually quite different from each other and may not behave the same way in the body,” says Lichtenstein.
Most sugar substitutes are non-nutritive:they are not absorbed by the body or are used in very small quantities and therefore provide virtually no calories or nutrients. Some non-nutritive sweeteners are also called high-intensity sweeteners because they are from 100 to 20,000 times sweeter than sucrose. Because they are so sweet, only very small amounts are needed to achieve a level of sweetness similar to sugar, so the typical consumer is likely to consume only small amounts of these compounds at a time. Non-nutritive sweeteners can be found in “diet,” “low-calorie,” “reduced-calorie,” or “sugar-free” beverages, baked goods, puddings, jellies, candy, yogurts and ice creams, for example.
Possible Health Benefits: Most research on the health impact of sugar substitutes and added sugars has focused on beverages, since they represent the vast majority of intake and these drinks are more likely to be reported accurately than intake of foods. “The consumption of sugar-sweetened beverages has been consistently linked with increased risk for a number of disorders, including type 2 diabetes, coronary heart disease, hypertension, excess body weight, and possibly even frailty,” says Lichtenstein. “Use of beverages and foods made with sugar substitutes, if successful in reducing the intake of added sugars, could result in health benefits. However, the jury is still out on how successful their use is in accomplishing this goal and what the health impact will be.”
Weight Loss: One of the main purposes of non-nutritive sugar substitutes is to reduce the number of calories in sweet foods, with the idea that these products will lead to a reduction in total calorie intake. It is difficult, however, to prove that sugar substitutes actually limit weight gain or help with weight loss. “Some observational studies have suggested that consumption of sugar substitutes may be associated with higher body weight,” says Lichtenstein. “However, these studies cannot determine whether sugar substitutes lead to excess weight gain or overweight individuals are more likely to choose (or report choosing) products containing sugar substitutes.” Observational studies also can’t determine how much sugar substitute an individual is actually consuming, and which type.
Short-term randomized controlled trials (which are needed to prove cause and effect) have shown that choosing beverages sweetened with sugar substitutes in place of those sweetened with sucrose has a beneficial effect on body weight, but long-term studies are lacking.
“If you do want to reduce calorie intake, substituting beverages sweetened with sugar substitutes in place of those sweetened with sugar may be helpful,” says Lichtenstein, “but make sure you’re not compensating by picking up those calories somewhere else.”
Diabetes: The American Diabetes Association (ADA) 2018 Standards of Medical Care in Diabetes states that “reducing caloric intake is of paramount importance for those at high risk for developing type 2 diabetes.” If cutting calories by using sugar substitutes does lead to weight loss, it could be a useful tool in preventing or treating diabetes. Additionally, sugar substitutes raise blood sugar levels less than sucrose. However, the ADA cautions some research indicates that even non-nutritive sweeteners may be associated with some rise in blood sugar. “Foods and beverages made with non-nutritive sweeteners are a better option than those with added sugar for people with diabetes,” says Richard Siegel, MD, co-director of the Diabetes and Lipid Center at Tufts Medical Center and an associate professor at Tufts University School of Medicine, “but I encourage my patients to focus on high quality foods, like fruits, vegetables, and nuts instead of low-calorie or low sugar versions of cookies and candy.”
Dental Health: It is generally accepted that replacing sugar with sugar substitutes reduces the risk of developing cavities. Some data even indicate that the sugar alcohol xylitol in chewing gum may play an active role in cavity prevention.
Exploring Safety Concerns: Although there is a large body of research looking at potential health hazards from consuming sugar substitutes, there has yet to be any conclusive proof of danger. Most sugar substitutes are classified as food additives and, as such, must be approved by the federal Food and Drug Administration (FDA) before being added to beverages and foods in the U.S. The FDA also monitors research for signs of possible adverse effects [see “Assessing Safety” below]. The 2015 Dietary Guidelines Advisory Committee did an extensive review of the research findings for aspartame, one of the most common sugar substitutes, and concluded that at current intake levels there appear to be no health concerns. “It is common for consumers to have concerns about the safety of sugar substitutes,” says Lichtenstein. “This is fed, in part, by a considerable amount of information on the web, not all of which is fact based.”
Cancer: The American Cancer Society and American Institute for Cancer Research both state there is no strong evidence that sugar substitutes, at the levels consumed in human diets, cause cancer or are associated with increased cancer risk. The concern about sugar substitutes and cancer goes back to the 1970s, when rats fed high doses of the first sugar substitute, saccharin, were reported to have an increased rate of bladder cancer. Scientists later discovered that rats and humans do not process saccharin in the same way, so the findings in rats cannot be applied to humans. Additionally, observational studies failed to find clear evidence of risk in humans. The FDA declared saccharin safe in 2001.
A recent study published in the journal Circulation, which included nearly 38,000 men and over 80,500 women followed for over 30 years, found no significant association between artificially sweetened beverage intake and death from cancer. (Note: Like most studies, this study grouped all sugar substitutes together. Since sugar substitutes are chemically different from each other, they may have differing effects in the body.)
Cardiovascular Disease: There is no established relationship between cardiovascular disease (CVD) and sugar substitutes. In fact, the large cohort study mentioned in the cancer section above suggests that artifically sweetened beverages could be a benefit to heart health if used to replace sugar-sweetened beverages. The authors estimated from their data that replacing one serving of a sugar-sweetened beverage with an artificially sweetened beverage was associated with a five percent lower risk of death from CVD, plus a four percent lower risk of all-cause mortality, and a four percent lower risk of death from cancer. That study did report that an increased risk of CVD and death from any cause was associated with the highest consumption of artificially-sweetened beverages in women (more than four servings a week), but these findings need to be confirmed before there is cause for concern.
Dementia and Stroke: Some studies have raised the possibility that there is an association between consumption of artificially sweetened beverages and increased risk for dementia and stroke. A study published recently in the journal Stroke found that women 50 and older who drank 24 or more ounces (two cans) of diet soda a day were 23 percent more likely to have a stroke than those who drank less than 12 ounces a week. A 2017 prospective cohort study in the same journal found that higher recent and cumulative intake of artificially sweetened soft drinks were associated with an increased risk of stroke, dementia, and Alzheimer’s disease. Sugar-sweetened beverages were not associated with stroke or dementia in this study. In both cases, study authors state the need for more research.
Looking at the body of research to date, sugar substitutes (in reasonable quantities) appear to be a safe alternative to added sugars. Consuming added sugars (in particular sugar-sweetened beverages) is strongly associated with a number of negative health effects, including diabetes and heart disease. Switching from products with added sugars to those sweetened with sugar substitutes can help reduce added sugar intake, but the truly healthy choice is to cut back on sweet-tasting foods in general. Drinking mostly water and getting one’s sweet fix from juicy, delicious, nutrient-packed fruits is truly a “sweet” choice.
While most sugar substitutes approved for use in the American food supply are non-nutritive, high-intensity sweeteners, sugar alcohols are a different kind of sugar substitute. They occur naturally in a wide variety of fruits and vegetables but are processed from other carbohydrates for commercial use. Although these compounds are classified as alcohols, they do not contain ethanol, so they will not get you drunk. They provide fewer calories than sucrose (table sugar) because they are not completely absorbed, but most must be used in higher amounts to achieve the same level of sweetness, so they don’t cut calories as much as other types of sugar substitutes. Sugar alcohols (like xylitol and sorbitol) are used in sugar-free products, in foods marketed to individuals with diabetes, and in products developed for low carbohydrate eating plans. They are likely to be found in chewing gum, hard candy and cough drops, baked goods, ice cream, and some sugar-free chocolate products. Sugar alcohols are known to cause gastrointestinal problems, including gas and diarrhea, when consumed in large amounts.
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Sugar substitutes are regulated as food additives, which means they must undergo premarket review and approval by the federal Food and Drug Administration (FDA) before being used in a food or beverage sold in the United States. Scientists must determine that each substance meets the safety standard of “reasonable certainty of no harm” under the intended conditions of its use. This safety standard is spelled out in the FDA’s regulations.
The exception is substances that fall under the FDA category “Generally Recognized as Safe” or GRAS. GRAS substances do not require premarket approval. For GRAS certification, experts qualified by scientific training and experience to evaluate a compound’s safety must conclude, based on publicly available information, that the substance is safe under the conditions of its intended use. Currently, sugar alcohols, certain steviol glycosides obtained from the leaves of the stevia plant, and extracts obtained from monk fruit (also known as Luo Han Guo or Swingle fruit) are approved under the GRAS category.
During premarket review, the FDA establishes an acceptable daily intake (ADI) level for sugar substitutes approved as food additives. An ADI is the amount of a substance that is considered safe to consume each day over the course of a person’s lifetime. Even high consumers of sugar substitutes are unlikely to exceed these ADIs.