Are “Natural” and Low-glycemic Sweeteners Healthful Alternatives to Sugar?
Added sugars come in several forms other than table sugar, such as evaporated cane juice and high-fructose corn syrup (HFCS). Calorie-containing sweeteners like maple syrup, honey, agave, and coconut sugar are marketed as “natural” and often touted as healthier alternatives to these types of added sugars. Is there any truth to these claims?
Similar to sugar, these alternatives are still low-nutrient concentrated sweeteners; they add substantial calories to the diet while contributing very little nutritional value. Maple syrup and honey elevate blood glucose similarly to sugar (sucrose), leading to disease-causing effects in the body. Agave and coconut sugar rank lower on the glycemic index, but are still empty calories and may have other negative effects. Repeated exposure to these excessively sweet tastes dulls the taste buds to the naturally sweet tastes of berries and other fresh fruits, which perpetuates cravings for sweets and can undermine weight loss. Since some natural sweeteners undergo fewer processing steps than sugar, they may retain some phytochemicals from the plants they originate from,1 but their nutrient-to-calorie ratio is still very low, and they contain minimal or no fiber to slow the absorption of their sugars. The negative health effects of added sugar and HFCS are well-documented, including increased risk of weight gain, diabetes, cardiovascular disease, and cancers.2-10
Agave nectar is marketed as a low-glycemic sweetener, due to its high fructose content (agave is approximately 90% fructose). Sucrose is half fructose and half glucose, made up of one fructose molecule linked to one glucose molecule. HFCS contains 55% fructose and 42% glucose. All sweeteners (and fruits) contain some combination of glucose, fructose, and the two bound together as sucrose. Maple syrup contains about 90% sucrose, so it is very similar to regular white sugar. Coconut sugar contains 70-80% sucrose, and honey contains 49% fructose and 43% glucose.11-14
Fructose and glucose are broken down differently by the body. When fructose is absorbed, it is transported directly to the liver, where it is broken down to produce energy. Fructose itself does not stimulate insulin secretion by the pancreas. However, much of the fructose is actually metabolized and converted into glucose in the liver, so it does raise blood glucose somewhat (although not as much as sucrose or glucose).15 Despite its low glycemic index, added fructose in the form of sweeteners still poses health risks. Fructose stimulates fat production by the liver, which causes elevated blood triglycerides, a predictor of heart disease.16, 17 Elevated triglycerides have been reported in human studies after consuming fructose-sweetened drinks and this effect was heightened in the participants who were insulin-resistant.15, 18 Fructose, when used as a sweetener, also seems to have effects on hunger and satiety hormones that may lead to increased calorie intake in subsequent meals.18
When you ingest any caloric sweetener, you get a mix of disease-promoting effects: the glucose-elevating effects of added glucose and the triglyceride-raising effects of added fructose. Sweeteners, unlike whole fruits, are concentrated sugars without the necessary fiber to regulate the entry of glucose into the bloodstream and fructose to the liver. All caloric sweeteners have effects that promote weight gain, diabetes and heart disease, regardless of their ratio of glucose to fructose, or what type of plant they originate from.
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