“What is sucralose, and how is it made? Is sucralose harmful for humans and/or the environment?”
To answer this question, we will discuss the chemical structure of sucralose; then we will describe some possible risks associated with the use of sucralose.
What is Sucralose?
Sucralose is an artificial sweetener, used in many commercial products, Splenda® being probably the most common example.
Sucralose is a chemical modification of common table sugar – sucrose. In sucralose, however, some chemical bonds are modified and 3 hydroxyl (OH) groups are replaced with chlorine (Cl) atoms (see the sucralose formula above).
Sucralose is produced at industrial level from sucrose; in the process, sucrose structure is modified and then three chlorine atoms are introduced in the molecule, with elimination of three OH groups.
Low Calories, High Sweetness Level
The sweetness of sucralose can be between 385 and 650 times higher than that of sucrose. Thus, only a very small amount of sucralose is needed to get a strong sweet taste. This means its caloric content is close to zero. Generally, however, sucralose-based products contain other compounds (additives), which have some caloric content. Despite this, the calories present in sucralose-based products are much less in comparison with those of sugar. A packet of Splenda, for instance, contains less than 4 calories, as opposed to the 11 calories from a packet of sugar.
Is Sucralose Safe?
Sucralose has been classified as safe, and approved as a food additive by several regulating authorities; these include the US Food and Drug Administration (FDA), the European Food Safety Authorities (ESFA) and the UK Food and Standard Agency (FSA). In the US, for instance, sucralose use as an additive has been approved for all categories of food and drink products from 1999.
Despite this classification, however, there is still a lot of controversy about sucralose safety, as numerous scientific studies seem to show that there are health hazards associated with this sweetener.
Effect on the “Good” Bacteria
Decoded Science spoke to Professor Susan Schiffman, from North Carolina State University (US); she studied sucralose and its effects for several years and in November 2013 published a review article in the Journal of Toxicology and Environmental Health B, which summarizes the most important findings on this topic.
“Daily consumption of sucralose can reduce the number and the balance of beneficial bacteria in the gastrointestinal tract by 50 % or more; moreover, bacterial populations do not return to their original level even after a 3-month recovery period.
We observed significant reduction in the beneficial bacteria with a dose of 1.1 mg a day per kilogram of body weight; this corresponds to a less than 1 diet soda per day for an average woman. A reduction in the beneficial bacteria could, in principle, cause digestive problems.”
Interaction with Drugs
Another problem associated with sucralose is the possible interaction that the sweetener can have with some drugs. According to Professor Schiffman:
“As sucralose alters processes in the gut, this can limit the absorption, and thus the effectiveness, of life-saving therapeutic drugs, including those for cancer and heart disease. These effects were observed for sucralose amounts equivalent to two diet drinks per day for a woman and 1 daily diet drink for a child.
These findings were already published in 2008, so 6 years ago; it is not recent news. Still, many people seem not be aware of this. For instance, an overweight woman receiving chemotherapy for breast cancer may think it is good to have diet drinks and may be unaware that these drinks could potentially interfere with her therapeutic treatment.”
Sucralose Use in Baking Products
One of the reasons which made sucralose so popular is that their producers claim it is stable at high temperatures; because of this, it is widely used as a sugar replacement in many baking products. According to Dr. Schiffman, however, this is not the case.
“Sucralose decomposition at high temperatures can generate potentially toxic compounds called chloropropanols. Decomposition during baking has been reported in several independent investigations; different laboratories in the US, Canada and Brazil all observed that sucralose breaks down with heat. The first report dates back to 1996, so again it is not recent news.”
Effect on the Environment?
Further to these risks to human health, there is also increasing worry for the effect that sucralose can have on the environment.
At present sucralose is found in wastewaters in relatively low concentrations (300 ng/L). The main concern, however, is that sucralose seems quite resistant to standard wastewater treatment. As only small amounts of sucralose get degraded, this compound can accumulate in waterways and cause significant damage to the environment. Although the levels of sucralose in environmental waters have not yet reached concentrations that pose a threat to bacterial communities, higher sucralose concentrations have been shown to suppress growth of bacteria from water and soil.
With increasing use of sucralose and the difficulties to eliminate it from waste water, it is likely that possible critical concentrations will be achieved. This could potentially be a problem for the health of some ecosystems.
Other studies confirm the difficulty in the elimination of sucralose with the standard methods used for other pollutants. Sang et al. showed that photocatalytic treatment can be a powerful tool to degrade sucralose. Their study, however, also show that it is also very important to assess the possible toxicity of the sucralose degradation products, as in some cases they can be more toxic than the sucralose itself.
Schiffman, S.S. and Rother, K. I. Sucralose, a synthetic organochlorine sweetener: overview of biological issues. (2013). Journal of Toxicology and Environmental Health, Part B: Critical Reviews. 16, 399-451. Accessed February 4, 2014.
Sang, Z. et al., Evaluating the environmental impact of artificial sweeteners: A study of their distribution, photodegradatin and toxicities. (2013). Water Research. Accessed February 4, 2014.
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