There's a new artificial sweetener on the block and it is already in a wide range of products, some even sold in health food stores and manufactured by nutritionally-oriented companies. But is it proven safe? Does it provide any benefit to the public? Does it help with weight loss? Are there any long term human studies? Has it been shown to be safe for the environment? The answer to all of these questions is unfortunately a resounding NO.
The artificial sweetener sucralose, which is sold under the name Splenda™, is one of the up-and-coming "next generation" of high-intensity sugar substitutes. It is non-caloric and about 600 times sweeter than sucrose (white table sugar), although it can vary from 320 tp 1,000 times sweeter, depending on the food application. The white crystalline powder tastes like a lot like sugar, but is more intense in its sweetness.
How it is Manufactured
Sucralose is produced by chlorinating sugar (sucrose). This involves chemically changing the structure of the sugar molecules by substituting three chlorine atoms for three hydroxyl groups.
Few human studies of safety have been published on sucralose. One small study of diabetic patients using the sweetener showed a statistically significant increase in glycosylated hemoglobin (Hba1C), which is a marker of long-term blood glucose levels and is used to assess glycemic control in diabetic patients. According to the FDA, "increases in glycosolation in hemoglobin imply lessening of control of diabetes.
Research in animals has shown that sucralose can cause many problems in rats, mice, and rabbits, such as:
Shrunken thymus glands (up to 40% shrinkage)
Enlarged liver and kidneys.
Atrophy of lymph follicles in the spleen and thymus
Increased cecal weight
Reduced growth rate
Decreased red blood cell count
Hyperplasia of the pelvis
Extension of the pregnancy period
Decreased fetal body weights and placental weights
A compound chemically related to sucrose, 6-chloro-deoxyglucose, is known to have anti-fertility and neurotoxic effects, although animal studies of sucralose have not shown these effects.
According to the FDA's "Final Rule" report, "Sucralose was weakly mutagenic in a mouse lymphoma mutation assay." The FDA aslo reported many other tests as having "inconclusive" results.
In terms of safety, it is not just the original substance (sucralose) that one needs to worry about. As the FDA notes, "Because sucralose may hydrolyze in some food products...the resulting hydrolysis products may also be ingested by the consumer."
Is There Any Long-Term Human Research?
None. According to the Medical Letter on Drugs & Therapeutics, "Its long-term safety is unknown." According to the Sucralose Toxicity Information Center, the "Manufacturer's '100's of studies' (some of which show hazards) were clearly inadequate and do not demonstrate safety in long-term use."
Is Sucralose Absorbed or Metabolized?
Despite the manufacturer's claims to the contrary, sucralose is significantly absorbed and metabolized by the body. According to the FDA's "Final Rule" report, 11% to 27% of sucralose is absorbed in humans, and the rest is excreted unchanged in feces. According to the Japanese Food Sanitation Council, as much as 40% of ingested sucralose is absorbed.
Plasma sucralose has been reported to have a half-life of anywhere from 2 to 5 hours in most studies, although the half-life in rabbits was found to be much longer at about 36 hours.
About 20% to 30% of absorbed sucralose is metabolized. Both the metabolites and unchanged absorbed sucralose are excreted in urine. The absorbed sucralose has been found to concentrate in the liver, kidney, and gastrointestinal tract. According to The Sucralose Toxicity Information Center, sucralose is broken down "into small amounts of 1,6-dichlorofructose, a chemical which has not been adequtely tested in humans."
The FDA acknowledges that sucralose "is produced at an approximate purity of 98%." While that may sound pretty pure, just what is in that other 2%? It turns out that the final sucralose product contains small amounts of potentially dangerous substances such as:
Heavy Metals (e.g., Lead)
Although manufacturing guidelines do specify limits on these substances there is no guarantee that such limits will always be met.
Despite the fact that a portion of sucralose is metabolized into some chemicals of questionable safety, a majory of the consumed sucralose is excreted unchanged in the feces and urine. While that may be good for the person using the product, it may not be so great for the environment.
Although sucralose is being flushed down toilets wherever sucralose is approved for sale, what happens to it next is simply a matter for speculation. I know of no studies showing what happens to the chemical when the raw sewage is treated and then released back into the environment.
Does it remain stabile or react with other substances to form new compounds?
Is the sucralose or any resulting chemicals safe for the environment?
How will this chemical affect aquatic life such as fish, as well as other animals?
Will sucralose begin to appear in our water supplies, just as some drugs are beginning to be found. (See my other blog postings.)
Of course, we will likely not know the answers to these questions for many years, if at all. One of the main reasons for this is that the FDA did not require an Environmental Impact Statement for sucralose, because in their words, "the action will not have a significant impact on the human environment."