Artificial Danger

‘Better living through chemistry’the official slogan of the DuPont company back in the 1950s and ’60s’implied that chemicals make life easier for all. Of course, that includes rich profits for chemical megaconglomerates such as DuPont. Few could reasonably argue that the advent of new chemicals has provided notable benefits for humankind. Drugs have eradicated fatal diseases. Still, the word chemical arouses suspicion’especially if a chemical substance is synthetic. Nowhere is that more evident than in the case of artificial sweeteners.

Numerous Internet sites warn of the dangers of artificial sweeteners, implying that you’d be better off sticking to natural sweeteners, such as sucrose (table sugar), honey, fructose and stevia. The idea is that, as natural sweeteners, they’re all safer than their artificial counterparts. Critics suggest that the human body isn’t meant for artificial sweeteners and that using them constitutes a risk. Conveniently ignored in such pontifications are the established dangers of eating too much refined sugar. Most health authorities now say that today’s obesity epidemic results mainly from intake of two processed substances: high-fructose corn syrup and trans fats. Too many simple carbs, such as sucrose, increase blood triglyceride, or fat, levels and set the stage for such health problems as the metabolic syndrome, which affects about 25 million Americans.

By far the most vilified of artificial sweeteners is aspartame. Aspartame consists of two amino acids, aspartic acid and phenylalanine, and small amounts of methanol, or wood alcohol, which is undeniably toxic’in large amounts. Anti-aspartame forces are fond of pointing that out, but according to the United States Food and Drug Administration, it takes 200 to 500 milligrams of methanol per kilogram (2.2 pounds) of bodyweight to produce enough of its metabolite, formite, to convert into toxic formaldehyde in the body. You’d have to drink 600 to 1,700 cans of aspartame-sweetened diet soda to accumulate that level of formite. The body metabolizes formaldehyde into S-adenosylmethionine, or SAMI, which is a natural antidepressant and a precursor of creatine synthesis.

Rumors persistently link aspartame to numerous maladies’everything from headaches to brain tumors. When such claims are investigated, they never prove true. So the biggest mystery of artificial sweeteners is what motivates people to lie about them.

The biggest fears about them, however, relate to cancer promotion. Let’s take a closer look at the issue.

Artificial Sweeteners and Cancer

Saccharin’the first artificial sweetener’was introduced in 1879. Although it was used without significant health problems for nearly 100 years, a series of studies involving rats indicted saccharin as a possible carcinogen.

The rats in those studies got diets averaging five percent saccharin’a dose far higher than any human being would ever take. That led one strain of rats to show higher rates of bladder cancer, but the rats used in the studies were frequently infected with a bladder parasite called Trichosomoides crassicauda, which made them more susceptible to bladder cancer.

The mechanism that causes bladder cancer in rats doesn’t apply to humans. Indeed, the rodents also developed bladder cancer when they got ascorbic acid, or vitamin C, in doses similar to those of saccharin. Why? Rats have more-concentrated urine than humans. Consequently, crystals form relatively easily and irritate the bladder tissue. That leads to tumor formation. Monkeys that were fed similar levels of saccharin developed no bladder cancer, and there’s no evidence that the sweetener causes human bladder cancer.

The forerunner of today’s artificial-sweetener scare occurred in 1970, when a sweetener called cyclamate was linked to cancer. Like saccharin, cyclamate caused bladder cancer in rats, and it was banned in the United States. It had been ubiquitous in everything from sodas to candy. Subsequent studies failed to find any evidence that cyclamate promoted bladder cancer in humans, but it’s still banned in the U.S.

Aspartame was introduced in 1981 after animal studies showed that it had no cancer-causing effects, even in high doses. Most cancers are related to damaged DNA, which leads to cell mutations. No evidence exists that sweeteners such as aspartame, cyclamate, saccharine, acesulfame-K and sucralose damage DNA.

In 1996, however, a physician theorized that the increasing rate of brain tumors since 1980 was related to aspartame use. The theory was based on an FDA study of 320 rats, 12 of which developed malignant brain tumors after two years on feed containing aspartame. Another theory was that aspartame became mutagenic when combined with nitrates, chemicals that form naturally in the body. ALL Critics of the aspartame-brain tumor link argued that the introduction of aspartame and the increased incidence of brain tumors was merely coincidental, an ‘ecological fallacy.’ There was no proof that people with brain tumors had taken any more aspartame than anyone else. Even the rodent brain tumors couldn’t be confirmed in later studies. A study of children with brain tumors showed no relationship between the disease and aspartame, whether consumed by the children or their mothers.

Aspartame does have problems, but none are related to health. It’s unstable under high-temperature conditions and breaks down in acidic solutions, such as fruit juices. Because it has limited shelf life, it isn’t an ideal sweetener.

Sucralose: A Health Danger?

The latest artificial sweetener to come under fire is sucralose. Discovered in 1976 by a British company investigating uses of sugar, sucralose was unlike previous artificial sweeteners because it was actually made from sugar, specifically sucrose. Sucralose contains three chlorine ions instead of the three hydroxyl (hydrogen and oxygen) groups sucrose has. That means the body can’t digest or assimilate sucralose. Even so, its sweetness is 600 times greater than that of sucrose; aspartame is 180 to 200 times sweeter.

Sucralose was approved in Canada in 1991, followed in 1998 by approval in the United States, where it’s sold under the trade name Splenda. Before it was approved, the substance underwent more than 100 toxicity studies during a 13-year period that revealed no carcinogenic properties or any adverse effects on reproduction, nervous system or genetic toxicology.

Sponsored by the company that markets sucralose, the studies showed that the estimated daily human intake of sucralose is 1.1 milligrams per kilogram of bodyweight. The acceptable daily intake is 16 milligrams per kilogram of bodyweight, with no adverse effect occurring at 1,500 milligrams per kilogram of bodyweight.1 In the experiments that led to sucralose approval, the animals got the sweetener in various doses, time spans and methods of administration, including orally, through a feeding tube and intravenously.2

Mice experienced no adverse effects when they got up to 16,000 milligrams per kilogram of bodyweight, and rats experienced none at 10,000 milligrams.3 That’s equal to a 165-pound human getting 1,000 pounds of sucralose in a single day. The rats, however, did eat less when they got sucralose in a dose equal to 5 percent of their entire diet, evidently because huge doses of sucralose made their food unpalatable. Decreased appetite, in turn, led to a decrease in the size of the animals’ thymus glands. Critics of sucralose call that evidence of sucralose-induced ‘immune suppression’; the thymus is where the immune system’s T cells are made.

Neither the appetite problem nor the decrease in thymus size occurs in humans. That hasn’t stopped several Web sites from warning of the dangers of sucralose and suggesting that the sweetener causes immune suppression and could lead to cancer. They offer zero documentation for their assertions, relying instead on the out-of-context animal data.

The human body excretes 85 percent of the sucralose it takes in, absorbing only 15 percent of it. What’s absorbed is excreted unchanged from the body within 24 hours. In other words, sucralose doesn’t accumulate in the body. It can’t enter the brain, cross the placental barrier in pregnant women or be absorbed into mother’s milk in lactating women. Nor does sucralose interfere with any type of nutrient absorption or promote insulin release. Studies with diabetics show that it’s safe for that population, too.

Another frequent criticism of sucralose is that it contains chlorine, which is found in pesticides. But chlorine is a natural element that also exists in such foods as lettuce, tomatoes, mushrooms, melons and peanut butter. Common table salt is sodium chloride.

Critics also say sucralose hasn’t been around long enough for definite health problems to have been identified. The fact is, it’s been used commercially in Canada since 1991; any adverse effects would have surfaced by now. None have. Besides, the animal-based studies used doses of sucralose equivalent to using the sweetener for 13 years or more. A study published three years ago compared intake of artificial sweeteners, including sucralose, and sugar.3 It lasted for 10 weeks and featured a group of overweight people who used either table sugar or artificial sweeteners. The subjects who ate large amounts of sugar (28 percent of energy intake), experienced increased energy, bodyweight, fat mass and blood pressure after 10 weeks. No such effects occurred in the group using artificial sweeteners.

Does that mean all artificial sweeteners can be used with impunity from a health perspective? As in all things, moderation is always best. On the other hand, it’s impossible for the human body to take in enough sucralose to cause human health problems. The sucralose toxicity profile in both human and animal studies is superior to any previous artificial sweetener. You’d have to drink so much sucralose-containing diet soda that the fizz would kill you far faster than the sweetener.

The true health hazard is believing the numerous Internet conspiracy crackpots, most of whom rarely identify themselves. Nor do they substantiate their wild claims with scientific evidence. The best defense against such malarkey is to take a close look at the ‘evidence’ they present and examine their sources and documentation. Most of the time it adds up to nothing. IM

References

1 Baird, I.M., et al. (2000). Repeated dose study of sucralose tolerance in human subjects. Food Chem Toxicol. 38:S123-S129.
2 Grice, H.C., et al. (2000). Sucralose: an overview of the toxicity data. Food Chem Toxicol. 38:S1-S6. 3 John, B.A., et al. (2000). The pharmacokinetics and metabolism of sucralose in the mouse. Food Chem Toxicol. 38:S107-S110. 4 Raben, A., et al. (2002). Sucrose compared with artificial sweeteners: different effects on an libitum food intake and bodyweight after 10 weeks of supplementation in overweight subjects. Am J Clin Nutr. 76:721-9. IM