THAT’S THE WAY THE COOKIE CRUMBLES (4 page)

There is an important aspartame story to be told. I’m just not sure what it is. Is this artificial sweetener the chemical from hell that is responsible for causing multiple sclerosis, brain tumors, seizures, and lupus, along with a host of other ailments, or is it one of the safest and best-tested food additives on the market? The answer seems to depend upon whom you ask.

We had best begin by covering the available facts about aspartame. The sweetener is commonly labeled “noncaloric,” although that term is technically inaccurate. Aspartame is broken down in the digestive tract into its components — namely, aspartic acid, phenylalanine, and methanol — which the body absorbs and metabolizes. Collectively, they contribute about four calories per gram, but since the substance is about 180 times sweeter than sugar, very little needs to be used in foods and beverages to achieve a satisfactory degree of sweetness. So the calorie contribution is essentially irrelevant.

Diet drinks normally contain about sixty milligrams of aspartame per one hundred milliliters, which translates into roughly two hundred milligrams per serving. To put this into perspective, we need to introduce the concept of acceptable daily intake (ADI), which the U.S. Food and Drug Administration uses to describe an intake level that, if maintained each day throughout a person’s lifetime, would be considered safe. The ADI for aspartame is fifty milligrams per kilo of body weight. The actual average daily intake is less than two percent of this, and even the heaviest aspartame consumer ingests only about sixteen percent of the ADI. To reach the ADI, an adult would have to drink twenty twelve-ounce soft drinks; a child would have to drink seven. An adult would have to consume ninety-seven packets of sweetener. Industry figures show that ninety-nine percent of aspartame users consume less than thirty-four milligrams per kilo of body weight per day. The average consumption is about five hundred milligrams per day. The ADI for a person weighing seventy kilos (about 150 pounds) is 3,500 milligrams. Aspartame cannot be used in cooked or baked foods since it breaks down into its components upon exposure to heat and loses its sweetening power.

Aspartame is perhaps the most widely researched food additive ever to have landed on the market. Its manufacturers were expecting reports of adverse reactions, because that is so often the case with newly introduced substances (and no amount of testing can preclude idiosyncratic reactions in some portion of the population); in fact, there have been only a few such reports about aspartame. Over seventy million North Americans consume aspartame on a regular basis, yet reported complaints average only about three hundred per year. The majority of complaints (sixty-seven percent) refer to headaches, dizziness, visual impairment, and mood alterations. Aspartame consumers have also reported gastrointestinal problems (twenty-four percent) and allergic symptoms such as hives, rashes, and swelling of tissues (fifteen percent). Some have linked seizures with aspartame exposure. In most instances, these difficulties occurred when aspartame intake far exceeded normal use.

Researchers have conducted double-blind challenges with aspartame. At Duke University, in one of the best designed of such studies, they investigated the effects of a single large dose of aspartame in people who had claimed to be sensitive to the substance. The results showed no difference in headache frequency, blood pressure, or blood histamine concentrations (a measure of allergenic potential) between the experimental groups and the control groups.

In another study, carried out at the University of Illinois and involving diabetics, subjects in the placebo group actually had more reactions than those in the aspartame group. Still, surveys taken by physicians in headache clinics reveal that aspartame precipitates headaches about eight percent of the time. This kind of conflicting data is characteristic of the research on the possible side effects of aspartame. Reported anecdotal experiences are not confirmed by carefully controlled scientific studies. This does not mean that the problems aren’t real, but it does imply that in many cases the symptoms are not caused by aspartame. People get headaches, upset stomachs, aches and pains of all kinds on a regular basis for no easily determined reason. If they recall having consumed aspartame just before one of these ailments struck, they may judge the sweetener guilty by association. This is even more likely if they are already familiar with some of the bad publicity that aspartame has received.

Sometimes a reaction attributed to aspartame may be due to something else that we can pinpoint. A caller on my radio show informed me with great conviction that the palpitations she had been suffering from for years disappeared immediately after she gave up aspartame-sweetened drinks. This seemed unlikely to me, so I asked her what she thought would happen if she drank a regular cola. “Nothing!” was her immediate reply. She agreed to take this simple test, and she was shocked when the palpitations resumed. The lady had been reacting adversely not to aspartame, but to caffeine, yet she had been convinced that aspartame was the culprit.

Certainly, there have been studies that have found adverse reactions to aspartame. At least one has confirmed allergic symptoms such as hives and swelling in sensitive individuals. We don’t really know how the allergy comes about, since researchers believe that none of the components of aspartame produces allergic reactions. But some have suggested that diketopiperazine, a compound that forms when aspartame decomposes, may be responsible.

Without a doubt, the three breakdown products of aspartame are all toxic in high doses. Phenylalanine is an essential amino acid, which must be included in the diet for normal growth and tissue maintenance, but sustained high blood levels of the substance can lead to brain damage. This is of major concern to the roughly one out of twenty thousand children who are born with an inherited condition called phenylketonuria, or PKU. These children cannot metabolize phenylalanine properly, and the substance builds up to dangerous levels in their brains. The condition therefore necessitates a severe curtailment of phenylalanine intake, at least for the first six years of life. This means that aspartame, due to its phenylalanine content, is not suitable for PKU sufferers; those who manufacture products containing aspartame must therefore include a warning on their products’ labels.

In members of the general population, blood levels of phenylalanine after aspartame ingestion fall into the same range as they do after ingesting any protein-containing food. Even at abusive amounts — equivalent to a child swallowing one hundred sweetener tablets — levels do not rise above those considered to be safe in children afflicted with PKU. The effects of aspartic acid, another aspartame breakdown product, have also been rigorously examined. When researchers administered extremely large amounts to primates, no damage resulted, even though the subjects’ blood levels were greatly elevated. Humans eliminate even high doses very quickly. Most significantly, aspartic acid levels in our blood do not rise after we eat foods containing aspartame, or after we drink sweetened beverages, even at the rate of three drinks in four hours.

Perhaps the most curious accusations leveled against aspartame have involved its methanol content. It is a fact that in large doses methanol can cause blindness, and even death. Alarmists have therefore referred to the methanol that is released from aspartame as an unsafe substance. We must remember, however, that there are no safe substances, only safe doses. The amount of methanol released from aspartame is inconsequential when we look at it in the context of the overall diet. Methanol occurs naturally in foods. The “natural” methanol content of fruit juice is actually about two and a half times greater than the quantity of methanol released in the body from a diet drink sweetened with aspartame. Aspartame opponents argue that our bodies handle methanol differently when we ingest it along with other alcohols, such as ethanol, which are found in juices. There is no evidence for this; and, furthermore, even the blood of those subjects who consume the greatest amounts of aspartame contains no detectable quantity of methanol.

One study, which was published in 1996, claimed that a ten-percent increase in brain tumors noted in the 1980s was associated with the introduction of aspartame. This study received a great deal of publicity. It suggested that aspartame, or its diketopiperazine breakdown product, may combine with nitrites in the diet to form nitrosated compounds. These compounds are indeed known to produce brain tumors in animals, but the manufacturers of aspartame point out that while aspartame use has increased dramatically since the 1980s, brain-tumor rates have not increase.

If we look at aspartame from a scientific perspective, we can hardly see it as a dastardly poison. But one could certainly get a different impression by reading a letter, attributed to one Nancy Markle, that has been making the cyber rounds. It alleges that virtually every ailment known to humankind is caused by aspartame. I talked about this issue on my radio show one day, commenting that such arguments are not supported by the vast majority of studies published in the scientific literature. It was at this point that I received an e-mail from Betty Martini, who runs Mission Possible International, an organization dedicated to ridding the world of the deadly scourge of aspartame. I was too soft on aspartame, she insisted, and I should open my eyes and see the misery that this devil of a chemical is inflicting on the public. Ms. Martini has since flooded me with information on aspartame — particularly, dozens of anecdotal reports from people who claim that their lives, or the lives of their loved ones, were ruined by aspartame. She also included accounts of the miraculous turnarounds people experienced when they gave up the vile substance. Without any evidence to back her up, the lady also maintained that thousands of Gulf War veterans succumbed to aspartame disease because they consumed diet drinks that were not refrigerated. Methanol, she explained, is released at warm temperatures, and it is the culprit.

Betty Martini is absolutely convinced that she has discovered a major cause of human suffering, and she has undertaken what she feels is an essential crusade against it. But the facts simply do not justify an all-out war on aspartame. The human body and the human mind are extremely complex. The likelihood that a single chemical entity can cause such a wide diversity of problems is small, but we often have a need to see cause-and-effect relationships where none exist. Numerous publications and Web sites promote dietary supplements, electrical devices, and specialized waters with testimonials galore. Other sites are dedicated to ridding the world of evils ranging from soy protein and canola oil to antiperspirants and dental amalgam. The allegations made by the contributors to these sites parallel those made by the foes of aspartame. But can there really be so many different causes and cures for the same conditions?

I am not a fan of aspartame, or any other artificial sweetener, although I recognize that they have certain advantages for diabetics. (Nondiabetics, however, should develop healthy diets instead of seeking shortcuts such as artificial fats or sweeteners.) But aspartame was not cast onto the market in a thoughtless fashion. Researchers conducted hundreds of studies on its safety profile. Yes, there are some problems. As I pointed out earlier, in a rare documented case aspartame has been linked to seizures. Some aspartame consumers have experienced headaches and episodes of dizziness. And one small study did show that people suffering from depression found that their condition deteriorated when they consumed the artificial sweetener. Yet these problems occurred only with high doses — and, as we well know, toxicity is related to dosage. Unfortunately, many people do consume staggering amounts of artificially sweetened products, starting their day with a six-pack of diet soda and finishing it with an array of diet desserts. This is an abominable practice, and we should heartily discourage it. Drinking a single diet beverage or chewing a stick of sugarless gum, however, is quite another matter.

We scientists need to look at all the available research. If we opt for selective viewing and blind dedication to various agendas, we will delude ourselves. Is multiple sclerosis, or MS, linked to aspartame consumption? The vast majority of researchers say no. A Medline search reveals no links to MS or lupus. Brain cancer? Dr. John Olney of Washington University maintains that there is a link. He claims that an increase in brain tumors has paralleled aspartame’s rise in popularity. Other researchers have demonstrated that this increase began about eight years before aspartame was introduced and that it has now leveled off, despite the fact that aspartame use has skyrocketed. Betty Martini’s answer to this divergence of opinion is that the MS associations, the FDA, and many researchers have been bought off by the manufacturers of the artificial sweetener. She would probably say the same thing about the researchers in California who published a paper in a 1997 issue of
The
Journal of the National Cancer Institute
describing how they collected information on aspartame exposure from fifty-six brain cancer patients, all under age nineteen, and compared their intake to that of ninety-four controls. Patients with tumors were no more likely to have consumed aspartame, and maternal consumption did not elevate risk in either breast-fed or bottle-fed children.

So, who is right? Well, I thought I would clear the air by going to the top. And at the top of this field is Dr. Richard Wurtman of MIT, probably the world’s leading expert on the relationship between nutrition and the brain. Betty Martini often refers to his work, and she calls Dr. Wurtman a brilliant researcher. He does not return the compliment. I was fortunate enough to have a long telephone conversation with Dr. Wurtman, and he told me that while he believes that, in rare cases, large amounts of aspartame may cause seizures, he sees no problems with the amounts people normally consume. He consumes diet drinks himself.

What is perhaps the best double-blind study ever carried out in this area failed to find an aspartame effect. Dr. Paul Spiers and some of his colleagues at MIT gave subjects aspartame at a dose equivalent to more than a dozen diet drinks a day, and they found no difference in brain waves, mood, memory, behavior, or physiology. Reports of headache, fatigue, and nausea occurred with equal frequency in the aspartame and the placebo groups. Opponents of this research cast a shadow on the study, saying that it was supported financially by the artificial-sweetener industry. But where else should researchers seek funds for sweetener research? From a lightbulb manufacturer? The fact that a researcher receives a grant does not indicate that he or she has been bought off.