A carefully controlled clinical study with individuals who were convinced that aspartame caused their headaches, published in the New England Journal of Medicine, demonstrated that aspartame does not cause headaches or migraines. The results showed that 35 percent of the subjects had headaches after taking aspartame, compared with 45 percent who had headaches after taking the placebo, confirming that aspartame does not trigger headaches.
Headaches are one of the most common human complaints. Many factors can cause headaches, ranging from stress and sleep disturbances to physical illnesses. It is potentially dangerous to assume that a headache is related to aspartame, when the cause may be a serious physical or psychological condition.
Additionally, aspartame does not cause cancer according to the American Cancer Society. Both the Food and Drug Administration and the National Cancer Institute have examined the allegation regarding aspartame and human brain tumors and concluded that aspartame does not increase the incidence of brain tumors.
Before the FDA approved aspartame in 1981, there was an extensive evaluation of aspartame in four long term studies in rodents. The animals studied received huge doses of aspartame, equal to more than 1,000 cans of diet soft drink daily for an adult human for up to two years. No increase in brain tumors or an other type of tumor occurred.
Importantly, aspartame never enters the bloodstream and therefore cannot travel to essential organs including the brain. Thus, there is no physiological reason why aspartame would cause cancer. When aspartame is digested, the body breaks it down into its components, aspartic acid, phenylalanine and methanol. People consume much greater amounts of these components in common foods, such as milk, meat, dried beans, fruits and vegetables. The body handles the components from aspartame in the same way it handles them when derived from other foods.
Phenylketonuria (PKU) is a rare inherited disease that prevents the essential amino acid phenylalanine from being properly metabolized. (An essential amino acid is required for normal growth, development, and body functioning and must be obtained from the diet, as the body cannot make it.) Because of this, phenylalanine can accumulate in the blood and the brain , and cause health problems including mental retardation
Now in the U.S. and many other countries, routine screening of newborns for PKU is required. In the U.S., about 1 in 15,000 babies is born with PKU. Early detection and treatment can help children with PKU lead normal lives. People with PKU are placed on a phenylalanine-restricted diet from birth to adolescence or after. Women with PKU must remain on the diet throughout pregnancy. Phenylalanine is found naturally in many protein containing foods such as chicken, hamburger, milk and vegetables, and is a component of aspartame
The body metabolizes the phenylalanine in aspartame in the same way as the phenylalanine from protein in foods. The amount of phenylalanine in aspartame is much smaller than that in other common foods eaten every day. However, individuals with PKU must consider aspartame as an additional source of phenylalanine so in the U.S. aspartame containing foods must state "Phenylketonurics: Contains Phenylalanine." The amount of phenylalanine derived from aspartame is small compared to the amount of phenylalanine derived from other food sources. For example, a 3-ounce portion of chicken contains about 1000 milligrams of phenylalanine and 8 ounces of skim milk has about 400 milligrams, while a 12-ounce can of diet soda contains about 90 milligrams
Changes in body weight are related to many factors such as diet, exercise and heredity. Products made with aspartame can help with weight control because they are lower in calories than their sugar-sweetened counterparts.
Several well-controlled scientific studies were conducted to determine the effect of aspartame on hunger, satisfaction and food intake, and body weight. Based on the overwhelming scientific evidence aspartame does not increase appetite, food intake or weight gain.
Blackburn et al. (1997) conducted a study to investigate whether the addition of aspartame to a multidisciplinary weight control program would improve weight loss and long-term control of body weight in obese women. The researchers found that aspartame consumption was positively associated with weight loss. The researchers concluded that aspartame, as part of a multidisciplinary weight control program, may facilitate weight control.
Aspartame was associated with weight loss in two additional long-term studies. Morris et al. (1989) investigated low-calorie sweetener consumption patterns of 35 overweight individuals before and after completing a 16-week weight loss program. At the end of the 16-week period, women lost more than 15 pounds and men lost more than 20 pounds while consuming aspartame and saccharin. The researchers concluded: “These results suggest that consumption of artificial sweeteners is not a barrier to weight loss and that foods containing artificial sweeteners can be incorporated into a weight-loss program.”
Drs. Tordoff and Alleva (1990) conducted a long-term study, monitoring the diet records and body weights of 30 normal-weight adults during three separate periods, each lasting three weeks. During each period, the subjects consumed 40 ounces daily of either aspartame-sweetened soda, high fructose corn syrup (HFCS)-sweetened soda or no experimental drinks.
The researchers observed that drinking aspartame-sweetened soda decreased the sugar and calorie intake of both sexes significantly compared to the control period. Consumption of aspartame-sweetened soda also led to a non-significant decrease in body weight in both sexes combined, while consumption of HFCS-sweetened soda resulted in a significant weight gain in both men and women.
Research shows that aspartame does not affect short-term or long-term blood sugar levels in people with diabetes. The American Diabetes Association states that, "Aspartame has been approved by the Food and Drug Administration, a governmental agency that conducts thorough scientific review to determine foods that are safe for public consumption. (We) follow FDA recommendations and recognize there is no credible scientific evidence linking aspartame to any health-related problems for people with diabetes."
Research shows that aspartame does not cause allergic reactions. Some people "claim" they have experienced symptoms related to consuming aspartame, but these anecdotal reports are not confirmed by carefully controlled scientific studies.
In one study published in the Journal of Allergy and Clinical Immunology (JACI), subjects who believed they were allergic to aspartame received up to 2,000 milligrams of aspartame, the amount contained in about 12 cans of diet soft drink. Not one of the subjects had an allergic reaction after receiving aspartame.
Results of a multicenter, randomized, double-blind, placebo-controlled, crossover study published in a later issue of the JACI, demonstrate that aspartame is no more likely than the placebo to cause urticaria (hives) or angioedema (swelling).
A wide variety of foods can cause allergic reactions in some people. Those who suspect a food allergy should seek diagnosis and treatment from a qualified medical professional, such as a board-certified allergist. Self-diagnosis can delay treatment of a more serious medical problem.
The Epilepsy Institute of New York and the Epilepsy Foundation of America both say aspartame is safe for use by people with epilepsy. Numerous scientific studies in animals and humans demonstrate that aspartame does not cause or worsen seizures in any group of people, including children and adults with epilepsy.
Aspartame is not an excitotoxin. An "excitotoxin" is a substance that reportedly overstimulates brain and nerve cells. The faulty premise behind this allegation about aspartame is that consuming large amounts of aspartame causes aspartic acid (one of the amino acids that makes up aspartame) to reach high levels in the blood. Critics claim that these high levels of aspartic acid circulate to the brain and kill nerve cells by over-stimulating them.
Carefully conducted scientific research with aspartame shows that this is not possible. Consuming extremely high levels of aspartame, even over a long period of time, does not result in high blood levels of aspartic acid.
Before aspartame was approved for use, it withstood rigorous FDA review. It is accepted as safe by regulatory authorities in 100 countries throughout the world. In addition, it has been found safe by numerous organizations, including the Multiple Sclerosis Foundation, the American Diabetes Association, the American Dietetic Association, and the Council on Scientific Affairs of the American Medical Association.
The Multiple Sclerosis Foundation has stated that, "There is no information whatsoever about deleterious effects of aspartame on MS, systemic lupus erythematosis (SLE or lupus), or fibromyalgia and "There is no evidence that aspartame in any way causes, provokes, mimics or worsens MS."
Although scientists know that huge amounts of methanol can affect vision, only small amounts of methanol are formed when aspartame and many fruits, vegetables and juices are digested. Methanol is part of a normal diet, and the body can easily metabolize small amounts. The methanol produced by the digestion of aspartame is identical to that produced by the digestion of fruits, vegetables and their juices. For example, a glass of tomato juice provides six times as much methanol as a similar amount of a drink sweetened with aspartame. During the digestion of aspartame in the gastrointestinal tract, methanol is released and then metabolized by normal body processes. Numerous scientific studies have shown that the methanol from aspartame does not accumulate in the body and thus cannot reach harmful levels.
Well controlled scientific studies conducted by behavioral experts at a number of respected academic centers, including the Massachusetts Institute of Technology (MIT), the University of Toronto, the National Institute of Mental Health, Harvard Medical School, Yale Medical School and Tufts University Medical School, indicate that aspartame is not associated with changes in mood, cognition or behavior, including memory loss.
One study published in the American Journal of Clinical Nutrition tested mood, aggression and selected cognitive functions in 48 healthy subjects who, after a one month baseline, consumed in a crossover fashion, doses of aspartame five times the daily amount consumed by those who consume large amounts of aspartame (90th percentile), 15 times the amount and a sugar sweetened placebo. During the four-month testing period, subjects received these test articles (either aspartame or placebo) for one month each, and underwent physical and psychological tests. Subjects showed no change in mood, memory, behavior, EEGs (which record the electrical signals of the brain), or any physical changes that could be linked to aspartame.