Aspartame: Safety Approved in 90 Nations, but Damages the Brain

By Dr. Mercola

More than 90 countries have given the artificial sweetener aspartame the green light to be used in thousands of food and beverage products.1

Two hundred times sweeter than sugar, aspartame allows food manufacturers to produce sweet foods they can market as “low calorie,” “diet,” or sugar-free,” appealing to hundreds of millions of consumers looking to cut sugar from their diets.

No doubt about it, the less sugar you include in your diet, the better. But replacing sugar with aspartame is not the solution, and in fact is likely to be even worse for your health.

Despite assurances from the U.S. Food and Drug Administration (FDA) and other public health agencies that aspartame is safe, the research says otherwise…

So What the Heck is Aspartame Made Of?

Virtually all of the marketing material emphasizes the fact that aspartame is natural and made of two amino acids, the building blocks of protein. But, like many deceptions, this is only partially true. While there are two amino acids that comprise 90% of aspartame, aspartic acid and phenylalanine, they are held together in a methyl ester bond that comprises 10% of the molecule.

The methanol is released from the aspartame within hours of consumption after hydrolysis of the methyl group of the dipeptide by chymotrypsin in the small intestine. Once this methyl ester bond is broken it liberates free methyl alcohol or methanol, which is commonly called wood alcohol. The problem with methanol is that it passes into your blood-brain barrier and is converted into formaldehyde, which causes the damage. You may recognize formaldehyde as embalming fluid.

Interestingly, methanol is only toxic in humans. All other animals are able to detoxify it before it causes damage.

Methanol is a toxin that destroys the myelin tissue in your body, which is the insulating material around your nerves that allows nerve signals to travel properly. Once injured, one can have what are called demyelinating symptoms that are commonly seen in diseases like MS and also migraines that can include bizarre and inconsistent visual field disruptions.

My sister that helped me start my practice in 1985 is actually one of the people that develops these symptoms when exposed to aspartame. In the late ‘80s I helped to diagnose her with this sensitivity and she has avoided it for over 25 years.

Why is Methanol So Toxic?

Methanol breaks down into formic acid and formaldehyde in your body. Many experts believe formic acid is the problem but the real problem is the formaldehyde, which is a deadly neurotoxin and carcinogen. An EPA assessment of methanol states that methanol “is considered a cumulative poison due to the low rate of excretion once it is absorbed. In the body, methanol is oxidized to formaldehyde and formic acid; both of these metabolites are toxic.”2

They recommend a limit of consumption of 7.8 mg/day. But according to Woodrow Monte, Ph.D, R.D., director of the Food Science and Nutrition Laboratory at Arizona State University:3

“When diet sodas and soft drinks, sweetened with aspartame, are used to replace fluid loss during exercise and physical exertion in hot climates, the intake of methanol can exceed 250 mg/day or 32 times the Environmental Protection Agency’s recommended limit of consumption for this cumulative toxin.”

Further, he states that due to the lack of a couple of key enzymes, humans are many times more sensitive to the toxic effects of methanol than animals. Therefore, tests of aspartame or methanol on animals do not accurately reflect the danger for humans.

“There are no human or mammalian studies to evaluate the possible mutagenic, teratogenic, or carcinogenic effects of chronic administration of methyl alcohol,” he said.

Symptoms from methanol poisoning are many, and include headaches, ear buzzing, dizziness, nausea, gastrointestinal disturbances, weakness, vertigo, chills, memory lapses, numbness and shooting pains in the extremities, behavioral disturbances, and neuritis. The most well known problems from methanol poisoning are vision problems including misty vision, progressive contraction of visual fields, blurring of vision, obscuration of vision, retinal damage, and blindness. Formaldehyde is a known carcinogen that causes retinal damage, interferes with DNA replication and may cause birth defects. The researchers in the featured study then reasoned that the aspartame-induced methanol exposure was likely possible for oxidative stress in the brain.

New Study Shows Aspartame Damages Your Brain

A newly published study with rats investigated the chronic effect of aspartame on oxidative stress in the brain. Researchers found that there was a significant increase in lipid peroxidation levels, superoxide dismutase activity, GPx levels and CAT activity, showing that chronic exposure of aspartame resulted in detectable methanol in the blood, which may be responsible for the generation of oxidative stress and damage in the brain.4

So the study found that aspartame exposure did result in “detectable levels” of methanol in the blood. Methanol is gradually released in the small intestine when the methyl group of aspartame encounters the enzyme chymotrypsin.

Are Artificial Sweeteners Stressing Out Your Brain?

Oxidative stress can be defined as the state in which damaging free radicals outnumber your antioxidant defenses. Oxidative stress tends to lead to accelerated tissue and organ damage.

Case in point, earlier this year another study investigated the effect of long-term intake of aspartame on the antioxidant defense status in the rat brain and also found it leads to oxidative stress.5 Male rats that were given a high dose of the artificial sweetener exhibited a lowered concentration of reduced glutathione (the active, antioxidant form of glutathione), and reduced glutathione reductase activity, a sign of increased oxidative stress-induced damage in the body.

Glutathione deficiency has also been linked to age-related diseases such as Alzheimer’s. Examination also revealed mild vascular congestion – an obstruction of the normal flow of blood within the brain – in these rats. Researchers concluded:

“The results of this experiment indicate that long-term consumption of aspartame leads to an imbalance in the antioxidant/pro-oxidant status in the brain, mainly through the mechanism involving the glutathione-dependent system.”

Adding to the problem, one of the amino acids in aspartame, aspartic acid is capable of crossing your blood-brain barrier. There it attacks your brain cells, creating a form of cellular overstimulation called excitotoxicity, which can lead to cell death.

Your blood-brain barrier, which normally protects your brain from excess aspartate, as well as toxins, is not able to adequately protect you against the effects of aspartame consumption because it:

  • Is not fully developed during childhood
  • Does not fully protect all areas of the brain
  • Is damaged by numerous chronic and acute conditions
  • Allows seepage of excess aspartate into the brain even when intact

That excess aspartate slowly begins to destroy neurons, and the large majority (75 percent or more) of neural cells in a particular area of the brain are killed before any clinical symptoms of a chronic illness are noticed. Then, when they do occur, they may or may not be associated with aspartame consumption, even though examples of chronic illnesses that are made worse by long-term exposure to excitatory amino acid damage include:

Multiple sclerosis (MS) ALS Memory loss
Hormonal problems Hearing loss Epilepsy
Alzheimer’s disease and dementia Parkinson’s disease Hypoglycemia
AIDS Brain lesions Neuroendocrine disorders

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