A Neurologist discusses Nutrasweet/Aspartame

In a letter from neurosurgeon Russell Blaylock, M.D., to a Neuropathy Association dated February 10, l999 he said: " .. recent findings have shed some light on the elusive compound (aspartame/Nutrasweet) and its deleterious effects of the human population. .. Aspartame and L- aspartyl L- phenylalanine methylester, is composed of two amino acids, aspartate and phenylalanine, linked by methanol. Inside the gastrointestinal tract, especially in the stomach it is broken down into its constitutent components . In some instances the dipeptide is lysed within the cells of the gut. As a consequence the methanol is rapidly absored and distributed throughout the tissues of the body. Within the tissues substantial amounts of methanol's two metabolic breakdown products (formaldehyde and formic acid) have been shown to accumulate in many tissues."

Further he said: " These breakdown products, formaldehyde and formic acid, have been shown in several important studies, to be extremely toxic to tissues in very small doses. In fact, even small doses of formaldehyde are considered to be carcinogenic. A recent study by Trocho, Pardo and co-workers, have demonstrated that following aspartame ingestion, significant amounts of formaldehyde accumulate in the tissues. Formaldehyde is known to bind strongly to proteins and nucleic acids , forming adducts that are extremely difficult to eliminate through normal metabolic pathways."

"In this study, they demonstrated that labeled methanol (as formaldehyde) accumulated in high concentrations in the liver (50%) and in lower, but substantial, concentrations in the kidney , adipose tissue, brain and retina. Within the cell, they found large amounts located within the DNA. It was interesting to note ethat these doses were lower than that used in toxicity studies. Previous studies have shown that very high doses of aspartame may not cause acute symptomatology. This study indicates that the damage may necessitate longer periods of time to manifest itself, and that the eventual effects can be quite deleterius."

"The doses used were within those recommended by the FDA as ADI for humans . This is especially of conern in children who may consume doses of aspartame as high as 75 to 90mg/kg. It is also important to note that in this study, the formaldehyde was accumulative as were its injury to cellular proteins and DNA. In the real life situation, humans are exposed to repeated doses of saspartame found in many foods, drinks, medicines and chewing gum."

"An earlier study by Shephard and co -workers, it was found that aspartame is nitrosated within the gut and that this nitrosation of the amine group is "quite cytotoxic" and represents a moderately strong mutagen in the Ames test."

"Another recent study, by Sorg, Willis and co-workers is also alarming. In this study, it was found that prolonged exposure to low concentrations of formaldehyde could cause chemical sensitization to cocaine, via a limbic mechanism. With increasing reports of multiple chemical sensitivity syndrome, one must be concerned about chronic low dose formaldehyde exposure via aspartame."

"It is my opinion, and the opinion of many others, that aspartame is a dangerous neurotoxin and its use should be discouraged generally, but especially so in those harboring neurological diseases."

Russell L. Blaylock, M.D.


  1. Shephard SE, Wakabayashi K and Nagao M. Mutagenic activity of peptides and the artificial sweetener aspartame after nitrosation. Food Chem Tox 31Z : 323-329, 1993 .
  2. Sorg BA, Willis JR , et al. Repeated low-dose formaldehyde exposure produces cross-sensitization to cocaine; possible relevance to chemical sensitivity in humans . Neuropsychopharmacol 18 : 385 , 394 , l998
  3. Trocho C, Pardo R, et al, Formaldehyde derived from dietary aspartame binds to tissue components in vivo. Life Sciences 63:337-349,1998
  4. Hardcastle JE, B ruch RT. Effect of L-aspartyl-L -phenylalanine methyl ester on leukotriene biosynthesis in macrophage cells. Prostagland Leuket Essen Fatty Acids 57 331 -333,1997

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