Naked Science Forum
Life Sciences => Physiology & Medicine => Topic started by: thedoc on 09/02/2010 17:19:07
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What is aspartame and what does it turn into when it gets into the body?
Asked by John, Werrington
Read the naked scientists answer here (http://www.thenakedscientists.com/HTML/content/questions/question/2545/)
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Well aspartame, the sweetener, works because it’s about 200 times sweeter as a molecule than sugar is. But because it contains virtually no calories compared with a large number of calories from sugar, you can use it to replace the sweetening things in food that would normally be sugar, and therefore, cut the number of calories in food. So that’s how it can be used to help people lose weight.
The worry is, whether or not it gets metabolised or broken down in the body into something toxic. So if you look at the molecular structure of aspartame, it consists of two amino acids. One of which is called phenylalanine – perfectly healthy there, no problem with that. Another one called aspartic acid – again, very common, no problem there. The two are linked together though with a bridge molecule which is a methyl group, a carbon atom attached to a couple of hydrogens. But when this molecule goes into your digestive tract, the acid and other chemicals in that environment actually break apart the two amino acids, the phenylalanine and the aspartate, and they get absorbed and used in the body in the same way any other amino acid would. But the methyl group actually gets turned into a methanol, and the other name for methanol is wood alcohol.
We know that methanol can be harmful to health when it goes into your body – although in itself, methanol is not harmful, it goes to the liver. There, enzymes break down alcohol, ethanol, ultimately into ethanoic acid, vinegar, and it’s just excreted. These enzymes also turn methanol initially into formalin, which is formaldehyde - a fixative - the same stuff you use to embalm bodies. Ultimately, the formalin gets oxidized to make formate or formic acid. This is the same stuff that ants squirt out their back end, which makes you sting. That’s not good because it’s very toxic to mitochondria, the powerhouses in our cells. Mitochondria supply energy to cells and if nerve cells don't have enough energy, they can die.
So if you have an intense ingestion of methanol, then the methanol can turn into formalin and fix your body internally, and also into formic acid which will deactivate your mitochondria, and that means nerve cells can die because they don't have enough energy.
The amount of methanol you get from aspartame is very, very low - a daily intake of probably less than a few milligrams or possibly 10 milligrams of methanol. So probably trivial, probably not going to harm you, but the jury is out. We just don't know, is really the answer.
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The amount of methanol you get from aspartame is very, very low, probably from a daily intake, probably less than a few milligrams or probably 10 milligrams of methanol. So probably trivial, probably not going to harm you, but the jury is out. We just don't know, is really the answer.
Trivial indeed, less than the amount you would get from a piece of fruit.
I disagree that the jury is out:
Over 20 years have elapsed since aspartame was approved by regulatory agencies as a sweetener and flavor enhancer. The safety of aspartame and its metabolic constituents was established through extensive toxicology studies in laboratory animals, using much greater doses than people could possibly consume. Its safety was further confirmed through studies in several human subpopulations, including healthy infants, children, adolescents, and adults; obese individuals; diabetics; lactating women; and individuals heterozygous (PKUH) for the genetic disease phenylketonuria (PKU) who have a decreased ability to metabolize the essential amino acid, phenylalanine. Several scientific issues continued to be raised after approval, largely as a concern for theoretical toxicity from its metabolic components--the amino acids, aspartate and phenylalanine, and methanol--even though dietary exposure to these components is much greater than from aspartame. Nonetheless, additional research, including evaluations of possible associations between aspartame and headaches, seizures, behavior, cognition, and mood as well as allergic-type reactions and use by potentially sensitive subpopulations, has continued after approval. These findings are reviewed here. The safety testing of aspartame has gone well beyond that required to evaluate the safety of a food additive. When all the research on aspartame, including evaluations in both the premarketing and postmarketing periods, is examined as a whole, it is clear that aspartame is safe, and there are no unresolved questions regarding its safety under conditions of intended use.
Unwarranted controversy over something can give off a false impression that both sides of the argument have merit, but this doesn't seem to be the case.
There is only one known health risk with Aspartame, and that is to people who cannot metabolize phenylalanine (a rare condition called phenylketonuria). But phenylalanine is an amino acid that's found in a million things, so aspartame is just one more to the list that people with this condition have to avoid.
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Listen to the answer to this question on our podcast. (http://www.thenakedscientists.com/HTML/podcasts/show/2010.02.07/)
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Good call. Thanks for your critical approach.
Chris
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http://www.sweetpoison.com/articles/0706/aspartame_symptoms_submit.html.....aspertame is really bad dont listen to any one that says it is not bad
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http://www.sweetpoison.com/articles/0706/aspartame_symptoms_submit.html