T Nation

Aspartame & Serotonin Levels.

Any thoughts on how aspartame supposedly lowers serotonin levels? I know it has something to do with phenylalanine, but anybody out there knows how much can do that to you (If at all)?

I’m asking because someone brought up a point at my gym and I didn’t really know what to say right off the bat(can’t know EVERY damn thing EVRY time someone asks ANY thing…).

I know one reason some people have sugar binge is because of low serotonin levels. That guy mentioned how aspartame can sometimes have a lowering effect on serotonine level, and it seems to be the case in large enough amounts.

Now aspartame is usually a “diet sugar”, but does it affect serotonin that much? I tried looking it up, but the info seems sparse.

Anyone has looked into it enough to help out??

[quote]Vinkomorf wrote:
Any thoughts on how aspartame supposedly lowers serotonin levels? I know it has something to do with phenylalanine, but anybody out there knows how much can do that to you (If at all)?

I’m asking because someone brought up a point at my gym and I didn’t really know what to say right off the bat(can’t know EVERY damn thing EVRY time someone asks ANY thing…).

I know one reason some people have sugar binge is because of low serotonin levels. That guy mentioned how aspartame can sometimes have a lowering effect on serotonine level, and it seems to be the case in large enough amounts.

Now aspartame is usually a “diet sugar”, but does it affect serotonin that much? I tried looking it up, but the info seems sparse.

Anyone has looked into it enough to help out?[/quote]

I researched this subject extensively a year or two ago. (I should write my thesis on it).

Aspartame even in small amount can have a markedly negative impact on Serotnin levels leading to depression.

I used to be a DMD (Diet Mountaiun Dew) Addict(2 liters+ daily) a few years ago and felt awful all of the time.

It wasn’t that caffeine that bothered me as much as the Aspartame.

Once I started using Splenda for everything instead of Aspartame/Nutrasweet I felt 100 times better even while consuming a lot of caffeine.

It makes me cringe whenever I see someone drink Asapartame sweetened Diet Pop.

I expereinced horrible head aches when consuming it and it has also been linked to Brain Tumors. That’s a risk I am not willing to take.

As far am I am concerned there a two Dietary evils in our society TRANS-FATS & ASPARTAME!

JUST SAY NO TO ASPARTAME!

fedorov91,

I don’t like aspartame and try to avoid it myself. Being able to defend this is another matter. How much aspartame do you have to consume to affect serotonin levels? References?

Thanks.

Yeah fedorov91: like Berner said, I’d just like to know how much, if you have those numbers.

I’m not saying aspartame does not have any negative effects, but then again you can say that about any and everything under the sun given a big enough dose. (I’ve heard one can drown given enough water!)

While a shot of whisky doesn’t do much harm, but 50 might. What about aspartame?

Doing a search of [i]serotonin aspartame[/i] on PubMed doesn’t generate a lot of hits. 26 to be exact. And there wasn’t anything I found that said for x amount of aspartame ingested, there was an x-percent decrease of serotonin. However, the following does suggest that there might be something to what fedorov91 is saying.

[center]Effects of Repeated Doses of Aspartame on Serotonin and its Metabolite in Various Regions of the Mouse Brain[/center]
Sharma RP, Coulombe RA Jr.

Following a finding that single doses (approximating to average intakes and to potential ‘over-use’) of aspartame administered orally to mice caused significant increases in norepinephrine and dopamine concentrations in various brain regions, the effect of repeated exposure to aspartame was studied. Male CD-1 mice were given a daily oral dose of 0, 13, 133 or 650 mg/kg for 30 days and 1 day after the last dose the animals were decapitated and their brain regions were quickly isolated. Analyses of the different regions for catecholamine and indoleamine neurotransmitters and their major metabolites indicated that the increases in adrenergic chemicals observed shortly after a single exposure were not apparent after repeated dosing. In contrast, concentrations of serotonin and its metabolite, 5-hydroxyindoleacetic acid, were decreased in several regions. An increased supply of phenylalanine may be responsible for a decrease in tryptophan uptake by the brain tissue or for a depression in tryptophan conversion to serotonin.

Very interesting stuff fedorov and TT. Thanks for the info.

I wonder if any of the other nonnutritive sweeteners can have similar effects?

Thanks TT.

Tampa-Terry wrote:
An increased supply of phenylalanine may be responsible for a decrease in tryptophan uptake by the brain tissue or for a depression in tryptophan conversion to serotonin.

I guess it would make a lot of sense to include 5-htp in the supplement protocol then.

I’ll keep looking on my end, but if anyone finds anything about quantity, let me know. I guess it varies from person to person, too.

[quote]Tampa-Terry wrote:

Male CD-1 mice were given a daily oral dose of 0, 13, 133 or 650 mg/kg for 30 days and 1 day after the last dose the animals were decapitated and their brain regions were quickly isolated.[/quote]

Its important to note the abstract did not state which of the treatments resulted in the effect, but if we take an average male @ 75kg, the doses are 0, 0.975g, 9.975g, or 48.75g

they are some substantial amounts of aspartame, especially with some putting intakes at 2-10mg/kg/day or 150-750mg/day

cycomiko, agreed! I only had access to the abstract. I would hope the study itself provided a little more information.

Too, we could even argue that the studies were done in mice, not men. (grin) Nonetheless, I found it interesting.

ref:

L-tryptophan is a precursor of Seratonin. It must cross into the brain but there are competing amino acids for the carriers transporting accross blood brain barrier. “Of these, L-phenylalanine inhibits the transport of L-tryptophan into the brain most effectively, while aromatic amino acids in general exclude L-tryptophan more effectively than do other neutral amino acids.”

An insulin spike will drive the competing amino acids into muscle cells and leave L-tryptophan free in the blood stream to then enter the brain. That diet drink should not cause an insulin spike and thus provide plenty of competition for carriers.

I wonder if a reduction in serotonin could explain the results of this study :

I avoid aspartame anyway as I am one of those who got severe headaches from its consumption.

[quote]Tampa-Terry wrote:
Too, we could even argue that the studies were done in mice, not men. (grin) Nonetheless, I found it interesting.[/quote]

While the study may be indicative of an analogous response in humans, attempting to formulate a threshold for the chemical based upon a cross-species study is not plausible. Yeah, I’m stating the obvious, but there may be someone out there trying to do a mg/kg bodymass conversion right now.

~Terumo

On a side note, I would be interested to know the strength of correlation between aspartame ingestion and formic acid induced acidosis. Blood pH change should be minute, even among the more zealous consumers of aspartame. However, any decrease in blood pH would also be a possible cause for decreased efficiency of SR catalysts.

I know… Wild hypothesis, but this is “Bodybuilding’s Think Tank,” right?

~Terumo