Three ingredients in aspartame are:
- 40% aspartic acid
- 50% phenylalanine
- 10% methanol (wood alcohol) -metabolized in the body to formaldehyde (embalming fluid)1
Aspartic acid and phenylalanine are amino acids.
Aspartic acid in high concentrations can be considered excitatory and contribute to anxiety and hyperactivity due to overstimulation of the nervous system.1
Phenylalanine is a precursor to the neurotransmitters dopamine and norepehinephrine/epinephrine. Phenylalanine is one of the large neutral amino acids that compete a transporter for uptake into the brain. It competes with tryptophan, tyrosine, methionine, and BCAAs (valine, leucine, and isoleucine).
These amino acids have a 100 times higher affinity for the brain transporter than they do for the peripheral transporters, so small imbalances in dietary sources can make a huge difference in brain chemistry. Higher dietary intake can mean less tryptophan for the availability to make serotonin which can lead to depression. And, since serotonin is the precursor to melatonin, then there will be less melatonin produced causing sleep disturbances.
It is difficult to excrete formaldehyde from the body so it may accumulate causing symptoms of:
- visual disturbances
- behavioral changes
- memory loss.1
The FDA has established an acceptable intake level of aspartame to be 40mg/kg/day.
This is 2.8gm per day in the average sized person that equals about 16 cans of soda that the FDA claims to be safe.3
But the EPA has determined that the intake of methanol should not exceed 7.8mg/day.1
A can of diet soda contains approximately 180mg of aspartame or 14mg of methanol.1,3
If one were to drink 16 cans of diet soda then their methanol intake would be 224mg which is 28.7 times the maximum safe limit as determined by the EPA.
Perhaps the EPA didn’t get the memo from the FDA that they needed to change their stance on methanol poisoning.
I think the EPA is not trying to please Monsanto, the maker of aspartame.
- Grazia A. Artificial Sweeteners, Maybe Not So Sweet & Innocent. [Week 5 Lecuture] pdf.
- Shen Y, Volique G, Odle J. etal. Dietary L-tryptophan supplementation with reduced large neutral amino acids enhances feed efficiency and decreases stress hormone secretion in nursery pigs under social-mixing stress. J Nutr. Aug 2012; 142(8):1540-6. doi: 10.3945/jn.112.163824.
- Crawley P. The complicated Truth Behind Aspartame. www.theglobeandmail.com http://www.theglobeandmail.com/life/health-and-fitness/health/the-complicated-truth-behind-aspartame/article16069158/. Accessed Aug 3, 2015.