Aspartame and the brain
As Americans, we assume and insist that our food be safe. We'll take spinach off the market the minute there's even a hint of e Coli. We're paranoid about mad cow disease. But when it comes to our beloved sugar? We'll go around and around and around about the safety of aspartame until we're blue in the face. We just don't want to admit that maybe we should not be insisting and expecting that we get to be healthy and have our sweeteners (and fake sweeteners) too.
Twelve years ago I wrote the American Dietetic Association's first book ever on eating disorders. Back then, I found a peer-reviewed reference on aspartame, suggesting that it had a particular ability to have a negative effect on individuals with a history of depression. In the years since, I've shared that reference with clients, challenged them to clear their systems of aspartame for 6 weeks, then go back and try a little bit of it to see how they feel. I've yet to have a single person come back to report they'd gotten back on it once they'd cleared their systems.
The problem is, aspartame was not intended to be consumed in large quantities by a population of people who insisted on being in denial about what it means to have insatiable cravings for a refined compound with no nutritional value. And while it started out in soft drinks, it eventually showed up in yogurts, and protein powders, and anything food manufacturers could think of to make a buck off of our addiction. As aspartame gradually crept into the food supply, and accumulated in larger and larger amounts in our bodies...we lost the ability to even remember how we felt when we were completely off the stuff. Which is why I love the power of my "washout experiment".
Now, it seems, there is more information suggesting that aspartame may not be so great for the brain. This new study is not even cited yet in Pub Med as I write this. I don't normally do this in this blog, but I am pasting the entire release for anyone who would like to evaluate the information for themselves.
A few years ago there was an aspartame e-mail circulating the Internet that quickly became regarded as urban legend. It illustrated the importance of doing your homework before speaking out about anything. The person who circulated this piece used a fake name, and did not take the time to gather data and citations. So most scientists dismissed the warning. I'd already seen the aspartame/depression study at this time. I was perturbed at the well-intended person who was more engaged in stirring up controversy than in helping people, because, having read that there may be some REAL dangers with aspartame, I knew that when those were eventually elucidated, it was going to be even harder to convince hard scientists that these dangers existed because they'd immediately think of the earlier "aspartame urban legend" and associate any other warnings with this irresponsible piece of Internet writing.
Which is why I'm giving you my source. Whether or not you use artifical sweeteners is your choice. But remember, as you've seen before in this blog, in medicine and science, there is no such thing as a perfect choice. Every food, every supplement, every treatment, you choose to try, has its benefits as well as its risks. Perhaps the best way for you to decide for yourself, is to try my washout challenge. What matters is not what a panel of experts says about aspartame in general, but how aspartame makes you feel. Only you know this, and the only person who gets to decide whether or not you should use it...should be you.
Below the review is the reference for the old study I mention as well.
Review raises questions over aspartame and brain health
By staff reporter
03-Apr-2008 - Excessive intake of aspartame may inhibit the ability of
enzymes in the brain to function normally, suggests a new review that
could fan the flames of controversy over the sweetener.
The review, by scientists from the University of Pretoria and the University of Limpopo and published recently in the European Journal of Clinical Nutrition, indicated that high consumption of the sweetener may lead to neurodegeneration.
Aspartame is made up of phenylalanine (50 per cent), aspartic acid (40 per cent) and methanol (10 per cent). It is commonly used in food products for the diet or low calorie market, including soft drinks and chewing gums. It was approved for use in foods in the US and EU member states in the early 1980s.
The sweetener has caused much controversy amid suspicions on whether it is entirely safe, with studies linking the ingredient and cancer in rats.
It has also previously been found that aspartame consumption can cause neurological and behavioural disturbances in sensitive individuals. Symptoms that have been reported include headaches, insomnia and seizures.
Despite strong concerns being raised from some quarters over the sweetener, both the European Food Safety Authority (EFSA) and the US Food and Drug Administration (FDA) have not changed their guidelines regarding the safety of the ingredient or intake advice.
The new review also challenges finding published last year in the journal Critical Reviews in Toxicology (Informa Healthcase) that considered over 500 studies, articles and reports conducted over the last 25 years - including work that was not published, but that was submitted to government bodies as part of the regulatory approvals process.
The earlier review concluded: "The weight of existing evidence is that aspartame is safe at current levels of consumption… No credible evidence was found that aspartame is carcinogenic, neurotoxic, or has any other adverse effect on health when consumed even at quantities many times the established ADI [acceptable daily intake] levels."
Writing in the European Journal of Clinical Nutrition, a Nature journal, the scientists behind the new review state: "The aim of this study was to discuss the direct and indirect cellular effects of aspartame on the brain, and we propose that excessive aspartame ingestion might be involved in the pathogenesis of certain mental disorders, and also in compromised learning and emotional functioning."
The researchers found a number of direct and indirect changes that occur in the brain as a result of high consumption levels of aspartame, leading to neurodegeneration.
They found aspartame can disturb the metabolism of amino acids, protein structure and metabolism, the integrity of nucleic acids, neuronal function and endocrine balances. It also may change the brain concentrations of catecholamines, which include norepinephrine, epinephrine and dopamine.
Additionally, they said the breakdown of aspartame causes nerves to fire excessively, which can indirectly lead to a high rate of neuron depolarisation.
The researchers added: "The energy systems for certain required enzyme reactions become compromised, thus indirectly leading to the inability of enzymes to function optimally.
"The ATP stores [adenosine triphosphate] in the cells are depleted, indicating that low concentrations of glucose are present in the cells, and this in turn will indirectly decrease the synthesis of acetylcholine, glutamate and GABA (gamma-aminobutyric acid)."
Furthermore, the functioning of glutamate as an excitatory neurotransmitter is inhibited as a result of the intracellular calcium uptake being altered, and mitochondria are damaged, which the researchers said could lead to apoptosis (cell death) of cells and also a decreased rate of oxidative metabolism.
As a result of their study, the researchers said more testing is required to further determine the health effects on aspartame and bring an end to the controversy.
Source: European Journal of Clinical Nutrition
2008, doi: 10.1038/sj.ejcn.1602866
"Direct and indirect cellular effects of aspartame on the brain"
Authors: P. Humphries, E. Pretorius, H. Naude
Biol Psychiatry. 1993 Jul 1-15;34(1-2):13-7. Links
Adverse reactions to aspartame: double-blind challenge in patients from a vulnerable population.Walton RG, Hudak R, Green-Waite RJ.
Department of Psychiatry, Northeastern Ohio Universities College of Medicine, Youngstown.
This study was designed to ascertain whether individuals with mood disorders are particularly vulnerable to adverse effects of aspartame. Although the protocol required the recruitment of 40 patients with unipolar depression and a similar number of individuals without a psychiatric history, the project was halted by the Institutional Review Board after a total of 13 individuals had completed the study because of the severity of reactions within the group of patients with a history of depression. In a crossover design, subjects received aspartame 30 mg/kg/day or placebo for 7 days. Despite the small n, there was a significant difference between aspartame and placebo in number and severity of symptoms for patients with a history of depression, whereas for individuals without such a history there was not. We conclude that individuals with mood disorders are particularly sensitive to this artificial sweetener and its use in this population should be discouraged.