February 22nd, 2006

Hi, my naturopath has told me that i should not eat drink anything containing aspartame as it will "kill my brain cells and poison my body". She said that it has been banned in America and Europe and that it should be banned here in Australia. It's the first i have heard of it. I notice your last question is dated July 2004, can you give me an update. Has it been banned, or is it an ongoing debate?

Matt Lowry, kid brother of Dr. Mark Lowry:

I cannot speak about Europe, but I can assure you that aspartame has not been banned in the United States. In fact, the most recent research on it shows that there is no link between aspartame-containing beverages (such as Diet Coke) and cancer... http://www.msnbc.msn.com/id/12155793/from/ET/ I'm not sure where your naturopath got their information, but I don't think they're giving you the straight story on aspartame. If you don't want to consume aspartame-containing products, fine by me. Just don't go claiming that using aspartame will kill you, because there is no evidence of this.

January 24th, 2006

I read Aspartame on heating beyond 30 degrees centigrade, decomposes to form methanol, the deadly poison. When Aspartame is consumed, doesn't it decompose within the body and harm us because our body is much warmer than that? Is it absolutely safe to consume low-calorie stuff? What are the long term side effects?

Matt Lowry, kid brother of Dr. Mark Lowry:

Note that this is essentially a cut-and-paste of a previous response, since the question is almost identical to an earlier one

Basically, what is often called wood alcohol is also known as methanol, and the anti-aspartamers often talk about the "methanol toxicity" of aspartame causing all sorts of problems. They make a lot of scary sounding claims in relation to such "methanol toxicity", but they are playing fast and loose with the facts. True enough, if you consume *enough* methanol on a daily basis, it'll hurt you - but it has to be a *lot* of methanol! I don't remember the exact numbers or proportions, but it came out to something like you would have to drink something insane, like a few gallons, of Diet Coke daily to get to the levels considered by scientists to be even mildly dangerous for methanol consumption. Personally I don't like the taste of Diet Coke, so I don't drink it. And to be honest, drinking water is probably better for you anyway, but if you do like Diet Coke, the amounts in which you are consuming it probably aren't going to cause you any problem.

Actually, there was just some recent research done on this. Here is a link to the article... http://www.msnbc.msn.com/id/12155793/from/ET/

July 23rd, 2004

I don't think there is a person on the planet who loves Diet Coke more than I do. I drink several large glasses every day. I have read a lot lately on the Internet about it being so bad for you. Your site has been interesting to read, but I worry that maybe since I drink "so much" that maybe I am at risk. Plus, I read a story where the six grade girl did a an experiment and she found wood alcohol in Diet Coke when it was heated up. Could I be at risk?

Matt Lowry, kid brother of Dr. Mark Lowry:

Someone a couple of years ago asked my brother, Dr. Mark Lowry, a very similar question when they visited our website. [See the December 28th, 2001 entry below for more]

Basically, what is often called wood alcohol is also known as methanol, and the anti-aspartamers often talk about the "methanol toxicity" of aspartame causing all sorts of problems. They make a lot of scary sounding claims in relation to such "methanol toxicity", but they are playing fast and loose with the facts.

True enough, if you consume *enough* methanol on a daily basis, it'll hurt you - but it has to be a *lot* of methanol! I don't remember the exact numbers or proportions, but it came out to something like you would have to drink something insane, like a few gallons, of Diet Coke daily to get to the levels considered by scientists to be even mildly dangerous for methanol consumption.

Personally I don't like the taste of Diet Coke, so I don't drink it. And to be honest, drinking water is probably better for you anyway, but if you do like Diet Coke, the amounts in which you are consuming it probably aren't going to cause you any problem.

July 8th, 2004

someone told me that I should stop introducing Aspartame in my diet because it causes memory loss and others diseases. I'm just wondering how aspartame works in the brain and in which way it could damage neurons. I tried to answer my question by myself and the only thing I can suppose is that an abuse of aspartame is like an abuse of monosodium glutamate because they both are made by amino acids. The abuse of MSG can increase the amount of glutamate in the body, the overactivity of glutamate would eventually fire neurons to death ('cause GABA inhibition couldn't be enough) causing various physical symptoms. I thought that maybe an abuse of aspartic acid and phenilalanine could excite neurons too much, causing problems.

In fact aspartame is made by natural ingredients, I thought, so why should it be so bad? Of course an abuse can damage the body, as far as alchool, fat, sugar, and other natural things do, but can you help me understanding the way aspartame works in the body?

Matt Lowry, kid brother of Doc:

It ends up that a chemist emailed me about this awhile back. He spoke specifically to the issue of aspartic acid and phenylalanine.

I will defer to him, as I am no chemist... briefly, here's what he said:

"I am a chemistry concentrator (that is, chem major) at Harvard College, and I just completed a lab course in synthetic organic chemistry. One of the projects I was assigned was the synthesis of aspartame from aspartic acid and phenylalanine...

... With the benefit of scifinder, I looked through a few of the papers they [anti-aspartamers] quote as evidence of aspartame's toxicity... with some comment to the effect that he wondered what you'd say now... Simply hilarious. Most of the papers he quotes are on *phenylalanine* toxicity; one of the few exceptions being a study by A.S. Leon et. al. on the long term effects of large doses of aspartame. The phenylalanine papers miss the question; and the Leon paper's abstract states that aspartame is safe up to the levels you'd get from drinking 10 L per day of diet soda...

My favorite quote from Betty Martini's website were the astonishing revelations that aspartame is "50% phenylalanine, 40% aspartic acid, and 10% methyl alcohol (wood alcohol)." (To quote my teaching assistant's response, the "[l]ast time I checked, I was about 5% phenylalanine, 5% aspartic acid, and I'm sure that my methyl alcohol is up around 10% on my best days," and he seems to be doing just fine. :-) Silly me for thinking that aspartame is a chemical compound instead of a mixture of three quite different substituents, and that it might have different properties from its components. Along that line of reasoning, perhaps we should ban organic compounds as well, since it has been shown that carbon soot is bad for us."

In addition, here is a response (http://caloriecontrol.org/response.html) on this same question from the United States Food and Drug Administration:

"Third, the claim that the two amino acids, phenylalanine and aspartic acid have neurotoxic effects. This is true in certain individuals and in high enough doses. The only subpopulation of individuals potentially susceptible to adverse effects from phenylalanine is homozygous phenylketonurics and in this case, food itself with much higher levels of phenylalanine from the protein in the diet contributes much higher toxicity for these unfortunate individuals. For those individual phenylketonurics who want to carefully control their intake levels of phenylalanine, they can do that by simply taking into consideration the amount of phenylalanine supplied by the aspartame product or, even more likely, simply refraining from use of these products. The USFDA requires that the aspartame product be labeled specially for phenylketonuric patients so that they will be aware of its presence in these products. As for the other amino acid in aspartame, the levels of aspartic acid ingested with aspartame use are many fold less than those levels responsible for causing adverse effects on the brain of animals and/or man. In fact, it is not clear that the experimentally derived data from animals is relevant to man. In any case, the levels of aspartic acid intake from aspartame are many fold below those needed to mediate neurotoxic effects."

So, to sum up, there is phenylalanine and aspartic acid in aspartame, but the concentrations of these chemicals that you would get in an average daily dose of Diet Coke is nowhere near what is necessary to even begin hurting you. The only people who should truly be concerned about this are those with PKU (phenylketonurics).

As for aspartame being "natural", I would say that is a dubious claim. It is an artificial sweetner in the sense that it doesn't just occur naturally - the hand of man is required to make it. That being said, don't fall into the trap of thinking that all things natural are good for you... the last time I checked, shark bites, volcanos and snake poison were pretty lethal things, despite being natural in origin.

January 29th, 2004:

For years I have been a diet soda drinker, and when Pepsi One came out a few years ago, I started drinking it, because I liked the taste. About two years ago, I started developing very severe headaches -- so severe that I would vomit and couldn't tolerate any light. Once I had to be taken to the hospital by ambulance, because the pain was so excrutiating. It took two shots of morphine to kill the pain. Prior to that, I had never had any type of headache except for sinus headaches. While these new headaches sometimes involved my sinuses, they were not sinus headaches, strictly speaking. But they weren't migraines either, according to the doctors. I underwent extensive sinus surgery, because I was desperate and the ENT convinced me that the headaches were from my sinuses (I did have Chronic Sinus Disease, nasal polyps and a deviated septum, according to the CAT Scans). Following the surgery, I kept getting the headaches. The ENT then said that the headaches were not caused by my sinuses, because my sinuses were then completely clear of infection and polyps and my septum was straightened (regardless of the headaches, that surgery was probably not a bad thing). It never even occurred to me that soda could be causing the headaches. I was not aware of any link between aspartame and headaches, and I've never seen the notorious e-mail mentioned on this site. I only discovered that the Pepsi One was responsible for my headaches when I decided to cut down on my caffeine intake a few months ago. I would drink caffeine-free diet soda most of the time and just have a glass of Pepsi One once in awhile. After a few times, I realized that everytime I had the Pepsi One, I got a very bad headache. I am 100% sure that it is the Pepsi One. If I have a glass of Pepsi One, YOU could feel the throbbing in my head with your finger and feel the extreme tightness of the muscles on one side on my neck. I did a Google search on "Pepsi One and headaches" and found out that Pepsi One is higher in caffeine than regular diet soda. I am very confused, because I can drink regular Diet Pepsi -- which contains both caffeine and aspartame -- without getting a headache. Do you have any idea what would be specific to Pepsi One that would cause severe headaches? Is there any significant interplay between caffeine and aspartame that only occurs when there is a high level of one or both that has been ingested? Are there other foods or beverages that I should be avoiding? Also, has there been anything reliable published of which you are aware that describes the quality of the headaches anecdotally described by people who believe that their headaches were caused by aspartame? I'm curious if my headaches are similar. Any input, thoughts or opinions would be greatly appreciated.

Matt Lowry, kid brother of Doc:

First of all, I would be wary of accepting anyone's anecdotal testimony (whether or not it is related to aspartame, caffeine, etc) in regards to your condition. I know of no relationship between aspartame and caffeine that could cause those kind of headaches.

I would suggest that you stay away from the Pepsi One if that seems to be the source of your headaches, but don't stop there. It may be a mistake to assume the Pepsi One is the cause of your pain, so you should consider seeing a doctor. You could have some other serious condition that needs looking into.

January 27th, 2004:

My husband was listening to a Sydney Radio Station last night and got up very worried . Apparently the Talk Back host was going on about Artificial Sweeteners causing Alzheimers and Arthritis. He claims to have proof that this is so. I have been using Artificial sweeteners for years and although I suffer from mild Osteoarthritis my memory is still pretty good. I am a 66 year old woman. What can you tell me about these claims please?

Matt Lowry, kid brother of Doc:

To my knowledge, there is no known connection between Alzheimer's (or arthritis) and aspartame. In fact, when I looked at the Alzheimer's Association's website, here's what I found...

http://www.alz.org/AboutAD/Myths.asp

August 15th, 2002:

I am 11 weeks pregnant with my 3rd child and was wondering why my prenatal vitamins contain aspartame. My OB/GYN gave me samples of 2 kinds of vitamins to see which ones I tolerate the best (I have been a little nauseated) and one type contains 6 mg, while the other contains 15 mg. I have always heard that aspartame is not safe and I do not let my 2 children have it. I'm sure that these vitamins have undergone rigorous testing, but I don't know why aspartame is in there to begin with.

Could you send me some info, or some websites that I read more about this topic? And from your medical opinion, is it safe to take these vitamins and why is aspartame in them?

Doc Lowry:

They are perfectly safe for you to consume, unless you have PKU. If you're concerned about this, ask your doctor to do a genetic test, but if you had it, you'd already know.

August 9th, 2002:

Hello... my mother has sugar diabetes. The question that i have for you is if my mother gets Aspartame into her system would it make her blood sugar go up or would it make it drop below normal. If she gets this into her system and affects her blood sugar how could i reverse that and make it better.

Doc Lowry:

Blood sugar up or down? Neither.

If her sugar drops, give her a cookie. If it goes up, adjust her insulin as her doctor prescribes.

Aspartame, in and of itself, has no effect of blood sugar levels. Intake of carbohydrates and levels of insulin do.

May 12th, 2002:

I am a 2nd year Journalism student studying in Deakin University and am seeking to write an article about diabetes and artificial sweeteners.

There are a few questions that I would like to ask about diabetes to help me with my article:

(1) How does a person get diabetes?

(2) How many people in the world suffer from diabetes (just an estimation would suffice)?

(3) Is there a certain age group or a particular group of people (eg: obese people) that are more susceptible to getting diabetes than others?

(4) What is the likelihood of younger people (say around the ages of 18-25) contracting diabetes?

(5) Is diabetes hereditary?

(6) Is there any cure for diabetes? If not, what sort of treatment for diabetes is there?

(7) What are the symptoms of diabetes? How does a person know if he/she has diabetes?

Any further information on diabetes will be much appreciated. Thank you for your time and attention.

Doc Lowry:

(1) Generally speaking, there are two types of diabetes. In Type I, the pancreas' production of insulin is diminished to the point that the sufferer has to have an external source of insulin in order to survive. In Type II, the pancreas produces plenty of insulin, but the person's body has an inadequate response to that insulin.

(2) No idea, but Type II diabetes seems to be more common in cultures where people tend toward obesity.

(3) Obese people and people who have a family history of Type II diabetes are at higher risk of themselves developing Type II diabetes. Family history or body type are less predictive of the development of Type I diabetes.

(4) Type I diabetes is also called Childhood Onset diabetes. It generally manifests itself within the first 20 years of a person's life. Type II diabetes used to be called Adult Onset diabetes, and was thought of as a disease of middle aged folks and older, but we are actually seeing more and more Type II diabetes in younger people, especially those that are overweight and who lead sedentary lives (i.e. lots of TV, lots of video games, very little physical activity).

(5) The tendency toward Type II diabetes shows a strong family connection. It used to be thought that there was a much smaller family connection in Type I diabetes, but there are some interesting trials underway to see if there is a way to predict the onset of Type I diabetes in people who have a close relative with the disease. The jury is still out on that one for now.

(6) Type I diabetes, where the sufferer requires an external source of insulin, can only be "treated" nowadays with injections of insulin several times a day. There have been a very few curative pancreas transplants, but that approach is still very much in the experimental phase. Type II diabetes is treated by dietary modification, exercise and medication taken orally. Interestingly enough, there is a significant cohort of Type II diabetics whose diabetes is "cured" by significant lifestyle changes including weight loss, diet change and exercise.

(7) The classic symptoms of new onset diabetes are increased drinking, increased urination and increased appetite. New onset Type II diabetes can have a relatively insidious onset, whereas new onset Type I diabetes typically has a much more rapid onset and the sufferer gets pretty sick fairly quickly. New Type I diabetics often present in a state called diabetic ketoacidosis which is a very serious condition and can lead to coma and death if not addressed fairly quickly.

There is no reliable indication that artificial sweeteners cause diabetes. The only connection is that obese people who are watching their weight by dieting and drinking diet sodas are also more likely to be at risk for Type II diabetes. But the risk for Type II diabetes has nothing to do with the artificial sweeteners, it has to do with body type, activity level and genetic predisposition.

December 28th, 2001:

How can you be sure that long-term exposure to methanol does not cause any serious health problems?. I personally wish people who want to lose weight would not resort to artificial chemicals of any description and reduce their intake of food while safely increasing their exercise which worked for me. Isn't it also true the liver has to work harder to detoxify the aspartame?

Doc Lowry:

I agree that the best way to lose weight is to moderate your food intake and increase your expenditure of calories. One doesn't have to resort to diet foods unless one wants to fool oneself into thinking you're still eating the sweet/salty/fatty foods that got one into weight trouble to begin with.

As to long-term exposure to methanol, you're half right. Long-term (or even short-term in high enough doses) exposure to methanol can cause damage, but only if you've ingested amounts that exceed your liver's ability to metabolize it. I don't know the numbers off the top of my head, but there is a certain amount of methanol that can easily be broken down by the human liver. The amount of methanol in an aspartame-containing beverage is miniscule by comparison. Here's an analogy: we can all assume that eating a 5 lb. pile of salt would cause serious health problems (not the least of which would be death if you didn't vomit it all up); however there are small amounts of salt in our everyday foods, and some people like to add quite a lot of salt to their food. Up to a certain point, people with properly functioning kidneys can easily excrete this additional salt load. The same principle applies to the liver metabolizing the tiny amount of methanol generated when the aspartame in a diet drink is digested.

Your question was, "How can you be sure that long-term exposure to methanol does not cause serious health problems?" The easiest way to answer that is to tell you that since the advent of aspartame as a food additive, and given the number of people consuming it on a regular basis, there have been no epidemics of blindness, brain damage, liver disease, etc. -- the problems one would associate with methanol poisoning.

If you are concerned about liver's ability to metabolize methanol, or anything else for that matter, go discuss it with your doctor. If the two of you decide to, there are some simple blood tests that can assess your liver function.

September 9th, 2001:

What is it about the aminio acids in Aspartame that make them sweet? How come when you eat meat it doesn't taste sweet?

Doc Lowry:

Answer: The chemical structure of aspartame is recognized by an octapeptide (8 amino acid in size) "sweetness receptor" on the tongue. Evidently, other "sweet" substances react with the same or other receptor sites on this larger molecule. Basically, this particular pair of amino acids (aspartame), joined together the way they are, stick to a receptor site on the surface of a cell on our tongues, and initiate a cascade of events that result in a "sweet" signal being sent to our brain. The reason meat doesn't taste sweet is that while it has all these amino acids present in its protein structure, it takes the particular arrangement of the two amino acids in aspartame (aspartic acid and phenylalanine) to attach to the receptor site and trigger the "sweet" signal.

An interesting side note: among the primates, only Old World primates and humans percieve aspartame as sweet; New World primates evidently don't have the same structure to their "sweetness receptor" that humans do. The part that recognizes sucrose as being sweet is the same, which is why, say, a lemur from the Amazon basin likes sugar water as much as a chimpanzee, but only the chimp would prefer water sweetened with aspartame over tap water.

September 6th, 2001:

I have started using aspartame tablets (called "Sugar Free" in this part of the world) as an artificial sweetener in place of normal cane sugar in an attempt to limit my caloric intake. I have come across a number of articles on the Internet warning against the use of aspartame. Kindly tell me if using aspartame, 3-4 tablets (supposed to be equivalent to 3-4 teaspoonfuls of sugar) a day is safe.

Doc Lowry:

I'm not familiar with the brand name product "Sugar Free", but if the amount you are taking is supposed to provide sweetness equivalent to 3-4 teaspoons of table sugar, then you are likely consuming much less aspartame than is found in even a single can of diet soda. There is no sound scientific evidence to support the proposition that aspartame causes the things claimed by those articles you found on the internet. My only caution about using aspartame is that persons with the genetically inherited condition PKU should not consume it because aspartame contains phenylalanine. Other than that, there is no valid evidence to cause the scientific/medical community to believe that aspartame is dangerous.

September 1st, 2001:

Does aspartame cause diarrhea?

Doc Lowry:

I have found no evidence in the medical literature that aspartame causes diarrhea. Without knowing any more about why you ask this question, I can't really offer any further advice. Having said that, there is the possibility that you have had some kind of reaction to whatever food it was that was sweetened with aspartame, but I very much doubt that aspartame was to blame.

Aspartame is composed of two amino acids that are found in our everyday foods anyway. It is broken down in the gut and is thereafter treated just like amino acids from any other dietary source. Additionally, the two amino acids are joined together by a chemical bond that itself breaks down to a minute amount of methanol, which, too, is metabolized rapidly by the body. Like the amino acids, methanol is found in many of the foods we eat: fresh fruits and vegetables and their juices for example, and our bodies metabolize the methanol from any source the same way.

August 8th, 2001:

I got the aspartame email from my mother in law. She has been telling me for years not to drink anything with aspartame in it, since it first came out actually. So when I got the email I believed it...I also have vertigo (menieres disease) fibromyalgia, osteoarthritis (joint pain), dizziness. I am 33 yrs old so 'this' made perfect sense to me..because I'm too young to have all these problems..right?? but I am also a skeptic so I decided to look around on the web to see what I could see on the matter. It was interesting to me that almost every site had reference to this Markle person and the "World Conference of 'something'". Do you know what this World Conference is? I emailed my husband the email my mother in law sent and he asked if it was a sect of the Branch Davidians. (he was joking but I got the impression that he had never heard of such a thing either.)

Matt Lowry, kid brother of Doc:

Since your question is not strictly medical, I'll answer it rather than passing it on to my brother, Mark. I tried looking around for this institution... it is (or was) called the "World Environmental Conference"; however, I was unable to find any information on this conference when I began researching this whole aspartame issue over two years ago. I just now conducted another search of the Internet and could find no reference to the WEC beyond it appearing in numerous incarnations of the anti-aspartame email that has blossomed across the Web. Does it really exist? Who knows?

Note that this does not in and of itself discount the existence of such a conference (or that that particular conference actually took place), but the fact that the author(s) of the Markle email did not provide any reference to this conference casts further doubt on the validity of the scare email.

August 1st, 2001:

I am pregnant and i wonder is phenyliketonurics safe? will it affect the baby inside of me? I am five months pregnant and my doctor said a little is ok. Please respond if you can!

Doc Lowry:

Answer: I am aware of several studies, both prospective and retrospective, examining what effect, if any, aspartame has on developing mammals (mice, rats, and humans). None of it indicates that there is any risk to your baby if you drink the occasional diet pop, with the following exception: if you know that you have phenylketonuria (PKU) or you know that you are a carrier for PKU, you should stay away from aspartame and you should talk with your obstetrician about the proper diet for you.

That said, I would not recommend you go over one or two a day anyway; not because I think aspartame poses any danger, but because there's no nutritional value in diet soda. If you're filling up with diet drinks, you're missing the opportunity to drink milk or fruit juice instead. In your pregnancy, you are eating for two, so to speak, and the extra vitamins and calcium are more needed than the caffeine and carbonation in diet sodas.

Mark Lowry III, M.D.

July 31st, 2001:

I am currently trying to gather information on whether or not aspartame is found in breast milk of mothers who consume this product. I am currently nursing my 6 month old child and am concerned about this issue. I am also concerned about the possible side effects of aspartame on my child if he is indeed getting it from my breast milk.

Doc Lowry:

I don't know any figures on what happens to the levels of phenylalanine and aspartic acid in the breastmilk of women who drink aspartame-containing beverages. There are, however, several studies that show that serum (blood) levels of phenylalanine and aspartic acid are essentially unchanged in normal people after they consume even huge amounts of aspartame. From this data, I feel fairly safe in concluding that the levels of these two substances would probably not be affected in your breast milk.

I should make the point that phenylalanine and aspartic acid are not foreign, artificial chemicals in aspartame. They are actually normal amino acids found in our everyday foods. A can of diet soda contains about 100 mg of phenylalanine, for example, but a hamburger contains nearly 9 times as much of this same amino acid.

The only reason I would give why you should not drink aspartame-containing drinks while breast feeding is that nutritionally, you'd be better off (as would your baby) if you drank milk or vegetable/fruit juice. Diet sodas have basically no nutritional value at all.

Mark Lowry III, M.D.

July 30th, 2001:

will anything ever be done about removing products that contain aspartame? about a year ago i was having a lot of pain in my arms and numbness. I went to the doctor several times. First time they said i had tennis elbow. It did not get any better. The next time they said I had arthritis and gave me vioxx. It did not help. My mother saw a brochure on aspartame explaining the effects it was having on people. I was drinking 2 and 3 diet cokes a day. I decided to stop the diet cokes to see if the pain and numbness went away. Guess What! It did. I went thru a lot of pain and spent some money going to the doctors. I know there is a lot of people out there who are suffering unnecessarly because of aspartame and have no idea. IS ANYTHING GOING TO BE DONE ABOUT THIS?

Doc Lowry:

When there is conclusive, verifiable evidence which scientifically proves that aspartame causes any human disease state, then we'll have something to hang our hats on.

As long as the "proof" consists of anecdotal stories about someone's subjective symptoms disappearing after they read a brochure, the mainstream scientific community (including me) will remain skeptical of aspartame's supposed dangers.

To be quite honest, I cannot discount the possible role that the counter-placebo effect may have played in the disappearance of your arm pain. There are actually scholarly papers published on the role aspartame may have in helping the pain of arthritis.

Mark Lowry III, M.D.

July 29th, 2001:

Hello. I am an avid diet coke (and anything else diet) drinker. Lately I've been getting stomach aches. I'm not sure if it's related to anything from these diet drinks or if it's just stress.

I have a carton of diet Nestea. It has aspartame as one of the ingredients. It has an * after it. I looked down further and it said this.... Phenylketonurics: contains phenylalanine

What exactly does that mean? Could I have developed some sort of allergy to diet drinks now or is it something more serious or less serious?

Doc Lowry:

Phenylketonuria (PKU) is a genetically inherited disorder wherein the sufferer lacks the ability to properly metabolize dietary phenylalanine. If undetected in an infant, it can lead to mental retardation and other consequences.

The problems related to PKU manifest in childhood since most foods (particularly proteins) contain phenylalanine. In short, if you had PKU, you'd probably know it. It's something you're born with, not something you can "catch" or develop later.

As to your stomach aches, you made brief mention of stress, but you didn't go into it that much. On such slight information, I'd have to say Sure, it might be the stress. Or the caffeine, or the acidity or just having a belly full of carbonated drinks.

Not to scare you, but it might be other things, too. What, I don't know. I would encourage you to take this up with your doctor if it continues to be a problem. Persistent stomach pains may indicate an ulcer, cancer, acid reflux disease or any of a number of other problems.

Mark Lowry III, M.D.