7 ms·

This article is both accurate and highly misleading. The author is correct that there is very little reliable evidence that links glutamic acid and/or glutamate

by dsrguru 13y ago

This article is both accurate and highly misleading. The author is correct that there is very little reliable evidence that links glutamic acid and/or glutamate to health problems. The backlash against MSG as a result of the "Chinese Restaurant Syndrome" craze, was not rooted in scientific inquiry. However, MSG is not just a source for glutamate like seaweed and tomatoes are. MSG is the sodium salt of glutamic acid and contains not just glutamate but also sodium ions. Having 2000mg of natural glutamate should be harmless. Having enough MSG to give you 2000mg of glutamate means you're getting a shit ton of sodium. That's not good for you, especially if you're one of the many people for whom excess sodium intake adversely affects your blood pressure. So while MSG is presumably no worse than NaCl (and is perhaps better in that the umami flavor means you don't have to use as much sodium to get an equally rich taste), to say that MSG is totally harmless without even mentioning sodium and hypertension is ridiculous. Even in terms of short term effects, I've had plenty of MSG-free hot and sour soups that made my head itch. Not from MSG but from thousands of mg of sodium found in their gratuitously added soy sauce and table salt.

ecopoesis 13y ago
The link between sodium and high blood pressure is not conclusive: http://www.todayifoundout.com/index.php/2013/02/why-does-salt-raise-blood-pressure/ http://www.todayifoundout.com/index.php/2013/02/why-does-sal...
- madlynormal 13y ago
  As a person with HBP who actively monitors it, I can tell you this much. Sodium intake definitely affects my blood pressure. It goes like this, the higher my intake the shittier I feel. I'm not saying sodium is the main or only cause of HBP, it seems to affect some more then others, and there may be other underlining causes. But to call it a myth is downright ridiculous.
- tptacek 13y ago
  The link between sodium and edema, water retention, and kidney stress is not inconclusive. Large doses of sodium clearly have some impact. The question is, is that impact sufficient to explain the symptoms of Chinese Restaurant Syndrome, not whether the average person needs to moderate sodium consumption to avoid hypertension.
- brianleb 13y ago
  In short: your blood is mostly water. Your blood is surrounded by a selectively permeable membrane (your vascular tissue). Solutes increase osmotic pressure (see: biology 101). Sodium chloride (table salt) is highly soluble in water (see: chemistry). Therefore, sodium and chloride increase the osmolarity of your blood. Water passes through the semi-permeable membrane back into your blood to decrease osmotic pressure caused by the excess of sodium/chloride in your blood versus in the surrounding cells. Your blood pressure increases because the water increases the volume of your blood while the vascular tissue tries to contain and mediate this reaction (see: physics). Blog posts are not a substitute for an education in biology, medicine, and science. If anyone is going to nitpick about things in this post, please understand that I am striving to be understood. While I could put an asterisk after every sentence ("*except for...,") it would not be productive to do so. If anyone wishes for clarification, I would be glad to provide.
  - sk5t 13y ago
    This explanation, while straightfoward and common-sensical, ignores the possibility that the body has some ability to eliminate excess solutes and/or excess fluids. Certainly the case is quite good that "more fluid in circulatory system yields higher blood pressure."
    - brianleb 13y ago
      Indeed, and this possibility is called the kidney. Young people with 'healthy' kidneys are able to eat and drink almost anything they want and are much more likely to have well-regulated blood pressure. However, as we age, our kidneys perform more poorly (a simple explanation as to why older people are more likely to take blood pressure medications than younger people). As our physiology weakens, our diet (and exercise, among other things) become more important to our physiological health. This, in conjunction with the hardening of our arteries due to age and atherosclerosis, means that our diet (particularly our sodium intake) becomes exponentially more important in our older age than our younger age. If this sounds unlikely, understand that the kidney is the direct or indirect target of many medications for blood pressure. Diuretics such as hydrochlorothiazide and loop diuretics such as furosemide act very directly on the kidney. Drugs such as ACE inhibitors (e.g. lisinopril), ARBs (e.g. losaratan), and renin inhibitors (aliskiren) act on the renin-angiotensin-aldosterone system, which directly involves the kidneys in a different manner. (I am a pharmacist).
refurb 13y ago
If you do the math, 2000 mg of MSG would give you the same amount of sodium as (2/169.11 * 58.44) 690 mg of table salt. In other words, the sodium intake from eating MSG is about 1/3 that of table salt on a per weight basis.
- nitrogen 13y ago
  The OP didn't say 2000mg of MSG, they said 2000mg of glutamate. So you'd have to modify your calculation a bit to know how much MSG contains 2000mg of glutamate, and from there how much sodium that would contain.
anonymous 13y ago
"Chinese Restaurant Syndrome" is real though. Or rather I personally can't eat most things at chinese restaurants and this article was the first time I heard that this is actually a named thing, i.e. this is the first time I hear of CRS. Though I think it's more to do with the fat they use to fry rice in -- there is one place around here which serves chinese-style stir-fried noodles, but eating there reliably does not trigger any symptoms. They are also the priciest noodles around. Maybe CRS should just be named "bad cheap fried food syndrome". It's not a TLA, but you can just smush all the words together and call it bacheff syndrome.
- justin66 13y ago
  Some people are allergic to MSG (or maybe just glutamate). I'm sure it is something an allergist could test you for.
- sk5t 13y ago
  Maybe you've just eaten at some dirty Chinese restaurants. Can you eat pizza? http://www.chow.com/food-news/69604/you-re-not-allergic-to-msg-and-7-more-secrets-from-a-research-chef/ http://www.chow.com/food-news/69604/you-re-not-allergic-to-m...
- brianleb 13y ago
  If you read the original New England Journal of Medicine article on which this is based (http://www.nejm.org/doi/full/10.1056/NEJM196804042781419 http://www.nejm.org/doi/full/10.1056/NEJM196804042781419), you will find that is it in fact an anecdote where quite literally a physician ate Chinese food and wrote a letter about it. There is no research, no evidence, no null hypothesis.
Figs 13y ago
Has anyone conducted a study to test if the headaches are actually just dehydration?
- tptacek 13y ago
  Yes, but the result was "we couldn't induce headaches at all, except in subjects who had in fact consumed a placebo". Studies have decisively refuted a link between MSG and CRS.
  - Figs 13y ago
    I meant -- has anyone tried to see if people who complain about headaches after eating at Chinese restaurants are just dehydrated from eating too much salt?
espeed 13y ago
It's not the sodium, it's the glutamate (the "G" in MSG). Glutamate is an excitotoxin, and it's an additive in almost all processed foods, in various forms with many different names (http://www.truthinlabeling.org/hiddensources.html http://www.truthinlabeling.org/hiddensources.html). Excitotoxicity is the "pathological process by which nerve cells are damaged and killed by excessive stimulation by neurotransmitters such as glutamate and similar substances" (https://en.wikipedia.org/wiki/Excitotoxicity https://en.wikipedia.org/wiki/Excitotoxicity). As the article says, when glutamate is consumed naturally, it is intertwined with fiber and other chemicals that regulate its uptake; however, glutamate additives are not and thus flood your body with glutamate, which can overload your blood-brain barrier (https://en.wikipedia.org/wiki/Blood%E2%80%93brain_barrier https://en.wikipedia.org/wiki/Blood%E2%80%93brain_barrier) and disrupt the delicate balance. This is akin to Dr. Lustig's (https://en.wikipedia.org/wiki/Robert_Lustig https://en.wikipedia.org/wiki/Robert_Lustig) findings on sugar (fructose): Eating whole fruits is fine because you're consuming fiber with the fructose (nature provides the antidote), but fruit juice is all fructose and no fiber so your body is flooded with fructose, which is toxic (http://www.nytimes.com/2011/04/17/magazine/mag-17Sugar-t.html?_r=0 http://www.nytimes.com/2011/04/17/magazine/mag-17Sugar-t.htm...).
- ricardobeat 13y ago
  But nobody eats MSG by itself like fruit juice, won't mixing it to food that contains fiber and 'other chemicals' have the same effect?
  - espeed 13y ago
    No, because adding extra glutamate means the ratio of glutamate will be higher than the counterbalance.
    - ricardobeat 13y ago
      That went over my head. What do you mean? When making a risotto I might use 100g of parmesan cheese, which can amount to ~8g of MSG according to the internets, plus eat tomatoes on the side. That's the equivalent of 12g of Ajinomoto, I can't imagine adding that much to any dish.
baby 13y ago
I went to this sketchy restaurant in Spain once, and started having pins and needles all around my skull. Reading what you just write, that might have been because of too much MSG. Pretty scary at that time.
ScotterC 13y ago
Point of reference. A chipotle burrito is about 2000 mg of sodium as well.
mathattack 13y ago
You hit the nail on the head. For most of us, it's not the MSG that causes the problem. It's what comes with it. For starters it's the sodium. For me it's the 1000 calories in a monster Doritos bag, or the 3000 calories when I eat three times what I should at a Chinese takeout.
lamontcg 13y ago
So here's the thing that happens to me... When I eat certain foods, I tend to wake up in the middle of the night feeling hot, and it feels like I've got elevated blood pressure and my mind is racing a bit and it keeps me up at night. This is a very particular effect and it seems to be food linked. I get it after eating Chinese food, I get it after eating Pizza, I get it after eating a pile of spaghetti with red sauce. I used to gorge on Triscuits and Cheese and I'd get the same effects. I thought it was the carbs at first since those seem to be bad for me with weight gain and thought it was all related. But, there's another link there which is that all of that has MSG or glutamate in it (and also lots of sodium of course). So if i stay away from those foods I don't get the horrible sweaty middle insomnia symptoms. I can eat carbs if I stay away from glutamate/sodium, so my first guess that it was the white rice, pizza crust and spaghetti noodles was incorrect. But the MSG is always correlated with the symptoms. Is it the MSG or is it that the MSG comes with the salt? I dunno. I'm not really certain that it matters either. (I've also had my BP taken by a cardiologist the day after eating Chinese food and it spiked enough to cross the line between normal and high blood pressure the next morning after the meal...)
akingoffools 13y ago
Another point worth considering is the chirality of the molecule. There is a strong bias in biological systems in favour of l-oriented amino acids; a bias often unreflected or different in synthesised chemicals. Biological systems often react differently to the different enantiomers of a chemical, sometimes being unresponsive to the enantiomer of a biologically active molecule, sometimes responding in a different but useful manner, and sometimes reacting adversely.
- not_clear 13y ago
  When I had first heard about this, it was the only anti-MSG argument that sounded even remotely plausible, but it seems that nowadays commercial MSG is made by bacterial fermentation, which means that they would also have the preference for L-oriented amino acids. Wikipedia confirms this http://en.wikipedia.org/wiki/Monosodium_glutamate#Production The referenced papers on the process (from 1957!) indicates that they were reporting L-glutamate producing bacteria specifically: https://www.jstage.jst.go.jp/article/jgam1955/3/3/3_3_193/_article Here is an overall history of MSG production, including chemical synthesis (now obsolete). Even when they were doing this, they screened out the D-glutamate and re-synthesized it to maximize L-glutamate production (might not have been 100% effective, as apparently it involved doing optical screening of the crystals) http://ajcn.nutrition.org/content/90/3/728S.full Disclaimer - I am Japanese American, so grew up with Ajinomoto MSG, dashi, tomato sauce, parmesan, Doritos, etc. as part of my diet, so am biased toward skepticism on this topic.
  - not_clear 13y ago
    Interesting - the metafilter referenced elsewhere on the thread had a pointer to a paper about D-glutamate vs L-glutamate. Apparently, bacterial fermentation generates a fair amount of D-glutamate, but this is true of "naturally occurring" fermentation (such as in cheese) too. The abstract claims foods to which MSG is added directly contained lower amounts of D-glutamate than foods where the MSG comes from fermented foods. I wonder why? Maybe due to better optimization / control for L-glutamate production in the bacteria? http://onlinelibrary.wiley.com/doi/10.1002/chir.530060410/abstract http://onlinelibrary.wiley.com/doi/10.1002/chir.530060410/ab...

by dsrguru 13y ago

ecopoesis 13y ago

The link between sodium and high blood pressure is not conclusive: http://www.todayifoundout.com/index.php/2013/02/why-does-salt-raise-blood-pressure/ http://www.todayifoundout.com/index.php/2013/02/why-does-sal...

madlynormal 13y ago
As a person with HBP who actively monitors it, I can tell you this much. Sodium intake definitely affects my blood pressure. It goes like this, the higher my intake the shittier I feel. I'm not saying sodium is the main or only cause of HBP, it seems to affect some more then others, and there may be other underlining causes. But to call it a myth is downright ridiculous.
tptacek 13y ago
The link between sodium and edema, water retention, and kidney stress is not inconclusive. Large doses of sodium clearly have some impact. The question is, is that impact sufficient to explain the symptoms of Chinese Restaurant Syndrome, not whether the average person needs to moderate sodium consumption to avoid hypertension.
brianleb 13y ago
In short: your blood is mostly water. Your blood is surrounded by a selectively permeable membrane (your vascular tissue). Solutes increase osmotic pressure (see: biology 101). Sodium chloride (table salt) is highly soluble in water (see: chemistry). Therefore, sodium and chloride increase the osmolarity of your blood. Water passes through the semi-permeable membrane back into your blood to decrease osmotic pressure caused by the excess of sodium/chloride in your blood versus in the surrounding cells. Your blood pressure increases because the water increases the volume of your blood while the vascular tissue tries to contain and mediate this reaction (see: physics). Blog posts are not a substitute for an education in biology, medicine, and science. If anyone is going to nitpick about things in this post, please understand that I am striving to be understood. While I could put an asterisk after every sentence ("*except for...,") it would not be productive to do so. If anyone wishes for clarification, I would be glad to provide.
- sk5t 13y ago
  This explanation, while straightfoward and common-sensical, ignores the possibility that the body has some ability to eliminate excess solutes and/or excess fluids. Certainly the case is quite good that "more fluid in circulatory system yields higher blood pressure."
  - brianleb 13y ago
    Indeed, and this possibility is called the kidney. Young people with 'healthy' kidneys are able to eat and drink almost anything they want and are much more likely to have well-regulated blood pressure. However, as we age, our kidneys perform more poorly (a simple explanation as to why older people are more likely to take blood pressure medications than younger people). As our physiology weakens, our diet (and exercise, among other things) become more important to our physiological health. This, in conjunction with the hardening of our arteries due to age and atherosclerosis, means that our diet (particularly our sodium intake) becomes exponentially more important in our older age than our younger age. If this sounds unlikely, understand that the kidney is the direct or indirect target of many medications for blood pressure. Diuretics such as hydrochlorothiazide and loop diuretics such as furosemide act very directly on the kidney. Drugs such as ACE inhibitors (e.g. lisinopril), ARBs (e.g. losaratan), and renin inhibitors (aliskiren) act on the renin-angiotensin-aldosterone system, which directly involves the kidneys in a different manner. (I am a pharmacist).

refurb 13y ago

If you do the math, 2000 mg of MSG would give you the same amount of sodium as (2/169.11 * 58.44) 690 mg of table salt. In other words, the sodium intake from eating MSG is about 1/3 that of table salt on a per weight basis.

nitrogen 13y ago
The OP didn't say 2000mg of MSG, they said 2000mg of glutamate. So you'd have to modify your calculation a bit to know how much MSG contains 2000mg of glutamate, and from there how much sodium that would contain.

anonymous 13y ago

"Chinese Restaurant Syndrome" is real though. Or rather I personally can't eat most things at chinese restaurants and this article was the first time I heard that this is actually a named thing, i.e. this is the first time I hear of CRS. Though I think it's more to do with the fat they use to fry rice in -- there is one place around here which serves chinese-style stir-fried noodles, but eating there reliably does not trigger any symptoms. They are also the priciest noodles around. Maybe CRS should just be named "bad cheap fried food syndrome". It's not a TLA, but you can just smush all the words together and call it bacheff syndrome.

justin66 13y ago
Some people are allergic to MSG (or maybe just glutamate). I'm sure it is something an allergist could test you for.
sk5t 13y ago
Maybe you've just eaten at some dirty Chinese restaurants. Can you eat pizza? http://www.chow.com/food-news/69604/you-re-not-allergic-to-msg-and-7-more-secrets-from-a-research-chef/ http://www.chow.com/food-news/69604/you-re-not-allergic-to-m...
brianleb 13y ago
If you read the original New England Journal of Medicine article on which this is based (http://www.nejm.org/doi/full/10.1056/NEJM196804042781419 http://www.nejm.org/doi/full/10.1056/NEJM196804042781419), you will find that is it in fact an anecdote where quite literally a physician ate Chinese food and wrote a letter about it. There is no research, no evidence, no null hypothesis.

Figs 13y ago

Has anyone conducted a study to test if the headaches are actually just dehydration?

tptacek 13y ago
Yes, but the result was "we couldn't induce headaches at all, except in subjects who had in fact consumed a placebo". Studies have decisively refuted a link between MSG and CRS.
- Figs 13y ago
  I meant -- has anyone tried to see if people who complain about headaches after eating at Chinese restaurants are just dehydrated from eating too much salt?

espeed 13y ago

It's not the sodium, it's the glutamate (the "G" in MSG). Glutamate is an excitotoxin, and it's an additive in almost all processed foods, in various forms with many different names (http://www.truthinlabeling.org/hiddensources.html http://www.truthinlabeling.org/hiddensources.html). Excitotoxicity is the "pathological process by which nerve cells are damaged and killed by excessive stimulation by neurotransmitters such as glutamate and similar substances" (https://en.wikipedia.org/wiki/Excitotoxicity https://en.wikipedia.org/wiki/Excitotoxicity). As the article says, when glutamate is consumed naturally, it is intertwined with fiber and other chemicals that regulate its uptake; however, glutamate additives are not and thus flood your body with glutamate, which can overload your blood-brain barrier (https://en.wikipedia.org/wiki/Blood%E2%80%93brain_barrier https://en.wikipedia.org/wiki/Blood%E2%80%93brain_barrier) and disrupt the delicate balance. This is akin to Dr. Lustig's (https://en.wikipedia.org/wiki/Robert_Lustig https://en.wikipedia.org/wiki/Robert_Lustig) findings on sugar (fructose): Eating whole fruits is fine because you're consuming fiber with the fructose (nature provides the antidote), but fruit juice is all fructose and no fiber so your body is flooded with fructose, which is toxic (http://www.nytimes.com/2011/04/17/magazine/mag-17Sugar-t.html?_r=0 http://www.nytimes.com/2011/04/17/magazine/mag-17Sugar-t.htm...).

ricardobeat 13y ago
But nobody eats MSG by itself like fruit juice, won't mixing it to food that contains fiber and 'other chemicals' have the same effect?
- espeed 13y ago
  No, because adding extra glutamate means the ratio of glutamate will be higher than the counterbalance.
  - ricardobeat 13y ago
    That went over my head. What do you mean? When making a risotto I might use 100g of parmesan cheese, which can amount to ~8g of MSG according to the internets, plus eat tomatoes on the side. That's the equivalent of 12g of Ajinomoto, I can't imagine adding that much to any dish.

baby 13y ago

I went to this sketchy restaurant in Spain once, and started having pins and needles all around my skull. Reading what you just write, that might have been because of too much MSG. Pretty scary at that time.

ScotterC 13y ago

Point of reference. A chipotle burrito is about 2000 mg of sodium as well.

mathattack 13y ago

You hit the nail on the head. For most of us, it's not the MSG that causes the problem. It's what comes with it. For starters it's the sodium. For me it's the 1000 calories in a monster Doritos bag, or the 3000 calories when I eat three times what I should at a Chinese takeout.

lamontcg 13y ago

So here's the thing that happens to me... When I eat certain foods, I tend to wake up in the middle of the night feeling hot, and it feels like I've got elevated blood pressure and my mind is racing a bit and it keeps me up at night. This is a very particular effect and it seems to be food linked. I get it after eating Chinese food, I get it after eating Pizza, I get it after eating a pile of spaghetti with red sauce. I used to gorge on Triscuits and Cheese and I'd get the same effects. I thought it was the carbs at first since those seem to be bad for me with weight gain and thought it was all related. But, there's another link there which is that all of that has MSG or glutamate in it (and also lots of sodium of course). So if i stay away from those foods I don't get the horrible sweaty middle insomnia symptoms. I can eat carbs if I stay away from glutamate/sodium, so my first guess that it was the white rice, pizza crust and spaghetti noodles was incorrect. But the MSG is always correlated with the symptoms. Is it the MSG or is it that the MSG comes with the salt? I dunno. I'm not really certain that it matters either. (I've also had my BP taken by a cardiologist the day after eating Chinese food and it spiked enough to cross the line between normal and high blood pressure the next morning after the meal...)

akingoffools 13y ago

Another point worth considering is the chirality of the molecule. There is a strong bias in biological systems in favour of l-oriented amino acids; a bias often unreflected or different in synthesised chemicals. Biological systems often react differently to the different enantiomers of a chemical, sometimes being unresponsive to the enantiomer of a biologically active molecule, sometimes responding in a different but useful manner, and sometimes reacting adversely.

not_clear 13y ago
When I had first heard about this, it was the only anti-MSG argument that sounded even remotely plausible, but it seems that nowadays commercial MSG is made by bacterial fermentation, which means that they would also have the preference for L-oriented amino acids. Wikipedia confirms this http://en.wikipedia.org/wiki/Monosodium_glutamate#Production The referenced papers on the process (from 1957!) indicates that they were reporting L-glutamate producing bacteria specifically: https://www.jstage.jst.go.jp/article/jgam1955/3/3/3_3_193/_article Here is an overall history of MSG production, including chemical synthesis (now obsolete). Even when they were doing this, they screened out the D-glutamate and re-synthesized it to maximize L-glutamate production (might not have been 100% effective, as apparently it involved doing optical screening of the crystals) http://ajcn.nutrition.org/content/90/3/728S.full Disclaimer - I am Japanese American, so grew up with Ajinomoto MSG, dashi, tomato sauce, parmesan, Doritos, etc. as part of my diet, so am biased toward skepticism on this topic.
- not_clear 13y ago
  Interesting - the metafilter referenced elsewhere on the thread had a pointer to a paper about D-glutamate vs L-glutamate. Apparently, bacterial fermentation generates a fair amount of D-glutamate, but this is true of "naturally occurring" fermentation (such as in cheese) too. The abstract claims foods to which MSG is added directly contained lower amounts of D-glutamate than foods where the MSG comes from fermented foods. I wonder why? Maybe due to better optimization / control for L-glutamate production in the bacteria? http://onlinelibrary.wiley.com/doi/10.1002/chir.530060410/abstract http://onlinelibrary.wiley.com/doi/10.1002/chir.530060410/ab...