Limb Swelling Overseas - From Dr. Warner
I like to think that I am fairly healthy. I have no known cardiac problems. I typically have low blood pressure. I watch my weight and try not to eat too much red meat. Therefore, when I developed leg swelling during a trip to Vietnam I became concerned. Because the travel involves about 20 or more hours in the air, my initial concern was a blood clot. However, I really only had about 1+ pitting edema and it was on both legs, and only to the mid-calf. Usually, a blood clot will cause more edema (2+pitting) and be unilateral (one leg only). This gave me some relief. In addition, I had no pain or calf cramping. Pain is sometimes associated with a blood clot. In addition, I checked my own Thompson test. That is, I passively stretched my ankle up (toe towards the nose) against a wall and felt no pain. This too was a sign that the swelling was from something else. I do not smoke and I am not obese.   These two factors (obesity and smoking) are associated with deep venous thrombosis. This gave me comfort again, but I do take a low-dose oral contraceptive to control cramping pain. Hormone therapy in females is associated with blood clots as well. This gave me pause, but I felt that the lower dose should not be a huge risk. I will need to discuss this with my OB-Gyn should world travel become a habit obviously. The limb swelling persisted during my trip. I was in Vietnam for a week. While there we walked a fair amount and I tried to make sure that my legs were elevated a lot. I went to the gym a couple of times to ensure that I was utilizing the natural muscle-based pump system for fluid return that my legs have. Nonetheless, my legs maintained a mysterious and low-level amount of swelling. At this point I began to suspect diet may be involved. In Asia, it is not uncommon to season food with monosodium glutamate or MSG. This is a substance that has been attached to the ‘Chinese Food Syndrome’ described by Dr. Ho Man Kwok; he actually wrote to the New England Journal of Medicine in 1968 and attributed symptoms that occurred often after eating chinese food to this substance. Namely, he stated that the headaches, numbness in the back of the neck that spread to the arms and legs and generalized weakness with palpitations he experienced were due to the MSG. In addition, limb swelling was blamed on MSG. Dr. Kwok’s letter stirred up a lot of controversy and created an abundant amount of work and research on this issue. Monosodium glutamate is the most stable salt (crystal) form of the common amino acid glutamate. This is a non-essential amino acid that lends itself well to the Umami taste. There are the tastes that we learn here in the USA such as sweet, salty, sour and bitter; however, there is another taste that is ‘meaty’ or ‘rich’ and that is umami. Think of the taste of a good steak or melted cheese. This is umami. Miso, a common Asian ingredient also encapsulates this flavor. MSG is the easiest and cheapest way to produce umami in one’s cooking. MSG was described in 1908 in Tokyo by a chemistry professor there. Dr. Kikunae Ikeda discovered the compound. MSG enriched Dr. Ikeda. He was able to isolate the flavor from Dashi. Dashi is a complex flavouring compound common in Japanese cooking. Once he isolated the flavor of ‘savory’ he then had to stabilize it so that it could travel, be stored and sold. He added sodium. This is known as Ajinomoto or ‘the essence of taste’. Basically, MSG mimics the taste of actual protein. By adding MSG, chef need add less meat; this is economical. It should be known that studies have shown that Chinese Food Syndrome occurs at the same rate if MSG or placebo is used. There is a lot of controversy regarding the purported ill effects of this substance. It has not been established to be definitively dangerous at this point. In fact, after exhaustive work, the FDA has declared MSG to be generally recognized as safe. The numbness sometimes associated with this compound is likely due to the activity of glutamate as a neurotransmitter. Some drugs that are utilized for the treatment of neuropathy employ glutamate blockers. Taurine and gamma amino butyric acid do the opposite. Bear in mind too, the body can convert aspartame into glutamate. So, if one drinks an abundance of Diet Coke and also eats Chinese food, there could be a problem. Glutamate is also converted into GABA when there is a lot of it around. GABA too is a neurotransmitter and can cause neuropathic symptoms. Diabetics lack this full ability due to a reduction in the converting enzyme (diabetes attacks that enzyme and limits its availability). So, to summarize the alleged symptoms due to MSG, a common ingredient in Asia:
  • Headache
  • Flushing
  • Sweating
  • Facial pressure or tightness
  • Numbness, tingling or burningIn face, neck and limbs
  • Palpitations (irregular and fast heart beats)
  • Nausea
  • Weakness
However, it was ridiculously hot over there and I was jet-lagged. Most of the symptoms could be chalked up to travel to a subtropical zone in South East Asia. Also, we could not eat the ice for risk of GI infection and air conditioning is not common. I did have a couple of episodes of an odd feeling in the face, but that is in retrospect and medical memory is notoriously poor. I definitely had 1+, bilateral, pitting edema throughout the week. MSG is basically another form of salt; with a high dose of this on a daily basis one osmotically retains water in tissues. This is especially true for tissues in a dependent position (fighting gravity) such as the legs and ankles. As I write this I am in Newark awaiting a connecting flight. I just flew 15 hours and I have no more swelling. I have to think that my legs just did not like MSG! Now that I am here, there will be no more MSG. In addition, the body is remarkably capable of eliminating offending chemicals and I think I am going to be OK.