MSG and lab rats and obesity, oh my

Ask Dr. Keith Roach M.D

MSG and lab rats and obesity, oh my

DEAR DR. ROACH: I discovered that when researchers set out to induce insulin resistance and obesity in lab mice, they use monosodium glutamate (MSG)! Then, reading labels in the grocery store, I found that MSG is in just about everything, from cereal to sausage patties!

So, if MSG causes obesity and insulin resistance in mice, and MSG is in everything we eat, do you think it also might cause obesity and insulin resistance in humans? — D.B.

ANSWER: It's a good thought. It certainly is true that in laboratory rodents, high doses of MSG can cause resistance to insulin. Researchers had the same thought as you do: Since vast amounts of MSG (650,000 tons per year, worldwide) are consumed, it could have a significant public health impact, were MSG to cause insulin resistance in humans.

The answer isn't definitively known, but a 2013 study in China (home to more diabetics than any other country) showed that people who consumed more MSG were at lower risk for development of high blood sugar, which is the opposite of the original hypothesis.

Not all of the information obtained from laboratory animals is directly translatable to humans.

DEAR DR. ROACH: I am not overweight, but I have a LOT of excess skin around my waist and under my chin. I am aware of facial 'tightening,' but I am afraid to get involved with that. I have been told that the excess skin around my waist is not fat, but is sagging skin. I presume this is caused by old age, since I have never been obese and therefore have never lost a lot of weight. Do you know of a procedure to remove excess skin from the waist? — W.S.

ANSWER: Yes. Twice I have sent my own patients to a plastic/reconstructive surgeon to get rid of excess skin around the waist, but in both cases it was after 100 or more pounds of weight loss. I haven't seen this problem in someone who hasn't lost weight. I would be concerned about loss of skin elasticity, which can come from smoking or from not getting as much fruits and vegetables as is optimal.

The other concern I have is that losing muscle bulk, which is common as we get older, can cause looseness in the skin.

A careful physical exam will help sort out why you have so much loose skin, and I would not recommend a surgical procedure until the reasons for it are clear.

DEAR DR. ROACH: Does the shingles vaccine help to eliminate HSV-1? Also, is there a vaccine being developed to cure HSV-1 and HSV2? If so, when will this be available to the public? — S.H.

ANSWER: Although the varicella-zoster virus, which causes both chickenpox and its recurrence as shingles, is a herpes virus, neither the shingles vaccine nor the chickenpox vaccine is effective at preventing HSV-1 or HSV-2. Also, vaccines generally are more effective in preventing infection than they are at getting rid of existing or incipient infections, although there are exceptions.

There currently is intense work being done on a vaccine for the herpes simplex viruses, which in addition to oral and genital ulcers, cause meningitis (inflammation of the lining of the brain) and encephalitis (inflammation of the brain itself). HSV-1 also is a cause of corneal blindness. Thus, a vaccine would be an immense public health benefit.

It's very difficult to make any vaccine, but one that protects against a disease without strong natural immunity is particularly problematic, and it won't be for several years, at least before one becomes available, from what I have read.