MSG Potentially Linked to Weight Gain
In addition to triggering headaches in susceptible people, monosodium glutamate (MSG), a flavor enhancer most often associated with Chinese food, may also be to blame for excessive weight gain. Researchers with the University of North Carolina at Chapel Hill studied the food additive and how Americans are eating more of it than in the past – and may not even realize it.
MSG Intake Increasing - And So Are Waistlines
Prior research into MSG have had conflicting results, but past researchers suspected the association between the food additive and weight gain was likely linked to making food taste better and thus increasing the amount of calories eaten. The latest research, conducted by nutrition expert Ka He, attempted to control for this possibility in a study of more than 10,000 adults in China for an average of 5.5 years.
People in Asian countries tend to consume more MSG than those in the United States. Estimates for residents of Japan and Korea, for example, find that average intake is somewhere between one and a half to 10 grams a day, versus a half of a gram for Americans. However, because MSG is being added to more foods, especially processed foods, intake could be increasing.
The research team measured MSG intake directly by weighing products such as bottles of soy sauce both before and after consumption. They also measured average daily intake indirectly by asking participants to estimate intake over a three-day period.
Men and women who ate the most MSG – about 5 grams a day – were about 30% more likely to become overweight by the end of the study than those who ate the least (less than ½ gram) even when controlling for total calorie intake. After excluding those who were overweight at the start of the study, the risk rose to 33%.
He notes that the reason for the association between MSG intake and weight gain isn’t yet clear, but may have to do with the hormone leptin which regulates appetite and metabolism. The research found that those who consumed more MSG did produce more leptin, perhaps causing resistance so that the body cannot properly process the energy it receives from food.
Care2, a Healthy and Green Living website, notes that MSG is added to many more foods than we realize, including soups, soy “meat” products, bottled sauces and salad dressings, protein powders, and even baby foods and infant formulas. “Everybody eats it,” He tells Reuters Health.
To limit intake of MSG, look for the following ingredients listed on the food label. These additives always contain monosodium glutamate, even if it isn’t expressly written:
• Hydrolyzed vegetable protein
• Hydrolyzed protein
• Hydrolyzed plant protein
• Plant protein extract
• Sodium caseinate
• Calcium caseinate
• Yeast extract
• Textured protein
• Autolyzed yeast
• Hydrolyzed oat flour
The following ingredients frequently, but not always, contain MSG:
• Malt extract
• Malt Flavoring
• Natural Flavoring
• Natural Beef or Chicken Flavoring
He K, et al “Consumption of monosodium glutamate in relation to incidence of overweight in Chinese adults: China Health and Nutrition Survey (CHNS)” Am J Clin Nutr/June 2011; doi: 10.3945/ajcn.110.008870Am J Clin Nutr