Can MSG Cause Obesity?
Monosodium glutamate (MSG) is a food ingredient that is used to enhance flavor and palatability. It is the glutamate—the amino acid part—of the MSG molecule that does the job in this respect. MSG (and other sources of glutamate) can be found in a wide range of processed foods with the blessing of our governments and food agencies.
However, there has been lingering concern that glutamate might have some adverse effects on health, paralleling the effects of the artificial sweetener aspartame.One concern about aspartame has been that, despite being virtually devoid of calories, it might be contributing to the burden of overweight and obesity. It seems that aspartame can stimulate appetite.Some have leveled a charge that MSG may promote weight gain on the basis of experiments that showing it has this unwanted side effect in animals. However, until recently, the relationship between MSG consumption and weight gain had not been assessed in humans.That changed on the publication of a study this month in the journal Obesity [1].
The study, conducted in China, assessed the relationship between MSG consumption and body mass index (BMI) in 752 men and women aged 40 to 59. The researchers divided the participants in this study into three bands, according to MSG consumption. Compared to those in the lowest consumption band, those in the highest were found to be 2.75 times more likely to have a BMI of more than 25.This link between MSG consumption and increased body weight may have many explanations. The two obvious ones are that MSG somehow led individuals to consume more food or be less active. However, in this study, the authors accounted for these potential factors, which means that the link between MSG consumption and increased body weight appears to be independent of these factors.
The suggestion here is that MSG, the glutamate part, may have one or more metabolic effects in the body that might predispose consumers to weight gain. As it happens, administering MSG to animals has been shown to induce various changes that promote fat accumulation, including suppression of fat breakdown (lipolysis) [2]. The free, full-text version of this study is linked to below, which details other effects of MSG that might affect body weight in the long term.What is required now is for more work to be done to assess what effects MSG might have on human physiology that might cause weight gain. If one of the most commonly used food additives does indeed have the potential to cause weight gain, then it’s only right that we should know.
References:1. He K, et al. Association of Monosodium Glutamate Intake With Overweight in Chinese Adults: The INTERMAP Study. Obesity 2008; 16(8): 1875–18802. Dolnikoff M, et al. Decreased lipolysis and enhanced glycerol and glucose utilization by adipose tissue prior to development of obesity in monosodium glutamate (MSG) treated-rats. International Journal of Obesity Related Metabolic Disorders 2001; 25(3): 426–33
Dr. John Briffa is a London-based physician and author with an interest in nutrition and natural medicine. Dr. Briffa's Web site
Last UpdatedOct 23, 2008
