Can MSG cause obesity?

Monosodium glutamate (MSG) is a food ingredient which is used to enhance flavour and palatability. It is the glutamate ” an amino acid – part of the MSG molecule that does the job in this respect. MSG (and/or 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 affects on health, in a way which parallels the situation with 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 rather than helping here. It seems that in the case of aspartame, this substance has some capacity to stimulate appetite.

Some have leveled a charge that MSG may promote weight gain on the basis of experiments which show it has the potential for this unwanted side-effect in animals. However, until recently, the relationship between MSG consumption and weight 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 40-59. 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/glutamate may have one or more metabolic effects in the body which 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. Because, 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″1880

2. 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. Int J Obes Relat Metab Disord. 2001;25(3):426-33.

7 Responses to Can MSG cause obesity?

  1. Liz 29 August 2008 at 5:42 pm #

    Do we know that the extra weight is a result of MSG? Could it not be that the overweight individuals consume more MSG because they eat more food – the MSG consumption is a result of the extra food they eat rather than the cause of excess consumption?

    I’m not trying to discredit the link between MSG and obesity, I’m merely curious as to cause and effect. Tasty food is tasty food and we’d all be inclined to eat more of it and may consume more MSG as a result.

    Of course the extra MSG might then contribute to altering fat cell metabolism and contributing further to weight gain!

  2. Dr John Briffa 29 August 2008 at 8:00 pm #

    In this study, food intake was accounted for. That’s why the suggestion is that the phenomenon is mediated through some metabolism-related effect.

  3. Diana 31 August 2008 at 8:56 am #

    About thirty years ago, I gave up eating Chinese food because I found that the following day I had a headache, puffy itchy watering eyes, and swollen fingers which made my rings feel tight. Eventually I discovered that the problem was MSG and ever since I’ve made every effort to avoid it. This is not easy as it’s in so many foods, especially processed meals, sauces, tinned soup, savoury snacks, stock cubes, etc. Restaurant meals and take-aways are usually full of it. Even a small amount will make my eyes itchy and puffy. If I drink plenty of water, the effect wears off after a couple of hours.

    I don’t know about the weight-gain effect, but for me it certainly has the effect of causing water-retention and inflammation.

    I remember reading an article written by a mother who returned from a three-week trip away, to find her children had gained a lot of weight and looked bloated in the face. It turned out that dad had been feeding them on take-aways and processed food in her absence. After researching it, she realised MSG was the culprit (not sugar, which she had assumed). After a few weeks of additive-free home cooking, the bloatedness went.

  4. Athinia Benjamin 11 September 2008 at 3:23 pm #

    Are there any links between MSG and diabetes and high blood pressure. The reason I ask is that it is the predominant ingredient in a lot of caribbean seasonings and this race does suffer with those two ailments. Have there been any studies on this.

  5. Jimmy Cruz 28 March 2010 at 6:56 pm #

    here in Philippines, obesity is also becoming a problem. More and more children are getting obese due to a lifestyle that is not fully of physical activities. most kids just wants to watch TV, play computer games and surf the net.

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