Study: eating less because of broth

Geschatte leestijd: 3 minuten Taking a savory broth before a meal can help you feel full faster with fewer calories. It can therefore be a useful tactic in weight loss. But does it really have to contain added MSG?

Umami

There are five basic tastes: salty, sweet, sour, bitter, and savory. The latter is also sometimes referred to by the Japanese term umami. I described these five basic tastes in an article last year about a type of hunger cell discovered in the brain. These cells, tanycytes, were found to work through the same receptors on the tongue that process a savory taste. Especially amino acids such as glutamate contribute to a savory taste. The tanycytes thus function as sensors that register the reception of amino acids and translate this into satiety. The scientists hoped to find ways in the future to activate these cells. For example, directly with newly developed medication, but also through more effective diets. A new study shows that drinking a broth with monosodium glutamate (MSG) before a meal may be a simple strategy to achieve this. MSG is a salt of glutamate. It is a fairly controversial flavor enhancer, also known as ve tsin. Not widely used in Dutch cuisine, but common in Asian cuisine. We often know it in Surinamese cuisine as well, albeit with a different pronunciation. Useful to know if, like me, you have a Surinamese wife who sends you to the store to get ‘fietjin’.

Indicators of self-control and satiety

The researchers specifically looked at the effect of a broth with MSG on hunger and food intake in a specific group: young, healthy women prone to overeating and weight gain. The study was conducted on women because their appetite would be more influenced by MSG. The tendency to overeat made it a special target group to measure the possible preventive effect on obesity. I personally make the link with the tanycytes. The researchers did not focus on that at all. They looked at three other means in the laboratory to determine the brain’s response.

• A computer test that determines self-control
• Buffet where participants were allowed to eat as they pleased while their gaze directions were recorded with special glasses
• A functional brain scan measuring activity while participants made food choices

After drinking the savory broth with MSG, the self-control test was performed better. They also found that after drinking the broth, participants focused more on their own plate and less on what others were eating. The brain scan showed that drinking the broth with MSG increased activity in the left prefrontal cortex. This has been associated with successful self-control in previous studies when deciding what to eat. Additionally, participants ate less saturated fats after drinking the broth.

MSG and overweight

Adding MSG was found necessary for this effect. Regular chicken broth did not show this result. The results are striking. MSG does not have a very good reputation. In general, but also specifically when it comes to its effect on body weight. A Chinese study from 2008 showed a positive relationship between the amount of MSG in the diet and the risk of overweight [2]. About 5 grams of MSG in the daily diet increased the risk of overweight by a factor of almost three. But the potential of MSG to increase weight has been demonstrated in animal studies since the 1970s [3]. In fact, MSG is sometimes intentionally used to make rats obese for obesity research [4]. MSG is said to disrupt the action of the ‘satiety hormone’ leptin, delaying satiety. A simpler explanation is that you would eat more because it tastes better. However, the Chinese study found that the increase in weight with high MSG intake was unrelated to an increase in calories. Leptin also plays a role in metabolism, which could lead to extra weight through another route. A slower metabolism could also result in higher weight. However, in 2008, a study was also conducted on rats which showed that MSG intake actually resulted in lower weight by increasing energy expenditure. Not exactly straightforward. Whether it has a positive or negative effect, MSG is appearing in more and more foods as a flavor enhancer (E621). So, I wouldn’t rush to the store immediately for a jar of fietjin.

References

1. Neurocognitive effects of umami: association with eating behavior and food choice. Greta Magerowski, Gabrielle Giacona, Laura Patriarca, Konstantinos Papadopoulos, Paola Garza-Naveda, Joanna Radziejowska & Miguel Alonso-Alonso Neuropsychopharmacology march 2018
2. He K. et al, Association of monosodium glutamate intake with overweight in Chinese adults: the INTERMAP Study, Obesity (Silver Spring). 2008 Aug;16(8):1875-80.
3. Bunyan J, Murrell EA, Shah PP. The induction of obesity in rodents by means of monosodium glutamate. Br J Nutr. 1976 Jan;35(1):25-39. PubMed PMID: 1106764.
4. Gobatto CA, Mello MA, Souza CT, Ribeiro IA. The monosodium glutamate (MSG) obese rat as a model for the study of exercise in obesity. Res Commun Mol Pathol Pharmacol. 2002;111(1-4):89-101. PubMed PMID: 14632317.
5. Takashi Kondoh, Kunio Torii, MSG intake suppresses weight gain, fat deposition, and plasma leptin levels in male Sprague–Dawley rats, Physiology & Behavior, Volume 95, Issues 1–2, 2008,