Hijacked By Food! MSG Receptors In Gut And Links To Sensory Disorders
When we think about taste, most of us think about the taste buds (sensors) on our tongues. But there are many chemical sensors or ‘taste’ receptors in our gut that play a huge role in our food choices. These receptors ‘taste’ our gut content and transmit signals that regulate nutrient absorption, and release gut hormones and neurotransmitters involved in the regulation of energy and glucose homeostasis. These receptors play a prominent role in communication between the gut, nerve fibers, muscles, the brain, and our microflora to trigger adaptive responses that affect gastrointestinal function, food intake and glucose metabolism. The relationship we have with our food is largely driven by the activation of these taste receptors in the small intestine and plays a large role in health and disease.
Many foods are intentionally manipulated or processed to increase addiction and consumption for food industry profit. I’m sure that comes as no surprise to many of you. However, how foods become addicting and the wide-ranging consequences may not be well understood. For example, many people do not connect how a disorder impacting the brain may be a result of their diet. Many industrially processed foods contain excess levels of chemicals that can over stimulate the ‘taste’ receptors in the gut and is a common pathology in many diseases and disorders. Most of these taste receptors are part of the vagus nerve system, one of the main cranial nerves that relay sensory information from various organs, including the gut, to and from the central nervous system, including the brain. Chronic over stimulation of the vagus nerve leads to sensory disorders that can have a wide range of consequences including impacting auditory processing, heart rate, energy homeostasis, thermal regulation, balance/muscle coordination, and light, sound, and touch perception.
One particular receptor that is targeted by much of the food industry is the umami receptor or the receptor that is activated by free glutamate (MSG). Because of the ever-growing awareness of the negative consequences of too much MSG, the food industry has adopted various strategies to conceal the amount of free glutamate available to bind these unami receptors. Why is it added to foods? Activation of unami receptors on the tongue or in the gut increase our cravings for the food and underlies the neural basis of addiction. Of course, we buy more of the foods to which we are addicted.
Here is another strategy that allows a food manufacturer to accurately claim there is no MSG in their product, yet the food product is able to stimulate the unami receptor and contribute to our food addictions. I had a gut feeling (pun intended) there was something behind the increased use of hydrolyzed protein in food products. Hydrolyzed proteins are created by hydrolyzing (or breaking the peptide bonds) intact proteins into a mixture of amino acids and smaller proteins (peptides).
Some manufacturers claim that analytical testing shows that there is no MSG in their product. For example, the company Great Lakes claim that they tested their hydrolyzed collagen (gelatin) product and it contains no MSG. Additionally, I reviewed several manufacturing protocols of wheat, collagen, and whey hydrolysates, to name a few. The reports reveal that some of these hydrolysate products contain many different sized peptides (amino acid polymers), but not free glutamate (MSG). So, then why is it important to avoid all protein hydrolysates for anyone trying to avoid the effects of MSG or anyone sensitive to MSG?
Protein hydrolysates can activate the umami receptors in the gut. Protein hydrolysates are broken down in the stomach to free amino acids. So while it may not be present in free form in the food or supplement product, the degraded protein through chemicals, heat and high pressure processes renders the degraded protein vulnerable to the conditions in the stomach. The umami or glutamate taste receptors in the small intestine are then saturated with free amino acids, like glutamate, activating the vagus nerve, which sends sensory information to the central nervous system. In this way, protein hydrolysates stimulate the same cravings for MSG as a food containing free glutamate that stimulates receptors on our tongue.
In contrast, intact proteins in foods don’t over activate the sensory nerve signals because of their regulated digestion. When proteins are intact and part of whole foods, the pH in the stomach and the enzyme pepsin break down proteins to polypeptides (polymer of amino acids linked together by peptide bonds). When these polypeptides are released into the small intestine, further digestion by release of pancreatic enzymes break these polypeptides into small peptides consisting of two to three amino acids. Further digestion into free amino acids takes place in the small intestinal wall, where brush border enzymes regulate cleaving these small peptides into free amino acids, a process that is regulated and based on our body’s need for particular amino acids.
The result of the wide use of protein hydrolysates in food is a large underestimation of our exposure to MSG or free glutamate that activates unami receptors in our gut. MSG is often considered as only something that targets the taste receptors on our tongue. When we calculate the amount of MSG that consumers are exposed to on tongue and gut taste receptors, some foods approach 2-3 grams of MSG per serving. This is a large discrepancy from reports that state the total MSG consumption across the diet is not even a gram per day.
As long as we have the trillion dollar Glutamate Industry funding research, that influences mainstream media reporting that MSG added to food is inconsequential, and many medical doctors never trained on how the contents of food impact health, people need to empower themselves to determine what impacts their and their family’s health. One only needs to review the diseases associated with glutamate dysfunction to understand the potential impact of excess free glutamate in the diet., Glutamate related diseases are increasing in numbers and so is the amount of free glutamate in foods that activate various glutamate receptors.
Processed food that is created in the lab involves much research to determine just the right combination of chemical additives that suppress satiety and create the ‘bliss point’ that drives our cravings for more. As a result, many people face health challenges resulting from being addicted to nutrient void foods. Parents find themselves constantly fighting food battles with their children, who are continuously bombarded with these highly addictive foods. Policies to help parents fight this battle like banning vending machines in schools and education about the importance of healthy food are far too little effort and far too late for many. Our health is being hijacked by our food addictions.
A major part of the health equation is keeping these chemical signals in balance so as to not over stimulate any sensory receptors. All refined proteins, carbohydrates, and fats can over stimulate sensory receptors in the gut. Sugar, the focus of another of our blog posts, is another common addiction that can over stimulate the taste receptors in the gut.
Join the Health Revolution today and find out how your food is impacting you and your family’s health. How? Well, how about a challenge?
I challenge you to remove all industrially processed foods and avoid restaurants for 30 days.
Sound too drastic? How about transitioning slowly with these steps?
Eliminate all sodas and juices (drink water)
Remove all refined sugars and sweeteners
Add more raw vegetables during day, including as snacks
Add green smoothies to your routine
Review all ingredients of everything you eat
Avoid any packaged food with more than 5 ingredients
Make going to the farmer’s market part of your weekly routine
Try a new recipe that uses at least 10 fresh herbs/spices
Stock house with only whole foods (if junk food is not in the house, you’ll eat something else)
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 Berthoud, Hans-Rudolf, and Winfried L. Neuhuber. “Functional and chemical anatomy of the afferent vagal system.” Autonomic Neuroscience 85.1 (2000): 1-17.
 Kalivas, Peter W., and Nora D. Volkow. “The neural basis of addiction: a pathology of motivation and choice.” FOCUS: The Journal of Lifelong Learning in Psychiatry 5.2 (2007): 208-219.
 Geha, Raif S., et al. “Review of alleged reaction to monosodium glutamate and outcome of a multicenter double-blind placebo-controlled study.” The Journal of nutrition 130.4 (2000): 1058S-1062S.
 Hawkins, Richard A. “The blood-brain barrier and glutamate.” The American journal of clinical nutrition 90.3 (2009): 867S-874S.
 He, Ka, et al. “Consumption of monosodium glutamate in relation to incidence of overweight in Chinese adults: China Health and Nutrition Survey (CHNS).” The American journal of clinical nutrition 93.6 (2011): 1328-1336.
 Monosodium glutamate (MSG) intake is associated with the prevalence of metabolic syndrome in a rural Thai population. Isawang et al, Nutrition & Metabolism 2012, 9:50 doi:10.1186/1743-7075-9-50. http://www.nutritionandmetabolism.com/content/9/1/50