The “Natural Flavoring” Smoke-screen: Does Ketchup Contain MSG?
When you turn over a bottle of standard Heinz ketchup, the ingredient list ends with a vague catch-all: natural flavoring. In the corners of food-media and wellness blogs, this term is frequently flagged as a corporate euphemism for hidden Monosodium Glutamate (MSG), the compound infamously (and incorrectly) blamed for ‘Chinese Restaurant Syndrome.’ But does this ingredient label actually mask added MSG, or is it a case of bad food chemistry spreading on the web? To understand what you are actually eating, you have to separate corporate proprietary blending from the reality of natural food science.
What Does “Natural Flavoring” Actually Mean to the FDA?
According to FDA regulations, the term ‘natural flavor’ encompasses essential oils, oleoresins, protein hydrolysates, or distillates derived from spices, fruits, vegetables, beef, yeast, or dairy. Its sole purpose is to provide flavoring rather than nutritional value.
Because this definition covers over 3,000 different food additives, it is impossible to determine if a product contains MSG based on the ingredient label alone. For a massive market leader like Heinz, listing ‘natural flavoring’ isn’t necessarily an attempt to hide a toxin; it is a legal safeguard to protect a highly proprietary, multi-billion-dollar flavor blueprint from being easily duplicated by competitors.
The Science of Glutamate: Added vs. Naturally Occurring
To completely demystify the ketchup myth, we have to establish a foundational rule of food science: if a food company explicitly adds Monosodium Glutamate to a recipe, FDA regulations strictly mandate that it must be listed as ‘Monosodium Glutamate’ on the panel. It cannot go by alternative names like ‘glutamic acid’ or ‘glutamate’ to disguise its presence.
However, the confusion deepens because tomatoes, the literal foundation of ketchup—are naturally packed with exceptionally high levels of free glutamic acid. When tomatoes are cooked down into a rich concentrate, those natural glutamates intensify, interacting with salt and vinegar to generate the quintessential, savory umami baseline that makes ketchup taste so addictive. Your body processes naturally occurring glutamates from a fresh tomato and added MSG in the exact same biological manner. Therefore, while Heinz may not explicitly add white MSG crystals to their vats, ketchup is chemically and inherently a high-glutamate food by default.
The Glutamate Double Standard: Deconstructing the Sandwich
The profound irony of ketchup alarmism is perfectly illustrated by looking at what ketchup is typically paired with. Consider the ham and cheese sandwich topped with a squirt of ketchup, above. Food blogs will frequently flag the ketchup bottle for its ‘natural flavoring,’ warning consumers of hidden, toxic umami enhancers.
Yet, the ham and cheese alone contain vastly more free glutamate than the condiment itself. The curing process of ham breaks down meat proteins to yield roughly 340 mg of free glutamic acid per 100g, while an aged cheese easily delivers anywhere from 180 mg to over 1,200 mg. The structural components of the sandwich are already a massive, concentrated umami bomb by default. Even the pickles could be a source. Naturally fermented pickles will contain glutamates naturally formed by the bacteria. Non-fermented pickles made with a vinegar brine, however, will be very low in glutamate unless MSG is added, which rarely happens.
Worrying about the microscopic trace of flavor compounds in a tablespoon of ketchup while ignoring the sea of natural glutamates in the proteins we eat is a complete failure of scientific perspective.
What is MSG?
Monosodium glutamate is the sodium salt of glutamic acid. Glutamic acid is an amino acid that, in its ionic form, is known as glutamate. It is responsible for the umami flavor in foods.
This amino acid is found abundantly in protein foods and is naturally present in the body, where it performs various important functions, including in nitrogen homeostasis, as a neurotransmitter, a building block for proteins, and as an energy source in the brain. It is present in high amounts in muscle tissue.
MSG is often portrayed as the “bad stuff” responsible for Chinese Restaurant Syndrome. Chinese Restaurant Syndrome is a myth. There was never any such thing. MSG is not all that bad for you and a little bit of it in your diet is no big deal, although it is certainly not perfect.
Glutamate and Glutamic Acid is Not Used On Labels Do Disguise MSG
You are exposed to very high levels of glutamate in many foods. It is found in all protein-contain foods, including plants. In addition to glutamate that is bound to proteins in foods, it occurs in a free form many common foods, including fermented foods, seaweeds, cheeses, tomatoes, mushrooms, cured hams, scallops, tuna, green peas, fish, beef, soy sauces, and more.
Glutamate in any form, including MSG, is highly metabolized in the body and it is not possible for you to ingest enough of it to have deleterious effects, even with added glutamate being used in the foods you eat.
In addition to MSG, the sodium form, glutamate is also added as other glutamic salts, such as potassium, calcium, ammonium, and magnesium salts.
All of these freely break down (dissociate) in an aqueous solution and will end up behaving the same as free glutamate in the body. The intake of glutamate naturally occurring in foods is far and above the intake of glutamate from added MSG.
It is often claimed, however, that MSG is hidden on food labels behind terms like “glutamate” or “glutamic acid.” You will NOT find these terms being used on a food label to disguise the presence of MSG.
MSG Causes Headache and Other Symptoms
Although more research is needed, especially ones with proper blinding, the preponderance of evidence from studies done with human subjects has failed to demonstrate convincingly that MSG ingestion causes a significant incidence of headache.
In fact, there has never been any scientifically valid research linking MSG to any of the symptoms associated with ‘Chinese Restaurant Syndrome’ and this includes research subjects that themselves identify as suffering from this reaction to MSG.
Allergic reactions notwithstanding, the symptoms variously reported to have occurred as a result of MSG-containing Chinese food are purely anecdotal and without merit. Chinese Restaurant Syndrome simply does not seem to exist.
MSG Causes Addictive Behavior Toward Food
A popular claim is that that MSG makes people keep eating and eating. When a food contains MSG, the potato chip slogan ‘Betcha can’t eat just one!” is mentioned. This is the slogan of Lays Potato Chips. Food alarmists claim that the reason you can’t eat just one is because (Lays) chips are full of MSG. Here are the ingredients in Lays potato chips:
Potatoes, Vegetable Oil (Canola, Corn, Soybean, and/or Sunflower Oil), and Salt.
No MSG is added to the potato chips. I think the most likely reason that you can’t eat only one potato chip is because they are potato chips, although naturally accruing glutamic acid will be present.
The question remains. Does MSG cause addictive behavior? Does it make people keep eating? The available evidence is mixed. According to one study, MSG produces the umami flavor and this certainly increases appetite. However, it has been shown to increase satiety. You fill fuller, longer. Another study showed the opposite , and a third showed no influence on the desire to eat.
Another study found that “a month-long diet high in umami stimuli attenuates perceived umami taste and appetite for savory foods in a young, healthy population.” In other words, prolonged exposure to MSG in the diet decreased their overall appetite for savory foods.
This study showed that repeated exposure to umami taste diminishes perceived umami intensity, at least in women. The same was found to be true of salt, a result that is not surprising and this aligns with previous evidence that any repeated exposure to certain types of food, sweet, salty, or fat, tends to attenuate the perceived intensity of that taste associated with that food and cause a shift to other taste preferences where the taste intensity is higher.
The same is true of diets low in sugar, salt, and fat. Even if prolonged exposure to ‘savory’ foods with MSG caused a person to shift toward, say, sweeter foods with empty calories, there is no reason to believe that a subsequent shift toward a different food preference wouldn’t also occur.
There is a very complex relationship, according to the study authors, between diet, umami taste, food preference, and appetite. The evidence to date does not support the idea that MSG causes addictive eating behavior!
MSG and Obesity
Part and parcel with addictive behavior is MSG’s correlation to obesity. Studies show mixed results. One study found no association between obesity and MSG over a 5-year period in Chinese adults, while another study showed an association between MSG intake and risk of being overweight.
An association is not causation and more research is needed to show whether there is a causal link between MSG and obesity, while subsequent results, again, show contrary findings. Many other food behaviors are positively correlated to obesity.
In the latter study, the MSG users had higher intakes of animal protein, fats, cholesterol, and calories than non-MSG users. The link between habitual MSG use and increased weight gain in this study purports to be strong. As the authors state, however, further studies are needed “to determine reproducibility of these findings, elucidate their etiopathogenetic pathway, and amass the evidence needed to assess whether the relation between MSG intake and body weight is causal.”
This study was called into question by Shi, et al. In this study, MSG intake and body weight were quantitatively assessed in 2002 and followed up in 2007. According to the authors, MSG intake was not associated with significant weight gain after adjusting for age, sex, multiple lifestyle factors and energy intake.
When total glutamate intake was added to the model, an inverse association between MSG intake and 5 % weight gain was found (P = 0.028), but when the model was adjusted for either rice intake or food patterns, this association was abolished.
The authors concluded that when other food items or dietary patterns are accounted for, no association exists between MSG intake and weight gain. It seems that the former study may have suffered from an interpretation bias, as it did not adjust for the fact that total fat intake increased, along with energy intake. You can read a much deeper analysis of these studies, along with others, here.
Different Names for Hidden MSG On Food Labels?
Another misleading assertion about hidden MSG in foods takes the form of lists of ingredients that contain MSG. These lists are used to prove that MSG goes by many names on food labels. It does not.
If MSG is added to a food then the label, by regulation, must list MSG on the ingredients panel. There are no other acceptable names for MSG on labels. Food companies cannot say that their food does not contain MSG by calling MSG something else. Below is a list of ingredients that are falsely claimed to be other names for MSG:
It is also claimed that MSG containing products like Ajinomoto, Vetsin, or Accent are listed on food product labels to hide MSG. You will never see any of these names on a food product label as these are all trademarked names for MSG products meant to be sold directly to consumers or restaurants.
As for the rest, none of these are alternative names for MSG. Instead, some of these items contain naturally occurring MSG. Hydrolyzed vegetable (plant) protein, autolyzed yeast, hydrolyzed yeast, yeast extract, soy extracts, and protein isolate all contain some level of naturally occurring MSG. Tomatoes and cheeses do as well.
The FDA does not require food makers to declare that the food contains naturally occurring MSG. However, if the product contains ingredients with naturally occurring MSG, it cannot claim NO MSG on the label.
Further Reading
- The Green Potato and Toxic Solanine FAQ
- Do McDonald’s French Fries Still Contain Beef?
- Canned Tomatoes Taste Metallic? Why it Happens and How to Fix It
- The Leidenfrost Egg Myth: Why “Science” Won’t Make Your Pan Nonstick