MSG vs. Salt: Umami, Sodium and How Far One Can Replace the Other

MSG and salt look alike in the jar, but they do different jobs. Salt makes food taste salty; monosodium glutamate (MSG) makes it taste savory, the taste called umami. MSG also carries far less sodium than salt, about 12% against 39% in one peer-reviewed analysis,¹ so cooks and food scientists use it to replace part of the salt in a dish. It can’t replace all of it, though, because umami isn’t saltiness.

Side by side

Two different tastes

Salt does more than make things salty. In lab taste studies, sodium chloride together with sugar was the main source of bitterness suppression in taste mixtures,⁹ which is one reason a pinch of salt can make a dish taste rounder. Those tests used simple solutions, so they show which way the effect goes, not how it plays out in every recipe.

MSG supplies glutamate. Umami is one of the five basic tastes, and it comes from three natural substances: glutamate, guanylate and inosinate. There’s nothing exotic about the glutamate in MSG. FDA notes that the free glutamate in foods like tomatoes and cheeses is chemically the same as the glutamate in MSG.⁴ The Japanese chemist Kikunae Ikeda first identified glutamate in 1908.

In a dish, the two are teammates, not rivals. Salt sets how salty the food tastes; MSG adds savory depth, like a long-simmered stock. That’s a description, not a measurement.

Sodium: the number that matters

MSG is still a sodium salt, so it does add some sodium. The peer-reviewed figure is about 12% sodium for MSG, less than a third of the 39% in table salt.¹ By our math, a gram of MSG carries about 120 mg of sodium and a gram of salt about 390 mg.

Three studies have tested what that difference can do:

Keep their limits in mind. The Wallace study is a model, not a feeding trial. Its authors note conservative assumptions, that they left out restaurant food, and that consumer acceptance of MSG has to be considered. It was funded by an unrestricted educational grant from Ajinomoto, which makes MSG.¹ The Halim abstract gives no single percentage for the sodium saved and no funding statement.¹¹ None of the three replaced all of the salt.

Safety

MSG. FDA considers adding MSG to food generally recognized as safe. It notes that some sensitive people who eat 3 grams or more of MSG without food may have short-term, generally mild symptoms such as headache, numbness or flushing. It adds that eating more than 3 grams without food at one time is unlikely, and that FDA was never able to confirm that MSG caused the reactions reported to it.⁴ Britannica reports no conclusive link between those symptoms and normal levels of MSG.¹² In the EU, EFSA set a group acceptable daily intake of 30 mg per kg of body weight a day for glutamic acid and its salts in 2017, which works out to 2.1 g a day for a 70 kg adult by our math. EFSA found that people whose diets are high in foods with these additives may go over it.⁸

Salt. The WHO names raised blood pressure as the main health effect of a high-sodium diet and recommends adults stay under 2,000 mg of sodium a day.⁷ The FDA’s Daily Value is less than 2,300 mg.³

You’ll often read that MSG raises blood pressure too, just more slowly than salt. We found no regulator or review that says so. The sodium MSG adds counts like any other sodium.

Labels. Foods with added MSG have to list it by name; it can’t hide under “spices and flavoring.” Ingredients like hydrolyzed vegetable protein naturally contain free glutamate, and FDA says products containing them can’t claim “No MSG” or “No added MSG.”⁴

Can one stand in for the other?

Partly. Every amount below is a starting point.

How we got these. The quarter cut is the low end of the 25% to 45% sodium reduction Wallace and colleagues modeled,¹ and the studies above replaced part of the salt, never all of it.¹⁰¹¹ Go easy on the MSG, since FDA puts a typical serving of food with added MSG at under half a gram.⁴ Going the other way, salt can’t supply umami, so if you’re out of MSG, a glutamate-rich food is the better fix. Parmesan carries about 1.2 g of free glutamate per 100 g and soy sauce 0.4 to 1.3 g, in figures from a 2003 Australian–New Zealand regulatory report tabulated by Germany’s food-safety commission.¹³

Which to use when

• Salt: in everything, sweet or savory, where you want food to taste seasoned. It’s the one you can’t do without.
• MSG: in savory dishes that need depth, like soups and broths, stir-fry sauces, fried rice, marinades, eggs and vegetables. A little goes a long way.
• Both: a little MSG alongside less salt, if you’re cutting sodium.

For techniques, see cooking with MSG.

What isn’t known

• The sodium savings above come from one model and two sensory studies of specific dishes, not long-term feeding trials.
• None of the sources we reviewed says whether MSG contains iodine.

Related

• Monosodium glutamate (MSG) and table salt, the full profiles
• MSG substitutes and cooking with MSG
• Soy sauce powder
• Iodized vs. non-iodized salt and table salt vs. sea salt
• Too much salt? How to rescue a dish