Is Mayonnaise Good or Bad for You?

America's love-hate relationship with its most popular condiment

Mayonnaise and Vegetables
Philippe Desnerck/Photolibrary/Getty Images

Americans seem to have a love-hate relationship with mayonnaise. It is the best-selling condiment in North America, and it is in a lot of popular American foods, from sandwiches and tuna salad to deviled eggs and tartar sauce. But mayonnaise has seemed to have acquired a bad reputation.

Some medical experts claim mayonnaise is unhealthy. For example, WebMD has rated mayonnaise as No. 1 on its "Worst Foods in Your Fridge" list.

Others worry that mayonnaise left out can be a hotbed for bacteria. Some have no problem with mayonnaise except for its texture.

What is the truth about mayonnaise? Is it really that bad? The truth is, "it depends." And, with careful selection, preparation, and moderate use, mayonnaise can be a helpful addition to a low-carb diet.

To set you at ease, the American Heart Association has a recipe for homemade mayonnaise, and the American Diabetes Association has recipes including mayonnaise in its suggested meal plans. It can be used, but moderation is always the key.

What Is Mayonnaise?

Mayonnaise is a magical substance. The beauty of mayonnaise is how two liquids come together to create a viscous, yet solid form. Mayo is almost all oil, combined with a bit of egg yolk, a little bit of an acidic liquid, like lemon juice or vinegar, and often a touch of mustard. It is a thick, creamy, stable emulsion.

The emulsion is the magical part. Mayonnaise is made into a solid substance because of emulsification, which is the process of combining two substances that would otherwise tend to not mix, like oil and water.

The Science Behind the Magic

For emulsification to happen, there is an emulsifier, in this case, egg yolk, to bring together the hydrophilic (water-loving) component and the lipophilic (oil-loving) component.

The emulsifier binds the lemon juice or the vinegar with the oil and does not allow separation to occur, in turn producing a stable emulsion. In homemade mayonnaise, the emulsifiers are mainly the lecithin from the egg yolk and a similar substance in mustard. Commercial brands of mayonnaise can sometimes use other types of emulsifiers and stabilizers.

What Is so Bad About Mayonnaise?

The biggest complaint about mayonnaise usually comes down to one thing that it is full of fat. While true that it is almost entirely made of fat, it is not made of saturated fat, since it is made from liquid oil.

The other common complaint is the number of calories that mayonnaise has: 100 calories per tablespoon. However, the same health writers who complain about the calories in mayonnaise also recommend olive oil as a healthy alternative. Olive oil mayo also has as much fat as regular mayonnaise and even more calories: 124 calories per tablespoon. 

The Oil Matters

The good news is that almost any edible oil can be used to make mayonnaise, so the oil itself is the biggest factor in the healthfulness of the recipe.

In the United States, most commercial mayonnaise is made with soy oil, which some experts feel is problematic due to its high levels of omega-6 fats.

The best-selling commercial mayonnaise in the U.S. is Hellman's brand in the east and Best Foods in the west. Those companies sell mayo made from soy oil in the U.S. and canola oil in Canada. Canola oil has much less omega-6 fats in it than soy oil.

If you make the mayonnaise yourself, you can use any kind of oil you want, including olive oil.

What About Bacteria in Mayonnaise?

The concern about bacteria in mayonnaise is mainly rooted in the fact that homemade mayonnaise is usually made with raw egg yolk. Commercial mayonnaise is not normally a problem because it is made with pasteurized eggs and is produced in such a way as to keep it safe.

If you think the potato salad made you sick, it was most likely not the mayo that was the culprit. All mayonnaise is acidic, which also helps keep bacteria at bay. 

Commercial mayonnaise may actually help fight bacterial growth in foods, though it is recommended to continue to follow usual food safety guidelines in terms of refrigeration

Homemade mayonnaise which has the correct form of acid and has one to two hours of "hold time" before the initial refrigeration has less worrisome bacteria. But subsequently, it should be kept refrigerated.

What About Reduced-Fat Mayonnaise?

The less fat in the mayonnaise, the more ingredients are added to improve texture and flavor. Starches and sugars are two ingredients that are commonly added. Still, if calories are a concern for you, you may feel the trade-offs are worth it.

Source:

Smittle, R. (2000) Microbiological Safety of Mayonnaise, Salad Dressings, and Sauces Produced in the United States: A Review.   J Food Prot. 63(8):1144-53.

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