Mayonnaise: Nutrients, What Research Shows and Safety

Mayonnaise is a thick sauce made by whisking oil into egg yolk with an acid such as vinegar or lemon juice. It is an emulsion, which means oil and a water-based liquid held together as a smooth cream. Reviews of its safety describe it as a raw-egg product when made at home. [6] USDA describes regular mayonnaise as a salad dressing. [1] Because it is mostly oil, it is a high-calorie condiment rather than a health food, and the main safety questions are egg allergy and, for homemade versions, raw egg. This page separates the store-bought product from home recipes and from hype.

Read this first

• It is mostly fat. USDA lists about 75 g of fat per 100 g and about 94 kcal in 1 tablespoon (13.8 g). [1]
• Homemade mayonnaise made with raw eggs can carry Salmonella. The FDA says fresh eggs, even with clean shells, may contain Salmonella, and recommends pasteurized eggs or egg products for recipes that use raw or undercooked eggs. [2] Children, older adults, pregnant women and people with weakened immune systems face greater risk. [2] The NHS says homemade mayonnaise made with raw egg is acceptable in pregnancy only if British Lion or Laid in Britain eggs are used. [3]
• Commercial mayonnaise is acidic, and a review of the literature found it very safe. The absence of reports of illness linked directly to commercially prepared acidic dressings supports that, according to a review in the Journal of Food Protection. [5]
• Egg allergy: egg is a major food allergen. [11] For trouble breathing or swelling of the face or throat, call 911 (or your local emergency number).
• Warfarin: USDA lists 163 micrograms of vitamin K per 100 g, about 22 micrograms in a tablespoon. [1] People on warfarin are advised to keep vitamin K intake steady. [8]

What is in it (USDA values)

The values below are for regular mayonnaise (USDA FoodData Central item 171009, SR Legacy, listed as "salad dressing, mayonnaise, regular"). [1] The serving column is the USDA household portion of 1 tablespoon, 13.8 g. USDA also lists 1 packet (10 g) and 1 cup (220 g).

% Daily Value uses the FDA 2016 Daily Values; the serving figures are the 100 g values multiplied by 0.138. USDA lists 0.19 g of trans fat per 100 g. [1] The USDA item also shows a vitamin D value that we could not confirm as plausible for mayonnaise, so we do not repeat it. Brands, "light" versions and homemade recipes differ from this average.

Plant compounds: we did not read a source that measured named plant compounds in mayonnaise, so none are listed.

What research says

Eaten as food vs other forms. Mayonnaise is eaten in small amounts as a condiment. The studies above are about eggs, cholesterol or bacteria, not about mayonnaise as a heart or health food.

How much is a normal serving

USDA's household portion is 1 tablespoon (13.8 g), about 94 kcal, and a single-serve packet is 10 g. [1] That is information from USDA, not a prescription. For fat limits, WHO says saturated fat should be under 10% of energy for people aged 2 and older, [13] and the NHS gives 30 g a day (men) and 20 g a day (women) as the saturated fat maximum. [14] One tablespoon of this mayonnaise has 1.6 g of saturated fat. [1]

Safety, allergy and medicines

• Raw egg and Salmonella: CDC lists children under 5, adults 65 and older, adults 50 and older with conditions like heart disease, and people with weakened immune systems as higher-risk groups for Salmonella. [4] The FDA says Salmonella usually causes diarrhea, fever, cramps and vomiting 12 to 72 hours after infection, and can be severe. [2]
• Egg allergy: egg must be named on packaged food labels in the US. [11] The NHS lists eggs among the most common food allergens and says to call 999 (911 in the US) for swelling of the lips, mouth or throat or struggling to breathe. [12] Mayonnaise is an egg-based sauce, so people with egg allergy should avoid it unless a product is labeled egg-free (vegan "mayo" is a different product).
• Soy: many mayonnaises are made with soybean oil; the FDA's allergen page says highly refined oils are not covered by the labeling rule. [11] We did not read a source on soy-oil mayonnaise and soy allergy, so ask an allergist.
• Warfarin and vitamin K: a review says plant oils and prepared foods made with them, such as salad dressings, add vitamin K, and that a constant intake is the accepted practice on warfarin. [8] A 53-patient study found each 100 mcg a day rise in dietary vitamin K was linked to a lower INR (blood clotting test) by 0.2, and that a consistent intake reduces variability. [9] Talk to your anticoagulation clinic; this is information, not advice.
• Pregnancy: use pasteurized-egg or Lion-mark products; the NHS advice is above. [3]
• Children: the saturated fat limit applies from age 2. [13]
• Kidney disease and diabetes: USDA lists 0.57 g of carbohydrate and 20 mg of potassium per 100 g. [1] We did not read advice specific to mayonnaise; ask your clinician.
• Sodium: about 88 mg per tablespoon (4% of the Daily Value). [1]

Choosing, storing and food safety

• Use pasteurized eggs for homemade mayonnaise if you serve it to anyone at higher risk. [2] A review found acidity helps but pH alone is not a reliable guard for raw-egg versions. [6]
• Lab results on storage are not a kitchen rule. In one lab study, E. coli O157:H7 added to commercial mayonnaise became undetectable after 72 hours at 25 C but stayed detectable for up to 35 days at 7 C. [7] We did not read an official storage time for opened jars, so follow the label.
• The FDA advises keeping eggs refrigerated at 40 F or below and not leaving egg dishes out for more than 2 hours (1 hour above 90 F). [2]

Related pages

• Saturated, unsaturated and trans fats explained
• Soybean and vegetable oil
• Which cooking fat to choose: what health bodies say
• Foods and medicine interactions: vitamin K, grapefruit and others
• Food allergy basics and emergency signs
• Foods in pregnancy: what official bodies advise