Mayonnaise has health-promoting properties such as , which improves heart health, and , which is important for blood clotting. It can also be made with healthy fats such as omega-3 fatty acids which keep your brain, heart, and skin healthy. Mayonnaise is mostly oil, so it is a high-fat and calorie-dense condiment with 100 calories per tablespoon. You will need to keep your nutrition goals in mind when selecting mayonnaise., Mayonnaise has health-promoting properties such as vitamin E, which improves heart health, and vitamin K, which is important for blood clotting. It can also be made with healthy fats such as omega-3 fatty acids which keep your brain, heart, and skin healthy., Many types of store-bought mayonnaise are unhealthy. In contrast, homemade mayo might be healthy, but can also have highly varied nutrition. The USDA reports that mayonnaise calories total 94 per tablespoon (14 to 15 grams)..