My family loves mayonnaise. We use it in all kinds of things: tuna salad, egg salad, potato salad, and deviled eggs. However, I never buy mayo in the store. I always make homemade mayonnaise. Why go to the trouble of homemade mayonnaise? Storebought mayonnaise is full of industrial oils you do not want to put in your mouth. Like soybean and canola oil. Soybean oil is damaging to your thyroid. It slows your metabolism and can lead to hypothyroidism and breast cancer.