I am unable to eat tomatoes. What can I use instead, especially in soups?

There is an alternate product available that does not contain tomatoes. It is called Nomato .

It is described on the home page as:

Nomato sauces are a delicious natural alternative to traditional tomato based products.

Additional info:

Nomato may be substituted in any recipe using tomato sauce, barbecue sauce, ketchup or salsa.

Nomato is made from vegetables and seasonings. It contains no soy, dairy, wheat, gluten, nuts and of course no tomatoes!

I am not promoting this product and, quite frankly, have not tried it. However, I did read several great reviews about it.

You are correct. Many home-made soups use a tomato base. After unsuccessfully trying every substitute I could find for tomatoes, I finally discovered that pear juice makes a great substitute base in soups. Buy just juice. If you are using pear juice packed with pears, you'll have to remove the pears. I haven't tried to puree them, but suspect that might work.

If you can’t eat tomatoes, stay away from all nightshades including peppers and potatoes. Your digestion will thank you. I use nomato sauce and don’t give up if the first version doesn’t turn out perfectly, when done right it’s almost a perfect match.

I suggest a little experimentation!

Tomatoes have a delicious blend of savory (umami) and acid. Use varying proportions of ingredients that are acidifying or are high in glutamates!

Vinegars and various citrus juices are a natural source of acid, as are yogurts and wines or beer (yum!).

Sources of glutamates can include aged cheese (like Parmesan or Asiago), anchovies/anchovy paste, soy sauces, miso paste, fish sauce, and Worcestershire (also containing fish).

You’ll likely go through a few iterations of each recipe until you find a balance that you like, but I bet you can get a pretty satisfying flavor profile out of it if your willing to tinker a bit.

Sour plums have a really similar texture and flavor to tomatoes - they are a base in a lot of Middle Eastern soups

For visual appeal sometimes you do just need the red of the tomato. I am unable to enjoy them either...so I substitute red peppers cut in 1/4" strips, as long or as short as I want them.