The kidneys are the major source of blood filtration to prepare excretory fluids in the body. Every person needs at least one healthy kidney to survive on their own (without the help of dialysis). But, something that has become less popular in modern times is eating kidney from other mammals. Despite the stigma, kidney is hugely nutritious and a great way to support our own kidney function (see my post, Why Everyone Should Be Eating Organ Meat). I have many recipes on my blog and cookbooks that utilize organ meats in a tasty way (that might even make it easier to incorporate into meals for kids). One of my favorites from The Paleo Approach Cookbook is my Steak and Kidney Pot Pie with Kufu.
The nutrition in kidney is going to vary according to the animal and the source (with grass-fed/pastured, organic kidney having much more nutrition due to having access to their natural food source). In general, kidney is a good source of protein (17g per 100g) and an excellent source of B vitamins (it has all of them, but 100g contains more than 100% of our B2 needs and more than 400% of our B12 needs!) as well as several minerals, including more than 200% of our daily selenium needs. Clearly, kidney is a hugely nutritious food!!
Since this organ’s nutrient content is also dependent on our sourcing, I like to get mine from either a local farmer or US Wellness Meats.