I've used fermented foods for a few years now. Some of the foods that I make are sourdough bread, muffins, pretzels, homemade Greek yogurt, yogurt cheese, and I am starting kombucha tea.
Fermented foods offer a natural support to the digestive tract and nourish the good flora within our gut.
Homemade greek style yogurt has a much different taste than many of the store bought versions, it is less tangy and you can also adjust the creaminess through the straining process. This style of yogurt is higher in protein than traditional yogurt.
Sour dough breads are denser than the store bought white and wheat varieties and they are also digested easier with less of a spike to blood sugars. I have a starter that began with catching wild yeast that continues to grow and give back it's benefits within our baking.
Sprouted flours are similar to sour dough in that they cause less of a sugar spike and are more easily digested.
Kombucha tea is a natural probiotic drink that I was introduced to by my brother. It is full of B vitamins as well as natural probiotics.
I've also been fermenting my stevia extract powder to make a liquid sweetener that doesn't have the bitter taste that many normally do.