I like to throw in some frozen fruits in the feeder and watch my son get relief from his achy gums. My personal favorite is frozen berries and mango. You still need to supervise your little one when using a mesh or silicone feeder.
Another go to for my little one are healthy smoothies which I prepare with either formula or breast milk. Again I grab frozen fruit, and blend it with the milk of choice. For a greener smoothie you can also add things like organic kale or avocado, and for added nutrition I sprinkle in some chia seeds.
Frozen treats and smoothies can get a bit messy, so if you want to avoid clean up opt for traditional teethers. My son is partial to silicone teethers, but he also loves his Sophie.