Body odour is due to bacteria breaking down sweat – it is not due to things like holding your poop when you were young, or dirty intestines that need to be cleansed.
You should be aware however that certain foods can cause body odor, such as garlic, curry and onions. Try to stay clear, and see if it helps.
Overall though, it sounds like you’ve already tried a lot of methods that have failed, so I’d suggest going to see a dermatologist.
Botox injections can be effective if your BO is due to perspiration problems – this treatment results in less sweating in the treated area, and can last from 2 – 8 months.
Cheers
