I suspect Candida Overgrowth. If you consume a lot of foods that are sugary, refined, or processed, all the foods that Candida loves to grow and overgrow can lead to the condition you describe. What does your diet mainly consist of?
The smelly foot problem is your body trying to detoxifiy and your shoes and socks promote sweating which can make it worse. Remember the largest organ for detoxification in the body is the skin. You may have an odor problem else where(no offense) but it's ampified on the feet.
I have a detailed posting on Candida and how to combat it at my forum, ask Kelley. Please go there and take a look at the posting. I hope that it will help. Diet and cleansing is key to fighting Candida. Cleanse before you consider a flush. A flush will flush toxins into your system some may be eliminated but most will be reabsorbed unless the body has been properly cleansed.
Candida Overgrowth can prevent a lot of nutrients from being properly absorbed including Vitamin B.