Stress can definitely cause many symptoms, as can a poor diet. These are solidly supported truths based upon clearly and easily definable physiological actions.
Although I'm sorry to hear that you've invested so much time and work in a field that you have now apparently lost much of your faith in, I'm hoping that a silver lining can be found. Sometimes the best lessons that we learn in life are the ones that are the most painful, time consuming and costly. Your studies in these areas will undoubtely be helpful in understanding the truths in many unrelated areas in the future.
You also have reason to be happy, in that you unlike many others, have found Truth. There are millions of people who go through their lives completely smitten by a particular fad, fashion or belief and never see the sunlight.
There are many old Marxist/Leninists who have gone to their graves honestly believing that "Uncle Joe" Stalin was a truly good man and that the famines of the Soviet era were entirely "Capitalist propaganda".
An all or nothing approach isn't much good for anything. I work in the 'alternative health' industry and do take A LOT of time to educate myself and pass on good information to customers. People should ALWAYS educate themselves whether it's alternative therapies or western medicine.
>>Although I'm sorry to hear that you've invested so much time and work in a field that you have now apparently lost much of your faith in, I'm hoping that a silver lining can be found. <<
Oh don't feel sorry for me! I gave it all up for the best job in the world, wife and mother. Now only Dad gets foot massages!