One of the most common factors to be percolating below the surface is sensitivity to chemicals which food manufacturers put into their products, often in the name of better health and nutrition - would you believe it! One of the most ubiquitous is Aspartame. Aspartamane is found in just about every processed product imaginable, including many vitamin and sports supplements (Read all labels carefully folks and be prepared to get a shock).
Do you have a question?
Email Gary: gary at myotec.co.nz (Replace the "at" with @ and remove spaces). Please include any relevant background information to your question.