I've been researching, as usual. I've read a study that concludes that stress can affect people two ways: it can cause the pineal gland to produce more melatonin from serotonin and cause depression, or stress can force the melatonin to be converted into serotonin. People whose bodies handle stress in this way will have less melatonin in their blood and are more likely to develop cancer.
Hmm. Something to think about. The pineal gland makes melatonin. Melatonin has been shown to help reduce tumors in some cases. But, the pineal gland calcifies with age. Fluoride quickens this process. Sodium fluoride is especially harmful and in most drinking water. Calcium fluoride is natural and not as harmful, but the sodium fluoride is industrial and may well be hurting us more than imagined.
I'm still processing this information, but I thought it was interesting and worth discussing.