Prevent Flu and Pale Faces with Niacin, Thiamin, and Vitamins A, C, and D: The Side Effect Problem
Working together, vitamins reduce the frequency and then the duration and severity of colds. The science for vitamin C is conclusive: the higher the dose, the stronger the response up to about 2 g/day. Past 2 g/day, it is impossible to conduct double blind trials because the patients know they are taking vitamin C.
The is similar excellent data for vitamin D. Again, however, the double blind data extends only to about 2000 IU/day. Above this threshold, the blind breaks because the users know they are taking the vitamin. Niacin hasn't been used much for colds, but I strongly suspect that doses much above 250 mg/day would break the blind.
Vitamin advocates like myself have been slow to fully appreciate this information. We welcome vitamin side effects as useful biofeedback. Most people react differently. I finally fully understand how upsetting vitamin side effects can be to users. Vitamin C advocates especially have a tendency to urge users to take vitamin C until it hurts. I know appreciate that intestinal cramps, very soft stool, gas, and other effects can cause some people to panic and go to see their physicians to make sure they aren't seriously ill. Just one such experience can be traumatic - sufficiently so to prevent any further experimentation with vitamin C - ever.
As a scientist I know that vitamin C and niacin are incredibly safe, and that accidental overdose do no more harm than causing temporary discomfort. Non-scientists will have a much harder time appreciating the data. As a scientist I know that all drugs carry much higher risks than vitamins - even though most drugs never cause me any immediate discomfort at prescribed doses.
I know that for me, taking more vitamins means taking fewer drugs. So - I know I'm reducing risks to my long term health.
I believe that vitamins are underused because so many have had side effects. In my experience, children benefit the most from extra vitamins and rarely experience discomforts. Parents experiment, experience side effects, and decide not to give vitamins to their children. I really don't know how to break this cycle. I do know that more and more people are getting more and more drugs and procedures at younger and younger ages. Each drug and procedure brings higher risks than vitamin C, niacin, or sunshine can bring at any dose. Perhaps slower and more careful use of vitamins would help. Staying just below the upper limits recommended by the Food and Nutrition Board most of the time, and just experimenting with high doses for three or four days while you are feeling unwell may product more satisfactory results.
Any ideas from readers?