It's BS.
But I often used to drink 20 of these 1 gram effervescent Vitamin C tabs per day,
simply because it tasted good. Never got an upset stomach. I can take 50 grams of creatine a day too with no stomach issues at all
http://beyondhealth.com/media/wysiwyg/kadro/articles/VitC-Bowel-Tolerance.pdfBeyond Health recommends that almost everyone suffering from a chronic disease take
Vitamin C (powder) to bowel tolerance.
Start out with a small amount and very gradually increase it at your own pace, gradually
taking a little more each day. Take small amounts frequently rather than large amounts
less frequently, at roughly equal intervals throughout the day.
Vitamin C can be taken at any time. Many people find it easiest to take some upon
awakening, some with each meal, and some before going to bed at night.
If at any time along the way, you get abdominal discomfort: a rumbling stomach, excessive
gas, or diarrhea, go back to the amount you reached before you encountered problems.
Use this as your maintenance dose.
Whereas most people tolerate around 10-20 grams/day, there have been cases where 50
and even 100 grams have been needed to reach bowel tolerance. The ability to tolerate
such large amounts means these large amounts are needed.
Similarly, if you are coming down with any kind of infection, your body requirements for
vitamin C go way up. At the first sign of a cold or flu, take C every hour or even every half
hour, and you can usually nip that virus in the bud. This may require 20 to 50 grams, and
100 grams is not unheard of. If you are unable to prevent the cold or flu, continue the
same frequent doses of vitamin C, and your recovery will be much, much quicker.