Every individual responds to substances differently. Vitamin C is no exception. Admittedly, there were relatively few older patients in my practice. Infants, small children, and teenagers tolerate ascorbic acid well and can take, proportionate to their body weight, larger amounts than adults.
Older adults tolerate lesser amounts and have a higher percentage of nuisance difficulties.
Patients with multiple food intolerances may have more difficulties but should attempt taking ascorbate because of benefits often obtained. For several years while I was treating only sick people with ascorbic acid, I was unaware of the number of people who had nuisance problems with maintenance doses. The tolerance of the sick person to ascorbate is so high as to prevent many of the complaints one would have if he were well. When ascorbic acid is prescribed to a sick person, the beneficial effect is obvious enough so that few complain of the gas and diarrhea. With illness the effects of an overdone do not last long because of the rapid rate of utilization.