An extreme vitamin c deficiency has the name scurvy with symptoms as bleeding, inflammation, muscle atrophy, increased risk of infections and death.
A lighter deficiency may be unrecognized over longer times periods. It is not comparable to scurvy, but scurvy shows what processes in the body require vitamin c to function properly.
Even at high dosages of vitamin c there are almost no negative immediate consequences recognizable2. At high oral intake digestion problems might occur, but this needs depending on the person more than 10g/day (10'000mg)1, which is about 100 times a recommended daily allowance of 100mg. This means that a short term high consumption of vitamin c seems to be unrisky.
Recommended Daily Intake (Total)
The recommended dietary allowance is at 90mg/day for males and 75mg/day for females 3.
But the human body seems to have usage for up to 400mg/day and and excretes the excess with urine4. This is an indication, that the optimal daily dosage might be higher at up to 400mg/day.
The detailed recommendations by age and gender of the US Institute of Medicine can be found here.
An adequate daily intake is possible by eating fruits and vegetables. Examples with a high vitamin-C content are:
|Vitamin C per 100g|
|Spinach, fresh, cooked8||9.8mg|
|Spinach, frozen, cooked9||2.2mg|
|Apples, raw, with skin11||4.6mg|
Generally, an optimal vitamin C supply should be strived for in order to enable the body to function properly and to avoid deficiency issues. The risk of excess consumption seems to be limited for vitamin C.
If a person does not eat almost every day larger amounts of fruits and vegetables high in vitamin C, then a supplementation is useful to achieve an adequate daily intake.
A vitamin C supplement should contain between 75 - 400mg of vitamin C per day.
Vitamin C is vital and involved in many processes1.