A patient recently questioned me on the amount of vitamin C that was in her multi-vitamin (500mg per day). She heard from her midwife that vitamin C supplementation should be kept down to just the recommended daily allowance (65-80mg per day depending upon age and if pregnant) because it can cause miscarriage or birth defects.
I never heard such a thing and decided to double check.
First of all, 500mg of vitamin C per day can be obtained by drinking 1 glass of orange juice, eating 1/2 cup of sweet red peppers, and two tomatoes. I don’t think anyone would call this combination toxic to a fetus.
Secondly, the recommended daily allowance for vitamin C is determined by the amount needed to prevent scurvy – far from an optimal health goal.
Thirdly, the tolerable upper intake limit as established by Food and Nutrition Board of the United States Institute of Medicine is 2,000mg per day for an adult. This level is established to prevent loose stools – if you take more vitamin C than your digestive system can absorb it causes osmotic diarrhea (caused by the unabsorbed vitamin C drawing water out of the body and into the bowel).
Fourth, there is no clear evidence that vitamin C causes any adverse effects that are commonly attributed to it including: kidney stones, genetic mutations, birth defects, atherosclerosis, rebound scurvy, or oxidative stress.
I have seen many patients benefit from vitamin C supplementation of about 2,000mg to 3,000mg per day, for brief or extended periods of time. While I don’t think that everyone needs to take that much every day, these doses are safe (as long as loose stools don’t occur) and therapeutically effective for a number of health concerns.
The Bottom Line:
Taking 500mg of vitamin C per day is a safe dosage for women even if they are pregnant or breast feeding.
Be Well,
Richard