From the Guidelines
The Recommended Dietary Allowance (RDA) for vitamin C is 90 mg per day for adult men and 75 mg per day for adult women, as recommended by the Institute of Medicine Panel on Dietary Antioxidants and Related Compounds 1.
Overview of Vitamin C Recommendations
The RDA for vitamin C varies globally, with recommendations ranging from 40 mg/d in the UK and India to 110 mg/d in several European countries 1. However, the most recent and highest quality study suggests that the RDA for vitamin C should be based on the potential health effects of vitamin C, including antioxidant protection and immune function 1.
Rationale for Recommendations
The criteria for deriving the RDA for vitamin C differ among countries, with some basing their recommendations on the prevention of deficiency and others considering the potential health effects of vitamin C 1. The Institute of Medicine Panel on Dietary Antioxidants and Related Compounds recommends an RDA of 90 mg/d for men and 75 mg/d for women, based on the amount of vitamin C that maintains near-maximal neutrophil concentrations with minimal urinary excretion of ascorbate 1.
Special Considerations
Pregnant women, breastfeeding women, and smokers may require additional vitamin C intake due to increased oxidative stress and other factors 1. Children's requirements vary by age, and adolescents require 65-75 mg of vitamin C per day, depending on gender 1.
Dietary Sources and Upper Limit
Vitamin C can be obtained through a balanced diet that includes citrus fruits, berries, tomatoes, peppers, and leafy greens 1. The upper limit for vitamin C intake is 2,000 mg per day, as excessive amounts may cause digestive discomfort 1.
From the Research
Recommended Dietary Allowance (RDA) for Vitamin C
The RDA for Vitamin C varies based on factors such as age, sex, and lifestyle.
- For adult women, the RDA is 75 mg/day 2 and 95 mg/day 3.
- For adult men, the RDA is 90 mg/day 2 and 110 mg/day 3.
- For pregnant women, the RDA is 105 mg/day 3.
- For lactating women, the RDA is 125 mg/day 3.
- For smokers, the RDA is higher, with 135 mg/day for female smokers and 155 mg/day for male smokers 3.
- Other studies suggest that the RDA for vitamin C could be as high as 120 mg/day 4 or even 200 mg/day 5, but these values are not universally accepted.
Factors Influencing RDA
The RDA for Vitamin C is influenced by various factors, including:
- Age: The RDA increases with age, with higher requirements for adolescents and adults 3.
- Sex: The RDA is higher for men than for women 2, 3.
- Pregnancy and lactation: The RDA is higher for pregnant and lactating women 3.
- Smoking: The RDA is higher for smokers due to increased metabolic losses and lower plasma levels of vitamin C 3.