Vitamin c daily requirements
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Vitamin C Daily Requirements: Minimum, Optimal, and Special Considerations
Minimum Vitamin C Intake to Prevent Deficiency
The minimum daily requirement of vitamin C to prevent scurvy, a deficiency disease, is about 10 mg per day. Many countries, including the UK and Australia, set their recommendations slightly higher, at 40–45 mg per day, to include a safety margin and ensure basic health needs are met .
Recommended Daily Allowance (RDA) for General Health
For many years, the RDA for vitamin C in adults was set at 60 mg per day, based on the amount needed to prevent scurvy. However, more recent research and expert panels suggest that this amount is not enough for optimal health and disease prevention. Current recommendations from European and North American authorities are higher, generally ranging from 75–110 mg per day for adults, with specific values as follows:
- Adult men: 90–110 mg/day
- Adult women: 75–95 mg/day
- Pregnant women: 105 mg/day (from the fourth month)
- Lactating women: 120–125 mg/day
- Children and adolescents: 20–100 mg/day, depending on age
- Infants: 20 mg/day 34510
Optimal Vitamin C Intake for Disease Prevention and Immune Function
Recent studies indicate that higher intakes of vitamin C may provide additional health benefits, such as reducing the risk of chronic diseases (e.g., cardiovascular disease, cancer, cataracts) and supporting immune function. Evidence suggests that intakes of 90–200 mg per day are associated with optimal reduction of chronic disease risk and better immune cell function 1567. Some experts recommend increasing the daily intake to 200 mg for healthy adults to ensure full saturation of plasma and immune cells, which may further reduce the duration of common colds and lower the risk of cardiovascular disease 57.
High-Dose Recommendations and Supplementation
Some researchers argue that the current RDA is still too low for optimal health and propose a much higher daily intake, ranging from 250 mg up to 1,000 mg (1 gram) or more, especially considering modern dietary patterns and nutrient losses during food processing and storage. These higher doses are considered safe for most people, with no clear evidence of harm below 1,000 mg per day, but there is little evidence that doses above 400 mg provide additional benefits 278.
Special Considerations: Smokers, Body Weight, and Obesity
- Smokers: Smoking increases vitamin C turnover and lowers plasma levels. Smokers are advised to consume an extra 35–40 mg per day, resulting in recommended intakes of 135–155 mg per day for adult smokers 3410.
- Higher Body Weight/Obesity: People with higher body weight need more vitamin C to achieve the same plasma levels as those with lower body weight. An additional 10 mg per day is recommended for every 10 kg above 60 kg. For example, someone weighing 90 kg should aim for about 140 mg per day 910.
Conclusion
The minimum daily requirement of vitamin C is about 10 mg to prevent deficiency, but most health authorities now recommend 75–110 mg per day for adults to support general health. For optimal immune function and chronic disease prevention, intakes of 90–200 mg per day are supported by recent research. Special populations, such as smokers and those with higher body weight, require even higher intakes. While very high doses (above 400 mg) are generally safe, there is little evidence of added benefit beyond this level for most people. A diet rich in fruits and vegetables is the best way to meet these requirements.
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