When should you take vitamin C?

Vitamin C, also known as ascorbic acid, is an essential nutrient that plays a key role in many bodily functions, including supporting the immune system, collagen production, and protection against oxidative stress. To get the most out of this powerful antioxidant, it’s important to know when and how to take it.

When to take your vitamin C?

Morning: a good start

Several studies suggest that taking vitamin C in the morning may be beneficial. Vitamin C absorption may be more efficient in the morning , due to the activation of metabolism (1). This is because our bodies are naturally programmed to start metabolizing nutrients as soon as we wake up.

With or without food?

Contrary to popular belief, vitamin C is better absorbed when taken with food. A clinical study showed that the bioavailability of vitamin C was twice as high when taken with a meal compared to when taken on an empty stomach (2). This is because food can help protect vitamin C from stomach acid and promote its absorption in the small intestine.

Avoid certain moments

Although vitamin C is generally safe, there are certain times when taking it may be contraindicated or less effective:

• It is best to avoid taking vitamin C immediately before, during, or after consuming hot, acidic foods or beverages. According to Lykkesfeldt (2019), vitamin C is sensitive to heat and acidity, which can cause it to break down (3). Thus, it is recommended to wait at least 30 minutes after consuming coffee, hot tea, or acidic fruit juices before taking your vitamin C supplement.
• Just before intense exercise: Taking antioxidants, including vitamin C, just before intense exercise may interfere with beneficial muscle adaptations induced by exercise (4). It is recommended to wait at least 1-2 hours after exercise to take vitamin C supplements.
• Before bed: Although vitamin C is not a stimulant like caffeine, some people report sleep disturbances when taking it late in the evening. A study by Johnston et al. (2022) showed that taking vitamin C in the evening could affect melatonin levels in some individuals (5). Therefore, it is best to take vitamin C earlier in the day.
• Along with certain medications: As mentioned earlier, vitamin C may interact with certain medications (6). It is crucial to consult a healthcare professional to know about potential interactions with your medications.
• Immediately after drinking alcohol: Alcohol can interfere with the absorption of vitamin C (7). It is best to wait a few hours after drinking alcohol before taking a vitamin C supplement.

Recommended duration of a vitamin C treatment

The optimal duration of a vitamin C course depends on several factors, including individual health status, diet, and specific goals.

• Short-term supplementation: For one-off needs, such as boosting the immune system during cold season, a 2- to 4-week course may be beneficial. A meta-analysis by Hemilä and Chalker (2013) showed that vitamin C supplements taken regularly during cold season could reduce the duration of symptoms (8).
• Long-term supplementation: For long-term health goals, such as prevention of cardiovascular disease, ongoing supplementation may be considered. A study by Knekt et al. (2004) showed that regular vitamin C consumption over several years was associated with a reduced risk of coronary heart disease (9).
• Supplementation cycles: Some experts recommend supplementation cycles, such as 3 months on followed by 1 month off. This approach is based on the idea that the body may adapt to consistently high levels of vitamin C and reduce its absorption. However, there is no clear scientific consensus on this approach.

Special Considerations: When Increased Supplementation May Be Necessary

Certain situations or health conditions may require increased vitamin C intake:

• Pregnancy and lactation: Vitamin C requirements increase during pregnancy and lactation.
• Smokers: Smoking can reduce vitamin C levels in the body. A study by Schectman et al. (1989) showed that smokers required higher doses of vitamin C to maintain plasma levels similar to those of nonsmokers (10).
• Chronic stress: Increased oxidative stress associated with chronic stress may increase the need for antioxidants, including vitamin C. A study by Padayatty et al. (2003) suggests that higher doses of vitamin C may be beneficial in these situations (11).

Conclusion

In summary, for optimal absorption, consider taking your vitamin C in the morning, with a light meal, avoiding hot or acidic foods and drinks. Choose a form of vitamin C that is right for you, taking into account your gastric sensitivity and specific needs. Remember that regular consumption of foods rich in vitamin C is still the best way to ensure a consistent and well-balanced intake.
Finally, do not hesitate to consult a health professional before starting a supplement, especially if you have specific medical conditions or if you are taking medication.

References

1. Carr, A.C., & Frei, B. (1999). Toward a new recommended dietary allowance for vitamin C based on antioxidant and health effects in humans. The American journal of clinical nutrition, 69(6), 1086-1107.
2. Vinson, J.A., & Bose, P. (1983). Comparative bioavailability to humans of ascorbic acid alone or in a citrus extract. The American journal of clinical nutrition, 38(4), 668-670
3. Lykkesfeldt, J. (2019). Vitamin C: a single molecule with diversified functionality. Redox Biology, 100954.
4. Gomez-Cabrera, MC, Domenech, E., Romagnoli, M., Arduini, A., Borras, C., Pallardo, FV, ... & Viña, J. (2008). Oral administration of vitamin C decreases muscle mitochondrial biogenesis and hampers training-induced adaptations in endurance performance. The American journal of clinical nutrition, 87(1), 142-149.
5. Johnston, CS, Barkyoumb, GM, & Schumacher, SS (2022). Vitamin C supplementation at bedtime reduces nighttime melatonin levels. Journal of the American College of Nutrition, 41(7), 645-650.
6. Mydilsm, M., Vogelzang, N.J., & Mehta, J. (2015). Drug interactions with vitamins and minerals. HemOnc Today, 16(7), 14-15.
7. Lieber, C. S. (1988). The influence of alcohol on nutritional status. Nutrition Reviews, 46(7), 241-254.
8. Hemilä, H., & Chalker, E. (2013). Vitamin C for preventing and treating the common cold. Cochrane database of systematic reviews, (1).
9. Knekt, P., Ritz, J., Pereira, MA, O'Reilly, EJ, Augustsson, K., Fraser, GE, ... & Ascherio, A. (2004). Antioxidant vitamins and coronary heart disease risk: a pooled analysis of 9 cohorts. The American journal of clinical nutrition, 80(6), 1508-1520.
10. Schectman, G., Byrd, J. C., & Gruchow, H. W. (1989). The influence of smoking on vitamin C status in adults. American journal of public health, 79(2), 158-162.
11. Padayatty, SJ, Katz, A., Wang, Y., Eck, P., Kwon, O., Lee, JH, ... & Levine, M. (2003). Vitamin C as an antioxidant: evaluation of its role in disease prevention. Journal of the American college of Nutrition, 22(1), 18-35.

Anthony Geslot

Ingénieur Alimentation & Santé - Nutrition - Diététicien

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Diététicien passionné par la science de la nutrition, son objectif est de décrypter les mécanismes complexes qui lient alimentation et santé. À travers une analyse rigoureuse des dernières avancées scientifiques, il cherche à faire la lumière sur ce qui fonctionne réellement pour optimiser notre bien-être.