Health Concern

Vitamin C is an essential micronutrient renowned for its crucial role as an immunity booster. Its powerful antioxidant properties strengthen the immune system and provide many other benefits for optimal growth and development. Although its benefits are widely recognised, many people mistakenly believe that higher doses can supercharge immunity.

Does consuming more vitamin C truly make your immune system stronger? To maximise its benefits while avoiding unnecessary adverse effects, let’s understand the roles and recommended dosage of vitamin C.

 

⁠Introduction to Vitamin C as an essential micronutrient and its food sources

Vitamin C, also known as L-ascorbic acid, is a water-soluble vitamin essential for overall health. Unlike most plants and animals, our human body cannot produce vitamin C. This is because our body is lack of L-gulonolactone oxidase (GLO), a key enzyme to produce vitamin C. As a result, we must get Vitamin C from the diet to prevent deficiencies like scurvy and support proper bodily functions.

Vitamin C is can be found naturally in various fruits and vegetables. Citrus fruits like oranges, tangerines, limes, and grapefruits are excellent sources. Other fruits rich in vitamin C include guava, longan, papaya, berries, and kiwi. Vegetables such as bell peppers, kale, broccoli, mustard greens, bok choy, and spinach are also packed with vitamin C. Additionally, we can get vitamin C through fortified foods and beverages, such as cereals and juices. 

 

How does Vitamin C support the immune system? 

Decades of research have shown the beneficial effects of vitamin C in supporting the immune system to ensure its optimal function.

Here’s how vitamin C helps:

• Antioxidant Protection

Our body’s metabolic processes or external environmental factors such as pollution, radiation, and cigarette smoke produce free radicals. These free radicals are unstable atoms which cause cell damage in our body. Vitamin C acts as a powerful scavenger of these free radicals by donating electrons and stabilising their reactivity. By neutralising these harmful molecules, vitamin C protects immune cells against oxidative damage.

• Wound Healing

The epithelial barrier is an important component of the body’s immune system. This barrier provides a physical, chemical, and immunological barrier against harmful external stimuli, including pathogens. However, the epithelial barrier is also being damaged from time to time. Vitamin C supports the healing of this barrier by promoting the formation of collagen. Collagen is a structural protein that aids in tissue regeneration and repair at the wound site, while the antioxidant properties of vitamin C help reduce inflammation. This can further speed up recovery and the healing process.

• Repair and Maintenance of Healthy Gums, Skin, and Cartilage

The role of vitamin C in collagen synthesis extends beyond wound healing. Vitamin C is essential for repairing healthy gums, skin, and cartilage. It helps prevent gum bleeding, supports skin elasticity, and strengthens connective tissues. This function is important for the maintenance of physical barriers against infection and supporting joint health. 

 

 How much vitamin C do we need and is it possible to overdose?

The daily recommended intake of vitamin C varies based on age. According to the Recommended Nutrient Intake (RNI) for Malaysia, children and adolescents require 30-65 mg/day, whereas adults and older adults need 70 mg/day. You can easily meet that requirement through a balanced diet rich in fruits and vegetables. For example, by consuming one medium-sized orange (140 g), you can get approximately 83 mg of vitamin C. 

We should always prioritise a food-first approach to achieve the recommended vitamin C needs. This can also prevent the negative side effects of vitamin C overdose. The tolerable upper intake level (UL) of vitamin C for adults is 2000 mg/day. When we consume more than the UL, adverse effects such as diarrhoea and other gastrointestinal discomfort may happen. 

However, individuals with increased needs, such as critically ill patients or those with limited dietary intake, can consider taking supplements under professional advice. 

 

Do athletes need more vitamin C?

During exercise, harmful compounds are produced in our body. Vitamin C can help to neutralize these harmful compounds and protect cells from damage. During intense periods of exercise, vitamin C may not prevent a cold, but it can support the immune system to reduce the severity and duration of the cold. 

It is also noteworthy that long-term high-dosage supplementation with vitamin C is not recommended to avoid blunting the intended physiologic adaptations to training.

 

Summary

Vitamin C is an essential micronutrient that plays a crucial role in various bodily functions. It is a powerful antioxidant that helps boost immunity, important for collagen synthesis to support wound healing, and helps maintain healthy gums, skin, and cartilage. We should consume a balanced diet rich in a variety of fruits and vegetables in order to meet our daily requirements. Higher dosage of vitamin C may be recommended for professional athletes or older adults.

 

Reference

Australian Institute of Sport. (2023). The Australian Institute of Sport (AIS) Supplement Framework. 

Carr, A. C., & Maggini, S. (2017). Vitamin C and immune function. Nutrients, 9(11), 1211.

Doseděl, M., Jirkovský, E., Macáková, K., Krčmová, L. K., Javorská, L., Pourová, J., … & Oemonom. (2021). Vitamin C—sources, physiological role, kinetics, deficiency, use, toxicity, and determination. Nutrients, 13(2), 615.

Ministry of Health Malaysia. (2017). Recommended Nutrient Intake for Malaysia.

Pehlivan, F. E. (2017). Vitamin C: An antioxidant agent. Vitamin C, 2, 23-35.

Spoelstra-de Man, A. M., Elbers, P. W., & Oudemans-Van Straaten, H. M. (2018). Vitamin C: should we supplement?. Current opinion in critical care, 24(4), 248-255.

U.S. Department of Agriculture. (2019). FoodData Central Food details. Retrieved November 25, 2024, from https://fdc.nal.usda.gov/food-details/746771/nutrients