Is Vitamin C Good For The Immune System

Trillions of cells inside our body encounter constant threats. This can occur either from poor nutrition, infections, biological factors, or environmental exposure. These threats are typically capable of harming cells and their other parts.

In order to combat these invaders and strengthen our immune system, the body requires sufficient amounts of natural nutrients. There are several nutrients that are necessary for immune cell function, but one of the most well-known and important nutrients for immunity is Vitamin C.

Vitamin C, or ascorbic acid, is critically important for our overall health. It not only acts as an immunity booster but also helps in healing wounds, has antioxidant properties, forms and maintains bones, blood vessels, the skin, and much more. Since vitamin C is not produced by the human body, it is necessary to keep it in your daily diet to avoid the risk of developing health conditions.

Vitamin C and the immune system

Generally, vitamins are organic compounds that we need to consume in small amounts. These are the building blocks that allow our bodies to function. They help to defend, build muscles, maintain bones, utilize energy, and repair wounds. Vitamin C is one of these essential nutrients required for our health.

Vitamin C, or ascorbic acid, is a water-soluble vitamin that aids in growth and acts as a vital source of immunity boosters. Vitamins are classified into two major types, which typically determine how the body will transport and store them. These two types are:

  • Lipid soluble - Vitamins A, D, E, and K.
  • Water-soluble - Vitamins C and B-complex vitamins.

Water-soluble vitamins such as vitamin C and vitamin B have relatively straightforward processes, meaning that they cannot be stored in the body. Since they are easily taken by the bloodstream, they can be expelled effortlessly via the kidneys as well. For this reason, it is essential to add them to your diet.

Vitamin C is a vital component needed to make collagen – a fibrous substance and a major unit of connective tissue, which is required to repair various tissues such as:

  • Skin.
  • Cartilage.
  • Bones.
  • Tendons.
  • Ligaments.
  • Blood vessels.
  • Teeth.
  • The gut.

Moreover, vitamin C serves as an antioxidant to neutralise free radicals that can harm cells and damage DNA material. It also plays an important role in controlling infections, wound healing, and stimulating white blood cells to enhance their response to the specific infection.

Sources of vitamin C

There are numerous sources of vitamin C besides the ever-popular oranges or a glass of orange juice. Vitamin C can be found in many vegetables and fruits. Some of the excellent sources of this vital nutrient include:

  • Citrus fruits like oranges, lemons, tangerines, and grapefruits.
  • Cruciferous vegetables, brussels sprouts, cauliflower, broccoli, and cabbage.
  • Berries such as raspberries, strawberries, and blackberries.
  • Bell peppers.
  • Tomatoes.
  • Potatoes.
  • Cantaloupe.
  • Kiwi fruit.
  • Papaya.

When foods are cooked or kept for extended periods of time, they can lose a significant amount of their vitamin C content. The best way to consume the majority of the nutrients is to eat fruits and vegetables raw or when lightly cooked.

Benefits of vitamin C to the immune system

Vitamin C is known as a crucial player that boosts defence by supporting the cellular function of our immune system. It benefits our body as an ideal source for preventing health problems, including immune deficiencies, and certain cancers, and promoting healthy ageing. The benefits of vitamin C involved in the immune system may include:

Skin barrier properties: Vitamin C is a primary component for making collagen. Collagen is present in our muscles, bones, and even our skin. Along with several functions, the skin also provides a barrier against environmental insults, including pathogens. According to research, vitamin C is prominently accumulated within the dermal (skin) layers, enhancing skin barrier properties and wound healing. Additionally, it is also suggested that vitamin C is involved in the genetic expression of specialised cells called fibroblasts.1 Fibroblasts are the cells that are programmed to build the collagen network.

Wound healing: White blood cells (WBCs), or leukocytes, are the special defence units of our body. White blood cells such as neutrophils and macrophages are particularly involved in wound healing. During the initial inflammatory phase, the WBCs migrate to the wound site to neutralise the pathogen. Vitamin C is known to influence various vital aspects of leukocyte function, which helps to clear the infection and enhance wound healing.1

Allergies: When an allergic reaction happens, our immune system stimulates an inflammatory response. Evidence has suggested that vitamin C can help reduce the allergic response.2

Common cold and viral infections: Vitamin C is widely suggested for its beneficial health effects against the common cold. Although the role of vitamin C in preventing common colds remains debatable, controlled studies have shown that vitamin C increases immunity against viral infections by reducing the severity and duration of cold symptoms.3 Recent research has also suggested that vitamin C may be useful in the treatment of COVID-19 and other viral infections.4

Should you take vitamin C everyday?

Unlike plants, fungi, and bacteria, which produce their own vitamins, the human body can't produce them, so we require vitamins from other sources. It is best to get vitamin C in your daily meals to keep your bodily functions running smoothly. The recommended amount of vitamin C per day for adults over 18 years of age is 40 mg. Pregnant and lactating women require an additional dose of vitamin C.

Vitamin C deficiency: Effects on the immune system

Vitamin C deficiency is usually caused by an insufficient nutrient supply in your diet. A prolonged lack of vitamin C can compromise the immune system and also reduce collagen formation.

This means an individual can become prone to several infections. Furthermore, chronic vitamin C deficiency (a lack of vitamin C for more than three months) can result in scurvy.

Scurvy is an illness caused due to severe lack of vitamin C. Although scurvy is rare in the UK and other countries, it is usually found in those who follow restrictive diets and in malnourished people. If left untreated, scurvy can cause symptoms like:

  • Bleeding, especially from the gums.
  • Muscular pain.
  • Brittle hairs.
  • Fatigue.
  • Loosen teeth.
  • Anaemia
  • Slow wound healing.
  • Oedema (fluid accumulation) in lower proximity
  • Infections.

Moreover, insufficient levels of vitamin C can upset the antioxidant balance in the body. This can lead to the development of free radicals (the byproduct made during normal metabolism). The surge of free radicals overwhelms the body, leading to a disturbance called oxidative stress. A lack of vitamin C might weaken the immune system and make you more susceptible to infections.


Vitamin C, also called ascorbic acid, is one of the most important nutrients for health. It is involved in several body functions, ranging from growth and development to repairing tissues and wound healing. Along with its diverse antioxidant properties, vitamin C is known as a crucial contributor to boosting our immune system. Since ascorbic acid is a water-soluble vitamin, our body is unable to store it, so we have to maintain its healthy levels by adding it to our daily diet. To maintain and build immunity against serious health diseases, it is essential to consume the recommended amounts of vitamin C on a daily basis.


  1. Carr AC, Maggini S. Vitamin C and immune function. Nutrients. 2017 Nov;9(11):1211.
  2. Vollbracht C, Raithel M, Krick B, Kraft K, Hagel AF. Intravenous vitamin C in the treatment of allergies: an interim subgroup analysis of a long-term observational study. Journal of International Medical Research. 2018 Sep;46(9):3640-55.
  3. Chambial S, Dwivedi S, Shukla KK, John PJ, Sharma P. Vitamin C in disease prevention and cure: an overview. Indian journal of clinical biochemistry. 2013 Oct;28(4):314-28.
  4. Shahbaz U, Fatima N, Basharat S, Bibi A, Yu X, Hussain MI, Nasrullah M. Role of vitamin C in preventing of COVID-19 infection, progression and severity. Aims Microbiology. 2022;8(1):108.
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Sadaf Ahmed

Master of Science - MSc, Physiology, Clinical & Molecular Hematology, Karachi University, Pakistan

Sadaf is an experienced writer who creates a quality and well-researched scripts particularly related to Health Sciences.

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