Vitamin C: Benefits, Side Effects, Dosage

Nutrients that the body needs are generally categorized as macronutrients and micronutrients.

Macronutrients generally refer to the fats, carbohydrates, and proteins that are found in food.

Micronutrients, on the other hand, refer to specific vitamins and minerals that cells in the body need to survive and function.

Each vitamin and mineral plays a specific role in contributing to the functions that are needed for a person to survive.

Vitamin C is among the most essential nutrients. This vitamin is often advised for people who have a cold. It does play a role in immune system regulation. Vitamin C, however, has many other functions too.

We take a closer look at what vitamin C is in this article. We also consider the roles that vitamin C plays in the body. The post also considers vitamin c benefits and the best sources of vitamin C.

What Is Vitamin C?

Vitamin C is one of the essential nutrients that people need every day. The nutrient is classified as a water-soluble vitamin1. This means it does not have to be consumed with fats to be absorbed into the bloodstream.

Vitamin C is also called L-Ascorbic Acid. It is available in a natural form. In some cases, a synthetic type of vitamin C can also be used. The synthetic type is produced in a laboratory.

Many mammals can produce vitamin C. Humans, however, do not have this ability. This is why it is important to obtain vitamin C in a person’s diet each day. When a diet lacks adequate amounts of vitamin C, then supplementation can be used. This can help to increase the level of bioavailable vitamin C in the human body.

Vitamin C is available as a single supplement. These supplements will contain L-Ascorbic Acid and no other nutrients. Most multivitamins that people take will also contain some added vitamin C. This is due to the risks that a person may face when they become deficient of the vitamin.

Vitamin C deficiency is linked to a risk of developing a condition known as Scurvy2. This condition is often classified as a clinical syndrome. It can cause many adverse effects on the body. These adverse effects can affect the gums, skin, blood, and other areas of the body.

There is a concern regarding vitamin C deficiency in various parts of the world, including the United States. According to one study, up to 13% of the population in the United States do not get enough vitamin C on a daily basis3.

Why Do We Need Vitamin C?

Many functions in the body depend on vitamin C. To understand why people need to ensure they obtain enough of the nutrient; it is vital to consider the specific functions of vitamin C.

We discuss a few important roles that vitamin C levels play in the body below:

  • Vitamin C acts as a cofactor for certain enzymatic reactions in the human body. In particular, vitamin C is a critical element in the biosynthesis of neuropeptides. The biosynthesis of carnitine and collagen also depends on the presence of vitamin C in the body.

  • Gene expression is regulated by vitamin C.

  • Vitamin C has also been shown to act as a powerful antioxidant in the human body. This means the vitamin plays a significant role in helping to protect the body against damage associated with free radicals.

  • Some evidence suggests that there may be a link between vitamin C and blood pressure regulation. In fact, in one study4, it was shown that the risk of developing hypertension could potentially be reduced with adequate intake of vitamin C. Even though an observational study, evidence still points to a positive association between blood pressure regulation and higher vitamin C intake.

  • Vitamin C has a role in the immune system’s function. People who obtain enough vitamin C might find that they experience a faster recovery from the common cold.

When it comes to looking at the antioxidant effects of vitamin C, there is another factor that should be taken into consideration. The main antioxidant that is found in tissue and plasma in the body is considered vitamin C. This makes the nutrient the most crucial antioxidant that a person can obtain.

Apart from protecting against free radicals, vitamin C helps to fight against reactive oxygen species in the body.

Other molecules are protected by vitamin C too. This includes lipids, carbohydrates, nucleic acids, and proteins. Vitamin C protects both the RNA and the DNA of the human body.

What Are The Benefits Of Vitamin C?

There are several important reasons why vitamin C should be a part of a person’s diet or supplements each day.

May Protect Against Heart Disease

We already considered the fact that vitamin C may be helpful for people at risk of hypertension. This is a condition that refers to an elevated blood pressure level.

When blood pressure is elevated, a person is at risk of certain complications. This includes being more likely to develop heart disease. Hypertension also damages the walls of arteries and blood vessels. In the long run, it further causes problems with the cardiovascular system.

Heart disease is considered the biggest killer throughout the entire world5. Millions of people die each year due to some type of heat-related illness.

Vitamin C could contribute to a reduction in blood pressure levels. One research paper analyzed results from 29 previously conducted human clinical trials. All trials looked at the effects of vitamin C on specific vitals of the participants.

Researchers found that vitamin C lowered systolic blood pressure by an average of 3.8 mmHg. Diastolic blood pressure was also reduced by an average of 1.5 mmHg. Some studies show a reduction in systolic blood pressure as high as 4.9 mmHg6.

A reduction in blood pressure may help to reduce the risk of heart disease. This is how vitamin C could be a protective agent against cardiovascular illnesses. The antioxidant activity of vitamin C should also be taken into consideration here. This protects the heart against oxidative damage.

Improves Immune Function

One of the most popular uses for vitamin C would be its ability to assist in strengthening the immune system. Several studies have looked at this. It has been confirmed and well-documented that vitamin C is a critical part of maintaining a healthy and functioning immune system.

Here, it is essential to consider the role of vitamin C in the immune system specifically. First, the vitamin assists with white blood cell protection. These are the cells that form part of the immune system.

Two specific types of white blood cells are produced with the help of vitamin C. These include phagocytes and lymphocytes. Both of these white blood cells have been shown to help the immune system fight against infections7.

Vitamin C also boosts the function of white blood cells. This is an integral part in allowing the immune system to fight off invading pathogens more effectively. The antioxidant activity of vitamin C protects the body against free radicals too. Free radicals can damage white blood cells.

The defense system of the skin also benefits from vitamin C8. The vitamin is distributed toward skin tissue. Here, it increases the skin’s general strength. It also helps to build a stronger barrier to the skin.

Improves Wound Healing

There is evidence that vitamin C may have a role to play in wound healing too. Multiple studies have provided evidence on this particular subject. It has been shown that wounds heal faster in people with higher levels of bioavailable vitamin C in their bodies.

One study showed that vitamin C, combined with zinc and arginine, effectively reduces healing time for pressure ulcers9. A total of 16 people participated in the study. All individuals had suffered a pressure ulcer at the time.

The ulcers were grade between stage two and stage four. A total of 500mg vitamin C was added to the formula each day. Improvements in wound healing were observed at a more significant level as week three among patients who took the vitamin C formula.

Other Benefits Of Vitamin C

While vitamin C is important for protecting the cardiovascular system and strengthening the immune system, there are other functions that we should not overlook. Below are a few additional benefits that people can expect from an increased vitamin C intake:

  • Vitamin C plays a role in mental health and brain health too. Increasing the intake of vitamin C could potentially reduce the risk of dementia and related conditions. It may also help to reduce inflammation and oxidative stress that affect the brain.

  • There is evidence that vitamin C may help to reduce the risk of iron deficiency. Vitamin C has been shown to help the body absorb iron more effectively. This can also help a person reduce their risk of complications like anemia. This condition is directly linked to a deficiency in iron.

  • People with gout may also benefit from vitamin C. The nutrient has been shown to reduce the level of uric acid in the blood potentially. Uric acid is linked to a higher risk of flare-ups linked to gout.
joint pain relief

Sources Of Vitamin C

Now that we have discussed the benefits of taking a vitamin C supplement, it is important also to note the best sources of this nutrient. There are quite a large number of foods that contain vitamin C. This makes it relatively easy for the average person to ensure they obtain enough vitamin C in their daily diet.

The daily intake value for vitamin C depends on a few factors. The age of a person plays a big role. In most cases, it is advised to obtain between 65mg and 90mg of vitamin C each day. Many people take more than this. It is generally considered safe to take up to 2,000mg of vitamin C on a daily basis.

There are both fruits and vegetables that contain vitamin C. It is important to note that some foods are higher in vitamin C than others. We take a look at some of the best foods that a person can consume to increase their vitamin C intake.

  • Chilli Peppers – A single green chili pepper offers about 109mg vitamin C content. This is more than 100% of the daily recommended intake value for vitamin C.

  • Guava – Guavas are also high in vitamin C, with about 126mg of the vitamin in one guava. This is 140% of the daily recommended value.

  • Blackcurrants – Half a cup of blackcurrants contain 101mg of vitamin C content. This is also more than 100% of the daily recommended intake for the vitamin.

  • Parsley – This one may come as a surprise, but parsley also contains vitamin C. Eight grams of parsley contains 10mg vitamin C. While this is not much, it still helps to add to the daily intake of the nutrient.

  • Kale – Kale is a leafy green vegetable with many nutrients and health benefits. Among these would be vitamin C. A cup of chopped kale offers about 80mg vitamin C. This is 895 of the daily recommended intake value for the nutrient.

  • Kiwi – Kiwis are also very high in vitamin C. A medium-sized kiwi offers about 79% of the daily recommended intake for vitamin C. This is equal to about 71mg of the nutrient.

  • Golden berries- Goldberries are rich in vitamin C and contain multiple polyphenols which block the release of certain inflammatory immune markers.

Other foods also contain vitamin C. This includes broccoli, brussels sprouts, papaya, strawberries, and citrus fruits including oranges and lemons.

Creating a balanced diet that contains some of these fruits and vegetables can help a person get enough vitamin C each day.

Many people do follow diets that do not offer them enough vitamin C, however. There are also cases where a person needs to increase their vitamin C intake for specific reasons. In such scenarios, opting for a supplement that contains vitamin C can be useful.

There are several supplements that people can use to increase their intake of the vitamin. A pharmaceutical-grade vitamin C supplement is also available. This is generally given to a patient with a more severe level of vitamin C deficiency. The supplement is administered to the patient intravenously to ensure vitamin C distributes through their body faster and more effectively.

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Vitamin C is an important nutrient. Several functions in the body rely on an adequate supply of this vitamin each day.

The immune system depends on vitamin C to fight off invading pathogens, including the common cold. Several enzyme reactions depend on vitamin C too. This includes enzymes involved in the biosynthesis of carnitine, collagen, and more.

Obtaining enough vitamin C can provide several potential health benefits to the body. It is also essential to understand why a person needs this particular vitamin. This can help people determine when it may be appropriate to increase their intake of vitamin C.


  1. Oregon State University. Vitamin C. [online] Available at
  2.  StatPearls. (2019) Vitamin C Deficiency. [online] Available at:
  3. American Journal of Clinical Nutrition. (2009) Serum vitamin C and the prevalence of vitamin C deficiency in the United States: 2003-2004 National Health and Nutrition Examination Survey (NHANES). [online] Available at:
  4. The American Journal of Clinical Nutrition. (2012) Effects of vitamin C supplementation on blood pressure: a meta-analysis of randomized controlled trials. [online] Available at:
  5. World Health Organization. (2017) Cardiovascular diseases (CVDs). [online] Available at:
  6.  American Journal of Clinical Nutrition. (2012) Effects of vitamin C supplementation on blood pressure: a meta-analysis of randomized controlled trials. [online] Available at:
  7. Journal of Leukocyte Biology. (2014) Technical advance: ascorbic acid induces development of double-positive T cells from human hematopoietic stem cells in the absence of stromal cells. [online] Available at:
  8.  Free Radical Biology and Medicine Journal. (1998) Modulation of UV-light-induced skin inflammation by D-alpha-tocopherol and L-ascorbic acid: a clinical study using solar simulated radiation. [online] Available at:
  9. Journal of Clinical Nutrition. (2005) Treatment with supplementary arginine, vitamin C, and zinc in patients with pressure ulcers: a randomized controlled trial. [online] Available at:

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