Vitamin C and Viral Infections

Vitamin C is an essential nutrient, benefiting us in many ways, particularly in the healthy functioning of the immune system. It’s found in various foods and sold as a dietary supplement, although it is historically perhaps best known for curing sailors at sea from scurvy!

The Role of Vitamin C in Viral Infections

In healthy individuals, the optimal intake of vitamin C is 500-1000mg per day. In diseased states, particularly in virally infected individuals and those with cancer, the body’s need for vitamin C is much greater, between 500-1000mg per hour! This is because vitamin C is integral to defence against viruses as it boosts many cellular and non-cellular antiviral defence mechanisms.

Dr Linus Pauling

Dr. Linus Pauling was a world-renowned scientist and humanitarian who won two unshared Nobel Prizes, one for chemistry (1954) and one for peace (1962). Later in his life, he became interested in the benefits of vitamin C and directed his research towards the use of vitamin C in combatting disease, particularly respiratory infections such as the common cold and flu. Awareness of vitamin C physiology in animals that are able to synthesise their own vitamin C laid the foundations for his research. He considered the fact that these animals showed increased resistance to viral infections and cancers.

Pauling hypothesised that taking daily doses of vitamin C would boost the immune response against viral infection and that once infected by a virus, one should take 1g/hr until symptoms subsided.

At the time, the medical world considered Pauling’s hypothesis unfounded. However, there have now been various studies looking into the effect of vitamin C on respiratory infection symptoms and recovery time, all of which seem to have an encouraging outcome! Nevertheless, many of these studies assessed single daily dose administration of vitamin C, i.e., 1-3g/day. So, it’s important to remember that more research is needed to assess the effects of vitamin C at regular intervals throughout the day, i.e., 1g/hr, in patients with viral respiratory infections.

Vitamin C and How It Supports the Immune System

Vitamin C is what is known as an antioxidant. Antioxidants help us by neutralising the harmful by-products of our metabolism. So, for smokers and frequent consumers of alcohol, vitamin C is used up much quicker than in those individuals that do neither. Consequently, these people need to have a higher vitamin C intake to maintain healthy levels. During this chemical process, vitamin C gets converted to a compound called dehydroascorbic acid, which is also a helpful pro-oxidant and possesses the ability to destroy viruses and cancer cells.

Viruses produce an enzyme called neuraminidase, which helps them infect our cells. Vitamin C is an inhibitor of this enzyme. It helps virally infected cells secrete increased amounts of interferon, which communicates with surrounding healthy cells to raise their anti-viral defense mechanisms.

Vitamin C plays multiple crucial roles in our body’s defense against infections. Firstly, it supports the production of ‘T’ and ‘B’ cells, essential for fighting off pathogens. Additionally, it aids cells like macrophages and monocytes in clearing dead/dying cells and virally infected cells through phagocytosis.

Getting your daily intake of Vitamin C

There are various ways in which you can get your recommended daily intake of vitamin C. The most straightforward being by eating lots of fresh fruit and vegetables! However, for many people, this is not enough to sustain optimal levels of vitamin C throughout the day.

Vitamin C supplements are an effective and affordable way of achieving optimum vitamin C levels in our bodies. You might take vitamin C as a chewable tablet, capsules, or water-soluble powder. However, out of all the supplementation methods, the best one to sustain vitamin C saturation in the body is by using vitamin C powder dissolved in juice or water.

Regardless of the format of your supplementation, it should always be taken with lots of fluid.

Getting Vitamin C From Your Diet

Of course, food is a critical source of vitamin C, so make sure you include plenty of fruits and vegetables that are rich in this vitamin in your everyday diet. These include:

Managing Vitamin C Levels

When the blood plasma levels of vitamin C rise above 60mM/L, it begins to be cleared from the blood by the kidneys and excreted in urine. This is problematic when the optimal blood plasma levels of vitamin C are 61-80mM/L. In short, this means that as vitamin C levels go up from dietary ingestion, so they go down through urinary excretion.

Additionally, we also have a ‘bowel tolerance’ for vitamin C. This means that we have a maximum amount of vitamin C that we can tolerate ingesting at one time before getting diarrhoea (around 4000mg for a healthy adult). Normal tolerance levels can vary; however, interestingly, this maximum value increases in diseased states, like during a flu infection.

For both reasons, it is beneficial to ingest small amounts of vitamin C at regular intervals throughout the day. This will enable a healthy blood plasma level to be maintained while preventing Vitamin C gut overload and minimising the loss of vitamin C in urine.

In Summary

Vitamin C is essential for immune health and collagen production. It acts as an antioxidant, protecting cells from damage. Sources like citrus fruits and bell peppers make it easy to incorporate into your diet. Adequate Vitamin C intake supports overall well-being and boosts the body’s ability to fight off infections.