Cold and flu season is here, which means a lot of people plan to safeguard their health by loading up on pills, powders and other forms of vitamin C. For many people, the nutrient is one of a wide lineup of supplements, from vitamin A to zinc, regularly taken to help boost immune health. But vitamin C, now a 2 billion dollar-a-year industry, is probably the most overused.

Vitamin C really does help boost the immune system and is an essential part of a healthy diet, but its benefits are often exaggerated. Those exaggerations have led many to megadose with vitamin C. During the pandemic, sales of vitamin C increased by 70 percent.

Vitamin C gained its superpower reputation in the 1970s from chemist Linus Pauling. The highly respected two-time Nobel Prize winner published a book, Vitamin C and the Common Cold, promoting the notion that megadoses of vitamin C—to the tune of 3,000 mg a day—were the secret to eliminating the common cold and fighting off more serious ailments like heart disease and cancer. But even though Pauling was a highly acclaimed scientist, his book was not supported by sound science.

So, What Does Vitamin C Do for You?

Vitamin C, also known as ascorbic acid, works as a powerful antioxidant by neutralizing free radicals. Free radicals are unstable molecules that contain an unpaired electron. Notorious for stealing electrons from molecules in blood, skin, and other cells, free radicals damage the molecules and possibly contribute to the formation of diseases like cancer and heart disease. Vitamin C and other antioxidants work by donating an electron to a free radical, rendering it harmless.

Vitamin C helps deliver a boost to the immune system by supporting the production of proteins, called interferons, that protect cells from a viral attack. Vitamin C also enhances the function of white blood cells, specifically phagocytes, that help engulf pathogens and stimulate the activity of other immune cells to fight off infections.

Your body also uses vitamin C to form collagen, that vital protein that’s essential for strong bones, muscles, and blood vessels. As we discussed a few weeks ago, collagen is an extremely important building block for all connective tissues, especially your skin. It can heal wounds, and prevent sagging, wrinkling, dark spots and acne. Vitamin C is commonly used in skin care products because it helps your body build its own collagen from the collagen you consume.

Finally, vitamin C helps make chemical messenger and hormones that are important in the brain and nervous system. This function of vitamin C plays an important role in reducing stress and anxiety.

Getting Enough Vitamin C

We need to consume vitamin C on a regular basis because our bodies don’t make it or store it. Going without vitamin C for eight weeks could lead you to fall prey to the famous pirate scourge called scurvy. That sea faring predicament led early scientists to discover vitamin C. In the 1700s, sailors figured out that oranges and lemons could cure scurvy. But not until the 1900s did scientists isolate vitamin C as the critical component of citrus fruits.

The recommended daily amount of vitamin C is 90 mg a day for men and 75 mg a day for women. Smokers need an additional 35 mg a day, due in part to the increased oxidative stress and free radicals.

Anyone who eats a decent amount or even a low number of fruits and vegetables will get plenty of vitamin C in their diet. A half a cup of red peppers, an orange, a kiwi, or a cup of broccoli or strawberries will provide enough vitamin C to meet most peoples’ needs. Other foods high in vitamin C include lemons, grapefruit, brussels sprouts, cabbage, cantaloupe and tomatoes.

Vitamin C has a tolerable upper limit of 2000 mg a day. Most people can tolerate overdoing it, but people with kidney issues need to be careful because the body can only use so much vitamin C at a time. If you consume too much, your kidneys have to handle the excess.

Can Vitamin C Supplements Prevent a Cold or Flu?

Linus Pauling’s claim about taking large doses of vitamin C never stood up to rigorous research. There is no consistent scientific evidence to support the idea that megadosing with vitamin C effectively prevents or treats the common cold.

A study published in 2018 set out to answer the question, “Does vitamin C prevent the common cold?” The researchers identified eight systemic reviews including 45 studies overall, of which 31 were randomized trials. They concluded that consuming vitamin C does not prevent the common cold.

The same group of researchers published another study in 2018 looking at the effects of vitamin C on the duration and severity of the common cold. The researchers identified four systemic reviews that included eight primary studies, of which seven were randomized trials. They concluded vitamin C has minimal or no impact on the duration of the common cold or the number of days at home or out of work.

Can Too Much Vitamin C be Harmful?

If you consume too much vitamin C, your kidneys have to work overtime to eliminate what you don’t need. There’s a good deal of evidence that high-dose vitamin C over long periods of time can result in kidney stones for men.

The Bottom Line

At Exercise Inc, we’ve always promoted healthy eating habits that include two servings of fruit and three or more servings of vegetables a day. Focusing on fruits and vegetables will provide your body with a wide array of nutrients that will help prevent and fight a cold or flu.

Not getting enough vitamin C causes fatigue, growth delay, easy bleeding, excessive bruising, and dental problems. A serving or two of fruit every day is more than enough to keep you covered.

Stay Strong,

Bo Railey