VITAMIN C - What is it Good For & Why is Deficiency Dangerous?
Vitamin C is an essential vitamin, meaning your body can’t produce it. Yet, it has many roles and has been linked to impressive health benefits.
Why we need vitamin C
Vitamin C is water soluble, and the body does not store it. To maintain adequate levels of vitamin C, people need to consume food that contains it every day.
The body needs vitamin C for various functions. Here are some of them:
- It helps the body produce collagen, L-carnitine, and some neurotransmitters.
- As an antioxidant, it helps remove unwanted substances known as reactive oxidative species (ROS) from the body.
- It helps the body absorb iron.
- It boosts the immune
- It enhances wound healing.
Vitamin C’s antioxidant activity may help reduce inflammation and lower the risk of developing various conditions, including some cancers.
The body needs vitamin C to produce collagen. This is the main component of connective tissue and makes up 1–2% of muscle tissue.
Collagen is a vital component in fibrous tissues such as:
Low levels of vitamin C in the body can lead to scurvy. Symptoms of scurvy include swollen joints, bleeding gums and loose teeth, anemia, and tiredness.
The benefits of vitamin C may include the following.
Wound healingVitamin C helps the body produce collagen and is present in skin, muscle, and other tissues.
People with a low intake of vitamin C may experience slower wound healing, as their bodies will be less able to produce collagen.
During times of recovery, healthcare professionals may recommend supplements for people with low vitamin C levels.
Cardiovascular healthVitamin C may benefit cardiovascular health for several reasons. Studies have suggested that it may:
- have antioxidant properties
- help widen the blood vessels
- improve nitric oxide production
- help reduce plaque instability in atherosclerosis
This could help protect against heart disease and hypertension, or high blood pressure.
However, there is not enough evidence to suggest that taking supplements will help protect heart health.
Cataracts and age-related Macular Degeneration
Vitamin C may help lower the risk of cataracts and slow the progression of age-related macular degeneration. However, more research is needed.
Experts believe that oxidative stress may be a factor in both conditions, so any benefit may be due to vitamin C’s antioxidant activity.
A 2019 study looked at 31 people aged around 60 years to see whether or not taking vitamin C supplements made a difference to their glucose levels after eating.
After taking supplements for 4 months, the participants’ glucose levels and blood pressure improved, compared with taking a placebo. This suggests that vitamin C could, one day, be a treatment for diabetes.
Vitamin C enhances the absorption of iron, and some healthcare professionals recommend taking vitamin C supplements with iron tablets to improve absorption in people with iron deficiency anemia.
One 2020 study looked at 432 people who took iron supplements for iron deficiency anemia. Some took vitamin C with their iron supplement, and others did not.
However, both groups saw similar increases in iron, suggesting that vitamin C supplementation is unnecessary for this purpose.
Air pollution consists of various substances and chemicals that can have a negative impact on people’s health.
Some research has suggested that a combination of vitamin C and vitamin E may have an antioxidant effect that can help reduce symptoms of asthma and chronic obstructive pulmonary disease.
During an allergic reaction, the immune system triggers an inflammatory response that can lead to symptoms such as swelling and hives. During this process, the body produces ROS, which can lead to oxidative stress.
In a 2018 study, 71 people with skin or respiratory allergies received various doses of intravenous vitamin C, and the researchers observed the severity of the participants’ symptoms. Their paper concludes that taking a high dose of vitamin C may help reduce allergy symptoms.
They also found evidence to suggest that low vitamin C levels were common in people with allergies.
In a 2014 study, 70 people took 2 grams of either vitamin C or a placebo and then spent 20 minutes on a life raft in a wave pool. Those who took the supplement had lower levels of seasickness.
Dementia is a broad term used to describe symptoms of poor thinking and memory.
It affects over 35 million people worldwide and typically occurs among older adults.
Studies suggest that oxidative stress and inflammation near the brain, spine, and nerves (altogether known as the central nervous system) can increase the risk of dementia.
Vitamin C is a strong antioxidant. Low levels of this vitamin have been linked to an impaired ability to think and remember.
Moreover, several studies have shown that people with dementia may have lower blood levels of vitamin C.
Furthermore, high vitamin C intake from food or supplements has been shown to have a protective effect on thinking and memory as you age.
Vitamin C supplements may aid against conditions like dementia if you don’t get enough vitamin C from your diet. However, additional human studies are needed to understand the effects of vitamin C supplements on nervous system health.
Vitamin C May Bolster Cancer Treatment
The Mayo Clinic notes that eating a diet filled with vitamin C–rich fruits and veggies appears to reduce the risk of certain types of cancer, but research isn’t clear about whether that’s directly related to the vitamin C content or the result of following a healthy diet more generally. Overall, the research regarding vitamin C’s role in cancer prevention is inconclusive. A meta-analysis published in November 2015 in the Korean Journal of Family Medicine, for instance, determined there’s no link between vitamin C supplements and cancer prevention.
But it seems vitamin C may make radiation and chemotherapy more effective when taken intravenously in extra-high doses, according to the Mayo Clinic. A February 2019 study published in Anticancer Research found high doses of vitamin C helps fight breast cancer cells when combined with anti-cancer drugs. One big caveat: The study participants were receiving extremely high doses of vitamin C that people shouldn’t expect to get through diet and supplements at home. “I recommend speaking with an oncologist about their experience with patient outcomes,” Samuels advises for those interested in the possible benefits. “Typically, outcomes depend on the individual's type of cancer, severity of cancer, and overall health status.”
How Much Vitamin C Is Enough?
The Institute of Medicine (IOM) has developed a set of reference values for specific nutrient intake levels, including for vitamin C.
One set of guidelines is known as the Recommended Dietary Allowance (RDA) and considers average daily nutrient intake from both foods and supplements.
RDA recommendations for specific gender and age groups should meet the nutrient needs of 97–98% of healthy individuals.
Here are the RDAs for vitamin C:
|Kids (1–3 years)||15 mg|
|Kids (4–8 years)||25 mg|
|Adolescents (9–13 years)||45 mg|
|Teens (14–18 years)||65–75 mg|
|Adult women (aged 19 and older)||75 mg|
|Adult men (aged 19 and older)||90 mg|
|Pregnant women (aged 19 and older)||85 mg|
|Breastfeeding women (aged 19 and older)||120 mg|
In addition to the RDA recommendations for vitamin C, the Food and Drug Administration (FDA) has issued a recommended Daily Value (DV).
The DV was developed for food and supplement labels. It helps you determine the percentage of nutrients in a single serving of food, compared with the daily requirements. On food labels, this is displayed as %DV.
Currently, the recommended DV for vitamin C for adults and children aged 4 and above is 60 mg regardless of gender. However, in January 2020, this will increase to 90 mg.
How much is too much?
The recommended maximum intake of vitamin C for adults is 2,000 mg per day.
Taking too much vitamin C is unlikely to cause any significant problems, but if a person consumes more than 1,000 mg of vitamin C per day, they will not absorb it all. This may lead to diarrhea and gastrointestinal discomfort.
People are unlikely to consume too much through their diet, and their bodies cannot store it. However, having a high intake through supplements may result in kidney stones.
This may also increase the risk of cardiovascular problems in females after menopause, but there is not enough evidence to confirm this.
People with hereditary hemochromatosis, which is an iron absorption disorder, should talk to their healthcare professional before taking vitamin C supplements. Having high vitamin C levels could lead to tissue damage.
Who is at risk of deficiency?Those at risk of vitamin C deficiency include:
- people who smoke or have exposure to secondhand smoke
- infants who consume only evaporated or boiled milk
- people who do not consume a varied diet
- people with certain health conditions, especially those that involve intestinal malabsorption
Do people who smoke need more vitamin C?
Smoking and having exposure to other pollutants can lead to oxidative stress. Antioxidants, such as vitamin C, can help reduce oxidative stress.
People who smoke tend to have lower levels of vitamin C than people who do not smoke. This may be due to having higher levels of oxidative stress.
Smoking also causes inflammation and damage to the mucous membranes of the mouth, throat, and lungs.
Vitamin C is necessary for healthy mucosa and helps reduce inflammation, so the National Institutes of Health (NIH) recommend that people who smoke consume an extra 35 mg of vitamin C each day.
Best food sources
Typically, the best sources of vitamin C are fruits and vegetables.
It’s important to note that vitamin C in food is easily destroyed by heat, but since many good sources of the nutrient are fruits and vegetables, simply eating some of those foods raw is an easy way to reach the recommended intake.
For example, a 1/2-cup (75-gram) serving of raw red pepper provides 158% of the RDA set by the IOM.
The table below displays the vitamin C content and contribution to the recommended Daily Value (DV) for some of the best food sources of the nutrient.
This table is based on the current 60-mg recommendation, but since any food providing 20% or more of the DV for vitamin C is considered a high source, many of these foods will still be great sources after the DV recommendation is changed to 90 mg in January 2020.
Great food sources of vitamin C include:
|Food||Amount per serving||%DV|
|Red pepper,1/2 cup (75 grams)||95 mg||158%|
|Orange juice,3/4 cup (177 ml)||93 mg||155%|
|Kiwifruit, 1/2 cup (90 grams)||64 mg||107%|
|Green pepper,1/2 cup (75 grams)||60 mg||100%|
|Broccoli, cooked,1/2 cup (78 grams)||51 mg||85%|
|Strawberries, fresh,1/2 cup (72 grams)||49 mg||82%|
|Brussels sprouts, cooked,1/2 cup (81 grams)||48 mg||80%|
Vitamin C is a water-soluble vitamin that must be obtained from the diet or supplements.
It has been linked to many impressive health benefits, such as boosting antioxidant levels, lowering blood pressure, protecting against gout attacks, improving iron absorption, boosting immunity, and reducing heart disease and dementia risk.
Overall, vitamin C supplements are a great and simple way to boost your vitamin C intake if you struggle to get enough from your diet.