The age-old advice to eat oranges when you're sick isn't entirely a myth.
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While vitamin C plays an important role in your immune function, that's just one of the many health benefits of vitamin C.
By getting enough vitamin C, you'll get skin health benefits, better absorption of plant-based iron and improved heart health. It's also tied to boosting your bones and cognitive function, and preventing certain illnesses like gout or even seasickness.
Although more research is needed in many areas of study, one thing is clear: Vitamin C is good for a number of functions in your body and can promote overall wellbeing.
While it's best to get your daily recommended amount of vitamin C through food sources (that way, you can soak up other beneficial nutrients along with it), there may be benefits of vitamin C supplements for some people as well.
However, always talk to your doctor before you start taking a new supplement.
1. Skin Benefits
Vitamin C benefits your skin in a number of ways, and is found in high levels in both the epidermis and dermis.
Overexposure to UV light or pollutants like cigarette smoke and pollution might lower vitamin C content, particularly in the epidermis, per the Oregon State University.
Collagen is the structural protein that gives skin elasticity, and vitamin C plays a crucial role in its production, which can maintain the appearance of your skin. With age, the vitamin C content in your skin naturally declines, per Oregon State University.
Besides aging, a low level of collagen in the body is most often caused by a poor diet, and it can lead to wrinkles and crepey skin. It can also cause joint pain, weakening muscles, osteoarthritis or gastrointestinal problems due to the thinning of your digestive tract lining, per the Cleveland Clinic.
Vitamin C improved perception of skin health and actual health of skin — including skin elasticity, wrinkling and appearance — in a March 2015 review in the journal Nutrition Research. But more research is needed in representative populations to determine the exact effect of dietary intake of vitamin C on appearance.
Vitamin C also helps to repair wounds due to its important role in collagen synthesis.
A deficiency in this vitamin is not uncommon among people in the hospital, particularly those at risk, per a 2016 case report in the International Journal of Surgery Open.
It may be necessary for people to be treated with vitamin C after operations or infections to reduce the duration of their stay in the hospital and the costs of extensive wound treatment.
It's important to note that topical or oral vitamin C cannot act as a sunscreen because it doesn't absorb light in the UVA or UVB spectrum. However, it can help protect against UV-induced damage caused by free radicals.
Multiple studies have shown that taking supplements with a combination of vitamin C and vitamin E increases Minimal Erythemal Dose (MED) — which is a measure of UV light photoprotection in the skin, per Oregon State University.
Vitamin C alone has not been found to have the same effect. The mix of vitamins can also lower erythema-induced blood flow (which causes redness and the sensation of warmth) to affected areas of skin.
For example, oral supplementation of vitamins C and E for three months helped to protect against DNA damage in participants with sunburn, per a February 2005 study in the Journal of Investigative Dermatology. This is important because DNA damage may lead to mutations that can result in UV-induced skin cancer.
A number of factors can cause dry skin, including aging, medications, illness, extreme temperature, wind exposure and low humidity, resulting in the loss of skin barrier lipids (fats) and natural moisture.
Vitamin C, however, can enhance the production of barrier lipids to decrease dryness, per an August 2017 review in the journal Nutrients.
Most studies in this area involve topical application, so it's unclear what effects the benefits of vitamin C tablets for the skin may be (or even if the topical applications were helpful due the vitamin C itself or the cream it was found in).
That said, the researchers note that nutritional support may also be useful — and oral intake of vitamin C improved the appearance of skin roughness in the Nutrition Research review.
2. Heart Protection
Vitamin C has been studied for a number of heart conditions, and could have benefits for your ticker.
Eating more antioxidants like vitamins C and E is linked to preventing coronary heart disease, per a February 2008 meta-analysis in the European Journal of Preventive Cardiology. Vitamin C supplements, however, did not show the same association.
Oxidative stress is associated with atrial fibrillation, a common arrhythmia that can lead to serious outcomes like stroke — and vitamin C, being an antioxidant, may affect it.
In fact, vitamin C is tied with preventing postoperative atrial fibrillation, per a February 2017 systematic review and meta-analysis published in the journal BMC Cardiovascular Disorders.
However, trials in different countries saw different outcomes. Out of several trials looking at atrial fibrillation in high-risk people, five trials were carried out in the United States — and vitamin C did not show a protective effect on postoperative atrial fibrillation.
That said, vitamin C was linked to decreased atrial fibrillation incidence in nine trials conducted outside of the U.S. This may have to do with access to nutrition, including vitamin C-rich foods, in certain parts of the world.
Still, the researchers note that further trials in countries like the U.S. could investigate the effect of vitamin C on atrial fibrillation in people who have particularly low levels of vitamin C.
Another way vitamin C may protect your heart is by lowering your cholesterol levels.
Observational studies have shown an inverse relationship between blood vitamin C concentration and total serum cholesterol, although results from experimental studies have been inconsistent, per a 2006 review in the Journal of Chiropractic Medicine.
The cholesterol-lowering and heart-protective benefit of vitamin C supplementation may be due to its ability to raise blood vitamin C concentrations in people with lower-than-normal vitamin C concentrations.
In particular, 500 milligrams of vitamin C per day for a minimum of four weeks resulted in a decrease in harmful LDL cholesterol and triglyceride levels in a June 2008 meta-analysis of 13 randomized controlled trials in the Journal of Chiropractic Medicine.
"Although these changes are modest, any small change can have beneficial effects on the incidence of coronary heart disease," note the researchers. However, it's important to speak to your doctor about your treatment plan before starting to take supplements for cholesterol or any other condition.
High Blood Pressure
An average of 500 milligrams of vitamin C daily was tied with lowering systolic blood pressure by nearly 5 mmHg and diastolic blood pressure by 1.67 mmHg in people with hypertension in a May 2012 meta-analysis in the American Journal of Clinical Nutrition.
Systolic pressure is the top number of your blood pressure reading and is the maximum pressure your heart exerts while beating. The bottom number is diastolic pressure, and is the amount of pressure in your arteries between beats, per the Mayo Clinic.
Despite the promising results of the study, the researchers did not recommend vitamin C tablets for blood pressure management.
"Before vitamin C supplementation can be recommended for the prevention of hypertension [or as part of] antihypertensive therapy, additional trials are needed, designed with large sample sizes," note the researchers.
Diabetes is a disease in which your blood sugar levels are too high, and it's a risk factor for heart disease and stroke. Having too much blood glucose can damage your eyes, kidneys and nerves over time, per the U.S. National Library of Medicine.
However, vitamin C may help: Individuals with type 2 diabetes who took a vitamin C tablet twice daily were observed to lower blood glucose spikes after meals by 36 percent in a small November 2018 study in the journal Diabetes, Obesity and Metabolism. The cohort was predominantly male.
Meanwhile, vitamin C and insulin together was linked to helping stop blood vessel damage in people with type 1 diabetes with poor glucose control in a small 2009 study published in The Journal of Clinical Endocrinology & Metabolism.
However, neither therapy had the same effect on its own, and the vitamin C was delivered intravenously rather than in a vitamin C tablet.
You may have a habit of loading up on vitamin C when you feel a cold coming on. Unfortunately, there's no evidence that vitamin C actually helps to prevent the common cold, per a July 2018 review published in Medwave.
However, it could help reduce some of your symptoms if you're already sick. Taking 480 milligrams of vitamin C with 800 milligrams of aspirin reduced early symptoms of a cold compared to a placebo in a December 2017 study of nearly 400 people in the Journal of Health Care and Prevention.
A higher dosage of vitamin C taken at the beginning of a cold also helped to reduce the duration of the cold and lessen its symptoms, per a meta-analysis of nine clinical trials in the journal BioMed Research International. But, the effect was only seen if people were already taking C regularly and used therapeutic doses at the onset of illness.
What's more, regular vitamin C intake appeared to reduce the duration of colds by 8 percent in adults and 14 percent in children in a January 2013 review of 31 studies in The Cochrane Database of Systematic Reviews. It also lowered the severity of colds.
"Given the consistent effect of vitamin C on the duration and severity of colds in the regular supplementation studies, and the low cost and safety, it may be worthwhile for [people with the common cold] to test on an individual basis whether therapeutic vitamin C is beneficial for them," note the researchers.
To really enjoy the benefits of vitamin C, you should aim to get it every day — and getting your vitamin C through food, so you can also take in other important nutrients, is typically best, per Harvard Health Publishing.
Aim for a varied diet rich in fruits and vegetables to stay healthy and keep your immune system strong.
5. Iron Absorption
Vitamin C improves the body's absorption of iron from plant-based foods, per the National Institutes of Health (NIH). Because of this, it can be helpful to eat vitamin C foods (think strawberries or bell peppers) with iron-containing plant foods like kale or spinach.
Getting enough iron is important because the body needs it for several functions. Iron is part of hemoglobin, a protein that carries oxygen from your lungs to the rest of your body. It also helps the muscles store and use oxygen, per the U.S. National Library of Medicine.
If you get too little iron (caused by issues like blood loss, poor diet or the inability to absorb enough dietary iron), you could develop iron deficiency anemia. Young children and women who are pregnant or have periods are at higher risk of iron deficiency.
That said, too much iron is dangerous, too. You should take caution with vitamin C if you have hemochromatosis, a condition that causes the body to store too much iron. Large amounts of vitamin C could worsen the overload of iron in your body and damage body tissues, per the NIH.
6. Cancer Treatment Potential
While some research suggests high-dose vitamin C may kill cancer cells, some experts believe C has often been used in an ineffective way in cancer treatments.
While many vitamin C therapies for cancer involve oral supplementation, giving vitamin C intravenously might benefit people with cancer the most, per a December 2016 study published in the journal Redox Biology.
Researchers found that vitamin C breaks down easily and produces hydrogen peroxide, which can damage tissue and DNA. But while normal cells can remove hydrogen peroxide and avoid damage, cancer cells are less efficient and doing so and more prone to death from high levels of hydrogen peroxide.
While this doesn't prove that vitamin C alone can kill cancer cells, researchers are currently investigating if it could boost the effectiveness of other cancer treatments like chemotherapy and radiation therapy (or reduce treatment side effects), per the Mayo Clinic.
In terms of cancer prevention, most case-control studies have linked dietary vitamin C intake with lower risk of cancers of the lung, breast, colon or rectum, stomach, oral cavity, larynx or pharynx and esophagus, per the NIH.
For instance, getting an average of 205 milligrams per day of vitamin C (the highest amount) compared to 70 milligrams day (the lowest amount) was associated with a 63 percent lower risk of breast cancer in premenopausal women with a family history of breast cancer, per an older March 1999 study of 83,234 women in the Journal of the National Cancer Institute.
However, evidence from prospective cohort studies is not consistent, possibly due to the varying amounts of vitamin C used in studies. Meanwhile, most randomized clinical trials suggest that moderate vitamin C supplementation alone or along with other nutrients does not affect cancer risk.
7. Eye Health
Some evidence shows that supplement formulations from the Age-Related Eye Disease Study (AREDS), a large, randomized, placebo-controlled clinical trial, might slow age-related macular degeneration (AMD) progression in those at high risk of developing advanced AMD.
These formulations include 500 milligrams of vitamin C, along with vitamin E, beta-carotene, zinc and copper.
Individuals at high risk of developing advanced AMD who received the supplements were observed to have a lower risk of progression to advanced AMD than individuals taking a placebo, per the October 2001 AREDS study in JAMA Ophthalmology. The results were confirmed by a follow-up May 2013 study in JAMA.
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Some studies have also associated high dietary intakes of vitamin C with lower risk of cataract formation, though clinical trial data are limited and evidence has been mixed, per the NIH.
8. Gout Prevention
A common type of inflammatory arthritis, gout is very painful and typically affects one joint at a time (usually the big toe joint). Symptoms can get worse during flares, which may last days or even weeks, per the U.S. Centers for Disease Control and Prevention.
Gout is caused by too much uric acid in the body, or hyperuricemia. The breakdown of purines, found in your body and foods you eat, results in uric acid — and too much of it can lead to the build-up of uric acid crystals (monosodium urate) in joints, fluids and tissues.
Although studies have been mixed, vitamin C is linked to helping prevent gout.
For every 500-milligram increase in vitamin C intake per day, gout risk was observed to drop in a March 2009 study of nearly 47,000 men in JAMA Internal Medicine. For those who took more than 1,500 milligrams of vitamin C daily, gout risk was observed to drop by 45 percent.
Vitamin C may protect against gout by helping to lower urate in the body, per the Arthritis Foundation. However, it's unclear what effect vitamin C might have on those with preexisting gout.
Vitamin C alone or in combination with gout medication did not have a clinically significant effect on lowering uric acid levels for people with gout in a small May 2013 study of 40 people in Arthritis & Rheumatology.
9. Cognitive Function
Vitamin C accumulates in the central nervous system and in particularly high amounts in the neurons of the brain. It's responsible for brain functions such as synthesizing the neurotransmitter norepinephrine from dopamine, per Oregon State University.
A deficiency in vitamin C results in oxidative damage to the proteins and fats in the brain. A large body of evidence shows that maintaining healthy vitamin C levels is tied to protecting against age-related cognitive decline and Alzheimer's disease, per an April 2012 review in the Journal of Alzheimer's Disease.
However, the researchers note that "avoiding vitamin C deficiency is likely to be more beneficial than taking supplements on top of a normal, healthy diet."
Intake of fruits and vegetables, particularly those rich in vitamin C, was positively associated with verbal memory in a September 2011 study published in The American Journal of Clinical Nutrition.
Vitamin C may also give you energy or improve your mood: While more research is needed, those with vitamin C deficiency often report feeling fatigued or depressed, per the Mayo Clinic.
Studies on hospitalized people, who typically have lower-than-normal levels of vitamin C, have observed that mood improves after people receive vitamin C.
10. Bone Health
The crucial role that vitamin C plays in the production of collagen also makes it an important nutrient for your bones.
Collagen makes up 90 percent of the organic matrix of bone, and collagen fibers twist around each other to provide scaffolding for minerals to be deposited on, per Oregon State University.
That said, observational studies have shown inconsistent associations with fracture risk and bone mineral density.
Overall, there is a positive but complicated association between bone density and vitamin C intake, which may be affected by interactions from other factors like smoking, calcium intake, vitamin E intake or estrogen use or hormonal therapy after menopause, per an October 2011 review in the journal Nutrition Reviews.
For instance, while there was no association between vitamin C intake and bone mineral density, the positive effects of hormone treatment on bone mineral density was stronger with greater intakes of vitamin C, per a September 2005 study from the Women's Health Initiative in The American Journal of Clinical Nutrition.
Vitamin C may help young people who get queasy at sea.
Women and men under 27 years of age had less pronounced symptoms of seasickness when they took in 2,000 milligrams of vitamin C before being exposed to one-meter-high waves on a life raft in an indoor pool for 20 minutes, per a 2014 study in the Journal of Vestibular Research.
Vitamin C may be an effective way to suppress symptoms of seasickness without unwanted side effects, note the researchers.
Several studies have associated higher vitamin C levels with lower C-reactive protein (CRP) levels, a marker of inflammation.
For instance, taking vitamin C supplementation (1,000 milligrams per day) for two months was observed to lead to a 16.7-percent decrease in the median level of CRP levels in those who had elevated CRP levels compared to an 8.6-percent increase in a placebo group, per a January 2009 study in the journal Free Radical Biology and Medicine.
Several of the diseases vitamin C has reported benefits for — like coronary heart disease and gout — also involve inflammation, per Oregon State University.
While less is known about vitamin C's anti-inflammatory effects than its antioxidant actions, it's known that vitamin C acts as an antioxidant to neutralize the harmful effects of pro-inflammatory free radicals.
13. Gum Health
Vitamin C can even benefit your dental health by keeping your tissues healthy and strong.
It may contribute to a lower risk of periodontal (gum) disease, according to a July 2019 review in the International Journal of Environmental Research and Public Health.
The study also suggests that the concentration of vitamin C in the blood influences the periodontal status, but not vice versa.
- Oregon State University Linus Pauling Institute Micronutrient Information Center: "Vitamin C and Skin Health"
- Cleveland Clinic: "The Best Way You Can Get More Collagen"
- Nutrition Research: "Can dietary intake influence perception of and measured appearance? A Systematic Review"
- International Journal of Surgery Open: "Ascorbic acid deficiency impairs wound healing in surgical patients: Four case reports"
- International Journal of Environmental Research and Public Health: "The Relationship between Vitamin C and Periodontal Diseases: A Systematic Review"
- Journal of Investigative Dermatology: "Ultraviolet B-Induced DNA Damage in Human Epidermis Is Modified by the Antioxidants Ascorbic Acid and D-α-Tocopherol"
- Nutrients: "The Roles of Vitamin C in Skin Health"
- European Journal of Preventive Cardiology: "Antioxidant vitamins intake and the risk of coronary heart disease: meta-analysis of cohort studies"
- BMC Cardiovascular Disorders: "Vitamin C for preventing atrial fibrillation in high risk patients: a systematic review and meta-analysis"
- Journal of Chiropractic Medicine: "The efficacy of vitamin C supplementation on reducing total serum cholesterol in human subjects: a review and analysis of 51 experimental trials"
- American Journal of Clinical Nutrition: "Effects of vitamin C supplementation on blood pressure: a meta-analysis of randomized controlled trials"
- Mayo Clinic: "Pulse pressure: An indicator of heart health?"
- U.S. National Library of Medicine: "Diabetes"
- Diabetes, Obesity and Metabolism: "Ascorbic acid supplementation improves postprandial glycaemic control and blood pressure in individuals with type 2 diabetes: Findings of a randomized cross‐over trial"
- The Journal of Clinical Endocrinology & Metabolism: "Long-Term Glycemic Control Influences the Long-Lasting Effect of Hyperglycemia on Endothelial Function in Type 1 Diabetes"
- Medwave: "Does vitamin C prevent the common cold?"
- Journal of Health Care and Prevention: "Aspirin plus Vitamin C Provides Better Relief than Placebo in Managing the Symptoms of the Common Cold"
- BioMed Research International: "Extra Dose of Vitamin C Based on a Daily Supplementation Shortens the Common Cold: A Meta-Analysis of 9 Randomized Controlled Trials"
- The Cochrane Database of Systematic Reviews: "Vitamin C for preventing and treating the common cold"
- Harvard Medical School: "Can vitamin C prevent a cold?"
- National Institutes of Health: "Vitamin C"
- U.S. National Library of Medicine: "Iron"
- Redox Biology: "Tumor cells have decreased ability to metabolize H2O2: Implications for pharmacological ascorbate in cancer therapy"
- Mayo Clinic: "High-dose vitamin C: Can it kill cancer cells?"
- Journal of the National Cancer Institute: "Dietary Carotenoids and Vitamins A, C, and E and Risk of Breast Cancer"
- JAMA Ophthalmology: "A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E, beta carotene, and zinc for age-related macular degeneration and vision loss: AREDS report no. 8"
- JAMA: "Lutein + zeaxanthin and omega-3 fatty acids for age-related macular degeneration: the Age-Related Eye Disease Study 2 (AREDS2) randomized clinical trial"
- U.S. Centers for Disease Control and Prevention: "Gout"
- JAMA Internal Medicine: "Vitamin C Intake and the Risk of Gout in Men"
- Arthritis Foundation: "Vitamin C May Help Prevent Gout"
- Arthritis & Rheumatology: "Clinically Insignificant Effect of Supplemental Vitamin C on Serum Urate in Patients With Gout: A Pilot Randomized Controlled Trial"
- Oregon State University Linus Pauling Institute Micronutrient Information Center: "Cognitive Function In Depth"
- Journal of Alzheimer’s Disease: "A critical review of Vitamin C for the prevention of age-related cognitive decline and Alzheimer’s disease"
- The American Journal of Clinical Nutrition: "Article Navigation Fruit and vegetable intake and cognitive function in the SU.VI.MAX 2 prospective study"
- Frontiers in Aging Neuroscience: "Plasma Vitamin C Concentrations and Cognitive Function: A Cross-Sectional Study"
- Mayo Clinic: "Can vitamin C improve your mood?"
- Oregon State University Linus Pauling Institute Micronutrient Information Center: "Bone Health in Depth"
- Nutrition Reviews: "Vitamins and bone health: beyond calcium and vitamin D"
- The American Journal of Clinical Nutrition: "Lack of a relation between vitamin and mineral antioxidants and bone mineral density: results from the Women's Health Initiative"
- Journal of Vestibular Research: "Impact of oral vitamin C on histamine levels and seasickness"
- Free Radical Biology and Medicine: "Vitamin C treatment reduces elevated C-reactive protein"