All About Vitamin C: Sources, Dosage and Benefits (Backed By Science)

You may already double down on vitamin C-rich foods when you want to give your immune system a kick, but this powerful vitamin is responsible for far more than helping you avoid a cold (and spoiler: There are better sources of it than oranges!).

Vitamin C is an antioxidant you can easily get from a variety of foods or from supplements. Because vitamin C is water-soluble, your body can't store it, and you need enough of it daily to prevent deficiency, per the National Institutes of Health (NIH).

When you get enough vitamin C, your body will be able to function better overall. This antioxidant can help reduce how long you feel sick with the common cold, boost your skin health and much more.

What Is Vitamin C?

Vitamin C is a water-soluble vitamin. Your body needs vitamin C to form collagen, which makes up the connective tissues in the body and helps heal wounds.

Vitamin C also contributes to the overall health of your bones, cartilage and teeth.

It also plays a role in your body's absorption of non-heme iron, which comes from plant sources. That's why it's best to eat iron-rich foods like spinach with vitamin C-rich foods, like tomatoes or peppers.

Antioxidants like vitamin C scavenge for free radicals, those wayward molecules that can cause DNA damage in the body. And regularly eating fruits and vegetables high in vitamin C is linked to better protection against cancer and heart disease, per the NIH.

The Benefits of Vitamin C

Here are all the benefits of vitamin C for your body.

1. Immunity

That said, the nutrient may help some people reduce their symptoms. In fact, 480 milligrams of vitamin C taken with 800 milligrams of aspirin did reduce early symptoms of a cold compared to placebo in a 2017 study in the Journal of Health Care and Prevention.

The extra amount, though, only benefited people who had already been taking vitamin C supplements on a daily basis.

2. Skin Health

Vitamin C also benefits your skin health: The collagen that vitamin C helps to form is a major component of your tissues. Beyond aging, too little collagen in the body is most often caused by an unhealthy diet, and it can lead to wrinkles and crepey skin.

Low levels of collagen can also cause health concerns like joint pain, weakening muscles, osteoarthritis or gastrointestinal problems due to the thinning of your digestive tract lining, per the Cleveland Clinic.

Although more research is needed, vitamin C might decrease dryness in skin and improve the appearance of skin roughness.

3. Wound Healing

Vitamin C helps to repair wounds thanks to its important role in collagen synthesis, per the NIH. It can also help increase UV light photoprotection for your skin when combined with vitamin E (though it's not a replacement for sunscreen!).

4. Heart Health

Some research shows that vitamin C is linked to benefits for your heart, including protection against high cholesterol and high blood pressure, per the NIH.

5. Blood Sugar Control

Vitamin C may help lower blood glucose spikes after meals in those with type 2 diabetes, but more research is needed.

6. Iron Absorption

Vitamin C helps you absorb more iron from plant-based foods, per the NIH.

7. Potential for Cancer Treatment

Some studies have shown that vitamin C may help kill cancer cells in large doses. It has also been linked to a lower risk of certain cancers like lung, breast and colon cancer, per the NIH.

8. Eye Health

Vitamin C may be part of a supplement formulation that's linked to reducing the risk of advanced age-related macular degeneration.

Though evidence has been mixed, some studies also associate high dietary intakes of vitamin C with a lower risk of cataract formation, per the NIH.

9. Gout Prevention

Vitamin C may help prevent gout, a type of inflammatory arthritis that is very painful, per Oregon State University.

10. Cognitive Function

Vitamin C is linked to helping protect against age-related cognitive decline and Alzheimer's disease.

11. Bone and Muscle Health

Because it plays a crucial role in the production of the structural protein collagen, vitamin C is an important nutrient for your bones.

12. Sea Sickness

Young people who get queasy at sea may benefit from taking vitamin C beforehand, some research shows.

13. Inflammation Fighter

As an antioxidant, vitamin C may lower levels of inflammation in your body, per Oregon State University.

How Much Vitamin C Should I Take Daily?

The recommended daily allowance for vitamin C â€” that is, the intake sufficient to meet the body's nutrient needs â€” varies according to several factors, according to the NIH.

Recommended Dietary Allowances (RDAs) for Vitamin C

Age

Male

Female

Pregnancy

Lactation

0-6 months

40 mg

7-12 months

50 mg

1-3 years

15 mg

4-8 years

25 mg

9-13 years

45 mg

14-18 years

75 mg

65 mg

80 mg

115 mg

19+ years

90 mg

75 mg

85 mg

120 mg

Smokers

Need 35 mg/day more vitamin C than nonsmokers.

Vitamin C Deficiency

Deficiency of vitamin C, which leads to a condition called scurvy, is rare in developed countries but can occur in those with poor diets.

Signs of deficiency can appear within a month of consistently low intake of this vitamin. Scurvy symptoms include fatigue, swelling of the gums and tooth loss, per the NIH.

Some people may need more vitamin C than others. Due to their higher levels of oxidative stress, smokers need 35 milligrams more vitamin C per day than nonsmokers (and those exposed to secondhand smoke should also ensure they meet the RDA for vitamin C).

Individuals with certain medical conditions like severe intestinal malabsorption or cachexia (wasting of the body due to severe chronic illness) may be at a higher risk of vitamin C inadequacy.

Those who have a limited food variety (such as some older people and, occasionally, children) may also not obtain enough vitamin C.

What Happens if You Get Too Much Vitamin C?

The tolerable upper intake level for vitamin C in those 19 years of age and older is 2,000 milligrams.

While too much vitamin C is unlikely to be harmful, a megadose may result in gastrointestinal issues, such as diarrhea, nausea and cramps, as well as headaches and insomnia, according to the Mayo Clinic.

The body absorbs less than 50 percent of a vitamin C dosage over 1,000 milligrams a day, per the NIH. What your body doesn't need it excretes via your urine, so you flush away those excess milligrams.

In contrast, at a more modest vitamin C dosage of 180 milligrams or less, the body will absorb 70 to 90 percent of the antioxidant.

Getting C From Food vs. Supplements

Natural vitamin C from food and synthetic vitamin C in supplements show the same bioavailability â€” meaning, the body seems to absorb both forms of the nutrient equally well, per the Oregon State University.

But, it's better to get vitamin C from food than to follow a nutrient-poor diet and then take supplements to make up for vitamin shortfalls.

Research on the benefits of multivitamins has mixed findings, and, as a result, the U.S. Preventive Services Task Force does not recommend vitamin supplements to prevent diseases like heart disease or cancer.

By including more fresh fruits and vegetables in your diet, you'll get all the nutrients you need on a daily basis, which leads to overall good health and disease prevention.

Top Vitamin C Foods

Getting vitamin C from foods is easy, as long as you eat plenty of produce.

You should aim to fill half of your plate at each meal with fruits and vegetables, per the USDA. Opt for whole fruits instead of juices, and vary the kinds of fruits and veggies you select each day.

You may automatically think of oranges and other citrus as the fruits highest in vitamin C, but in fact, guavas, kiwis and strawberries all contain more of the nutrient than oranges, per the USDA.

Among vegetables, broccoli, cauliflower, Brussels sprouts and cabbage are all rich sources of vitamin C. Tomatoes and bell peppers also supply vitamin C, as do leafy greens such as kale, Swiss chard and spinach.

Eat vitamin C-rich foods at every meal to get the milligrams you need daily and to replenish your stores of this nutrient. For instance, try any of the below meals to up your levels of vitamin C.

For breakfast:

Slice a half-cup of strawberries onto your morning oatmeal.
Add half a medium- sized grapefruit alongside your eggs and toast.
Sweeten up your Greek yogurt with a half-cup of blackberries or a half-cup of pineapple chunks.

For lunch:

Construct a salad from a base of leafy greens; choose one cup of baby kale or Swiss chard.
Along with your protein of choice, top your greens with a half-cup of cherry tomatoes and the same amount of sweet bell peppers.
Add a small orange on the side.

For dinner:

Have a half-cup of steamed broccoli with a clove of garlic.
Enjoy a medium baked sweet potato.

Considering a Vitamin C Supplement? Here's What to Shop For

If you do decide to take supplements to help you reach your daily dose of vitamin C, be aware that there are many varieties and not all of them are created equal.

Three different kinds of vitamin C pills â€” liquid, tablets and chewable tablets â€” all appear to have equally good absorption, per Oregon State University.

But, studies present conflicting evidence on the efficacy of timed-release vitamin C, and only one showed a positive effect on nutrient absorption from bioflavonoids.

If you're looking for the best vitamin C for adults and kids, check out the reputable brands according to Consumer Lab:

Nature's Bounty Vitamin C ($9.83, Amazon.com)
Emergen-C Vitamin C 1,000 Milligram Powder ($9.06, Amazon.com)
Nature Made Vitamin C 250 Milligrams Gummies ($9.99, Amazon.com)

Drug Interactions and Risks

Always speak to your doctor before starting a new supplement, including vitamin C. There are several interactions that could take place when you take vitamin C, per the Mayo Clinic:

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