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These days, we don’t really have to worry about catching scurvy on a journey across the open seas. Still, it seems like we constantly hear people saying we should “Take more vitamin C!”

So what exactly does ascorbic acid (vitamin C) do, how much do you need, and is there such a thing as too much? We hit up nutritionists and medical experts to get the scoop on C.

Ascorbic acid is a water-soluble vitamin found in a variety of fruits and vegetables. Often, we think of citrus fruit as the best vitamin C delivery system, but you can also get it from peppers, tomatoes, and cauliflower.

Once it’s in your system, the C helps your immune system function at its best and protect against damage from free radicals. Plus, ascorbic acid is needed to make collagen, that wondrous protein that helps heal wounds and keep our skin looking young and lovely (among many other things).

Our bodies can’t make vitamin C on their own, so it’s important that we get enough ascorbic acid from food or other outside sources.

Vitamin C deficiency is fairly rare in Western countries, but it can happen. If you take a long break from fresh produce (or have an ailment that impedes your absorption of vitamins), it’s possible to get scurvy — which causes inflamed gums, skin spots, depression, and eventually death.

It’s not common or likely if you have access to healthy food and produce, but it’s good to be mindful of your vitamin C intake all the same.

“Vitamin C dissolves in water and is not stored in the body, so we do need a consistent supply to maintain adequate levels,” says registered dietician Jillian Greaves. “The recommended daily intake is about 75 mg per day for women and 90 mg per day for men.” For women, you could get more than your daily requirement by eating one kiwi and men could have half a papaya and call it a day.

“The tolerable upper intake for adults is 2 grams of Vitamin C — consuming more than that can result in diarrhea and other unpleasant GI disturbances,” says Greaves. She admits that severe side effects from too much ascorbic acid are very rare, but you may experience some discomfort if you take too much. It’s pretty much impossible to have a vitamin C overdose, but let’s not test that out.

The real problem with taking more vitamin C than you need is that it all goes to waste. “Up to 100 mg a day of vitamin C will get almost completely absorbed, says Francesco-Maria Serino, MD, PhD. “Above 100 mg a day and the fraction of vitamin C absorbed is progressively smaller. If you take more than 1 gram (1000 mg) of vitamin C per day, less than 50% is actually absorbed and it’s eliminated by the kidneys.”

That literally means that a 500 mg vitamin C supplement mostly gets peed down the drain.

Both experts stress that the best way to take vitamin C is through food. “Whole foods contain a vitamin and micronutrient complex which cannot be fully replicated in vitamin supplements,” says Dr. Serino. Also, your body absorbs more of the vitamin through food than through a supplement.

“In my experience, most people do not need to supplement with vitamin C since it is abundant in food,” says Greaves. “The best sources of vitamin C are foods like bell pepper, brussels sprouts, strawberries, and citrus fruit. For example: A half cup of raw red pepper has about 95 mg of vitamin C.”

If you don’t like any of that stuff, you can eat a medium potato (with skin) and a cup of red cabbage to get your daily dose. If you’ve got guava around, you’ll get 206 mg from eating just one!

Make sure to eat a few servings of fruits and vegetables each day, and you’ll likely have more than enough vitamin C to make your body happy. “It’s important to know that research doesn’t show any benefit of supplementing with vitamin C beyond the recommended daily intake,” says Greaves. “So more is definitely not better!”

Many people pop vitamin C pills when they feel a cold coming on. Though vitamin C helps the immune system, it does very little for a cold.

A study from the Australian National University found that vitamin C supplements did not prevent colds at all. Supplementation, in a few cases, helped people get over the cold a little bit faster since about 8 percent of participants had one less day of sickness due to vitamin C.

If you want to play it safe and add more vitamin C when you’re sick, it’s still best to do it through food. Add more citrus or greens. Even if the vitamin C doesn’t make a difference, the healthy food will help you feel better.

Since our bodies can’t make vitamin C on their own, it’s recommended that you get it through food (or supplements) to the tune of 75 mg per day for women and 90 mg per day for men.

It’s not necessary to take a vitamin C supplement, unless your doctor has advised you to. Otherwise, it’s best to stock up on citrus, peppers, broccoli, and brussels sprouts for your ascorbic acid needs.