But, vitamin C has also made headlines as singer James Blunt confessed over the summer that going on the carnivore diet (a plan that involves primarily eating meat and drinking water) when he was studying as a university student caused him to develop scurvy. Scurvy is a disease caused by a severe vitamin C deficiency, notes the U.S. National Library of Medicine. Scurvy is rare in the United States. Centuries ago, it was once common among sailors who ate little or no vitamin C on their long voyages, according to the NIH. In the mid-1700s, it was determined that eating citrus cured scurvy. Scientists didn’t know it at the time, but vitamin C was the antidote. RELATED: The Top Foods High in Vitamin C Currently, the recommended dietary allowance (RDA) for vitamin C is 90 milligrams (mg) for men ages 19 and over and 75 mg for women ages 19 and over. (If you are pregnant or breastfeeding, your requirement is 85 mg or 120 mg per day, respectively. If you smoke, you need an additional 35 mg on top of your personal RDA.) Scurvy doesn’t just happen because you skimped on fruits and vegetables for a couple of days. Only when you eat below 10 mg of C per day for a month will you be at risk for deficiency and thus scurvy, points out the NIH. Thing is, it’s overwhelmingly easy to get the amount of C you need because it is present in all fruits and vegetables. “Vitamin C is fairly ubiquitous in the diet,” says Stella Volpe, PhD, RDN, professor and department head, human nutrition, foods, and exercise at Virginia Tech in Blacksburg, Virginia. Even if someone isn’t packing in the produce onto their plates, simply drinking orange juice or eating a baked white potato will help you reach your quota. “The RDA is pretty low and typically not hard to hit. One or two vegetables will get you there,” says New York City–based sports dietitian Lauren Antonucci, RDN. For reference, one cup of strawberries contains 88 mg of vitamin C, a single kiwi contains 56 mg of vitamin C, and a cup of raw green peppers has 121 mg of vitamin C, per the U.S. Department of Agriculture (USDA). These are all excellent sources of vitamin C. “Consuming a wide variety of fruits and vegetables will not only provide a lot of vitamin C and prevent scurvy, but also delivers a bunch of additional benefits,” she says. RELATED: Why Are Healthy Eating Habits Important?

Signs of Vitamin C Deficiency or Scurvy

Vitamin C supplements may help shorten the duration of the common cold, per research outlined in an article published in April 2017 in Nutrients. Nonetheless, the vitamin’s role in preventing or treating COVID-19 remains unclear, according to the NIH. Otherwise, vitamin C is known to play a role in collagen formation and wound healing, aids in absorption of iron, and is a powerful antioxidant, says Volpe. If you are running low in vitamin C, you may experience the following symptoms, according to Merck Manual:

FatigueWeaknessIrritabilityWeight lossMuscle and joint aches

Scurvy takes a while to develop. If you have had a vitamin C deficiency for a few months, you may also experience the following signs and symptoms of scurvy:

Bleeding and bruisingChanges in gums, such as swelling, bleeding, and developing a purple colorLoose teethDry, brittle hairRough and scaly skinAnemiaPoor wound healing

RELATED: 15 Recipes That Can Help Support Immunity

Are You Screened for Vitamin C Deficiency?

Vitamin C levels “are not part of any normal blood panel,” says Antonucci. Blood testing can be ordered if your healthcare provider or registered dietitian suspects that you might not be fully absorbing vitamin C or that your levels are low for another reason. In addition, following certain diets, exercising heavily, being perimenopausal or menopausal, or being under a lot of stress may mean you need more vitamin C than the RDA, and your provider may be interested in checking your levels, she says. Cancer and kidney disease and alcohol abuse can also deplete vitamin C in your body, says the Mayo Clinic. A diagnosis of scurvy is frequently based on a physical exam with your doctor. RELATED: How to Boost Your Immune System Naturally

How Vitamin C Deficiency Is Treated

As mentioned earlier, in developed countries and with proper food access, it’s easy to meet the RDA for vitamin C. Therefore, if someone has a vitamin C deficiency, it may be because they are perhaps purposefully avoiding fruits and vegetables. “We want to get people to eat more, but supplementing is likely the way to go to get levels back up,” says Volpe. The hope is that people will also increase consumption of C-rich foods in their diet, and then the dosage of the supplement can be lowered. Taking vitamin C isn’t risk-free. “Vitamin C is a water-soluble vitamin, which means it’s not stored in the body’s tissues. But that doesn’t mean you have carte blanche to consume as much as you want and be fine,” says Volpe. The tolerable upper limit for both adult men and women is 2,000 mg, according to the NIH. That means if you consume more than that (likely via taking a vitamin supplement), you could suffer side effects. Diarrhea is common. But vitamin C also helps your body absorb iron. It’s possible that, in severe cases, excess C could cause an overabsorption of iron, leading to a condition called hemochromatosis (iron overload), says Volpe. Be safe and consult with your doctor about how much you need to take. Keep in mind that if you have severely reduced or eliminated fruits and vegetables because you’re following a strict diet, consider if there are ways to fit them in so that you can get the nutrients you need. Along with a range of vitamins, minerals, and fiber, they’re also lower in calories, which supports weight loss, says Volpe.