Joey Hadden/Business Insider
You likely don't need to run to the supplement aisle for vitamin C supplements.
Supplement sales skyrocketed in 2020, and analysts expect the trend to continue into the decade. Vitamin C supplements in particular exploded in popularity, as Nutritional Outlook reported sales increased by 61.8% in 2020.
But data and expert interviews suggests very few Americans need to take vitamin C supplements, particularly those that have far more milligrams than the daily recommendation. Even in cases where a diet could result in low vitamin C, experts told Insider not to rush to the supplement aisle, but rather eat more fruits and veggies.
"If people truly are consuming all of the vitamin C that they are purchasing, then it is likely that there are many people over consuming vitamin C," Kirstin Vollrath, a registered dietitian and professor at the University of Houston, told Insider.
In 2018, the Food and Drug Administration stopped requiring that companies list the amount of vitamin C in food products because deficiency in the nutrient is "rare today."
About 6% of the US population is deficient in vitamin C, according to the 2021 National Health and Nutrition Examination Survey. The survey, which included more than 6,000 participants, did not find an association between age, race, gender, or obesity and vitamin C deficiency, though the problem was more prevalent among smokers.
An independent team of preventative medicine experts recently said there isn't enough evidence that shows taking dietary supplements can prevent cardiovascular disease.
The team did not recommend healthy adults take supplements, though the advice did not apply to pregnant people, the chronically ill, children, and those with diagnosed deficiencies.
Americans eating a balanced diet will likely get enough vitamin C through foods like potatoes, apples, tomatoes, bell peppers, and oranges, Vollrath said. A red pepper or a third cup of orange juice provides more than enough daily recommended vitamin C, per the National Institutes of Health.
Some fad diets may result in lower vitamin C levels, Philippe Hujoel, an epidemiology professor at the University of Washington, told Insider. People on carnivorous, ketogenic, or low-carb diets eating more meat than fruits and veggies could be at risk of not meeting their daily allowance.
But running to the supplement aisle may not be the best solution to low vitamin C.
Hujoel said a "big problem" is that supplements tend to have more vitamin C than necessary.
Popular brands like Emergen-C and Nature Made tout supplements with 1,000 milligrams of vitamin C, far above the country's 75 mg recommendation for men and 90 mg recommendation for women. A 2013 class action lawsuit alleged the maker of Emergen-C "deceptively" marketed its product as boosting the immune system without evidence. The company denied the allegations, but settled the suit for $6.45 million. (Emergen-C and Nature Made did not respond to Insider's request for comment.)
Taking extra vitamin C will not make a person healthier, Vollrath said, as the body only uses the amount of vitamin C it needs to function, and excretes the rest. She explained that when a person consumes vitamin C, the nutrient is absorbed in the intestines and taken up to the cells to help with things like making proteins and hormones.
The body will store some vitamin C in cells, but the kidneys will filter the blood and excrete the excess vitamin C in urine.
Thus, spending a ton of money on high-dose vitamin C ends up being "very expensive pee," Vollrath said.
Vollrath said the more cost-efficient move is to add more vitamin C-heavy fruits and vegetables to your diet if you think you're not getting enough. Foods also offer biochemicals and fiber that pills can't offer.
"It would be difficult to manufacture a supplement that would mimic the exact nutrient profile of these foods and yield the same health benefits," Emma Laing, a clinical professor at the University of Georgia and a registered dietitian, previously told Insider.
Some people take vitamin C supplements when they feel a cold coming on, but the research indicates the nutrient itself can't prevent a cold, Vollrath said.
A 2013 review of placebo-controlled trials did not find evidence vitamin C supplementation prevents colds.
The National Center for Complementary and Integrative Health said vitamin C may slightly lessen the length and severity of a cold, but studies where participants take the supplement after already getting the virus shows vitamin C does not improve symptoms. Vollrath said vitamin C must already be present in your body before the onset of a cold to lessen its severity.
"Vitamin C can be helpful in combination with zinc, it can help to perhaps lessen the severity and length of a cold, but it will not prevent you from getting sick," Vollrath said. "And vitamin C by itself is not really shown to have much effect."