If you weigh more you will need more vitamin C.

Researchers in New Zealand have determined the amount of vitamin C you need for immunity is relative to your body weight and should be increased if you are heavier.


An apple a day keeps the doctor away may need to be revised to an extra apple a day if you carry a little more weight. That’s because researchers in New Zealand have determined the amount of vitamin C you need for immunity is relative to your body weight and should be increased if you are heavier.

Vitamin C is one of the most important nutrients for immune health and researchers at the University of Otago, in conjunction with colleagues from the U.S. and Denmark, have been able to calculate how much extra is necessary depending on how much you weigh. They published their findings in a recent edition of the journal Nutrients.

These scientists say for every extra 10 kilograms of weight (22 pounds) you carry you should add 10 milligrams of vitamin C to your daily intake. They used 60 kilos (132 pounds) as the baseline figure and said that would require a daily intake of 110 milligrams of vitamin C. Therefore, someone who weighs 90 kilos (198 pounds) would need 140 milligrams per day for optimal immune health.

"Previous studies have already linked higher body weight with lower vitamin C levels," says lead author and Associate Professor Anitra Carr. "But this is the first study to estimate how much extra daily vitamin C is actually needed for people, relative to their body weight, to help maximize their health."

While admitting no specific amounts of vitamin C intake have been set for the goal of protecting from COVID-19, Carr says the findings of the study have the potential to help heavier people protect themselves.

"We know obesity is a risk factor for getting COVID-19 and that obese patients are more likely to struggle to fight it off once infected," Carr said. "We also know that vitamin C is essential for good immune function and works by helping white blood cells fight infection. The results from this study therefore suggest that increasing your vitamin C intake if overweight might be a sensible response.

"Pneumonia is a major complication of COVID-19 and patients with pneumonia are known to be low in vitamin C," Carr added. "International research shows that vitamin C decreases the likelihood of people getting pneumonia and decreases the severity of it, so finding the right levels of vitamin C to take if you are overweight may help to better support your immune system."

Researchers say adding extra vitamin C to your daily diet can easily be done by increasing your dietary intake of certain fruits or vegetables. Supplementation is also an option for those who don’t have access to or won’t eat fresh fruit.

"The old saying of 'an apple a day keeps the doctor away' is actually useful advice here," Carr said. "An average-sized apple contains 10 milligrams of vitamin C, so if you weigh 70 to 80 kilograms, achieving the optimal amount of vitamin C your body needs could be as easy as eating an extra apple or two to give your body the extra 10 to 20 milligrams of daily vitamin C it needs. If you weigh more than this, then perhaps an orange, which contains 70 milligrams of vitamin C, or a kiwifruit with 100 milligrams, may be the easiest solution.

"There are a large variety of vitamin C supplements available over-the-counter, most are relatively cheap, safe to use and easily accessible from a local supermarket, pharmacy or online," Carr said. "My advice for those who choose to get their vitamin C from a multivitamin, is to check the exact amounts of vitamin C per tablet, as some multivitamin formulations may only contain it in very low doses."

Click here to read more in the journal Nutrients.

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