People who weigh more need more vitamin C for a strong immune system to help fight against respiratory infections including COVID-19 and flu during colder months.
Experts have estimated how much vitamin C we need relative to our body weight to boost the immune system and also reduce the odds of heart disease.
So, it would be wise for heavier people to add to their diet more fruits and vegetables high in vitamin C such as strawberries, oranges, kiwis, and kale.
Past studies suggest that poor vitamin C levels in overweight and obese people could imbalance enzyme functions and so increase the risk of low-grade inflammation, cardiovascular diseases, respiratory infections, and getting frequent colds.
Researchers identified that for every extra 10 kilograms an individual carries they need to take 10 milligrams more vitamin C per day to maximise immune system functioning.
For example, if a 60 kg adult requires 110 mg of vitamin C per day then someone who weights 90 kg needs a 140 mg daily intake to obtain a comparable plasma vitamin C concentration.
Professor Carr, the study’s first author, said:
“Previous studies have already linked higher body weight with lower vitamin C levels.
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.”
Public health officials should revise the guidance on vitamin C intake levels as the nutrient is important for immune health and helps protect our body against viral infections such as COVID-19 and flu.
Taking the correct amount of vitamin C could protect heavier people from such diseases.
Professor Carr said:
“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.
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.
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.”
The best way to achieve the optimal levels of vitamin C is eating fruits and vegetables rich in vitamin C rather than taking supplements.
Professor Carr said:
“The old saying of ‘an apple a day keeps the doctor away’ is actually useful advice here.
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.”
The study was published in the journal Nutrients (Carr et al., 2022).