Some vitamins and other micronutrients in higher dosages than the recommended dietary guidelines are more effective and safe in warding off common respiratory tract infections as well as COVID-19, experts suggest.
Dietary supplements containing certain vitamins, minerals, and essentials fatty acids are important for a healthy immune system.
Among these nutrients docosahexaenoic acid (DHA), an omega-3 fatty acid, vitamin D, vitamin C, and zinc are crucial for our immune system:
- Exposure to the sun is the main source of vitamin D,
- citrus fruits such as oranges are rich in vitamin C,
- red meat, nuts and seeds are good sources of zinc,
- and oily fishes are rich sources of DHA.
Professor Adrian Gombart, the study’s senior author, said:
“The roles that vitamins C and D play in immunity are particularly well known.
Vitamin C has roles in several aspects of immunity, including the growth and function of immune cells and antibody production.
Vitamin D receptors on immune cells also affect their function.
This means that vitamin D profoundly influences your response to infections.
The problem is that people simply aren’t eating enough of these nutrients.
This could destroy your resistance to infections.
Consequently, we will see an increase in disease and all of the extra burdens that go along with that increase.”
Researchers argue that taking a daily multivitamin supplement is not good enough.
To see their beneficial health effect we need to take the correct amounts of these micronutrients.
For instance, the current national dietary guidelines for vitamin C is 50 milligrams (mg) for women and 75 mg for men but that needs to be corrected to a dosage of 200 mg or even higher.
The Federal recommendation for vitamin D intake, depending on age, is from 400 to 800 international units, but vitamin D dosage should be 2,000 international units.
Professor Gombart said:
“Around the world, acute respiratory tract infections kill more than 2.5 million people every year.
Meanwhile, there’s a wealth of data that shows the role that good nutrition plays in supporting the immune system.
As a society we need to be doing a better job of getting that message across along with the other important, more common messages.”
Professor Gombart notes that the potential damage is very high.
Around the world, influenza alone causes millions of people to be hospitalized and several hundred thousand to be killed each year.
Professor Gombart said:
“A number of standard public health practices have been developed to help limit the spread and impact of respiratory viruses: regular hand washing, avoiding those showing symptoms of infection, and covering coughs.
And for certain viruses like influenza, there are annual vaccination campaigns.”
We all hope an effective vaccine against SARS-CoV-2 will be available soon, but a vaccine alone is not the complete answer to infections.
The impact of nutrition on the immune system should be part of public health strategies as this can reduce the infection rates and save many lives.
Professor Gombart concluded:
“The present situation with COVID-19 and the number of people dying from other respiratory infections make it clear that we are not doing enough.
We strongly encourage public health officials to include nutritional strategies in their arsenal.”
The study was published in the journal of Nutrients (Calder et al., 2020).