Vitamin D and Respiratory Infections
In our ongoing battle against Coronavirus and Covid-19, some fascinating new research shows "a clear link" between the patient's level of vitamin D, and the severity of symptoms experienced.
Scientists in Dublin, Ireland believe that the high prevalence of vitamin D deficiency in people who live in Northern Hemisphere countries - like Italy, Spain and the US - is contributing to the more severe respiratory infection symptoms that many Covid patients there are facing. In a new piece in the Journal of Alimentary Pharmacology and Therapeutics, these authors contrast the Coronavirus situation in Southern Hemisphere countries like Australia, where there is a lower level of mortality from the disease. Latitude 35 degrees North appears to be a dividing line; above that, the populations as a whole receive insufficient sunlight for adequate vitamin D production in the winter and spring. Interestingly, Nordic countries above this latitude appear to be an exception, but this actually strengthens the vitamin D link because in those countries, there is widespread vitamin D supplementation.
Vitamin D sufficiency, according to these and other researchers, appears to play a critical role in the reduction of respiratory infections, as well as the prevention of immune system misfires, including the often fatal "cytokine storms" that kill many Covid patients.
So how does this information impact those of us at home now, who may be getting less vitamin D even than usual, due to less sun exposure from staying inside? Well, it is clear that this is a nutrient we need to pay attention to, especially if recent blood work indicates that your vitamin D level is low. Many scientists also believe the current recommendation of 600 international units a day is too low, and encourage us to aim for 4,000 - 6,000 units.
Here are some good sources:
- Spend some time outside, every day, in the sunlight. The body uses sunlight to make vitamin D naturally; 15 - 20 minutes of sunlight exposure at midday results in production of 10,000 - 20,000 international units.
- Some foods are fortified with vitamin D - orange juice, soy milk, cereals. It's also found in fatty fish like mackerel, tuna and salmon, as well as egg yolks and cheese.
- Consider supplementation, especially since risk of toxicity from overexposure is very low. If supplementing, aim for 2,000 international units a day.