THE LOSS OF SMELL AND TASTE  (called Anosmia)  (This can often appear in COVID-19).
This is a long known symptom of zinc deficiency.  Zinc also plays a role in immunity where neutrophils transport zinc to peripheral tissues for healing wounds or infections.  Zinc helps unwind and duplicate strands of DNA, then zips them back up again.
​(https://conta.cc/3aRp7OE)

​DIABETES TYPE II   (This can aggravate COVID-19).
Zinc is also imperative for the production of insulin, which is crucial for controlling Diabetes Type II.  Every insulin molecule contains 2 molecules of zinc at the center of the insulin molecule.  Hence diabetics are at greater risk for serious outcomes with COVID-19.

VITAMIN D3   (This is a deficiency that often appears in COVID-19).
​       Vitamin D is essential to calcium homeostasis and bone health.  But just as important, it also modulates the immune system.  Specifically, it promotes regulatory or suppressor T8-cells, which kill infected cells (viruses) and tumor cells (cancer).   It can also inhibit inappropriate immune responses that cause disease, such as: autoimmune disease, poor respiratory function, asthma, and Multiple Sclerosis, even inflammatory bowel disease.  Deficiencies of it have been implicated in innate and adaptive immunity, and in prostate cancer in men, and breast cancer in women.  

     We have vitamin D receptors on every cell in our bodies.  Supplemention with vitamin D improves atopic dermatitis in children and immunity.  It is made by the sun shinning on our skin  (from March through September).  Those with very dark skin require greater amounts.  Vitamin D2 is the plant form.  Vitamin D3 is the animal / human form.  The conversion of D2 to D3 depends on your genes.  Some people lack this gene, and need to take only D3.  The recommendations for intake in adults is about 2000 iu per day.  For seniors = 5000 iu per day.   Your blood levels should be between 30  - 100 (mean = 65).  Anything below 30 is risky; anything below 20 is a frank deficiency.