Vitamin D

Very little in the diet. To get from sunlight, you need at least 30 minutes of sunlight daily.

Category	25(OH)D (ng/mL)	25(OH)D (nmol/L)	Interpretation	Treatment
Deficient	<15	<37.5	Severe deficiency	D-Cure 25,000 IU, 2x/week for 8 weeks
Insufficient	15–30	37.5–75	Mild deficiency	D-Cure 25,000 IU, 2x/week for 4 weeks
Sufficient	>30	>75	Adequate	Maintenance (D-Cure 1-2/month OR 1000 IU daily)

Monthly maintainence dose works better to maintain Vit D levels compared to daily dose
Dr Leong Hoe Nam says that when people go into ICU, they tend to have single digit Vit D levels, so he believes it has an immunological function as well. And hence he recommends replacing to >50.
Vitamin D levels inversely associated with risk of respiratory tract infections
Can reduce risk of URTI, reduce COVID and its severity
1000 iu/day child, 2000-4000 iu/day adult
In very sick patients, even D-cure daily x 1/52

# Vitamin D