Vitamin D3 Deficiency in America
https://www.sciencedirect.com/science/article/pii/S0271531710002599
https://www.scientificamerican.com/article/vitamin-d-deficiency-united-states/
Vitamin B12 Deficiency in America
https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/
https://www.ncbi.nlm.nih.gov/books/NBK441923/
Omega 3 Deficiency in America
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3992162/