Cod liver oil, the ratio of vitamins A and D, frequent respiratory tract infections, and vitamin D deficiency in young children in the United States.
Full reference:
Cannell JJ, Vieth R, Willett W, Zasloff M, Hathcock J, White JH, Tanumihardjo SA, Larson-Meyer E, Bischoff-Ferrari HA, Lamberg-Allardt CJ, Lappe JM, Norman AW, Zittermann A, Whiting SJ, Grant WB, Hollis BW and Giovannucci E. Cod Liver Oil, Vitamin A Toxicity, Frequent Respiratory, Infections, and the Vitamin D Deficiency Epidemic. Annals of Otology, Rhinology & Laryngology Volume 117, No. 11. 2008.
