2 of 4 parts on Vitamin D currently loaded on YouTube. Will have the other two parts as soon as possible. FREE EVALUATION when you subscribe to HealthQuest e-NEWSLETTER, at www.AdvancedClinicalNutrition.com, for at least 3 issues. To key points are blood testing alone is not sufficient to determine all you need to know about whether you have a Vitamin D deficiency and there is only one Vitamin D supplement on the market today safe for daily intake. CONTACT: (940) 761-4045 – www.AdvancedClinicalNutrition.com. for a free Inquiry Telephone Consultation to discuss how Dr. Smith can help you improve your health, whether you are currently experiencing the symptoms of Vitamin D Deficiency or have any other health concerns.