Yes, you can deduct vitamins and supplements if they are specifically recommended by your doctor as treatment for your medical condition.  If you take them to maintain your general health - they are not deductible.

Per IRS: "You can't include in medical expenses the cost of nutritional supplements, vitamins, herbal supplements, “natural medicines,” etc. unless they are recommended by a medical practitioner as treatment for a specific medical condition diagnosed by a physician. These items are taken to maintain your ordinary good health and aren't for medical care.