The two big issues with a plant based diet are b12 and iron based anemias.Dr. Gabriel Cousens addresses these issues in his book Consious EATING.The nutrient profile of algea blue green/spirulina or green/chlorella are great.I personaly wouldnt take a synthetic multivitamin like centrum.I get my algea from iherb.com they have good prices and great service.The powders are the best buy but the taste factor may be an issue.