A vegetarian diet should be able to provide enough iron, if it is a well balanced diet. I wonder about iron, as it is one of the things that can be shorted if not enough iron containing foods are consumed. I am a vegetarian and have no problems with iron, but it took me a while being a vegetarian before my iron was at the proper levels. Lower iron stores would be the most likely effect of the dietary change. More focuis on iron containing foods should be helpful. If you are eating plenty of folate containing green vegetables and other foods, the change in diet shouldn't lower your Hb. But, and this is quite common, many thal minors notice changes with age and need more help than they can get from diet. Many minors find that as they age, folate supplements can help. Folate is more effective than folic acid and is preferred. The other thing about a veg diet is that you have to find a way to get vitamin b-12, as it is missing from most veg foods. A sublingual supplement that melts under your tongue can be very beneficial for thals. I don't carry thal, but as I've gotten older, I started taking B-12 and last year added folate. I take 5 mg of each daily and it helps greatly getting me through my work days.