Nightflyer,
The Hb threshold varies depending which country you are in, so I can't tell you how strict they are where you live or if a waiver can be provided. Thal minor should not automatically disqualify you, but low Hb may.
I would suggest a minimum of 2 mg folic acid daily, a B complex 100, and 400 IU natural vitamin E. If you can get wheatgrass in some form, take it. You may be able to find tablets. There is another supplement named resveratrol that you should also take if you can get it. Both are known to raise Hb levels in some patients. Now there is also one little trick you might consider when your Hb is going to be tested. The more hydrated you are, the lower your Hb appears to be, so make sure you are NOT well hydrated when your Hb will be checked. It's simply a matter of fluid volume and it affects the tested Hb level.