as far as i am aware of,none really. if you are a totally healthy person,the blood loss will replenish itself again. my hubby has been donating blood since the early 80s and just recently recieved a 16 gallon pin from the red cross for his trouble. and having the knowledge that his donations have helped to save many lives. my son also needed alot of donated blood,and other blood products when he went into liver failure. it IS a true lifesaving gift to others,believe me.
i am sure there have been people who have had some issues develop along the way but i would think,just seeing what my hubby has been thru,they are the very big exception and not the rule,you know what i mean? if you are healthy and meet the criteria for donating blood, do it. it really makes an impact in others lives,trust me on that one. if you really want the answers to any questions reguarding the effects of donating blood,just contact your local chapter of the american red cross. they know EVERYTHING there is to know on this subject. FB