Recently I have asked on Facebook:
Anemia is a condition in which there is a deficiency of red cells or of haemoglobin in the blood, resulting in pallor and weariness. It can also be defined as a lowered ability of the blood to carry oxygen.
Anemia goes undetected in many people and symptoms can be minor. The symptoms can be related to an underlying cause or the anemia itself. Most commonly, people with anemia report feelings of weak or tired, and sometimes poor concentration. They may also report shortness of breath on exertion. In very severe anemia, the body may compensate for the lack of oxygen-carrying capability of the blood by increasing cardiac output.
Though, the oral iron supplementation is a very common therapeutic measure to correct anemia it should be only used when dietary measures have failed. Moreover, iron supplement cannot correct anemia which is not due to iron deficiency. A moderate degree of iron-deficiency anemia affected approximately 610 million people worldwide or 8.8% of the population. It is slightly more common in females (9.9%) than males (7.8%). Mild iron deficiency anemia affects another 375 million.
A study reveals that there is strong correlation between blood group and anemia. The individuals with blood group antigen alpha and beta are comparatively more prone to be anemic,whereas the individuals devoid of these antigens are resistant to anemia. So, it can be concluded that the regular intake of iron and vitamin rich diet in individuals having blood groups A, B, and AB can prevent the occurrence of anemia.
To treat your anemia, your doctor may suggest eating more meat—especially red meat (such as beef or liver), as well as chicken, turkey, pork, fish, and shellfish. Nonmeat foods that are good sources of iron include: Spinach and other dark green leafy vegetables.
According to the study mentioned above, there is no difference between anemia frequencies amongst rh negatives and rh positives.
However:
Before the introduction of prophylactic treatment in 1968, a positive frequency dependent selection systematically penalized the less abundant allele because lots of children of RhD-negative women in the mostly RhD-positive population as well as children of RhD- positive men in the mostly RhD-positive population were dying of hemolytic anemia.
Source: Worse Health Status and Higher Incidence of Health Disorders in Rhesus Negative Subjects