Are African-Americans anemic at a higher rate than whites? It seems so and, in fact, it has been shown in a number of studies that African-Americans have lower hemoglobin levels than ‘whites’, even when the studies account for several other contributing factors, such as the higher rates of sickle cell anemia and thallasemia, as well as socioeconomic status and income. Since so many studies have shown this finding, researchers have declared it ‘normal’, but it is really normal?
Or are millions of African-Americans being given a sentence of fatigue and decreased cognitive function because doctors haven’t done any further research on the topic, especially when it comes to simple iron deficiency? Hemoglobin is a molecule present in blood that carries oxygen for use in the body. The molecule is tested on most routine blood tests under the Blood Test Abbreviation of Hgb.
When hemoglobin levels drop below ‘normal’, doctors call this condition anemia and treat it depending upon what the underlying cause is. If the cause is lack of iron, then it is called Iron Deficiency Anemia, but there are many other kinds of anemia and it’s important to find the cause so that the proper treatment can be used. The problem becomes: how to define anemia, and additionally the problem of lack of treatment (in both whites and people of color) of Symptoms of Iron Deficiency that has not (yet) progressed to anemia, a problem we continually mention on this site because it’s such a huge problem that goes almost completely unaddressed by the medical community.
In a previous page, we discussed the Definition of Anemia, and how doctors define anemia as lower than ‘normal’ levels of hemoglobin and how these nubers are determined. On that page, we discuss these normal levels and briefly note the different ‘normal’ levels for ‘blacks’ and for ‘whites’.
On this page we will delve more deeply into the different ranges of normal given for blacks and whites and why we believe there should not be a different normal level, even though some ressearchers believe differently. For instance, the study entitled Different Definition of Anemia in Blacks and Whites gives the following statement,
“The evidence appears to be overwhelming that there is
Black-White difference in hemoglobin level which is real
and is not explainable on an income or socioeconomic basis.”
They base this observation on several other studies that have noted the same thing, a fact that we have no disagreement with. However, they, as well as other studies 1 seem suggest that this phenomenon is likely to be an inherent difference between white and black physiology and not a mystery that needs to be delved into in order to find the underlying cause.
Here at Anemia Central, we suggest and provide evidence of a different hypothesis: that this difference is actually a pathologic difference with a preventable underlying cause that doctors have yet to recognize because they have erroneously accepted this variation as ‘normal’ without further investigation.
Are African-Americans Anemic Because of the Wrong Definition?
It’s frustrating to read studies like the one above where the researchers do not seem to have looked into any other possible causes for the problems they are studying. In the case above, the authors merely make a conclusion based on widespread observations of the same thing. They seem to conclude that if many other researchers have observed the same thing, then it must be a normal variation.
In the case of lower hemoglobin levels in blacks, we respectfully dispute the conclusion that lower hemoglobin is a normal variation between the races, despite the fact that this finding is consistent across many studies. This is because there is a logical explanation as to why blacks have lower hemoglobin levels, and the answer is that it’s due to the one vitamin deficiency that is widely agreed to be lower in people with darker skin- Vitamin D.
In fact, I’ll make the argument that Vitamin D and Iron are integral cofactors for one another and that low Vitamin D Levels CAUSE lower hemoglobin, not just in blacks, but in non-African-Americans as well.
However, those with darker skin have a more difficult time getting Vitamin D and, as a general rule, have lower Vitamin D levels than lighter skinned individuals in the same geographic locations 2, but people of color living traditionally have high levels of Vitamin D, dispelling the notion that people of color simply need less vitamin d, as has been suggested in some studies 3.
How Vitamin D Deficiency Leads to Anemia
At first glance, that Vitamin D deficiency causes anemia does not make any sense, but I’ll explain in detail how it actually makes perfect sense that Vitamin D deficiency leads to lower hemoglobin levels. There are three reasons why this is the case.
Reason #1: Hepcidin Feedback
Please see the Hepcidin page for more detailed information on this molecule that is essential for understanding how the uptake of iron in the body works. In some ways, the author of the study concluding that the difference in hemoglobin between blacks and whites is simply a normal variation can be excused for his ignorance because the hepcidin molecule was not even discovered until more than 20 years after his article was written, so he would not have known about this important molecule.
Unfortunately, there has been little dispute of these studies since they were done and, more unfortunately, the author of the study was a doctor who published the article in a journal called ‘PUBLIC HEALTH BRIEFS’, a journal dedicated to the Public Health profession, and the journal article makes recommendations for the implementation and change of public health programs based on his incomplete information and erroneous assumptions.
The Dangers of Public Health Recommendations
This is the danger of making public health recommendations like this, and is similar to public health officials making the recommendation in the 60’s and 70’s for mothers to feed their infants formula rather than to breast feed because science could find no substances in breast milk that were not found in formula, and therefore had erroneously declared them equal.
Since the time of public health officials recommending mothers feed their infants formula, irreparably harming an entire generation of children, we now know of literally dozens of reasons that breast feeding is superior to formula feeding, including: the mother-baby attachment from skin to skin contact, the acquisition of antibodies from the mother, the intake of substances such as lauric acid and DHA that are important for human health, and many more.
This study declaring that lower hemoglobin in blacks commits a similar offense of not acknowledging that what we do not know may be important, and even vital, for understanding the difference in these laboratory results. But because he ‘doesn’t know what he doesn’t know’, he makes the mistake of declaring this difference a normal variation without sufficient evidence to do so; a declaration which could harm millions of people suffering from the damaging effects of Iron Poor Blood and Iron Deficiency Anemia who might not receive proper treatment if government officials were to base government policy on suggestions such as these.
Hepcidin and Vitamin D
But back to hepcidin. Hepcidin is a molecule that the body has created in order to have a tightly regulated feedback system for the absorption of iron in the body. You see, while iron is extremely important, it’s also very toxic, and it is important to get ‘just enough’ for the maximum health benefits, but not ‘too much’ such that it causes health problems. Hepcidin is the ‘gatekeeper’ that determines how much is ‘enough’ or ‘too much’. The body regulates this delicate balance by increasing hepcidin in order to reduce iron absorption, and decreasing it in order to absorb more iron.
Vitamin D fits into this equation because Vitamin D is involved in one of the feedback loops that regulate hepcidin. When you have sufficient vitamin D, the body decreases hepcidin levels in order to allow more iron to be absorbed. There have actually been quite a few studies noting that raising vitamin D levels, specifically in people on hemodialysis, significantly decreases their need for drugs like erythropoetin (EPO, the stuff that Lance Armstrong used to ‘dope’ his blood before the Tour d’France) 4,5, thus showing the relationship of vitamin D and the maintenance of blood markers. In fact, just a single dose of Vitamin D can reduce circulating serum hepcidin levels by as much as 35% 6,7.
But when you have insufficient vitamin D, hepcidin rises, telling the body to prevent any more iron from being absorbed. Why this Vitamin D and Iron feedback loop is in place is not fully understood at this point, but there is no doubt that it exists. So, if you connect the dots, you’ll see that someone with low vitamin D levels will absorb less iron. Since dozens of studies have shown that darker skin correlates with lower vitamin D levels, it’s logical to see that these lower Vitamin D levels will lead to increased hepcidin levels, and thus less iron absorption.
Reason #2: Inflammation Leads to Lower Iron Absorption
The second reason that lower vitamin D levels can lead to lower iron is that vitamin D is an anti-inflammatory 8. Sufficient levels of vitamin D lead to a decrease of inflammation, while the opposite is also true; low levels of vitamin D can allow inflammation to proliferate when it’s present.
So what? What does inflammation have to do with anemia?
A lot. In fact, it’s well-known that inflammation itself leads to anemia. There is even a classification of anemia called Anemia of Chronic Illness where having any inflammatory disease leads to less iron absorption, and can progress to anemia over time.
Interestingly, low iron levels can also lead to low Vitamin D levels in a feedback loop that goes both ways. See our page on Vitamin D and Iron for more details about why keeping African-Americans anemic is also likely to be keeping their vitamin D levels lower in a vicious cycle.
This is Why Lower Hemoglobin Levels, In Blacks are Not a Normal Variation
If you haven’t caught that connection yet, blacks tend to have low vitamin D levels, low vitamin d levels can lead to higher levels of inflammation, and high levels of inflammation can decrease iron absorption and lead to anemia. So, since blacks have lower vitamin D levels than whites, on average, it makes sense that their vitamin D deficiency can be causing their lower hemoglobin levels.
“Based on our findings of an association between D25 deficiency and anemia, further investigation needs to be conducted to evaluate whether there is a direct causal effect of D25 deficiency on anemia. If vitamin D does improve erythropoiesis then correction of a D25-deficient state may lead to improvement in anemia…”
Vitamin D deficiency and anemia: a cross-sectional study
It follows that if their lower hemoglobin levels are caused by low vitamin D levels, then their lower hemoglobin levels are pathologic rather than a normal variation caused by genetic differences. I’m not the first to suggest this connection, and potentially even a role of vitamin D deficiency causing anemia.
There have been researchers who noted that some people both have lower vitamin D levels and lower iron levels, and put two-and-two together 9, 10, 11, 12. Rather than doctors and scientists proposing public health programs aimed at lowering the definition of anemia for blacks based on limited information and bad assumptions, a better public health initiative would be to raise vitamin D levels, such as is the goal of Grassroots Health and the Vitamin D Council, and do studies to see if raising vitamin D levels in blacks throughout childhood normalizes their iron levels to that of their white peers.
Other public health initiatives might be to actually find out how blacks with lower hemoglobin levels FEEL in comparison to their counterparts, black and white, with higher hemoglobin levels. But it seems that there are few studies on iron deficiency that actually ASK anyone how they FEEL when their iron levels are low, instead focusing only on whether they have anemia or not.
When they DO ask these questions, it becomes clear that those with low Iron and Ferritin levels, even when they do not have anemia, feel tired and have Symptoms of Iron Deficiency, such as cognitive problems such as ‘brain fog’. As we point out on the Iron Poor Blood page, when these studies are taken into account, it’s easy to see that evaluating iron and ferritin levels, something rarely done, is more important to those with fatigue than just setting a marker for when anemia occurs before iron treatment is instituted.
Such as is done with thyroid blood levels, it seems that researchers are more interested in finding normal levels from mathematical calculations of populations than finding out levels of hemoglobin, iron, and ferritin that optimize health and well-being.
- Hemoglobin concentration in white, black, and Oriental children: is there a need for separate criteria in screening for anemia ↩
- INCREASED SKIN PIGMENT REDUCES THE CAPACITY OF SKIN TO SYNTHESISE VITAMIN D3 ↩
- Traditionally living East Africans have Vitamin D Levels of 46 ng/ml ↩
- The effects of changing vitamin d levels on EPO in CKD patients ↩
- Prevalence of Vitamin D Deficiency and the Safety and Effectiveness of Monthly Ergocalciferol in Hemodialysis Patients ↩
- suppression-of-hepcidin-by-vitamin-d ↩
- The role of vitamin D in regulating the iron-hepcidin-ferroportin axis ↩
- Renal anaemia and EPO hyporesponsiveness associated with vitamin D deficiency: the potential role of inflammation ↩
- Prevalence of 25-hydroxyvitamin D deficiency in subgroups of elderly persons with anemia: association with anemia of inflammation ↩
- Resurrection of Vitamin D and Rickets ↩
- Vitamin D deficiency and anemia: a cross-sectional study ↩
- Plasma 25-Hydroxyvitamin D Is Independently Associated with Hemoglobin Concentration in Male Subjects with Type 2 Diabetes Mellitus ↩