Are you wondering about B12 deficiency testing and understanding what your B12 levels are? Maybe you have been told that your B12 levels are not low enough to actually qualify as deficient. In this article, we look at what some of the B12 deficiency myths are, regarding testing and how to understand when your body needs more B12.
If you want to understand B12 deficiency, when it is present and what to do, keep reading.
What Is B12 Deficiency?
This study (link below) looks at some of the myths surrounding vitamin B12 deficiency from both a functional assessment and also a more standard assessment of B12 deficiency. Before we get into what the myths are and the assessment techniques, we want to define what deficiency is to begin with. Generally speaking it means not enough, but not enough for what? When you are deficient you don't have enough B12 for your red blood cells to divide. You don't have enough to carry out the natural functions that the body is needing to do on a daily basis. This definition of deficiency is more of a functional way to look at it. The other way is using a reference lab.
When you do a test for deficiency this is done at a reference lab like Quest or Labcorp. They define deficiency based on what they have established as a normal and abnormal range. When you are using a reference range you do want to understand how they came up with that reference range. This informs you how it could be flawed and the assumptions involved. This is not to suggest that it is totally flawed. Still we want to understand where the reference numbers are coming from.
Serum B12 is the more standard way to check for B12 deficiency. How do they come up with their reference ranges? A lab creates a reference range by looking at a subset of the local population. For easy numbers, let's say they use 100 "healthy" people to use and check their B12 levels. Then they will average the numbers and take so many standard deviations above and below the averages to create the reference range. If you have twenty five people that are very deficient (in B12), it will really skew the results. (of the one hundred) They have to take a large enough sample size to make sure you're accounting for all subsets of the population. This also implies that you will miss people using this form of testing. Therefore you may miss out on some problems that are occurring from B12 deficiency. This is true for any serum blood test or any reference range. You will miss some of the people that actually have the problem when you are looking for deficiency or excess etc. This gets at the relative sensitivity of the test. Will the test pick up all the the people that have the problem or is it going to pick up half or or what is it?
B12 Deficiency Myths
There are many myths about B12 deficiency centered around how to look at serum B12 test results. Whether or not to interpret those as gospel or dig a little bit deeper and have stricter criteria for what we're considering deficient. It has been noted in case studies and research that even people with normal serum B12 levels can have low functional B12 using functional assessments of tissue levels. These myths are from that study The many face of cobalamin deficiency. The first B12 deficiency myth is no anemia, no B12 deficiency.
Some doctors will say if you don't have anemia, then you don't have B12 deficiency. This s false because you have to be deficient in B12 for a long time in order for you to stop producing red blood cells. If you wait until you have anemia, then you are really are going to have a problems. You can have B12 deficiency even if your serum levels look ok. The question is do your tissues have enough. Sometimes problems like neuropathy, fatigue, and other things show up before there is anemia. In fact this happens quite often. People don't have anemia but they still have B12 deficiency. We know this because they respond when we give them B12. All their symptoms go away. Does that mean you have B12 deficiency? Yes, I should think so.
The second B12 deficiency myth is, you have no macrocytosis (or macrocystic anemia). In order for your cells to divide through mitosis they need enough DNA based pairs. These are things like guanosine cytosine etc. If you don't have enough of those, then the cells cannot replicate the DNA within themselves to pass it on to the daughter cell. B12 is one of the critical elements that is needed to produce those new cells. If you wait until you have Macrocytosis (or macrocytic anemia). A lot of your tissues will be deficient as well as your red blood cells. Obviously when you are anemic you don't have enough red blood cells. You can see evidence of macrocytosis before you become anemic. Your red blood cells will start to get larger and that suggests B12 deficiency (there are other reasons this can happen though).
The next B12 deficiency myth to know about is, serum B12 levels are within the labs reference range. The myth says, use your labs reference range to determine if your serum B12 level is normal. If it is not low, then you don't have a problem with B12 and you don't need any more B12. That's the myth.
The reference range from your local lab may have more of a picograms per ml reference range. These units will make your reference a little bit higher. It's usually around 300 to 400 gg/ml or something like that on the low end. In reality, you can have B12 deficiency symptoms or problems at the tissue level even when you have 600 pg/ ml in your blood. How do we know that? We do other functional and sensitive tests at picking up B12 deficiency. It is a myth to only rely on the reference range because this way of testing will inherently miss some people. We know this because they have some (or all ) of their symptoms or problems resolve when they start taking B12. The serum test and reference range is designed to capture most of the people with deficiency but not all.
Another B12 deficiency myth is serum vitamin B12 is only moderately low. With this myth the assumption is your B12 levels have to be well below the reference range for it to negatively effect your body. As mentioned above, if you are low on the reference range, there probably is a problem.
Methylmalonic acid (MMA) is one of the most sensitive ways to look for B12 deficiency. You may want to look at this test when it is unclear. Let's say your B12 levels are low but your MMA is normal. Since this is a more sensitive way to look at B12 levels, is this normal result telling us you don't need anymore? No. There are different stages of B12 deficiency and the deficiency may not be showing up in the MMA levels yet. It is possible to find someone with B12 deficiency on the serum but the MMA looks normal and they still respond to taking B12? A low serum B12 levels now may develop into high MMA later ( which is a sign of B12 deficiency). So any of these tests being abnormal is a sign of B12 deficiency.
Another B12 deficiency myth is, it only occurs in elderly people. This is absolutely not true. As you get older, yes your absorption of B12 does go down and it is more common. We recently posted an article, how common B12 deficiency and yes it is more common as you get older because of absorption issues. However it is not unheard in children and young adults. In fact we see it all the time. It's really just based based on how well you absorb it, your diet, and sometime it is genetically determined.
If you're getting tested for B12 deficiency, these are some of the things to keep in mind. You may do different tests at different times to track your progress with getting your levels up. I suggest following the blood test that are low over time to see if it's coming into the normal range. You want to make sure that your treatment is actually getting into your body and getting into the normal ranges. This will help you know when you need to stop or decrease that therapeutic treatment and decrease the amount you're taking etc
That should give you a better understanding of what some of the B12 deficiency myths are and how to think about your B12 levels. If you have questions about the content in this article, please ask it in the comment section below.
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