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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 5 of 5. This is the beginning of the thread.
Posted by scatterbrained on March 14, 2005, at 0:52:46
Are there any blood tests that one could take to tell you what sort of vitamins you may be lacking or may have to much of? If so, sign me up!!!
Posted by Larry Hoover on March 26, 2005, at 12:09:08
In reply to blood tests for vitamins?, posted by scatterbrained on March 14, 2005, at 0:52:46
> Are there any blood tests that one could take to tell you what sort of vitamins you may be lacking or may have to much of? If so, sign me up!!!
It may seem strange to hear this, but blood concentrations of vitamins and minerals are generally very poorly correlated with intake or demand. What is most useful is blood work for measurable signs of deficiency, e.g. a specific decrease in enzyme activity, when the enzyme requires a specific nutrient to function.
Lar
Posted by banga on March 27, 2005, at 8:34:28
In reply to Re: blood tests for vitamins? » scatterbrained, posted by Larry Hoover on March 26, 2005, at 12:09:08
Lar,
I have wondered about something....I have very high levels of B12, partly due to supplementation, that I started when I finally recognized my bizarre physical symptoms as B12 deficiency.
My question is: if my blood levels (and spinal fluid) were high to begin with, what do you think--might it indicate that my body is unable to maximally utilize B12, thus it builds up in the blood?
My deficiency was largely caused by alcohol consumption, but since B12 is not known to be directly affected by alcohol consumption, I have wondered if the alcohol simply hit me at the weakest point--that I already had subclinical B12 deficiency and the alcohol pushed it over the edge..
Posted by Larry Hoover on March 27, 2005, at 12:05:49
In reply to Re: blood tests for vitamins? » Larry Hoover, posted by banga on March 27, 2005, at 8:34:28
> Lar,
> I have wondered about something....I have very high levels of B12, partly due to supplementation, that I started when I finally recognized my bizarre physical symptoms as B12 deficiency.
> My question is: if my blood levels (and spinal fluid) were high to begin with, what do you think--might it indicate that my body is unable to maximally utilize B12, thus it builds up in the blood?
> My deficiency was largely caused by alcohol consumption, but since B12 is not known to be directly affected by alcohol consumption, I have wondered if the alcohol simply hit me at the weakest point--that I already had subclinical B12 deficiency and the alcohol pushed it over the edge..Speculating can be useful.
Vitamin B12 is a very unusual structure, when compared to the other vitamins. It closely resembles hemoglobin in structure, but instead of iron in the centre, it contains cobalt. It is called cobalamin.
Cobalamin takes part in a number of reactions, at enzyme active sites, acting as a methyl donor, for example. However, the form of B12 we take must be methylated in the liver before it can become a methyl donor.....so, it's a methyl transporter (something like SAMe). It makes methyl groups more available right at enzyme active sites.
So, you can think of B12 as a team player. A supporting role, rather than the lead.
The liver is the central site in the systemic utilitization of B12. It not only "activates" it, by methylating it, it also stores it. So, B12 status is a surrogate marker for liver function. It's not an excellent marker, but it does suggest something about liver physiology. Maybe you have some cirrhosis?
When I looked at the National Academy of Sciences derivation of the RDA and so on (that's the ultra-conservative and totally evidence-based group that sets these levels), I found that there is no evidence for an Upper Limit (UL) for cobalamin. No known toxic overdose, essentially. I'm not saying there isn't one (don't chug a whole bottle down, and prove the point), but they have no evidence of having adverse effects from too high a B12 level.
Your finding that you have "very high" levels of B12 is based on a normalized level. What that means is they sampled a bunch of people, and graphed the results. Your results lie near the upper edge of the normal curve they developed. One of the foundation assumptions of such a sampling program is that the subjects being sampled *truly are normal*. What if everybody they tested had sub-optimal levels of B12 in their blood? That skews the results, eh?
High circulating B12 levels are a blessing. B12 is a potent antioxidant, with particular capacity to destroy peroxynitrite. There is a whole theory based on chronic fatigue and fibromyalgia (and PTSD and depression) being caused by peroxynitrite. High B12 is good, IMHO. Very good.
In the end, I think we make intuitive decisions for ourselves. We try to find rational bases for our decisions, but.....
<shrug>
Lar
Posted by banga on March 27, 2005, at 20:08:25
In reply to Re: blood tests for vitamins? » banga, posted by Larry Hoover on March 27, 2005, at 12:05:49
Thanks. I also have heard no uppper limits on B12....only tried to reconcile high blood levels with symptoms of deficiency. I do now take methylcobalamin instead of cyanocobalamin to make sure I have the potent form circulating...
My liver by and large is fine--I am sure there is minor damage and scarring, but no visible cirrhosis and liver enzymes are fine. Most likely I depleted my liver store of B12 over the years, then the severe abuse of alcohol impaired the methylation process....my body is still recovering from this I am sure, I guess I will never know how much residual damage remains. It was very scary and frustrating--I would have spontaneous darkening of vision, loss of sensory perception, tingling in hands and feet, marked cognitive difficulties, discoloration of skin, and other odd symptoms. I had a history of alcohol abuse but since my liver enzymes were fine, no doctor would believe me there was something very, very wrong--thought I was just a neurotic female. Sort of a reverse prejudism---me being a petite, caucasian, innocent-looking, well educated middle class female, they simply would not believe me how severe my alcoholism was, and the toll it had taken on my body. Pretty funny if you think about it--me trying to break the DOCTOR's denial that I had had a severe problem.
This is the end of the thread.
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