“How to Test for Functional
Vitamin B12 Deficiency” Two cases of young, strictly
vegetarian individuals with no known vascular risk factors, yet
suffering a stroke or multiple strokes. Why? Most probably because they
weren’t taking vitamin B12 supplements, which leads to high homocysteine
levels, which can attack your arteries. So those eating plant-based
failing to supplement may increase one’s risk of
both heart disease and stroke. Now vegetarians have so much
heart disease risk factor benefit that they’re still at lower risk overall,
but this may help explain why vegetarians were
found to have more stroke. Presumably this disparity would disappear
with adequate B12 supplementation, and this benefit would grow even larger. Compared with non-vegetarians,
vegetarians enjoy all these other advantages: better cholesterol,
blood pressures, blood sugars, and obesity rates. But, like
what about that stroke study? And even among studies that show
benefits, they’re not as pronounced as one might expect, which may be a
result of the poor vitamin B12 status. Vitamin B12 deficiency may negate some
of the cardiovascular disease prevention benefits of vegetarian diets, so
in order to further reduce the risk of cardiovascular disease, vegetarians should be advised
to use B12 supplements. How can you determine your B12 status? By the time you’re symptomatic
with B12 deficiency, it’s too late. And initially the symptoms can be so
subtle that you might even miss them. And well before you
develop clinical deficiency, you develop metabolic vitamin B12
deficiency: a missed opportunity to prevent strokes, where you have enough
B12 to avoid deficiency symptoms, but not enough to keep
your homocysteine in check. Underdiagnosis of the condition results
largely from failure to understand that a normal B12 blood level may not reflect
adequate functional B12 status. The levels of B12 in your blood
does not always represent the levels of B12 in your cells.
You can have a severe functional deficiency of B12 even though your
blood levels are normal or even high. Most physicians tend to assume that
if the B12 level in your blood is normal, then there’s no problem. But
within the lower range of normal, 30% of patients could have metabolic B12
deficiency with high homocysteine levels. Measuring methylmalonic acid
levels or homocysteine directly are a more accurate reflection
of vitamin B12 functional status. Methylmalonic acid can be a
simple urine test; you’re looking for less than a value of 4 micrograms
per milligram of creatinine. Elevated MMA is a specific marker
of vitamin B12 deficiency, while homocysteine rises in
the context of both vitamin B12 and folate deficiencies, and so metabolic B12 deficiency is
defined by an elevation in MMA levels or by an elevation of homocysteine
in people getting enough folate. Even without eating beans and greens,
which are packed with folate, folic acid is added to
the flour supply by law. And so high homocysteine levels these
days may be mostly a B12 problem. Ideally, you’re looking for a
homocysteine level in your blood down in the single digits. Measured this way, the prevalence
of functional B12 deficiency is dramatically higher than
previously assumed, like 10%-40% of the general population,
and more than 40% in vegetarians, and the majority of vegans who aren’t
scrupulous about getting their B12. Some suggest that those on plant-based
diets check their vitamin B12 status every year, but you shouldn’t need to
if you’re adequately supplementing. And evidently, there are rare
cases of vitamin B12 deficiency that can’t be picked up on any test, so better to just make
sure you’re getting enough. Now, if you do get your
homocysteine tested and it’s still up in the double digits
even despite B12 supplementation, I do have a suggestion in
the final videos of this series, which we’ll turn to next. Video source: https://www.youtube.com/watch?v=Vlr7aXD5hqI
