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View Full Version : Vitamin B-12 Status of Long-Term Adherents of a Strict uncooked Vegan Diet



Korn
Dec 28th, 2010, 10:39 PM
http://jn.nutrition.org/content/125/10/2511.full.pdf

This study is already mentioned elsewhere on this forum, but IMO this material deserves it's own thread - and also some comments...

Clueless Git
Jan 2nd, 2011, 10:53 AM
The test results there appear to be that all vegans are going to die of B12 defiency and that not even seaweed can save us Korn?

Korn
Jan 2nd, 2011, 03:26 PM
Sure - we'll all die of B12 deficiency in 2012. Did I forget to tell you that? :-)

I think it's important to look at all the studies about potential B12 sources - not only eg. the (newer) ones which suggest that real, active B12, available for humans may be found in some plant products. The plants they describe should - since they have reported to measure true, bioavailable B12 and therefore not cause false/too positive blood tests in humans.

There are many strange, incomplete B12 studies out there, and quite a few surprising comments to them as well. One study, for example, found that a plant source, in the amount that were used, was capable of maintaining B12 levels in people who were taking them. Instead of concluding that this is good news, one writer instead complained and said that maintaining healthy B12 levels isn't good enough - the plant should also be capable of increasing B12 levels in those people. I don't know if that plant can do that - but of course we don't want our B12 levels to escalate continuously. If a study finds that plants can maintain healthy B12 levels, and that the B12 found is real, active B12 - that is good news.

When discussing B12 in plants, It's all about whether the B12 is active; if it improves the B12 condition in those who eat those plant products - not only in blood tests, but prohibits or repairs conditions caused by too low B12 levels.

The tricky part is: what if someone appears to have good B12 levels, but suddenly gets symptoms of serious B'12 deficiency, and in worst case - symptoms which cannot be reversed? (There are conflicting opinions re. whether serious problems can occur in such a sudden manner, but I'll skip that part for now).

So - what if some of us trust that we can just eat any seaweeds, or not wash our carrots, and even have blood tests that seem fine - but get a surprise in 5 years? This dilemma must be looked at both by vegans and non-vegans. Eating a lot of animal products isn't the solution: many non-vegans have low B12 levels as well - and animal products also contain some inactive B12 which may cause 'false good news' in blood tests. Their blood tests may look good, but their real life health may not look so good.

Not only that, but when eating B12 in high amounts, the relative absorption rate, in percent, decreases, which complicates analyzing what humans may get from B12 rich food and supplements. Bioavailability is a main ingredient to look for here, real life results are even more important. But it's sometimes hard to measure improved health in humans which already appear to have perfect health. High B12 levels in blood is just 'the packaging', so to speak, and that's true for meat eaters as well. So numbers which may look high on paper may not have as high real life value as it seems. Besides, if we consume more B12 than our bodies can or want to store, the B12 is flushed out in the toilet - and this may influence studies about increased/decreased B12 levels.

Back to the Finnish study from 1995...

...significantly lower serum vitamin B-12 concentrations in the vegans compared with their matched omnivorous controls.
That's old news (and the study isn't new either). :-)
Some important considerations: how would the levels have been in vegans if they would have avoided all the stuff which we today know is B12-antagonistic? And: should vegans strive for the same B12 levels as people who live on a B12-rich diet; a diet which is associated with a lot of diet related (and sometimes B12 related) health problems? While we want to be in the normal B12 range, I'm not sure if we want levels as high as people who eat a lot of animal flesh, and we definitely shouldn't aim for too low B12 levels.

Here's how the article starts out:

"In fact, only minute amounts of vitamin B-12 are found in fermented foods (√sterdahland Johansson 1989), and most of vitamin B-12 in seaweeds are analogues of the true vitamin (Herbert and Drivas
1982, van den Berg et al. 1988). Therefore, it remains to be shown whether the long-term use of large amounts of uncooked fermented foods and seaweeds could actually supply enough biologically active vitamin B-12."

From the abstract:

The vegans consuming Nori and/or Chlorella seaweeds had serum vitamin B-12 concentrations twice as high as those not using these seaweeds [---] On the basis of these results we conclude that some seaweeds consumed in large amounts can supply adequate amounts of bioavailable vitamin B-12. This confirms that the B12 in the products makes it way to these vegans' blood stream. It is bioavailable. But how active is it? Although vegans usually are healthy, and animal products are associated with lots of problems we don't want, it's IMO a good idea to try to think like the skeptics do, inactive B12 is useless and specific studies document that the B12 found in certain products (eg. Spirulina) is inactive. Maybe this wasn't know when this was done? At least some Spirulina may affect the B12 levels in a negative direction. This spirulina isn't neutral - it'a probably plain bad for us, at least as a main source of B12 oe if taken with other B12 sources -which is why I wonder why Spirulina users were in the test.


In the longitudinal study, six of nine vegans showed slow, but consistent deterioration of vitamin B-12 status over a 2-y observation period.


Although the B12 deterioration referred to in one case was so low that it could be considered irrelevant (only 2.2% after two years), this is very interesting. If three of the nine vegans did not even show a low deterioration of vitamin B-12 status over a 2-y observation period, one should look at what was different in these vegans' diet or lifestyle. Did they avoid sugar, alcohol, coffee or consume other stuff know is bad for our B12 status? Did they user other brands? More fresh/non-dried products? Eat more organic food?
Remember that these studies usually are made by people who aren't really eager to find answers to such questions. They are usually not vegans, and Department of Clinical Nutrition and Physiology at that university isn't a vegan organization. Maybe they're only happy to have found that 6 of 9 vegans showed a slow B12 deterioration, had their non-vegan lunch and moved over to new study, forgetting that they just documented that 33% of the subjects did not even showed a slow deterioration of B12 levels - and not even after 2 years. If you would study, say, gravity, and drop 9 apples from the top of a your house, and 3 of them wouldn't fall down, you wouldn't conclude that absolute gravity always exists at that height. :-) In any study which strive for absolute conclusions 33% is a very high percentage.

The researchers in Kuopio, Finland have already told us that they aren't really familiar with veganism, when they post that "Strict vegans, called "living food eaters," consume all of their food uncooked, and most of the daily food
items are fermented or sprouted".


However, the average use of seaweeds and fermented foods by "living food eaters" will not supply enough vitamin B-12 to maintain the body vitamin B-12 status.
The study isn't that interesting, due to a mix of several types of seaweeds and a low number of subjects, including one who may have cheated a little before the test started. But the quote is interesting still, since they don't claim that use of seaweeds and fermented foods will not supply enough B12 - they talk about ' the average use' of seaweeds, in this particular group. They must put it that way, because they looked for B12 bioavailability, which they actually have documented in 3 out of 9 vegans. If only one of these vegans had eaten what the these three others had, maybe the results would have been 4/5, and not 3/6. Please don't get me wrong: I'm not saying that seaweed generally can be seen as a reliable B12 source in terms of bioavailability/sustainability - the folks at University of Kuopio wrote that, but only for some of these people.

Note that this part is also interesting: "Those who smoked, suffered from the active phase of any illness, or used regular medication, were excluded from the study." Does this suggest that people who used 'irregular' medication, or suffered from a passive phase of illness were included?

Also: "None of the study subjects had used any vitamin B-12 supplementation." This is also interesting, given that several of them had healthy B12 levels even after many (5, 9, and 14) years - and that and "as judged by the routine clinical blood chemistry, all participants were healthy." And, I don't suggest that people shouldn't take B12. :-)

There's a table in there. It covers each of the 9 rawfooders. If you look at it in this context, you need to mainly look at the first two columns, saying 1992 (1) and 1994 (1), because 1994 (2) is using a different test method.
Since scientists sometimes post the results they like the least at the bottom of their reports, I'll reverse that order. :-)

Subject 9, vegans for 9 years: Between 1992 and 1994, his levels increased from 217 to 393 using seaweeds. 81% increase.
Subject 8, vegan for 6 years: his levels increased from 173 to 190 in the same period. 9.8% increase.
Subject 7, vegan for 6 years: His levels increased from 84 to 85. An insignificant 1.2% increase.
Subject 6, vegan for 14 years, but started out with a very high B12 level: decreased from 825 to 640 over two years. Too much B12 isn't good, so he should be glad the levels dropped. 22% decrease.
Subject 5, vegan for 5 years: decrease from 360 to 328. 8.9 % decrease.
Subject 4, vegan for 14 years: decrease from 151 to 135. 11% decrease.
Subject 3, vegan for 5 years: decrease from 112 to 99. 12% decrease.
Subject 2, vegan for 6 years: decrease from 84 to 78. 7.1% decrease.
Subject 1, vegan for 10 years: the decrease was from 136 to 133 between 1992 and 1994. An insignificant 2.2% decrease.

As shown in the article... whether levels increased or decreased, the numbers suggest that circa half of these vegans had too low B12 levels (after 8.3 years as vegans without supplements). And - although a small amount of vegans actively suggest that we don't need more studies - they claim to know that there are no reliable vegan B12 sources out there, but I really hope we'll see a lot more studies like this. If this would have been a large study, we would have emphasized/extracted useful info from these numbers as well, for example:

• 5-7g Chlorella/day is listed as one of the B12 sources for the person who had the highest B12 increase.
• The person with the highest levels used Nori only - no Spirulina, Arame, AKS, Chlorella or Dulce.
• Those who included Spirulina, known to have a high amount of inactive B12 analogues both had a B12 decrease, even if they also used Nori.
• The person who only used Nori had very high B12 levels even after 14 years as a vegan without any supplementation prior to this test - also after the test was finished (in spite of a 22% reduction over two years).
• Starting out with a very high (out of the normal range) B12 levels (835 pmol) may cause the levels to drop faster (see below).
• Starting out with a very low (out of the normal range) B12 level may mean that the level remain stable (but very low) if one is taking what subject 7 did.
• The overall, average change seen in all the subjects was only a 2.8% reduction in B12 levels over two years.
• If we exclude the Spirulina users from the study, since Spirulina has a bad B12 reputation, the result would have been better: only a 1,7% average reduction over two years.
• We know that the body will, at least to a certain degree, get rid of B12 it can't/won't store. Not only will the results in such a study be affected by what the body is utilizing daily, but reflect that levels will change since generous amounts of B12 will end in the toilet. Subject 6, who took only Nori and had B12 levels which were so high that they were outside the normal range influences these results in a negative way (in terms of change). An unusual high level of reduction should probably be expected, since our bodies don't seem to want to contain so much B12. Who knows - maybe he was cheating and having an extra jar of seaweeds daily just before the test started. :-) It's probably good that the body is capable of getting rid of some of the very high B12 levels he had, but if we exclude him from the test, the overall average for all the participants would have been a 9.4% increase in B12 levels over this two year period.
• If we exclude both Mr. Turbo-Nori and the two Spirulinists who shouldn't have been there, the overall result over the two year period is a B12 increase of 14.5%.

And an average decrease over two years as low as 2.8% is rather insignificant in such a small study anyway.

There's a lot more that could be said about such studies - eg. that if high amounts of seaweeds would be needed, maybe most vegans wouldn't eat high amounts of eg. Nori, but take some sort of Nori extract. The samples have also been frozen before they were analyzed, and just like with plants which are analyzed after having been heated to well above 100C, freezing may have affected the results. And so on. But this is long already. :)

Remember that real B12 activity, and not only bio-availability is important.