by Dr. Stephen Walsh
I have been informed that some people who have read the recently produced B12 information sheet have proposed that Klamath lake algae is a reliable B12 source and suggested that the sheet is therefore incorrect.
I see no need for any correction, but rather for a reemphasis of the general arguments in the B12 information sheet in relation to this specific case.
This posting may be reposted freely.
Klamath lake blue-green algae (aphanizomenon flos-aquae) is used by quite a number of vegans, particularly raw food vegans, as a purported source of B12. As this algae is marketed as a living food some people find it more acceptable as a potential source of B12 than using fortified foods or supplements.
The comments below from CellTech (forwarded to me by Brenda Davis several months ago) are representative of the evidence for this belief.
"The Super Blue Green Algae (SBGA) strain, Aphanizomenon flos-aquae, has been tested by Lancaster Labs for B12 analog levels using microbiological testing methods that are comparable to methods 952.20 and 960.46 of the Association of Analytical Chemists (AOAC).
Vitamin B12, which is in the corrinoid family, contains four main analogs(cyanocobalamin, hydroxycobalamin, aquacobalamin and methylcobalamin) that show significant bioactivity. The testing results on Aphanizomenon flos-aquae, while not discerning exactly which corrinoids are present, indicate significant B12 activity.
Unlike other plant foods such as Spirulina, which contain corrinoids with virtually no vitamin B12 activity, Aphanizomenon flos-aquae is a reliable source for vegetarians seeking to supplement their diets with a bioactive form of this important nutrient."
This does not inspire me with confidence. "Significant B12 activity" is so vague as to be meaningless. The fact that a method is defined by the AOAC doesn't mean it is good at detecting analogs. Indeed, "microbiological testing" sounds very much like the old method that has been shown to be poor at distinguishing analogues from true B12.
Dagnelie, J. of Nutrition, 1997, 127: 379 notes, "The classic Lactobacillus leichmannii assay includes not only true vitamin B-12 but also noncobalamin vitamin B-12 analogues that are unavailable to humans and may even block vitamin B-12 metabolism."
Herbert, Am J Clin Nutr, 1994,59:1213S-22S notes that many microbiological assays may read noncobalamin corrinoids as true B12 and recommends the use of competitive inhibition radioassays.
I attach abstracts from two recent papers on the evaluation of B12 in algae.
Both abstracts highlight major deficiencies of microbiological assay methods. The first paper confirms dried nori to be an inadequate source of B12. The second confirms spirulina to be an inadequate source of B12.
Yamada K, Yamada Y, Fukuda M, Yamada S
INTERNATIONAL JOURNAL FOR VITAMIN AND NUTRITION RESEARCH
69 (6): 412-418 NOV 1999
Abstract:
We have already reported that raw nori (Porphyra tenera) contains cobalamin (Cbl) but not Cbl analogues (J. Nutr, Sci. Vitaminol., 42, 497, 1986). It seems, therefore, that it is an excellent natural vegetable source of Cbl. On the other hand, it has been reported that the Cbl nutritional status of vegetarian c hildren deteriorated as estimated by the hematological index, mean corpuscular volume (MCV), after they had dried nori as a source of Cbl. Such a discrepancy between raw and dried nori as a source of Cbl led us to investigate whether Cbl in dried nori had different properties from that in raw nori. We found that contents of Cbl homologues determined by a bioassay method in both raw and dried nori were similar. The urinary methylmalonic acid excretion increased when human female Volunteers were given 40 g of dried nori daily during the test period. On the other hand, the urinary methylmalonic acid excretion did not change when volunteers were daily given 320 g of raw nori, which was equivalent to 40 g of the dried one on the basis of dehydrated weight, during the test period. By paperchromatography: 65 % of the Cbl homologues were found to be comprised of Cbl analogues in dried nori, while 73% of the Cbl homologues in the raw nori were genuine Cbl. These results were confirmed by the finding that the bioassay method gave higher values for Cbl homologues than those obtained by a competitive binding assay method using an intrinsic factor as a Cbl-binding protein.
Our present data demonstrated that Cbl in raw nori can be changed into harmful Cbl analogues by the drying process.
Watanabe F, Katsura H, Takenaka S, Fujita T, Abe K, Tamura Y, Nakatsuka T, Nakano Y
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
47 (11): 4736-4741 NOV 1999
Abstract:
The vitamin B-12 concentration of an algal health food, spirulina (Spirulina sp.) tablets, was determined by both Lactobacillus leichmannii ATCC 7830 microbiological and intrinsic factor chemiluminescence methods. The values determined with the microbiological method were similar to 6-9-fold greater in the spirulina tablets than the values determined with the chemilumine scence method. Although most of the vitamin B-12 determined with the microbiological method was derived from various vitamin B-12 substitutive compounds and/or inactive vitamin B-12 analogues, the spirulina contained a small amount of vitamin B-12 active in the binding of the intrinsic factor. Two intrinsic factor active vitamin B-12 analogues (major and minor) were purified from the spirulina tablets and partially characterized. The major (83%) and minor (17%) analogues were identified as pseudovitamin B-12 and vitamin B-12, respectively, as judged from data of TLC, reversed-phase HPLC, H-1 NMR spectroscopy, ultraviolet-visible spectroscopy, and biological activity using L. leichmannii as a test organism and the binding of vitamin B-12 to the intrinsic factor.
The level of chemical testing required to reliably separate analogues from true B12 goes far beyond a simple microbiological assay.
As emphasised in the recent B12 information sheet, spirulina and dried nori have both been directly shown from human testing to be inadequate sources of B12.
Klamath lake algae has not yet been shown so definitively to be inadequate, but neither has evidence been presented that either (a) it has a sufficient amount of true B12 and a sufficient ratio of true B12 to analogues to make it a potentially useful source of B12 or (b) it can prevent or correct deficiency (as measured by a reliable method such as MMA testing). Given the abysmal track record of algal B12 sources and the lack of positive evidence to say Klamath lake algae is different, the presumption should be that it is not an adequate source and anyone relying on it should recognise that they are carrying out a dangerous experiment and take heed of the warnings in the B12 information sheet.
I have sadly needed to advise one young vegan woman, who had been relying on Klamath lake algae as a B12 source, that she was showing clear symptoms of B12 deficiency. Tingling and later blurred vision and lack of energy developed gradually ove r about a year, during which time the Klamath lake algae was being consumed. Deficiency was confirmed by a blood test indicating B12 levels of about 100pg/ml. Fortunately she seemed to be gradually recovering after B12 injections and permanent damage is unlikely.
This individual case supports the view that this algae, like spirulina and dried nori, is not an adequate source of B12. The burden of proof should be on suppliers and promoters of this algae to show that reliable tests indicate its effectiveness in preventing and correcting B12 deficiency.
Old-fashioned microbiological assay data is completely inadequate for this purpose.
It is not impossible that some algae will eventually prove to be reliable sources of vitamin B12. The paper below is encouraging in that respect.
Miyamoto E, Watanabe F, Ebara S, Takenaka S, Takenaka H, Yamaguchi Y, Tanaka N, Inui H, Nakano Y
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
49 (7): 3486-3489 JUL 2001
Abstract:
A unicellular coccolithophorid alga, Pleurochrysis carterae, contained 125.4 ± 1.2 mug of vitamin B-12 per 100 g dry cell weight of the lyophilized algal cells. A vitamin B-12 compound was purified from the lyophilized algal cells and partially characterized. The silica gel 60 TLC and reversed-phase HPLC patterns of the purified pink-colored compound were identical to those of authentic vitamin B-12, but not those of vitamin B-12 analogues inactive for humans. When 22-week-old B-12-deficient rats which excreted substantial amounts of methylmalonic acid (75.5 ± 12.3 mg/day) in urine were fed the P. carterae (10 g per kg diet)-supplemented diet for 12 d, urinary methylmalonic acid excretion (as an index of vitamin B-12 deficiency) of the rats became undetectable and hepatic vitamin B-12 level of the rats was significantly incre ased.
Even this level of evidence, which is vastly more than has been presented for Klamath Lake algae, is not enough. The only acceptable test for a B12 source to be considered adequate is consistent prevention and correction of B12 deficiency in humans without impaired absorption.
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