Vitamin B12 for Vegetarians from Natural Sources
Herbert E. Gratzl *
Vegetarians do not eat meat and fish, their natural vitamin B12 intake comes mainly from milk
and dairy products, where B12 is not very concentrated and which are not always consumed in
sufficient amount or even lacking, risky for health.
If the supply of B12 by milk and dairy products is not sufficient and less than recommended by the
WHO, sources from plants should be considered too:
10% of the daily B12 intake may be obtained from sea or freshwater algae. The quantities are
limited due to restrictions in a safe diet. Nori algae are very rich in iodine, chlorella algae stimulate
the immune system, they can be used with caution, clinical studies would be interesting.
As soon as nori algae with little iodine and chlorella with higher B12 content are becoming
available, they can supply a larger part of the recommended daily B12 .
A few hundred millions of the world population claim to be vegetarians, but there are more, forced
by malnutrition and undernourishment.
In vegetarian diets vitamin B12 may be scarce. It is contained in animal products like fish, meat,
eggs, milk and dairy products. The average diet in industrial countries contains more B12 than
necessary, the meat consumption is above the world average. A lactovegetarian diet might provide
sufficient B12 too, but it is not very concentrated in milk and dairy products, which should be
consumed in sufficient quantity. The storage of 2-5 mg B12 in the liver is depleted in few years
after starting a vegetarian diet with too little B12 .
The majority of vegetarians lives in India, but a larger part of the population does not have access to
enough dairy products. Occationally fish or meat does not help much for B12 or one or two meals
of fish or meat within a week, since not much more than 1,5 µg B12 can be digested per meal. Daily
or nearly daily two or three moderate portions containing B12 is more effective.
In India consumption of meat is very low anyway, beef is largely banned for religious reasons. Meat
consumption per capita is not rising much there, very different from China, Vietnam and other
Milk and dairy products as jogurt and cottage cheese are voluminous, rich in protein, calcium and
other ingredients, but less concentrated in B12 in comparison to meat and fish. Therefore
lactovegetarians tend to be short in B12 and have to consider sources carefully.
Cobalamin ( B12 ) is a bacterial product and supplied to animals from feed contaminated by
bacteria or from internal bacterial production as in one of the stomachs of cows. The sources for
human nutrition are external: organisms which are auxotrophic, i.e., which need B12 for the
metabolism of their cells.
Unfortunaltely plants don´t use B12, with some exceptions in rhizoms of certain plants, but
hardely transported to edible parts above earth.
B12 is nevertheless present in soil and at plants surfaces, home of many bacteria .
In addition to bacteria and to animal products, some algae are a third source: Sea algae used in East
Asia and at the atlantic coasts of Europe and furthermore chlorella microalgae produced in
Dairy products were used since neolithicum
Milk and dairy products were introduced northward in Europe by migration from Southeast
reducing the consumption of fish. At four thousand years B.C. the coasts of the Baltic sea were
reached ; cattle came to India two and a half thousand years later.
A single mutation ( LCT-13910*T ) brought the LP allele ( Lactase Perseverance ) to the european
population favoring the digestion of fresh milk by adults, whereas between East Afrika and India
other mutations did appear independently, but with the same effect. The singular european mutation
was very successful and spreading fast, only at the edges south of Europe and in the Northeast of
Finland people digest milk less well until now. The mutation was found to be present over
thousands of years during the neolithicum at a site in central Poland.  Today it is estimated that a
large minority of the human population can tolerate fresh milk.
Milk and dairy products became more important as sources of vitamin B12. The agricultural
revolution of the neolithicum produced more herbal products. Storing fodder for cows allowed to
have fresh milk nearly the year round.
In the middle of the first millennium B.C, vegetarian ideas sprouted in Greece and India and
influenced religions. In Europe the influence was weaker; in christian traditions pescetarianism
plays a role allowing some fish in addition to vegetarian food.
One third of the 18 million adventists are vegetarians. More than 90% of the Indians are Hindus and
35% of the indian population are vegetarians, about four hundred millions. Modern vegetarism
started in the 19
century, when ideas from India were taken up, and is florishing among educated
people in industrial countries, where the total number of vegetarians is still small compared to India.
Fish, meat, eggs, alcohol and tobacco are considered impure in Hinduism and to be avoided or
restricted. Western vegetarians often follow similar lines. Most hindus restrain from meat, at least
Tuesday and Friday; strict rules are followed by the brahman leaders.
In many places of the industrial countries a weekly Veggie Day was established in recent years.
The concern is about health and environment. Meat production is waste and emitts climate gases,
what can be reduced.
Digestion needs the bacteria present in human body, being some kilos. The composition of this
bacteria flora depends much on the type of food. It is changed slowly, if the composition of the
food is changed, or the type of protein.
Human health depends on many factors, one being nutrition. As well known, too much is as harmful
as too little; protein can often be obtained better from plants than from animal sources. Less healthy
is refined and processed food, where additions may be problematic..
Products containing B12 should be eaten moderately but regularly for good results, artificial
supplements are not needed hopefully.
Algae as possible sources of vitamin B12
A large part of sea algae species is auxotrophic, they have special tools ( as animals too ) to digest
B12 from bacterial origin.
In East Asia sea algae like nori containing B12  are used traditionally. During the drying process
a part of the vitamin B12 becomes transformed and ineffective.
The authors of Ref. 3 suggest, eating such sea algae as nori in larger quantity than traditionally in
East Asia might satisfy the need of vegetarians to get enough B12. However, the high iodine
content could exceed the safety limit. Therefore eating sea algae is limited and does not provide
enough B12 alone.
Ref. 3 quotes the concentration of ( 0.32 to ) 0.78 µg B12 per gram nori, which is sold often in
thin sheets of 0,3 g. Therefore 1,3 gram nori can supply a microgram B12. Since 1 gram contains
between 50 and 150 µg iodine, such dosis may be eaten during one week without danger to get too
much additional iodine.
Freshwater microalgae of chlorella species can contain 1 ( to 2 ) µg B12 in 1g dried mass. 
The author of Ref.4 mentions the value of M. Ecke , referring to the Chlorella production in
glass tubes of Roquette Klötze GmbH, Sachsen-Anhalt .
After hundred years of research now chlorella is known in many details, which might help to
produce more in coming years and hopefully use it for nutrition.
Presenty the food industry offers chlorella with 0,6 to 0.8 µg B 12 per gram from organic
Using the natural sources of B12 for vegetarians
The recommended intake of B12 is 2,4 µg per day according to the WHO, which is satisfied by 0,6
liter milk or dairy products made from it.
Such an average daily consumption of milk products is not far from the average consumption in
many industrial countries. In India, the classical vegetarian country, less is consumed or available ,
B12 deficiency being widespread.
Many western vegetarians don´t eat enough dairy products either. The risk of vegetarians for B12
deficiency is generally very high as compiled in review articles  , particularly for newborns and
their mothers and for elderly.
If less dairy products daily are consumed than obtainable from 0.6 l milk, vegetarians need
additional sources for B12.
To add cobalamin to milk and dairy products – fortifying the intrinsic 1,6 µg methylcobalamin of
0,4 l milk by additional 0,8 µg - could solve the problem in principle, the material costs being low.
However, since vegetarians cannot be obliged to consume an enriched dairy product on the basis of
jogurt daily, the organizational problems seem to be immense.
Additional natural sources can help , as the nori sea algae, which are obtained in East Asia from
conventional and relyable providers in good and certified quality , but are less popular in Europe
and the ingredients are not known precisely very often. 1,3 g nori weekly ( yielding 1 µg B12,
satisfying 6% of the rda, the recommendation of the WHO ) would not add too much iodine to the
A daily B12 gap of 0,15 µg B12 ( 6%) can be filled by about 0,19 g dried chlorella, what is 1 µg
B12 per week , contained in 1,3 g chlorella.
Producers give the safety limit, not to eat more than 2,5 or 3g chlorella daily , elsewhere there
are 1-2 g recommended. Anyway one has to accostum to such product and find a tolerable low
dosis. Moreover, chlorella stimulates the immune system, what is not indicated to do continuously.
A relatively high daily dosis of 1 g might be useful for a few days of infection, but not continuously.
In conclusion, there are little additional natural sources for lactovegetarians apart from milk and
dairy products, to be tried at own risk: 190 mg nori and/or 190 mg chlorella in the daily
average, both yielding 0,15 µg B12 , 6 % of a daily need of 2,4 µg .
Ovolactovegetarians can also eat two eggs per week, without danger of too much cholesterol,
what contributes 0,1 µg B12 in the daily average.
Two of these three choices bring 10 % or more to the daily intake, which has to come mainly from
milk and dairy products ( needing 0,54 l milk produced) .
Even less than for sea algae there are few data about the consumption and effects of freshwater
microalgae, e.g., if their B12 helps to nourrish people; cohort studies are lacking.
Individuals can use Chlorella at own risk – comparing blood values before and after
supplementing, best by the B12 urin test measuring MMA.
Hopefully microalgae will become a natural supplement to overcome B12 deficiency in some
countries. Sea algae of high iodine content can contribute little, nori algae of low content  should
Chlorella is produced industrially, its quality depends on the production conditions, at best it is
grown organically. Possibly the concentration of B12 can be rised depending on the fertilizer used;
cobalt is a limiting factor and essential for a high yield of B12
WHO recommendations for B12 are essential and can be satisfied with natural sources
In studies of migrant indian preadolescent girls was shown, that vegetarians do not always get as
much B12 as recommended risking consequences. Deficiencies may exist over generations. 
However, if the intake is at least 2,4 µg B12 per day, i.e. 17 µg per week, the risks are minimized. A
larger number of vegetarians worldwide should reach this level.
Vegetarianism is present strongly in India and other not very wealthy countries, whereas in Berlin
and New York some people may think, that it is a new style of some western people.
The following example shows, how the need could be satisfied with three meals per day:
At breakfast 200 g jogurt and 50 g cottage cheese 1,3 µg B12
lunch(vegan) with a bit algae ( 8% of daily B12 ) 0,2 µg
dinner 50 g jogurt and 70 g cottage cheese 0,9 g
Non-animal sources of B12 may contribute around 10% to the supply of B12 and thus help to
overcome deficiencies of B12 – best, if also the supply of milk and dairy products is kept high.
People may prefer either milk or dairy products products, nori or chlorella algae, depending on their
genetic disposition too. It would be interesting to explore in clinical studies, how people in Europe,
India, Japan and other countries profit from using milk products, nori or chlorella algae.
Artificial supplements of B12
Passive diffusion lets pass only 1 to 2 two percent of B12 supplements to the body, so that B12
quantities of up to thousands µg B12 can provide B12 for about a week or less.
Supplements as well as injections of B12 are not a natural way, but can be justified in emergency.
Furthermore, in the supplements for passive diffusion as well as in injections cyanocobalamin is
used, which is stable over years in contrast to B12 in nature and living organisms:
methylcobalamin, adenosylcobalamin or hydroxocobalamin. Irritations cannot be excluded in the
Irritations of the body are known from many artificial supplements.
Calcium supplements in moderate daily doses, but more concentrated than in vegetables of milk
showed effects of discontinuous deposition in human body. Therefore a more continuous supply
together with meals is safer in general and less demanding to the organs too.
If or what high doses of the usual B12 supplements could do harm in the long run, is not known. It
might be detected after years or decades as were the consequences of other products.
A natural supplement from algae seems to be more reliable, provided it is produced without harmful
A compromise affecting less the digestion organs is supplementing with an enriched toothpaste or
gel.  Passive diffusion works too, if instead of eating supplements they are only kept in mouth,
but not swallowed.
Such means may be considered by lactovegetarians, if a good B12 level cannot be reached with
natural sources. Vegans need artificially enriched products; using the toothpast or gel regularly
other supplements may not be necessary very often.
The Vegetarierbund Deutschland (VeBu ) shows the B12 problem  and gives literature
references, for nori and chlorella algae clinical studies would be lacking, what is still the case .
The present results on chlorella [4,5) are not taken into account.
Comparison with people eating a bit meat: Recommendations for one to two meals with fish or
meat weekly are not the most effective , although fournishing protein, which however is not scarce
for well nourished vegetarians, but green politicians ( see ref.11 ) favor the sunday steak, as
concession to people, but not very helpful to the malnourished ones.
The outlook that chlorella algae might help to fill a B12 gap in nutrition is presently not backed
much by the production lines working mainly for nonfood purposes and more for spirulina than for
chlorella Spirulina are cyanobacteria under the popular name blue-green algae, the production
devices being similar. 
Chlorella was a vain hope in the years afterWorld War II to overcome food and protein shortage as
is quoted in the english ( but not in the german ) Wikipedia article: Chlorella .
The present world production of chlorella of thousand of tons could supply B12 for millions of
people, if it would be used for nutrition.
To become a source of B12 comparable to the traditional ones, the production capacity had to be
increased considerably and the price lowered.
Declaring spirulina a source of B12 ( still to be found in ref.10 ) should be omitted, since clinical
studies showed no effect; this was even certified by court ( OLG Hamm 2010 ) . 
For chlorella clinical studies would be necessary, before it can be recommended as source for B12.
Likewise nori should be studied in comparison.
Chlorella might become an effective source of B12 and it should be used in a safe way avoiding
too much immune stimulation. Unless such questions are settled, it cannot be recommended
1 A.Curry Nature 500,20-22 ( 01 August 2013 ) doi:10.1039/50020a
K.J.Gron, J.Montgomery, P. R.-C. Plos One doi:10.1371/journal,pone 0131267 July 6,2015
2 H.W. Witas et al. Plos One doi:10.1371/journal.pone 0122384 April 8, 2015
3 F. Watanabe et al. Nutrients 2014 6(5) 1861-1873
4 J. Ullman Paracelsus Magazin 83-heft-032015/1359
5 M. Ecke www (PDF) Dr.Ecke-danziger138.de
6 R. Pawlak et al. Nutr. Rev. 2013 Feb , 71(2) 110-7
R. Pawlak et al. Eur. J. Clin. Nutr. 2014 May 68(5) 541-8
7 IQ Pharma GmbH, Bad Reichenhall www.vitatrend.com
8 E.C. Rush et al. Eur. J. Clin.Nutr. 2009 63, 585-7
refering to: M. Keller, C. Leitzmann Vegetarische Ernährung, 2.Aufl. 2010 Ulmer, Stuttgart
( uni-gießen download open access )
11 Barbara Unmüßig Heinrich-Böll-Stiftung in: Fleischatlas 2014
„ Zurück zum Sonntagsbraten“
12 ( Heck) Algen-Parks AG, Berlin Marktanalyse Mikroalgenproduktion Nov. 2013
13 Wikipedia ( Deutsch ) Spirulina