1. eat fortified foods two or three times a day to get at least three micrograms
(mcg or mg) of B12 a day or
2. take one B12 supplement daily providing at least 10 micrograms or
3. take a weekly B12 supplement providing at least 2000 micrograms.
If relying on fortified foods check the labels carefully to make sure you are
getting enough B12. For example, if a fortified plant milk contains 1 microgram
of B12 per serving then consuming three servings a day will provide adequate
vitamin B12. Others may find the use of B12 supplements more convenient and
economical.
The less frequently you obtain B12 the more B12 you need to take, as B12 is
best absorbed in small amounts. The recommendations above take full account
of this. There is no harm in exceeding the recommended amounts or combining
more than one option.
Good information supports vegan health, pass it around.
If you don't read another word about B12 you already know all you need to know.
If you want to know more, read on.
This information sheet was prepared by Stephen Walsh (Stephen_walsh@vegans.fsnet.co.uk),
a UK Vegan Society trustee, and other members of the International Vegetarian
Union science group (IVU-SCI), in October 2001. This information may be freely
reproduced but only in its entirety (list of endorsers may be omitted).
What every vegan should know about vitamin B12
Very low B12 intakes can cause anaemia and nervous system damage.
The only reliable vegan sources of B12 are foods fortified with B12 (including
some plant milks, some soy products and some breakfast cereals) and B12 supplements.
Vitamin B12, whether in supplements, fortified foods, or animal products, comes
from micro-organisms.
Most vegans consume enough B12 to avoid anaemia and nervous system damage, but
many do not get enough to minimise potential risk of heart disease or pregnancy
complications.
To get the full benefit of a vegan diet, vegans should do one of the following:
1. eat fortified foods two or three times a day to get at least three micrograms
(mcg or mg) of B12 a day or
2. take one B12 supplement daily providing at least 10 micrograms or
3. take a weekly B12 supplement providing at least 2000 micrograms.
If relying on fortified foods check the labels carefully to make sure you are
getting enough B12. For example, if a fortified plant milk contains 1 microgram
of B12 per serving then consuming three servings a day will provide adequate
vitamin B12. Others may find the use of B12 supplements more convenient and
economical.
The less frequently you obtain B12 the more B12 you need to take, as B12 is
best absorbed in small amounts. The recommendations above take full account
of this. There is no harm in exceeding the recommended amounts or combining
more than one option.
Good information supports vegan health, pass it around.
If you don't read another word about B12 you already know all you need to know.
If you want to know more, read on.
This information sheet was prepared by Stephen Walsh (Stephen_walsh@vegans.fsnet.co.uk),
a UK Vegan Society trustee, and other members of the International Vegetarian
Union science group (IVU-SCI), in October 2001. This information may be freely
reproduced but only in its entirety (list of endorsers may be omitted).
Endorsers
"Note for participants in the King's College study"
1. eat fortified foods two or three times a day to get at least three micrograms
(mcg or mg) of B12 a day or
2. take one B12 supplement daily providing at least 10 micrograms or
3. take a weekly B12 supplement providing at least 2000 micrograms.
If relying on fortified foods check the labels carefully to make sure you are
getting enough B12. For example, if a fortified plant milk contains 1 microgram
of B12 per serving then consuming three servings a day will provide adequate
vitamin B12. Others may find the use of B12 supplements more convenient and
economical.
The less frequently you obtain B12 the more B12 you need to take, as B12 is
best absorbed in small amounts. The recommendations above take full account
of this. There is no harm in exceeding the recommended amounts or combining
more than one option.
Good information supports vegan health, pass it around.
If you don't read another word about B12 you already know all you need to know.
If you want to know more, read on.
This information sheet was prepared by Stephen Walsh (Stephen_walsh@vegans.fsnet.co.uk),
a UK Vegan Society trustee, and other members of the International Vegetarian
Union science group (IVU-SCI), in October 2001. This information may be freely
reproduced but only in its entirety (list of endorsers may be omitted).
Vitamin B12 and vegan diets
Lessons from history
B12 is an exceptional vitamin. It is required in smaller amounts than any other
known vitamin. Ten micrograms of B12 spread over a day appears to supply as
much as the body can use. In the absence of any apparent dietary supply, deficiency
symptoms usually take five years or more to develop in adults, though some people
experience problems within a year. A very small number of individuals with no
obvious reliable source appear to avoid clinical deficiency symptoms for twenty
years or more. B12 is the only vitamin that is not recognised as being reliably
supplied from a varied wholefood, plant-based diet with plenty of fruit and
vegetables, together with exposure to sun. Many herbivorous mammals, including
cattle and sheep, absorb B12 produced by bacteria in their own digestive system.
B12 is found to some extent in soil and plants. These observations have led
some vegans to suggest that B12 was an issue requiring no special attention,
or even an elaborate hoax. Others have proposed specific foods, including spirulina,
nori, tempeh, and barley grass, as suitable non-animal sources of B12. Such
claims have not stood the test of time.
In over 60 years of vegan experimentation only B12 fortified foods and B12 supplements
have proven themselves as reliable sources of B12, capable of supporting optimal
health. It is very important that all vegans ensure they have an adequate intake
of B12, from fortified foods or supplements. This will benefit our health and
help to attract others to veganism through our example.
Getting an adequate amount of B12
National recommendations for B12 intakes vary significantly from country to
country. The US recommended intake is 2.4 mcgs a day for ordinary adults rising
to 2.8 mcgs for nursing mothers. The German recommendation is 3 mcgs a day.
Recommended intakes are usually based on 50% absorption, as this is typical
for small amounts from foods. To meet the US and German recommendations you
need to obtain sufficient B12 to absorb 1.5 mcgs per day on average. This amount
should be sufficient to avoid even the initial signs of inadequate B12 intake,
such as slightly elevated homocysteine and MMA levels, in most people. Even
slightly elevated homocysteine is associated with increased risk of many health
problems including heart disease in adults, preeclampsia during pregnancy and
neural tube defects in babies.
Achieving an adequate B12 intake is easy and there are several methods to suit
individual preferences. Absorption of B12 varies from about 50%, if about 1
mcg or less is consumed, to about 0.5% for doses of 1000 mcgs (1 mg) or above.
So the less frequently you consume B12, the higher the total amount needs to
be to give the desired absorbed amount.
Frequent use of foods fortified with B12 so that about one microgram of B12
is consumed three times a day with a few hours in between will provide an adequate
amount. Availability of fortified foods varies from country to country and amounts
of B12 vary from brand to brand, so ensuring an adequate B12 supply from fortified
foods requires some label reading and thought to work out an adequate pattern
to suit individual tastes and local products.
Taking a B12 supplement containing ten mcgs or more daily provides a similar
absorbed amount to consuming one mcg on three occasions through the day. This
may be the most economical method as a single high potency tablet can be consumed
bit by bit. 2000 mcgs of B12 consumed once a week would also provide an adequate
intake. Any B12 supplement tablet should be chewed or allowed to dissolve in
the mouth to enhance absorption. Tablets should be kept in an opaque container.
As with any supplement it is prudent not to take more than is required for maximum
benefit, so intakes above 5000 mcg per week should be avoided despite lack of
evidence for toxicity from higher amounts.
All three options above should meet the needs of the vast majority of people
with normal B12 metabolism. Individuals with impaired B12 absorption may find
that the third method, 2000mcg once a week, works best as it does not rely on
normal intrinsic factor in the gut. There are other, very rare, metabolic defects
that require completely different approaches to meeting B12 requirements. If
you have any reason to suspect a serious health problem seek medical advice
promptly.
Symptoms of B12 deficiency
Clinical deficiency can cause anaemia or nervous system damage. Most vegans
consume enough B12 to avoid clinical deficiency. Two subgroups of vegans are
at particular risk of B12 deficiency: long-term vegans who avoid common fortified
foods (such as raw food vegans or macrobiotic vegans) and breastfed infants
of vegan mothers whose own intake of B12 is low.
In adults typical deficiency symptoms include loss of energy, tingling, numbness,
reduced sensitivity to pain or pressure, blurred vision, abnormal gait, sore
tongue, poor memory, confusion, hallucinations and personality changes. Often
these symptoms develop gradually over several months to a year before being
recognised as being due to B12 deficiency and they are usually reversible on
administration of B12. There is however no entirely consistent and reliable
set of symptoms and there are cases of permanent damage in adults from B12 deficiency.
If you suspect a problem then get a skilled diagnosis from a medical practitioner
as each of these symptoms can also be caused by problems other than B12 deficiency.
Infants typically show more rapid onset of symptoms than adults. B12 deficiency
may lead to loss of energy and appetite and failure to thrive. If not promptly
corrected this can progress to coma or death. Again there is no entirely consistent
pattern of symptoms. Infants are more vulnerable to permanent damage than adults.
Some make a full recovery, but others show retarded development.
The risk to these groups alone is reason enough to call on all vegans to give
a consistent message as to the importance of B12 and to set a positive example.
Every case of B12 deficiency in a vegan infant or an ill informed adult is a
tragedy and brings veganism into disrepute.
The homocysteine connection
This is not however the end of the story. Most vegans show adequate B12 levels
to make clinical deficiency unlikely but nonetheless show restricted activity
of B12 related enzymes, leading to elevated homocysteine levels. Strong evidence
has been gathered over the past decade that even slightly elevated homocysteine
levels increase risk of heart disease and stroke and pregnancy complications.
Homocysteine levels are also affected by other nutrients, most notably folate.
General recommendations for increased intakes of folate are aimed at reducing
levels of homocysteine and avoiding these risks. Vegan intakes of folate are
generally good, particularly if plenty of green vegetables are eaten. However,
repeated observations of elevated homocysteine in vegans, and to a lesser extent
in other vegetarians, show conclusively that B12 intake needs to be adequate
as well to avoid unnecessary risk.
Testing B12 status
A blood B12 level measurement is a very unreliable test for vegans, particularly
for vegans using any form of algae. Algae and some other plant foods contain
B12-analogues (false B12) that can imitate true B12 in blood tests while actually
interfering with B12 metabolism. Blood counts are also unreliable as high folate
intakes suppress the anaemia symptoms of B12 deficiency that can be detected
by blood counts. Blood homocysteine testing is more reliable, with levels less
than 10 mmol/litre being desirable. The most specific test for B12 status is
methylmalonic acid (MMA) testing. If this is in the normal range in blood (<370
nmol/L) or urine (less than 4 mg /mg creatinine) then your body has enough B12.
Many doctors still rely on blood B12 levels and blood counts. These are not
adequate, especially in vegans.
Is there a vegan alternative to B12-fortified foods and supplements?
If for any reason you choose not to use fortified foods or supplements you should
recognise that you are carrying out a dangerous experiment - one that many have
tried before with consistently low levels of success. If you are an adult who
is neither breast-feeding an infant, pregnant nor seeking to become pregnant,
and wish to test a potential B12 source that has not already been shown to be
inadequate, then this can be a reasonable course of action with appropriate
precautions. For your own protection, you should arrange to have your B12 status
checked annually. If homocysteine or MMA is even modestly elevated then you
are endangering your health if you persist.
If you are breast feeding an infant, pregnant or seeking to become pregnant
or are an adult contemplating carrying out such an experiment on a child, then
don't take the risk. It is simply unjustifiable.
Claimed sources of B12 that have been shown through direct studies of vegans
to be inadequate include human gut bacteria, spirulina, dried nori, barley grass
and most other seaweeds. Several studies of raw food vegans have shown that
raw food offers no special protection.
Reports that B12 has been measured in a food are not enough to qualify that
food as a reliable B12 source. It is difficult to distinguish true B12 from
analogues that can disrupt B12 metabolism. Even if true B12 is present in a
food, it may be rendered ineffective if analogues are present in comparable
amounts to the true B12. There is only one reliable test for a B12 source -
does it consistently prevent and correct deficiency? Anyone proposing a particular
food as a B12 source should be challenged to present such evidence.
A natural, healthy and compassionate diet
To be truly healthful, a diet must be best not just for individuals in isolation
but must allow all six billion people to thrive and achieve a sustainable coexistence
with the many other species that form the "living earth". From this
standpoint the natural adaptation for most (possibly all) humans in the modern
world is a vegan diet. There is nothing natural about the abomination of modern
factory farming and its attempt to reduce living, feeling beings to machines.
In choosing to use fortified foods or B12 supplements, vegans are taking their
B12 from the same source as every other animal on the planet - micro-organisms
- without causing suffering to any sentient being or causing environmental damage.
Vegans using adequate amounts of fortified foods or B12 supplements are much
less likely to suffer from B12 deficiency than the typical meat eater. The Institute
of Medicine, in setting the US recommended intakes for B12 makes this very clear.
"Because 10 to 30 percent of older people may be unable to absorb naturally
occurring vitamin B12, it is advisable for those older than 50 years to meet
their RDA mainly by consuming foods fortified with vitamin B12 or a vitamin
B12-containing supplement." Vegans should take this advice about 50 years
younger, to the benefit of both themselves and the animals. B12 need never be
a problem for well-informed vegans.
Good information supports vegan health, pass it around.