Especially at risk of B12 deficiency are those on a long-term vegan diet such as raw food or macrobiotic vegans who eat little or no vitamin B12-fortified foods and infants of vegan mothers who breast feed and have low B12 reserves. Also, vitamin B12 deficiency is relatively common in the elderly and is associated with dementia and neurological problems. The neurological problems stemming from B12 deficiency can often be remedied with vitamin B12 therapy. However, nerve damage may take weeks or months and possibly even be irreversible. 

Symptoms may develop gradually over months to a year or longer. Because B12 is efficiently reabsorbed after excretion in the bile, which varies from 1 to 10 mcg (micrograms) a day, depletion can take over 20 years in people on low B12 diets. However, if B12 deficiency is caused by absorption problems, deficiency problems may result in as little as three years. If treated soon enough, the condition is usually reversible with B12 supplementation. Otherwise, permanent damage may result. The patterns of development vary per individual. Other conditions can also cause the symptoms listed below, so diagnosis from a health care provider is recommended.

Adult Symptoms of Deficiency

•   Abnormal gait	•   Loss of appetite
•   Blurred vision	•   Loss of one’s sense of position
•   Breathlessness	•   Memory loss
•   Confusion	•   Moodiness
•   Constipation	•   Neurological problems
•   Damage to the myelin sheath	•   Numbness/tingling in hands & legs
•   Dementia	•   Pallor
•   Depression	•   Pernicious or megaloblastic anemia
•   Disorientation	•   Personality changes
•   Excessive fatigue	•   Poor resistance to infection
•   Hallucinations	•   Psychiatric disturbances
•   Imbalance, difficulty walking	•   Reduced sensitivity to pain/pressure
•   Irregular menstrual cycles	•   Sore tongue
•   Irritability	•   Weakness

Vitamin B12 Therapy Is Used to Treat

•   Bursitis	•   Hepatitis	•   Pernicious anemia
•   Cancer prevention	•   Insomnia	•   Post-surgery
•   Debilitated states	•   Mental disorders	•   Shingles
•   Depression	•   Multiple sclerosis	•   Smokers
•   Fatigue	•   Neuritis	•   Stress

The Following Substances Contribute to the Depletion of B12

•   Alcohol	•   Anti-gout medication	•   Diuretics
•   Ant-acids	•   Aspirin	•   Estrogen
•   Antibiotics	•   Caffeine	•   Laxatives
•   Anticoagulant drugs	•   Contraceptives	•   Sleeping pills
	•   Cooking temperatures - high & prolonged

Those at Risk

•	Alcoholics or those who drink excessively and whose diets tend to lack B12
•	Infants born to vegan mothers who breastfeed and have low B12
•	Older adults
•	People with gastrointestinal (GI) disorders such as celiac disease or Crohn's disease
	or who have had GI surgery
•	People with pernicious anemia
•	Strict vegetarians

Sources of Vitamin B12
All natural sources of vitamin B12 come from micro-organisms. Non-vegetarian sources include dairy products, eggs (especially the yolk), fish, shellfish (especially clams and oysters), liver, meat, and organ meats. Reliable sources of B12 for a vegan are B12 supplements or foods fortified with B12 such as plant milks, some soy products, and some breakfast cereals. Even though most vegans consume sufficient amounts of B12 to avoid anemia and nerve damage, many may have a deficiency severe enough to put them at risk of heart disease or pregnancy complications.
The active form of vitamin B12, cyanocobalamin or hydroxocobalamin, should be taken by vegetarians. Fermented foods contain little active B12 or cobalamin, even if they are touted as good sources. Instead, many of these foods may contain analogs of B12 that are inactive and could even block the absorption of B12.

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Testing B12 Status
A measurement of blood B12 levels is unreliable for vegans, especially if algae are used as a source of B12. Blood counts are also unreliable because high folate intakes suppress the symptoms of anemia caused by B12 deficiency. Testing blood homocysteine and methylmalonic acid (MMA) levels are more reliable. Homocysteine levels under 10 mmol/litre are desirable and MMA levels less than 370 nmol/L in the blood with less than 4 μmol/mmol of creatinine in urine are normal. Even though blood B12 levels and blood counts for testing B12 deficiency are inadequate, particularly for vegans, there are doctors who still use them.

Recommendations
Recommendations for B12 intakes vary greatly from one country to another. Generally recommendations are based on 50% absorption, typical of absorption from small amounts of food. Absorption varies from about 50%, if about 1mcg or less is consumed, to about 0.5% for 1000 mcgs (1 mg) or more. If B12 is not taken often, a greater amount is needed since B12 is absorbed best in small quantities. RDA recommendations are in the table below. Health care professionals have varying opinions of vegan B12 guidelines. Listed below are some of those professional opinions and general guidelines.

•	Eat B12-fortified foods to get about 1 mcg of B12 3 times/day within several hours of each
	other.
•	Availability and amounts of B12 in fortified foods varies from one country and brand to
	another. Therefore, reading labels is important if attempting to receive all B12 from
	fortified foods.
•	B12 tablets should be chewed or dissolved in the mouth or under the tongue (sublingual)
	for best and fastest absorption.
•	Tablets should be kept in a dark container out of the light.
•	B12 supplements for the total vegetarian should contain an active form of
	cyanocobalamin or hydroxocobalamin.
•	Even though there is no evidence of toxicity, few studies are available. Therefore,
	prudence is advised when taking larger amounts of vitamin  B12 than the RDA.
•	A multivitamin may have insufficient amounts of B12. Talk with a health care provider
	about supplementation.
•	If you suspect a serious health problem concerning B12, seek medical advice promptly.
•	To prevent the risk of psychiatric problems and permanent neurological damage, a total
	vegetarian should have serum B12 levels checked periodically and if pregnant checked
	more routinely. Anyone with serum B12 levels below 300 pg/ml should be tested for.
	urinary methylmalonate levels or
•	If attempting veganism with fortified foods only without supplements, have B12 levels
	checked yearly. If homocysteine or MMA is even slightly high, supplementation is
	advised as it is often difficult to meet B12 needs with fortified foods only.
•	Nutrition labels on fortified foods are based on 6 µg/day. For example, if a food contains
	8% of the Daily Value = .08 x 6 µg = 0.48 µg that the food is supplying.
•	The Institute of Medicine recommends infants of vegan mothers be supplemented with
	B12 from birth due to potentially low levels received from their mother and potentially low
	mother's milk supply.
•	Anyone with digestive or malabsorption diseases (such as pernicious anemia), B12
	metabolism defects, kidney failure or cyanide metabolism defects should consult a
	health professional concerning B12 supplementation.
•	Cigarette smokers are advised to use a non-cyanocobalamin source of B12.

B12 Guidelines for Deficient or Long-term Vegans without a Source of B12

•	Talk with a health care provider about supplementation.
•	Sublingual B12 such as Twin Lab Vegetarian B12 Dots 500 mcg taking 2000 mcg
	once a day for 2 weeks (4 tablets), then cut back to the daily label recommendations.
	For best results, each Dot is to be held under the tongue until completely dissovled to
	maximize absorption of the B12.

92% of vegetarians are said to be vitamin B12 deficient! It is advisable not to depend only on fortified foods for vitamin B12. People regularly fail to get sufficient amounts. If attempting veganism without fortified foods or supplementation, have B12 levels checked annually. If homocysteine or methylmalonic acid (MMA) levels are even slightly high, health risks are impending. MMA becomes elevated when B12 is deficient during the metabolism of certain amino acids because B12 is needed in the chemical reactions. If breast feeding, pregnant or planning pregnancy, supplementation is critical. The dangers of low B12 is one of the main reasons children are advised to not be vegans. The benefits of a raw food diet do not protect against B12 deficiency.

Be Healthy
To be as healthy as possible, vegans need to use fortified foods and/or B12 supplements. To ensure sufficient amounts, supplementation is safer than fortified foods alone. By using these options, vegans will be getting their B12 from the same source as every other animal and that is from micro-organisms that produce the vitamin.

Vegans consuming sufficient amounts of fortified foods or B12 supplements are much less likely to have a B12 deficiency than a meat eater. The Institute of Medicine explains that since 10-30% of the elderly may not be absorbing vitamin B12, those over 50 should consume fortified foods or B12 supplements. It is unnecessary for vegans to be B12 deficient, only informed. To learn more about nutrients of concern to a vegetarian, click Vegetarian Diet Planning.

Disclaimer
Forethought and caution have been taken in preparing this information and everything is believed to be accurate. However, this information is not intended to be an absolute authority according to Food and Drug Administration rules and regulations.

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