What Everyone Needs To Know About B12
Vitamin B12 helps to keep your nerves and blood cells healthy. The consequence of not having enough B12 in your diet are extremely serious and should not be ignored. People who do not get enough B12 can suffer from weakness, heart palpitations, shortness of breath, pale skin, diarrhea, hair loss, and mental conditions.
In severe cases of deficiency, a lack of vitamin B12 can even cause death. Most vegans make sure they get enough B12 to survive, but can sometimes still be borderline deficient. In order to maintain optimal health, it is really important that you make sure you're getting enough. A simple test with your doctor will reveal if you are getting enough or not.
Humans get vitamin B12 from the food that we eat. Whether vegan, vegetarian or omnivore, it is extremely important that you monitor your vitamin B12 intake and take a supplement if you are not getting enough. It is estimated that approximately one third of the general population does not achieve the recommended daily dose of vitamin B12.
So What is Vitamin B12?
Vitamin B12 is a complex molecule; its common name, cobalamin reflects the presence of the mineral cobalt in the centre of its structure. As with the other B vitamins, B12 helps build the material that makes up our genetic blueprint; our DNA. It is also particularly important in the production of red blood cells and in maintaining a healthy nervous system. B12 also helps release energy from our food. A further important role of B12 is to act in conjunction with folic acid (another B vitamin) in the synthesis of the amino acid methionine; this limits the build up of a potentially damaging molecule known as homocysteine (more on this later). Humans only need around 3 mg of vitamin B12 a day, but the consequences of B12 deficiency can be deadly, so it's important that you make sure you are getting as much as you need. It is unlikely that a plant-based diet alone will supply you with an adequate amount of vitamin B12. You must make sure that you're eating and drinking products that have been fortified with the vitamin, or take special supplements to avoid deficiency.
How Much Vitamin B12 Do We Need?
In the UK, the reference nutrient intake value (RNI) is used; this is similar to the Recommended Daily Amount (RDA) used previously. The RNI value for a nutrient is the amount of that nutrient that is sufficient for 97.5 per cent of the people in a given group. The UK government currently suggests that the RNI value for vitamin B12 in adults aged between 19 and 50 years of age is one-and-a-half micrograms per day (1). The current European Union (EU) recommended daily allowance is even lower at only one microgram per day. These figures are based on preventing B12 deficiency and therefore may not represent the optimum intake. It has been suggested that three micrograms per day from fortified foods (or 10.0 micrograms per day from a supplement if you don’t eat fortified foods) should ensure an adequate intake of B12 and minimise the build up of homocysteine (2). Currently, there isn’t enough evidence to know what the effects of taking high doses of vitamin B12 supplements each day might be.
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 micromol/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 mcg /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.
How do I know if I'm B12 deficient?
If you’re deficient in B12, you might find you have the following symptoms.
- Hair loss
- Shortness of breath
- Heart palpitations
- Lack of appetite
- Weakness of muscles
- Issues with walking
- Vision loss
- Memory loss
- Behavioral changes
Vitamin B12 Deficiency
B12 deficiency can be divided into four stages. First of all, levels of B12 in the blood drop, then levels of B12 in the cells fall, then a biochemical deficiency occurs whereby levels of B12-related compounds are disrupted and finally clinical deficiency (or megaloblastic anaemia) occurs. This condition is characterised by abnormally enlarged immature red blood cells that are unable to divide properly. The abnormal cells are unable to transport oxygen efficiently thus chronic vitamin B12 deficiency can lead to a range of problems from fatigue, tingling and numbness of the limbs to damage to nerve cells, the spinal chord and the brain. In extreme cases paralysis or death may result from vitamin B12 deficiency.
What Causes B12 Deficiency?
B12 deficiency is relatively rare; the most common cause is malabsorption which results from some condition of the stomach or of the small intestine. This type of deficiency usually requires treatment with B12 injections. This type of deficiency has nothing to do with the amount of B12 present in the diet - it arises from inadequate absorption due to a wide range of physiological or medical conditions. Furthermore, B12 absorption tends to decrease with age. For example, in the elderly a decline in the production of acid in the stomach may reduce B12 absorption, although this mainly affects B12 absorption from meat. The most common cause of B12 deficiency in the UK is the loss of intrinsic factor; this may result from a genetic predisposition and tends to be age-related.
B12 deficiency can arise if any of the stages of metabolism are not completed. For example B12 malabsorption may occur if surgery has been performed on the digestive system (such as a gastrectomy or ileal resection) or in the case of gastrointestinal disorders such as Crohn's disease. In autoimmune diseases the body’s normal responses to molecules perceived as foreign invaders (such as bacteria and viruses) go wrong and the body attacks itself. A condition called pernicious anaemia may result from an autoimmune disease that targets the cells that produce intrinsic factor, this condition is characterised by large immature red blood cells. Pernicious anaemia is most common in older people. It affects about 1 in 8,000 people over the age of 60. It is more common in women than in men and in people with fairer colouring. Symptoms of anaemia include tiredness, shortness of breath and palpitations. In some more serious cases symptoms may include soreness of the tongue, weight loss, paling skin colour, diarrhoea and poor resistance to infections. In extreme cases there may be a tingling sensation in the fingers and toes, muscle weakness and confusion.
Additional causes include stomach infections with the bacterium Helicobacter pylori, the single-celled parasite Giardia lamblia or the parasitic worm Enterobius vermicularis. These parasites can interfere with normal B12 absorption by competing with the host organism (that could be you!) for the B12 present in the diet.
How is B12 Deficiency Diagnosed and Treated?
Vitamin B12 deficiency may be diagnosed by measuring the levels of serum B12 or by measuring the levels of homocysteine which can accumulate to high levels in the absence of B12. However, high homocysteine levels can also be caused by folate or vitamin B6 deficiencies. Conventionally vitamin B12 deficiency is treated with a course of intramuscular injections. A B12-like compound called hydroxocobalamin is injected into the muscle every two to four days. Around six injections are given to build up stores of vitamin B12 in the liver. Blood tests are given periodically to monitor the success of the treatment.
Where is B12 found?
Vitamin B12 is a water soluble vitamin that is found naturally in some foods and added as a supplement to others.
It’s produced by bacteria found in soil and in the guts of animals. Because non-vegans eat the flesh of animals who produce b12 within their guts, they tend to consume more B12 than vegetarians and vegans do, but eating meat doesn’t mean that you are not B12 deficient. Both vegan and non-vegan individuals suffer from B12 deficiency.
The National Health and Nutrition Examination Survey estimates that 3.2 percent of adults over 50 have a seriously low B12 level, and 20 percent are borderline B12 deficient. Vitamin B12 deficiency is not a vegan issue, it's a human issue.
Humans produce vitamin B12 in their guts, but the process happens too far through our system to be absorbed by our blood, and it is instead excreted from our bodies.
Wild animals with vegan diets tend not to be vitamin B12 deficient because they accidentally eat soil and excrement, something not many humans are willing to do.
Why don't vegans get B12?
Intensive farming has ruined soil quality, and our vegetables are over sanitised because we don't want to eat animal faeces or pesticides.
This means that the B12 we used to get naturally from plants is no longer available to us, and vegans must supplement their diets to make sure that they're getting enough.
How to get B12 on a vegan diet
If you are vegan, there are vegan sources of B12 you should be making a conscious effort to consume. You'll find vegan products that are fortified with B12 in most supermarkets. Great sources of vitamin B12 foods vegans can eat include:
- Vegan cereals
- Plant based milks
- Some soy products
- Some nutritional yeast
- B12 supplements
Always check the packaging to make sure that the products you are purchasing are fortified with vitamin B12, and choose the brands that are.