From the Guidelines
Vegetarians need their B12 levels checked regularly due to the high risk of deficiency, which can lead to severe health complications, including neurological damage, anemia, and cognitive impairment, if left untreated. The main risks associated with vitamin B12 deficiency in vegetarians include:
- Neurological damage
- Anemia
- Fatigue
- Weakness
- Cognitive impairment As noted in the study by 1, a substantial number of vegetarians and vegans are in the deficient or borderline-deficient range for B12, despite the well-publicized need for B12 supplementation. To prevent or treat B12 deficiency, vegetarians should consider taking oral B12 supplements containing 25-100 mcg daily or 2000 mcg weekly, as well as consuming B12-fortified foods like nutritional yeast, plant milks, and breakfast cereals, as suggested by 1. Regular blood testing is advisable to monitor B12 levels, particularly for long-term vegetarians, to ensure early detection and treatment of any potential deficiencies. According to 1, B12 deficiency is particularly dangerous during pregnancy, childhood, and adolescence, making regular check-ups crucial for these populations. In cases of severe deficiency, healthcare providers may recommend initial B12 injections, typically 1000 mcg hydroxocobalamin or cyanocobalamin, given daily or weekly until levels normalize, followed by maintenance oral supplementation. It is essential for vegetarians to be aware of the potential risks associated with vitamin B12 deficiency and take proactive steps to maintain adequate levels, as the body's limited storage capacity means consistent supplementation is necessary, as highlighted by 1.
From the FDA Drug Label
A vegetarian diet which contains no animal products (including milk products or eggs) does not supply any vitamin B12. Patients following such a diet, should be advised to take oral vitamin B12 regularly The need for vitamin B12 is increased by pregnancy and lactation. Deficiency has been recognized in infants of vegetarian mothers who were breast fed, even though the mothers had no symptoms of deficiency at the time. Vitamin B12 is not present in foods of plant origin, but is abundant in foods of animal origin In people with normal absorption, deficiencies have been reported only in strict vegetarians who consume no products of animal origin (including no milk products or eggs).
A vegetarian needs their B12 checked because vegetarian diets lack vitamin B12, which is essential for growth, cell reproduction, and hematopoiesis. Vitamin B12 deficiency can lead to permanent degenerative lesions of the spinal cord if left untreated for more than 3 months 2. Additionally, pregnancy and lactation increase the need for vitamin B12, and deficiency has been recognized in infants of vegetarian mothers who were breastfed 2. Therefore, it is crucial for vegetarians to have their B12 levels checked and consider taking oral vitamin B12 supplements to prevent deficiency 2 and 2. Key risks of vitamin B12 deficiency in vegetarians include:
- Permanent degenerative lesions of the spinal cord
- Incapacitating and irreversible damage to the nerves of the spinal cord
- Increased risk of carcinoma of the stomach Treatment options for vitamin B12 deficiency in vegetarians include:
- Oral vitamin B12 supplements
- Intramuscular injections of vitamin B12
- Dietary changes to include animal products or fortified foods
From the Research
Risks of Vitamin B12 Deficiency in Vegetarians
- Vegetarians are at risk of vitamin B12 deficiency due to limited intake of animal-based foods, which are the primary sources of this nutrient 3, 4, 5, 6.
- The risk of deficiency is higher among vegans compared to vegetarians, and among individuals who have followed a vegetarian diet since birth 4.
- Vitamin B12 deficiency can lead to various health problems, including megaloblastic anemia, neuropsychiatric symptoms, and other clinical manifestations 7.
Prevalence of Vitamin B12 Deficiency in Vegetarians
- Studies have reported high rates of vitamin B12 deficiency among vegetarians, ranging from 11% to 90% in different populations 4, 5.
- Pregnant women, children, adolescents, and the elderly are particularly vulnerable to vitamin B12 deficiency 4.
- Even lacto-ovo-vegetarians, who consume dairy products and eggs, are at risk of becoming deficient in vitamin B12 6.
Diagnosis and Treatment of Vitamin B12 Deficiency
- Diagnosis of vitamin B12 deficiency can be made through a combination of diet history, serum vitamin B12 level, and testing of homocysteine, holotranscobalamin II, or methylmalonic acid serum levels 3, 5, 7.
- Treatment options include oral administration of high-dose vitamin B12 (1-2 mg daily) or intramuscular injections, with oral administration being as effective as intramuscular administration for correcting anemia and neurologic symptoms 7.
- Vegetarians are recommended to consume foods fortified with vitamin B12 or take vitamin B12 supplements regularly to prevent deficiency 3, 7, 6.