Vitamin B12 is an essential to good health. The major reason that vitamin B12 is so important is that it is needed in production of red blood cells. If you have too little of this vitamin, you may be unable to make enough red blood cells, a condition called Vitamin B12 deficiency anaemia.
What is it?
Vitamin B12 is an essential to good health. The major reason that vitamin B12 is so important is that it is needed in production of red blood cells. If you have too little of this vitamin, you may be unable to make enough red blood cells, a condition called Vitamin B12 deficiency anaemia.
Red blood cell is essential as it carries oxygen and nutrients throughout the body and anaemia can make a person feel tired or lethargic. Vitamin B12 is needed to form red blood cells and DNA. It is also a key player in the function and development of brain and nerve cells. It is required for normal nerve function in the brain, spinal cord and whole body. So, deficiency of this vitamin may also cause problems with sensation, muscle strength and thinking.
Because the human body cannot produce its own vitamin B12, we must consume it via our food or supplements.
Vitamin B12, or cobalamin, is naturally found in animal foods or supplements.
Vitamin B12 binds to the protein in the foods we eat, once it is in the stomach, hydrochloric acid and enzymes unbind vitamin B12 into its free form. From there, vitamin B12 combines with a protein called intrinsic factor so that it can be absorbed further down in the small intestine.
Causes of vitamin B12 deficiency:
There are two main reasons that your vitamin B12 level might be low: too little intake of vitamin enriched foods or an inability to absorb the vitamin.
Too little intake of vitamin B12 may be due to: Weightloss diet’s, Vegetarian (low in animal products such as meat, poultry, eggs, or other dairy products). For example, people who are malnourished, on weightloss diet, appetite suppressant (Ozempic, Wegovy or Mounjaro) or following a strict vegan or certain keto diet may be at risk of malabsorption of Vitamin b12.
(Pregnant women who have a diet low in animal products should be particularly careful to get enough vitamin B12 since the baby needs this vitamin to develop normally- See your GP for further advice).
Poor absorption of vitamin B12 may be due to:
Medications that interfere with absorption:
· Long-term use of metformin, a drug commonly prescribed for type 2 diabetes (Ozempic, Mounjaro, Wegovy, Saxenda, Victoza) is strongly associated with vitamin B12 deficiency and lower folic acid levels as it can block absorption, which may lead to increased homocysteine levels and risk for cardiovascular disease.
· Proton pump inhibitors (such as omeprazole/Prilosec) and Lansoprazole/Prevacid — commonly prescribed medications for heartburn, reflux, or ulcers, can lower the stomach acid and are also associated with lowering vitamin B12 levels
Symptoms and signs of vitamin B12 deficiency
These include:
· Fatigue, weakness and lethargy
· Depression
· Lack of appetite or extreme hunger
· Problems with concentration
· Changes in bowel habits (including constipation or diarrhoea)
· Shortness of breath or an inability to exercise
· Pallor (pale skin)
· Nerve damage- tingling or numbness in the hands and feet
· Poor balance
· Confusion or dementia, memory loss, fogginess.
· Megaloblastic anaemia—a condition of larger than normal sized red blood cells and a smaller than normal amount; this occurs because there is not enough vitamin B12 in the diet or poor absorption
· Pernicious anaemia—a type of megaloblastic anaemia caused by a lack of intrinsic factor so that vitamin B12 is not absorbed
· Seizures
However, if the deficiency is developed due to recent lifestyle changes, you may have no symptoms at all. In such cases, the blood test and checks may be abnormal for certain types of anaemia (called megaloblastic anaemia).
How is vitamin B12 deficiency diagnosed?
The first steps include a thorough review of your symptoms and a physical examination looking for the symptoms and signs described above. A particularly important part of the examination is checking the function of the nervous system; for example, your doctor will check reflexes, strength, and sensation in the extremities as well as memory and thinking ability.
The diagnosis can be confirmed with blood tests, including a blood count to identify the typical type of anaemia and a Vitamin B12 level. A blood methylmalonic acid (MMA) level may also be measured because it tends to rise as B12 levels become low. Depending on the situation, additional tests of the stomach or intestines may be performed. For example, your doctor may recommend an esophagogastroduodenoscopy (EGD) or colonoscopy to see whether there is evidence of intestinal disease contributing to the problem.#
Note: Measuring vitamin B12 in the blood is actually not the best way to determine whether someone is deficient, as some people with a deficiency can show normal B12 blood levels. Blood levels of methylmalonic acid, a protein breakdown product, and homocysteine are better markers that capture actual vitamin B12 activity. These values increase with a vitamin B12 deficiency. It is estimated that up to 15% of the general population has a vitamin B12 deficiency.
Food Sources:
Recommended Amounts :
RDA: The Recommended Dietary Allowance for men and women ages 14 years and older is 2.4 micrograms (mcg) daily. For pregnancy and lactation, the amount increases to 2.6 mcg and 2.8 mcg daily, respectively.
UL: A Tolerable Upper Intake Level (UL) is the maximum daily dose is unlikely to cause adverse side effects in the general population. No upper limit has been set for vitamin B12, as there is no established toxic level. However, some evidence suggests that supplements of 25 mcg per day or higher may increase the risk of bone fractures.
Prognosis:
While the anaemia can be readily and reliably treated by increasing the vitamin B12 level, nerve damage may be permanent.
Prevention:
Most healthy people who have a well-balanced diet do not need to worry much about vitamin B12 deficiency. However, for those at risk (such as those with celiac disease), people on diet, people using weightloss medication or appetite suppressant – need to have regular blood test to check their blood vitamin B12 levels and in some cases, preventive therapy with vitamin B12 may be recommended.
Permanent nerve damage can be prevented with early diagnosis and treatment. Checking labels of foods for vitamin B12 levels can be helpful if you've had low or borderline levels in the past.
Vitamin B12 deficiency treatment:
Although vitamin B12 deficiency treatment varies depending on the cause, the goal is to increase the blood level of vitamin B12. This can be done by changing your diet, discontinuing medications (with your Prescriber's approval) that can impair B12 absorption, moderating alcohol use, eliminating gluten from the diet (if you have celiac disease), receiving treatment for Crohn disease, adding oral supplements or having regular injections of vitamin B12. Many people will require more than one of these approaches.
Toxicity:
Vitamin B12 is a water-soluble vitamin, so any unused amount will exit the body through the urine. Generally, up to 1000 mcg a day of an oral tablet to treat a deficiency is considered safe. The Institute of Medicine states “no adverse effects have been associated with excess vitamin B12 intake from food and supplements in healthy individuals. However, it is important not to start a high-dosage supplement of any kind without first checking with your doctor.
Final Note:
Fortunately, as our understanding of this remarkable vitamin has increased, debilitating or deadly vitamin B12 deficiency is relatively rare today. If you have symptoms of vitamin B12 deficiency, see your doctor. It could turn out be something else, but it's worth getting checked out, especially since delayed diagnosis can lead to permanent complications.
