Discover the causes, symptoms, and treatment options for vitamin B12 deficiency. Learn more about this common nutritional deficiency at Meri Sehat.

Vitamin B12 Deficiency

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Syed Intisar Hussain

Overview

Also called cobalamin deficiency, vitamin B12 deficiency is defined as serum or plasma levels lower than 200 or 250 pg/ml (148 or 185 pmol/L).<a href="#accordion">[4]</a>&nbsp; 
Vitamin B12 deficiency in the body leads to the production of abnormally large red blood cells that are unable to function properly. It can lead to megaloblastic anemia. 
&nbsp;

Vitamin B12 is needed for the proper functioning of the body&rsquo;s cells and nerves.&nbsp; Insufficient B12 levels might cause a decrease in the synthesis of normal red blood cells, reducing oxygen delivery.<a href="#accordion">[3]</a>&nbsp;According to research, 1-2% of anaemia cases are due to vitamin B12 deficiency.<a href="#accordion">[1]</a>&nbsp;It is more common in the elderly, irrespective of the cause.

There is a lack of national-level data on vitamin B12 deficiency prevalence in Pakistan. However, a small-scale study reported 6.8% of Pakistani male and female adults aged 46+10.5 years as vitamin B12 deficient.<a href="#accordion">[7]</a> 
&nbsp;

Your body needs vitamin B12 as a necessary nutrient for functions like DNA synthesis, energy production, and central nervous system health. B12 concentrations above 300 pg/mL are regarded as normal, concentrations between 200 and 300 pg/mL are regarded as borderline, and those below 200 pg/mL are regarded as deficient.<a href="#accordion">[4]</a>

Unlike other vitamins, B12 is extensively stored, primarily in the liver, until the body requires it. It typically takes the body 3 to 5 years to deplete its stocks if a person stops taking it.

Due to insufficient laboratory testing and non-specific symptoms, vitamin B12 deficiency is not commonly diagnosed and mostly goes unnoticed. 
&nbsp;

Signs and Symptoms

Vitamin B12 deficiency can result in physical, neurological, and haematological symptoms. These signs and symptoms develop gradually and appear as the deficiency worsens. 
&nbsp;

Anaemia caused by vitamin deficiency typically presents with

<ul>
	<li>Fatigue</li>
	<li>Breathing difficulty</li>
	<li>Dizziness</li>
	<li>Pale or yellow skin</li>
	<li>Abnormal heartbeat</li>
	<li>Weight loss</li>
	<li>Tingling or numbness in the hands and feet (paraesthesia)</li>
	<li>Muscle tremors</li>
	<li>Behavioural shifts</li>
	<li>Erratic motions</li>
	<li>Confusion in mind or forgetfulness</li>
</ul>

In some cases, these symptoms may appear without <a href="https://merisehat.pk/disease/anemia">anemia</a>. 
&nbsp;

Causes

Vitamin B12 (cobalamin), in conjunction with other necessary vitamins, is required for the production and maturation of red blood cells. A vitamin B12 deficiency causes the body to produce unusually large red blood cells that are unable to function correctly. As a result, the tissues and organs do not receive enough oxygen. If the body does not receive adequate oxygen, it is unable to function.

Moreover, vitamin B12 also plays an important role in DNA synthesis; development, myelination, and functioning of the nerves.<a href="#accordion">[4]</a> 
&nbsp;

Vitamin B12 deficiency anaemia can develop from a lack of vitamin B12 in your diet or if your body has difficulties absorbing or processing these nutrients.

<ol>
	<li>
	<h5>Diet</h5>
	</li>
</ol>

Meat, eggs, dairy, and certain fortified foods such as cereals and bread are good sources of vitamin B12. Thus, people who don&rsquo;t regularly eat these foods can develop vitamin B12 deficiency. Thus, vegans and vegetarians who don&rsquo;t take vitamin B12 supplements are at a greater risk. However, since the body has enough stores to last years, it can take years for the development of symptoms due to dietary changes. 
&nbsp;

<ol start="2">
	<li>
	<h5>Pernicious Anaemia</h5>
	</li>
</ol>

Pernicious anaemia is an autoimmune condition characterized by the production of antibodies against stomach cells responsible for forming a protein called intrinsic factor. The intrinsic factor helps the intestines absorb vitamin B12. Thus, pernicious anaemia can result in a vitamin B12 deficiency. This is more common in people of northern Europe.<a href="#accordion">[1]</a> 
&nbsp;

<ol start="3">
	<li>
	<h5>Gastric Surgeries</h5>
	</li>
</ol>

Gastric surgeries such as gastric bypass reduce the amount of intrinsic factor generated and the amount of space available for vitamin B12 to be absorbed. 
&nbsp;

<ol start="4">
	<li>
	<h5>Intestinal Problems</h5>
	</li>
</ol>

Both Crohn&#39;s disease and celiac disease, as well as tapeworms that may be consumed by eating infected seafood, can prevent the absorption of vitamin B-12. 
&nbsp;

<ol start="5">
	<li>
	<h5>Gastritis</h5>
	</li>
</ol>

Inflammation of the stomach lining reduces the acid content of the stomach. Hydrochloric acid, present in the stomach, plays a major role in vitamin B12 absorption. Thus, gastritis is a common cause of vitamin B12 deficiency. 
&nbsp;

<ol start="6">
	<li>
	<h5>Medications</h5>
	</li>
</ol>

Certain drugs such as proton pump inhibitors can reduce the acid content of the stomach, and in turn reduce the levels of vitamin B12 in the body. 
&nbsp;

<ol start="7">
	<li>
	<h5>Functional Vitamin B12 Deficiency</h5>
	</li>
</ol>

This is characterized by people developing problems related to B12 deficiency despite having normal levels within the blood. Functional vitamin B12 deficiency results from problems with a protein that transports the vitamin between cells. 
&nbsp;

Diagnosis

If a doctor suspects vitamin deficiency, initial lab tests include a complete blood count (CBC) with a peripheral smear, and serum folate and B12 levels. These blood tests check for

<ul>
	<li>Size and quantity of the red blood cells (RBCs)</li>
	<li>Blood levels of folate and vitamin B-12</li>
	<li>Haemoglobin levels</li>
</ul>

Tests that check for the presence of intrinsic factor antibodies may also be conducted. 
&nbsp;

Treatment

A dose of the deficient vitamin is given to treat vitamin deficiency anaemia. Vitamin B12 is typically administered intravenously. In case of pernicious anaemia, you may need to take it on a daily oral basis. 
&nbsp;

The following forms of vitamin B12 are available for supplementation:

<ul>
	<li>Intramuscular or subcutaneous injections</li>
	<li>Oral pills</li>
	<li>Nasal sprays or gels 
	&nbsp;</li>
</ul>

Other than supplements, doctors also advise dietary changes. Increasing the consumption of the following food items is often recommended:

<ul>
	<li>Fish such as salmon and cod</li>
	<li>Chicken, beef, and liver</li>
	<li>Eggs</li>
	<li>Low-fat milk and other dairy products</li>
	<li>Fortified cereals 
	&nbsp;</li>
</ul>

The amount of daily vitamin B12 dose required is based on your age, eating habits, medical history, the medications you take, and other factors. 
&nbsp;

The age-specific average suggested doses, expressed as micrograms (mcg), are as follows:<a href="#accordion">[4]</a>

<ul>
	<li>Birth to 6 months: 0.4 mcg</li>
	<li>7 to 12-month-old infants: 0.5 mcg</li>
	<li>Children aged 1-3 years: 0.9 mcg</li>
	<li>Children aged 4-8 years: 1.2 mcg</li>
	<li>Children aged 9-13 years: 1.8 mcg</li>
	<li>Teens aged 14-18: 2.4 mcg (2.8 mcg per day for nursing mothers and 2.6 mcg per day for pregnant women)</li>
	<li>Adults: 2.4 mcg (2.8 mcg per day for nursing mothers and 2.6 mcg per day for pregnant women)</li>
</ul>

Note: Any form of supplementation should only be started after a consultation with a healthcare professional. 
&nbsp;

Your chance of developing a wide range of health issues increases if you are vitamin B12 or folate deficient, including

<ol>
	<li>
	<h5>Problems With Pregnancy</h5>
	</li>
</ol>

Birth defects of the spinal cord and brain can result from vitamin B12 deficiency in pregnant mothers. 
&nbsp;

<ol start="2">
	<li>
	<h5>Nervous System Disorders</h5>
	</li>
</ol>

Without treatment, vitamin B-12 insufficiency can cause neurological issues like vision loss, memory loss, persistent tingling in the hands and feet, and balance issues. Because vitamin B-12 is essential for normal brain function, it might also result in mental disorientation and forgetfulness. 
&nbsp;

<ol start="3">
	<li>
	<h5><a href="https://merisehat.pk/disease/gastric-cancer">Gastric Cancer</a></h5>
	</li>
</ol>

Gastric or intestinal cancer risk is increased by pernicious anaemia. 
&nbsp;

The following factors increase one&rsquo;s risk of vitamin B12 deficiency

<ul>
	<li>Family history of vitamin B12 deficiency</li>
	<li>Gastric surgery that removes all or a portion of the intestines or stomach</li>
	<li><a href="https://merisehat.pk/disease/diabetes-type-1">Type 1 diabetes</a></li>
	<li>Any autoimmune illness</li>
	<li>Crohn&#39;s disease</li>
	<li><a href="https://merisehat.pk/disease/hiv-61">HIV</a></li>
	<li>Some medicines</li>
	<li>Strict vegetarian and vegan diets</li>
	<li>Being an older adult</li>
	<li>Excessive alcohol consumption 
	&nbsp;</li>
</ul>

The following measures can help prevent vitamin B12 deficiency:

<ul>
	<li>Some types of vitamin deficiency anaemia can be avoided by eating a well-balanced diet that includes a range of foods such as meat, eggs, and dairy products.</li>
	<li>Vitamin B12 supplementation - Most adults require a daily dose of 2.4 micrograms (mcg) of vitamin B12. Women who are breastfeeding or pregnant may need more of each vitamin. The majority of people consume enough vitamin-rich foods. However, if your diet is restricted or you&#39;ve undergone gastric bypass surgery, you might consider taking a multivitamin.</li>
	<li>Quit alcohol consumption</li>
	<li>See a healthcare professional for any digestive diseases such as celiac disease or Crohn&rsquo;s disease. 
	&nbsp;</li>
</ul>

Potential Role of Certain Biomarkers Such as Vitamin B12, ROS, and Albumin, as Early Predictors for Prognosis of <a href="https://merisehat.pk/disease/covid-19">COVID-19</a> Outcomes.<a href="#accordion">[6]</a> 
Several biochemical markers, including ferritin, B12, and reactive oxygen species (ROS) can be used to assess the severity of COVID-19 disease. Vitamin B12, ROS, total protein and albumin, in particular, can play a significant role in the early detection of infection from the very initial stages of the disease. Other biochemical markers, such as ferritin and CRP, grow as the disease advances 
So when the disease progresses to its most serious stages, there is a statistically significant rise in various diagnostic indicators (ferritin, B12, AST, glucose, urea, calcium, total protein, albumin, triglycerides). 
 
Furthermore, it is critical to remember that the therapeutic regimen to be followed for the patient&#39;s treatment should be based not only on symptoms but also on diagnostic and clinical observations. According to research findings, B12 and ROS can be used as early indicators for the advancement of COVID-19 disease. 
COVID-19 symptoms vary depending on the patient&#39;s health history as well as their genetic profile. As a result, all prognostic tools must be evaluated to avoid the disease&#39;s severe and catastrophic outcome. All biochemical and inflammatory biomarkers must be monitored at all phases of COVID-19. 
&nbsp;

Key Points

<ul>
	<li>Also called cobalamin deficiency, vitamin B12 deficiency is defined as serum or plasma levels lower than 200 or 250 pg/ml (148 or 185 pmol/L). The lack of vitamin B12 in the body leads to the production of abnormally large red blood cells that are unable to function properly. Thus, resulting in megaloblastic anaemia</li>
	<li>Your tissues and organs do not receive adequate oxygen if there are insufficient red blood cells. Your body can&#39;t function as properly without enough oxygen.</li>
	<li>Weak muscles, numbness, difficulty walking, nausea, weight loss, agitation, fatigue, and an elevated heart rate are some symptoms.</li>
	<li>Vitamin B12 supplements may be used in treatment. A well-balanced diet should also be consumed.</li>
	<li>It is critical not to self-diagnose a vitamin shortage because some can be harmful if taken improperly and/or hide other vitamin deficiencies. Seek counsel from your doctor or a dietician.</li>
</ul>

[1] Ankar A, Kumar A. Vitamin B12 Deficiency. [Updated 2022 Aug 12]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-.

[2] Wolffenbuttel BHR, Wouters HJCM, Heiner-Fokkema MR, van der Klauw MM. The many faces of cobalamin (vitamin B12) deficiency. Mayo Clin Proc Innov Qual \& outcomes. 2019;3(2):200–14.

[3] Tardy A-L, Pouteau E, Marquez D, Yilmaz C, Scholey A. Vitamins and minerals for energy, fatigue and cognition: a narrative review of the biochemical and clinical evidence. Nutrients. 2020;12(1):228.

[4] of Health NI, others. Vitamin B12: fact sheet for health professionals. Off Diet Suppl. 2020;

[5] Johnson LE. Vitamins and Aging. Annu Rev Gerontol Geriatr. 1995;15(1):143–86.

[6] Lymperaki E, Kazeli K, Variti G, Gerothanasi M, Gkinoudis A, Tsamesidis I, et al. Potential Role of Certain Biomarkers Such as Vitamin B12, ROS, Albumin, as Early Predictors for Prognosis of COVID-19 Outcomes. Medicines. 2022;9(6):36.

[7] Soofi S, Khan GN, Sadiq K, et al. Prevalence and possible factors associated with anaemia, and vitamin B 12 and folate deficiencies in women of reproductive age in Pakistan: analysis of national-level secondary survey data. BMJ Open. 2017;7(12):e018007. Published 2017 Dec 22. doi:10.1136/bmjopen-2017-018007