All You Need To Know About Vitamin B12 Deficiency

Vitamin B12 is an amazing vitamin. It is responsible for the production of DNA and RNA, which are vital components in every cell in our body. Not just that, vitamin B12 is also responsible for blood and nerve health. It is an essential compound for the normal growth of red blood cells that deliver oxygen to the whole body.

Vitamin B12 deficiency affects all body cells and gives rise to a lot of problems that may interfere with a person’s life. Vitamin B12 deficiency is affecting more than 40% of people worldwide, and 60% of them are under a plant-based diet, like vegans and vegetarians. It is essential to understand the effect of vitamin B12 on our body and how to prevent or treat its deficiency.

Why vitamin B12 and what’s its benefits?

○ Elevate the mood

It is a part of the production of brain chemicals such as dopamine and serotonin. They improve our mood.

○ Boosts energy

Vitamin B12 is responsible for the conversion of carbohydrate in our body to glucose, which is the primary substance for energy production in all body cells.

○ Maintains a healthy body weight

It is responsible for cells development, growth, and maturation. Decrease vitamin B12 levels may cause loss of muscle, fat, and other significant cells for normal body functions, which leads to unhealthy weight loss.

○ Improves thyroid function

Thyroid hormones and their functions are regulated by vitamin B12, and any changes in its levels affect the levels of thyroid hormones.

○ Support heart function

Vitamin B12 is responsible for homocysteine levels in the blood. Homocysteine is inversely proportional with vitamin B12, so when vitamin B12 levels are high, homocysteine levels are low and vice versa. Studies show that homocysteine is responsible for many risk factors in cases of heart diseases.

○ Aid digestion

It supports healthy or good gut bacteria and decreases abnormal bacteria that cause digestive system diseases like inflammatory bowel syndrome. Healthy GIT flora or good bacteria are essential for normal gut motility, and help with constipation and bloating.

○ Support a healthy pregnancy and reproductive system

It creates DNA, making vitamin B12 essential for a healthy pregnancy.

○ Prevents and treats anemia

It is crucial for the healthy development of red blood cells. Its deficiency may lead to a type of anemia called megaloblastic anemia that causes chronic fatigue and tiredness.

○ Reduces the risk of Alzheimer

Vitamin B12 supports the healthy growth of all cells, and brain cells are part of them. It also plays a significant role in improving the transmission of nerve impulses. Studies show that people who have Alzheimer also suffer from vitamin B12 deficiency.

Where can I get vitamin B12 from?

Vitamin B12 also known as cobalamin is a vitamin the only found in animal products like clams, lamb liver, and kidney, beef liver and kidney, octopus, oysters, mussels, mackerel, herring, king crab, tuna, sardines, salmon, swiss cheese, lamb and trout.

Here are some of the highest vitamin B12 sources and the amount of vitamin B12 in 100 grams of each source:

  • Clams: 84 μg, 1402% of daily vitamin B12 intake.
  • Beef liver: 70 μg, 1178% of daily vitamin B12 intake.
  • Fortified breakfast cereal: 6 μg, 100% of daily vitamin B12 intake.
  • Trout: 5.5 μg, 90% of daily vitamin B12 intake.
  • Salmon: 4.8 μg, 80% of daily vitamin B12 intake.
  • Tuna: 3 μg, 42% of daily vitamin B12 intake.
  • Haddock: 2 μg, 30% of daily vitamin B12 intake.
  • Milk: 1.2 μg, 18% of daily vitamin B12 intake.
  • Swiss cheese: 0.9 μg, 15% of daily vitamin B12 intake.

How much vitamin B12 do I need daily?

Vitamin B12 daily recommendations differ according to age, sex, daily activity, person status of health, metabolic, and medical conditions. However, the recommended vitamin B12 amounts according to the World Health Organization (WHO) are:

  • From birth to 6 months: 0.4 μg
  • Infants from 7 to 12 months: 0.5 μg
  • Children from 1 to 3 years: 0.9 μg
  • Children from 4 to 8 years: 1.2 μg
  • Children from 9 to 13 years: 1.8 μg
  • Teens from 14 to 18 years: 1.8 μg
  • Adults from 19 to 50 years: 2.4 μg
  • Pregnant teens and women: 2.6 μg
  • Breastfeeding teens and women: 2.8 μg
  • Seniors from 50 years and older: 2.6 μg

People at risk of vitamin B12 deficiency may need more than the daily vitamin B12 recommendation.

Who is at risk, and what are the causes of vitamin B12 deficiency?

• Seniors older than 50 years old

Older people are at risk for developing vitamin B12 deficiency because their digestive system does not absorb vitamin B12 as younger people do, and their enzymes functions are not at their best to convert vitamin B12 to its active form.

• Alcoholics

People with high alcohol intake increase vitamin B12 execration in the urine. Consumption of alcohol for over 2 weeks regularly shows a decrease in vitamin B12 absorption from the intestine.

• Vegan and vegetarian

A plant-based diet is the main cause of vitamin B12 deficiency because vitamin B12 can only be found in animal products. Vegan and vegetarians should take vitamin B12 supplements along with their diet.

• Bacterial overgrowth

Increase the number of healthy gut bacteria or abnormal bacteria is called overgrowth. This causes vitamin B12 deficiency because the bacteria are competing with the intestinal cells over vitamin B12 absorption. They also compete over the intrinsic factor in the stomach, which is essential for vitamin B12 absorption.

• Diabetic patients

As a part of treating diabetic patients are usually treated by metformin to decrease blood glucose levels. Metformin has the side effect of reducing vitamin B12 absorption, which may lead to vitamin B12 deficiency.

• Stomach bypass surgery

People with gastric bypass are at risk of vitamin B12 deficiency because the part of the stomach that secrete the intrinsic factor, which is essential for vitamin B12 absorption, is removed during this surgery. Bypass surgery patients should take vitamin B12 supplements daily to prevent vitamin B12 deficiency.

• Malabsorption and digestive system diseases

Patient with an intestinal disease that decreases vitamin absorption, such as celiac and Crohn’s diseases, should consider vitamin B12 supplements. Additionally, these conditions must be treated to avoid vitamin B12 deficiency.

When do you consider vitamin B12 deficiency?

Healthy vitamin B12 ranges are 190 to 950 picogram per millimeter (pg/ml). Having lower levels than 200 pg/ml is considered vitamin B12 deficiency. There are 3 ways to test vitamin B12 levels:

  1. Vitamin B12 blood test
    It measures vitamin B12 in a blood sample. It is a fast and easy test but not accurate.
  2. Methylmalonic acid test in blood or urine
    It measures methylmalonic acid levels in blood or urine. It is a substance that the body secretes when levels of vitamin B12 drops. The higher MMA levels in the blood, the lower vitamin B12 levels. This test is more accurate than vitamin B12 blood test.
  3. MTHFR gene testing
    Usually used for patients with chronic fatigue, and it shows multiple vitamins deficiency.

How do you know that you have a vitamin B12 deficiency and when you need to seek professional advice?

Vitamin B12 deficiency affects more than 40% of the world population and is the most vitamin deficient worldwide. Decrease vitamin B12 levels in the blood will affect all body cells, their growth, and maturation, leading to a lot of symptoms. The first cells to be affected are the fastest dividing cells, such as skin cells, those located in the mucous membranes, and red blood cells. Vitamin B12 is responsible for DNA and RNA production, which is used in all our body’s cells function.

♦ Pernicious anemia

Severe Anemia

It is also called megaloblastic anemia, and it is a characteristic symptom for vitamin b12 deficiency. Pernicious anemia is a type of anemia characterized by large round red blood cells and low red blood cells count. These types of cells are not efficient in delivering oxygen to body cells.

♦ Weakness and fatigue

Weakness and fatigue

The body cells don’t receive enough oxygen, which decreases energy production, leading to fatigue.

♦ Decrease thyroid function


Vitamin B12 regulates thyroid hormones and their functions. Studies show a link between vitamin B12 deficiency and decreased thyroid function, a medical condition known as hypothyroidism. Patients with hypothyroidism show a reduction in symptoms and fast recovery after adequate vitamin B12 supplements.


depression symptoms

B-complex vitamins which contain Vitamin B12 are responsible for the production of brain chemicals as dopamine and serotonin, which affect mood and other brain functions. Depression may be included as a mental health problem associated with vitamin B12 deficiency, but this cause of depression is usually overlooked.

♦ Numbing sensation

Numbing sensation

This results from nerve endings damage and demyelination of nerves, which happens as a result of decreased oxygen supply to the nerves. It usually affects peripheral body parts such as the legs, hands, and fingers. It may also reduce the mechanical sensation in these areas.

♦ Infertility

Infertility, Celiac Disease Symptoms

It is a clinical problem that occurs in prolonged vitamin B12 deficiency because it affects the normal development of the reproductive system cells in both males and females.

♦ Memory loss and confusion

Thinking Problems, Memory loss and confusion

The brain cells are lacking oxygen, which is their primary source of nourishment. This will decrease the productivity and cognitive function of the brain. Its deficiency affects nerve signal transmission, which delays reaction and response time.

♦ Blurred vision

Blurred Vision

In the early stage of vitamin B12 deficiency, this happens because of inadequate oxygen delivery to the retina and a subsequent reduction in retinal cells growth and maturation. In a late stage of vitamin B12 deficiency, it happens because of optic nerve demyelination. Vitamin B12 deficiency is responsible for myelination, also known as the covering or isolation of the nerve.

♦ Pale skin

pale skin, iron deficiency

Hemoglobin is the component that gives the blood its color. When vitamin B12 levels decrease, hemoglobin levels drop as well, and the red blood cells count along with it. That will reduce the red blood cells that reach the skin, giving patients the characteristic pale appearance of anemia.

How to maintain vitamin B12 at a healthy level and prevent vitamin B12 deficiency?

– Having sufficient foods rich in vitamin B12 from animal sources as clams, lamb liver, and kidney, beef liver and kidney, octopus, oysters, mussels, mackerel, herring, king crab, tuna, sardines, salmon, swiss cheese, lamb and trout.

– Treating medical conditions that affect the metabolism of vitamin B12, such as Crohn’s, celiac and liver diseases.

– Use vitamin B12 supplements, especially in case of people how are at risk of vitamin B12 deficiency (vegans and vegetarian, infants of plant-based pregnant and breast-feeding women and older people).

– Avoid drinking coffee after meals because it reduces vitamin B12 concentration in the blood by increasing its excretion in the urine.

– Avoid alcohol intake as it decreases vitamin B12 absorption from the intestine.

How can you treat a vitamin B12 deficiency?

– You should increase your vitamin B12 levels in the blood by working on the same points as in the prevention of vitamin B12 deficiency. You can ask your doctor as he may recommend vitamin B12 supplements to increase vitamin B12 levels. Vitamin B12 supplements are available over the counter, and for most adults the recommended daily allowance is 25-100 μg.

– In severe vitamin B12 deficiency, it is better to start with intramuscular vitamin B12 as it has a higher absorption rate than oral vitamin B12. Sublingual is also better than oral bills as it passes the degeneration in the gut, and it is absorbed directly into the blood.

– In treating vitamin B12 deficiency, especially with pernicious anemia, the starting doses should be high to replenish the vitamin B12 stores in the liver. The starting dose is usually 1000 μg, and 150 μg of this dose is usually stored in the body. There are two types of vitamin B12 muscular injection: cyanocobalamin and hydroxocobalamin. Cyanocobalamin needs to be converted first to hydroxocobalamin and requires more frequent doses. Hydroxocobalamin is the precursor form of vitamin B12, and it needs to be converted to vitamin B12 active form so the body can use it, so it requires fewer doses.

– In the case of gastric bypass surgery, vitamin B12 supplements must be taken daily because the absorption of vitamin B12 becomes impaired after the surgical removal of gastric cells responsible for secreting the intrinsic factor, which essential for vitamin B12 absorption.