Vitamin B12 Deficiency- How Long does it Take?

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Vitamin B12 deficiency is on the rise in the US and many other developed countries. Why? Because modern dietary restrictions, bariatric surgery, and autoimmune disorders  increase your chances of developing  vitamin B12 deficiency anemia before you reach your senior years.

Vitamin B12 Deficiency- How Long does it Take?

Where’s the B12?

Vitamin B12 is a water-soluble nutrient that only exists in animal-based foods such as meat, poultry, fish, milk, and eggs. The richest sources of vitamin B12 are shellfish and organ meats.

Unlike other vitamins, B12 requires a cofactor for absorption; digestive enzymes that help your body break down and utilize the benefits of the vitamin. Without intrinsic factor or stomach acids, you cannot process the vitamin B12 you ingest from the foods you eat.

Pernicious anemia

Without vitamin B12, your body can’t function properly. Vitamin B12 is crucial for building healthy red blood cells containing hemoglobin, which move oxygen to your brain, muscles, and organs.

Untreated, you may develop pernicious anemia, which causes symptoms such as extreme fatigue, depression, memory loss, disorientation, and painful numbness and tingling in the extremities. Pernicious anemia can result from autoimmune disorders, or it can be caused by gastritis, damage to the stomach cells.

Vitamin B12 is also important for protecting the nervous system, boosting energy, sustaining a speedy metabolism, and delaying the effects of age-related dementia.

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How long does it take to become deficient?

Vitamin B12 deficiency symptoms can creep up slowly, as your vitamin B12 levels decline over the course of years.

Vegans and vegetarians

Among young healthy individuals, vegans and vegetarians are the highest risk categories for vitamin B12 deficiency. Usually, after about two years of strict vegan dieting, vitamin B12 levels will begin to decline. For vegetarians that number may be larger, as cheese and eggs have small amounts of vitamin B12, although not enough to prevent vitamin B12 deficiency.


Most people start noticing the first signs of vitamin B12 deficiency around their 40s. This is because as you age, your ability to digest vitamin B12 from food sources declines, as your body begins to slow down in producing stomach acids. By the time you reach middle age, you should receive regular blood test screenings for vitamin B12 deficiency.

By the time you reach the age of 60, you should be extra vigilant in monitoring your vitamin B12 levels, as vitamin B12 deficiency may increase your chances of experiencing signs of Alzheimer’s disease dementia earlier than senior citizens who supplement with vitamin B12. Also read Vitamin B12, a Must for Senior Citizens

Autoimmune disorders

If you have autoimmune disorders, then you should get your vitamin B12 levels checked routinely, as your risk for developing autoimmune pernicious anemia is that much higher. Also, many of the symptoms of vitamin B12 deficiency can mimic those of fibromyalgia, chronic fatigue syndrome, celiac disease, and other autoimmune system disorders. So, to catch vitamin B12 deficiency early and prevent neurological ailments, it’s important to take regular blood screenings for vitamin B12 deficiency.


Certain medications interfere with your ability to absorb vitamin B12; these include metformin for diabetes, protein pump inhibitors (PPIs) for GERD or heartburn, and various other popular prescription and over-the-counter drugs.

If you take any of the 25 Medications that Cause Vitamin B12 Deficiency for longer than 12 months, then you may need to take large doses of vitamin B12 regularly to prevent vitamin B12 deficiency.

Gastrointestinal surgery

Modern gastro surgeries that were previously unheard of have contributed to the rising rate of vitamin B12 deficiency. Patients of weight-loss surgeries (gastric bypass) and ilium removal or resectioning for Crohn’s disease are required to supplement with non-dietary vitamin B12 for life.

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