How is B12 absorbed?
The body absorbs vitamin B12
from food in a two-step process. First, hydrochloric acid in the stomach separates vitamin B12
from the protein to which it is bound. Second, the released vitamin B12
is then combined with a protein produced by the stomach, called endogenous factor, and the body absorbs them together.
Symptoms of vitamin B12 deficiency
is found in many foods and is easy to consume. However, vitamin B12
deficiency is common in the general public. Vitamin B12
deficiency is usually due to either insufficient dietary intake of B12, or the body's inability to absorb vitamin B12
Here are some of the common vitamin B12
- Low energy levels/Fatigue: Low B12 levels can reduce the normal production of red blood cells, which reduces the oxygen supply and makes you feel weak and tired.
- Headache: Headaches are very common in people with vitamin B12 deficiency and are among the most commonly reported symptoms.
- Pain in the mouth or tongue have also been seen in people with vitamin B12 deficiency.
- Muscle weakness: Because B12 affects the function of motor and sensory nerves, its deficiency can cause a feeling of weakness in the muscles, which can lead to cramps.
- Mental health: Depression, confusion and poor memory are some of the most common mental health related symptoms of vitamin B12 deficiency.
Who may develop a deficiency?
- Many older adults, as well as people with atrophic gastritis, do not have enough hydrochloric acid in the stomach to absorb vitamin B12 that is present, naturally in animal-based food products. For this reason, people over 50, should get most of their vitamin B12 from fortified foods or supplements. It should also be noted that people, with a medical history of mental illness, need to pay even more attention to their vitamin B12 levels.
- People with pernicious anemia do not produce the endogenous factor, needed to absorb vitamin B12. As a result, they have difficulty absorbing vitamin B12 from food and supplements. Doctors usually treat pernicious anemia with injectable B12, although very high doses of vitamin B12 taken orally can also be effective. Supplements in spray form can also be a very good alternative option for these cases.
- People who eat little or no animal foods, such as vegetarians and vegans, may not get enough vitamin B12 from their diet because only animal-based foods contain natural vitamin B12, except fortified plant-based products and nutritional yeast.
Vitamin B12 & Mental Health
plays a critical role in the production of dopamine
, neurotransmitters that help regulate mood. When you don't get enough B12 in your diet, your body doesn't process it properly and it can lead to unwanted mental health side-effects
, such as symptoms of depression, irritability and/or anxiety/stress.
Recommended daily intake
- Children aged 9-13 years: 1.8 µg
- Adolescents aged 14-18 years: 2.4 µg
- Adults: 2.4 µg (2.6 µg per day if pregnant and 2.8 µg per day if breastfeeding)
Supplemental administration: For an adult 14+ per day 250µg or 2500µg per week (or 1000µg 3x per week) & For over 65s, 1000µg per day is recommended.
In conclusion, vitamin B12
participates in a multitude of functions in the human body, with a leading effect in red blood cell formation and the proper functioning of the nervous system. Regular monitoring of vitamin B12
, through blood testing, is very important to ensure its adequacy, especially in people with increased chances of vitamin B12
deficiency. Holland & Barrett provides a variety of vitamin B12
supplements for everyone and every need.
Sahu, P., Thippeswamy, H., & Chaturvedi, S. K. (2022). Neuropsychiatric manifestations in vitamin B12 deficiency. In Vitamins and Hormones (Vol. 119, pp. 457-470). Academic Press.
Sangle, P., Sandhu, O., Aftab, Z., Anthony, A. T., & Khan, S. (2020). Vitamin B12 supplementation: preventing onset and improving prognosis of depression. Cureus, 12(10).
Dietitian & Nutritionist, QMU
Specialized in Eating Disorders & Metabolic Diseases