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Vitamin B12 Benefits, Uses, and Side Effects

By Sasha de Beausset Aparicio, MSc

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Vitamin B12

Vitamin B12 was first known by the name of “anti-pernicious anemia factor” due to the events that led to its discovery. Particularly, researchers were looking for a cure for a disease known as pernicious anemia, Biermer’s anemia, Addison’s anemia, or Addison-Biermer anemia, a disease characterized through various very serious symptoms such as fatigue, depression, low red blood cells count, nausea, weight loss, pale lips, dark circles around the eyes, muscle weakness, clumsiness, impaired urination, inability to focus, and mild cognitive impairment to mention only a few.

Cobalamine was the first treatment ever found for the conditions that were killing elderly people at a fast and alarming pace. The treatment is still used today to replenish B12 deficiencies that usually cause the disease. The vitamin is one of eight water-soluble B Complex vitamins, together with other seven essential nutrients including Thiamine (Vitamin B1), Folic Acid (Vitamin B9), Pyridoxine (Vitamin B6), Vitamin B2 (riboflavin), Pantothenic Acid (Vitamin B5), Niacin (Vitamin B3), and Biotin or Vitamin B7. Each of these key nutrients plays a distinctive role in the overall health. At the same time, the vitamins in the B complex have a synergistic effect that extends over the neurological function, energy production, heart health and many other processes and functions in the body.

Vitamin B12 Functions & Benefits

Vitamin B12 helps maintain a normal nerve function, is involved in DNA production, helps regulate mood, keeps homocysteine levels within normal ranges and may help prevent a large number of health conditions usually associated to a depletion of this nutrient. We will next mention the most important health issues associated with Cobalamine, either a cure or prevention treatment. Many of these roles are supported by actual scientific evidence, which recognizes the importance of the nutrient for a normal and balanced life.

Anemia is a disorder that means a low red blood cell count, which, in turn, means the body is unable to properly deliver oxygen to tissues and hence a large number of symptoms affecting the neurological function and other vital functions of the body. Folic acid, Vitamin B12, and Iron deficiencies are associated with this disease, hence prevention is mandatory.

The link between depression and vitamin B12 deficiencies has closely been studied and has been the subject of numerous clinical trials. It appears that depressed people suffer from a form of B12 deficiency, although the exact nature of the cause-effect relationship has not yet been clearly established. High amounts of B12 supplied into the body (usually by injection) have been known to suddenly pick-up mood, however, a B12 deficiency should be prevented by regular oral supplementation of the nutrient into the system.

Homocysteine and B vitamins work together, in the sense that many B vitamins help lower levels of this dangerous amino acid and hence prevent a number of associated diseases. Particularly, Folic Acid, Vitamin B6, and Vitamin B12 can have that effect. The connection of Homocysteine to heart disease, cognitive impairment, and even Alzheimer’s disease has long been investigated, and certain conclusions have been drawn, although many incomplete or unconvincing. Further research is needed to confirm any conclusion.

Age-related cognitive decline related to a B12 deficiency may be corrected by applying a B12 based treatment scheme. Improvements of basic cognitive function indicators have been identified in one small-scale clinical trial conducted on 22 elderly people given daily dosages of vitamin B12. Experimental studies also reveal that injectable B12 may be a solution to treating specific age-related cognitive decline.

People suffering from Chronic Fatigue syndrome who were given injectable B12 every 2 to 3 days for a period of several weeks seem to have improvements in Chronic Fatigue Syndrome specific symptoms. A doctor’s opinion is necessary before applying any of these treatments to oneself. Lower back pain medication may be enhanced by taking B12 supplementation dosages. According to one study showed that a combination of vitamin B1, B6 and B12 can reduce the amount of anti-inflammatory drugs required to manage back pain.

Other conditions claimed to benefit from intakes of Vitamin B12 include age-related macular degeneration, migraine headaches, Bell’s Palsy, osteoporosis, retinopathy, tinnitus, insomnia, immune function, hives, hepatitis, heart attack, type 2 diabetes, schizophrenia, diabetic neuropathy, or Celiac disease.


A deficiency of Vitamin B12 is rare; however, early symptoms include numbness in the hands and feet, depression feelings, inability to sleep, moodiness, memory loss, dizziness, loss of balance, etc. Serious deficiencies of the vitamin may lead to anemia, a condition with severe implications on the overall health. There are certain groups of people predisposed to developing a deficiency, and these include pregnant and breastfeeding women, smokers, people older than 50 years of age, vegetarians or vegans who fail to consume dietary sources of this vitamins and people suffering from various stomach problems (where the Vitamin is absorbed).

Dietary supplements of Cobalamine are generally safe for most people. Certain categories of people should, however, use them with caution. Not enough is known about use of B12 by pregnant and breastfeeding women, while the following categories should use them under strict medical supervision: people with dermatological concerns, people with genitourinary concerns, those with a history of gout or with cardiovascular concerns to mention several cases in which extreme caution is advised.

The best source of reliable information regarding the opportunity of taking a B12 supplement is a healthcare provider, which is why we strongly recommend you talk to a specialist prior to using any supplement.

Best Vitamin B12 Sources

The recommended dietary allowance of Cobalamine depends on the age and health status of the patient. Infants are recommended 0.4-0.5 mcg of b12 daily, while the dose increases to 1.8mcg for children aged 9 to 13 years old and to 2.4 to 14 years old and older. Pregnant women are allowed a daily dose of 2.6 mcg while lactating women should consume a maximum of 2.8 mcg per day.

The most abundant Vitamin B12 food sources are clams, beef and chicken liver, tuna fish, and eggs, yogurt, cottage cheese, milk, and other dairy products. 3 ounces of cooked clams are able to provide 84 mcg of B12, which is 14 times the daily recommended dose, while 1 large hardboiled egg can provide 10% of the necessary daily dose of this nutrient.