According to the US Department of Health and Human Services, vitamin B12 deficiency affects between 1.5% and 15% of the American population. 
Recently, various health associations have raised awareness about this vitamin deficiency, due to its misleading and wide-range symptoms that are often neglected or confused with other types of deficiencies and health conditions.
This article will guide you through the function of vitamin b12 in the body, as well as the symptoms of vitamin B12 deficiency, the diagnostic methods, and will give you some tips on how to ensure balanced B12 levels in your body.
Even though this incentive has the goal to raise awareness and motivate patients to get medically diagnosed, many people reach for vitamin b12 supplements before getting tested.
Such unsupervised and unprescribed supplementation can not only be dangerous and pose additional health risks, but may also lead to vitamin toxicity and long term health issues. That’s why we emphasize the importance of knowing the symptoms and the ways to get diagnosed!
Let’s get started!
Why do we need vitamin B12
Vitamin B12 (also called cobalamin) is a water-soluble vitamin that the body can’t make by itself, so you have to supply it with food. As it’s water-soluble, the excess amounts of this micronutrient are normally excreted with the urine and are not stored as reserves “for later use.” That being said, vitamin B12 should be consumed every day to support healthy body functions and prevent insufficiency or deficiency. 
Nonetheless, overdosing with cobalamin is possible if you take megadoses of this micronutrient. Such doses can be associated with dependency, withdrawal symptoms and toxicity. 
Cobalamin is responsible for supporting the healthy formation of red blood cells (that transport oxygen to the tissues), proper functioning of nerve cells in the body, as well as DNA synthesis.  This way, vitamin B12 is much needed for overall health and wellbeing.
The symptoms of cobalamin deficiency can be both physiological and psychological, unique, or imitating the symptoms of other health conditions. Their intensity may also vary according to the severity of the deficiency. Here are the psychological, neurological, vascular, and other symptoms of vitamin B12 deficiency, according to a 2017 study published in the American Academy of Family Physicians  :
- Cognitive impairment (memory issues that can imitate dementia or Alzheimer’s disease)
- Occasional psychotic episodes
- Confusion or impaired perception of body posture, position, weight, and movement (e.g., when you can’t “feel” where your hands or feet stand without looking at them)
- Fatigue, lack of energy to conduct daily tasks
- Loss of smell (partially or fully
- Unusual changes in walking
- Areflexia (lack of automatic muscle reflexes)
- Inflammation of the tongue
- Low white blood cells count
- Insufficient or extremely high thrombocytes blood levels
- Numbness or tingling sensation in hands and feet (imitating Parkinson disease or Multiple Sclerosis )
- Muscle tremors and twitches (can happen in every muscle in the body)
- Heart palpitations
- Hyperpigmentation or hypopigmentation (paleness) of the skin
- Jaundice (imitating hepatitis)
Besides, according to the source, pregnant and breastfeeding women with cobalamin deficiency may cause early damage to the baby, including slow development, anemia, and ataxia (a degenerative disease of the nervous system).
Often, symptoms like fatigue and irritability are neglected and underestimated, as those can be caused by other temporary factors like stress, changes in the environment, hormonal imbalance, etc.
On the other hand, some of the more severe cobalamin deficiency symptoms can be falsely confused with a brain, autoimmune, psychological, and neuro diseases.
A blood test is probably the most accurate way to identify B12 deficiency. However, your doctor may suggest various blood tests in order to ensure an accurate diagnosis  :
- Serum B12 ( the result is often inconclusive, as about 50% of patients with early symptoms have normal levels of serum B12)
- Serum homocysteine
- Serum methylmalonic acid
Homocysteine, MMA and a basic blood panel for anemia tell us how a b12 deficiency is affecting our body. These other labs are indirect measurements of b12, but are more useful because they can tell us if there is a deficiency and whether or not it is starting to affect how our body is functioning.
A 2020 medical review confirmed that some individuals are more likely to develop cobalamin deficiency than others, for reasons that most often include insufficient consumption of foods rich in vitamin B12, or impaired absorption of the vitamin in the body. 
That being said, John Hopkins Medicine has summarized the risk factors for cobalamin deficiency  :
- Genetic predisposition (family members suffering from such deficiency)
- Undergoing surgical procedure for partial removal of intestine/stomach
- Autoimmune diseases
- Crohn’s disease (Inflammatory Bowel Disease)
- Strict vegan diets
- Being an older adult
- Intake of certain medication (consultation with your healthcare provider is essential)
These would be the 3 most common causes of poor B12 absorption, when you exclude diseases of the digestive tract.
Foods rich in B12
They bypass the digestive track to deliver the b12 directly into your blood and tissues. This is important because the more deficient you become in b12, the harder it can be to absorb it. This is because we need b12 to maintain the integrity of our digestive tract. Therefore, if we are severely deficient in it, our intestinal tract will become compromised and further limit our ability to absorb it. Injections are very helpful in these situations.
You are in good health, don’t suffer from chronic or autoimmune diseases, and absorb cobalamin effectively, you can easily supply enough vitamin B12 from a diverse and balanced diet. That means regularly consuming moderate amounts of the following foods  :
- Diary foods
- Fortified foods (like cereal or plant milk)
*Keep in mind that vitamin B12 is not naturally available in plant-based foods.
For those who follow a vegan diet, it’s a good idea to consult your dietary choices with a health professional who can prescribe you vitamin supplements and give you relevant advice to prevent B12 deficiency.
Individuals who cannot absorb cobalamin effectively should strictly follow the recommendations and treatment plan prepared by their doctor.