Perhaps less popular than other vitamins, such as C or D, vitamin B12 is essential for the proper functioning of the nervous system and the formation of red blood cells. Therefore, its lack can cause symptoms such as persistent physical and mental fatigue and lead to neurological alterations.
The biggest problem with this deficiency is that it is silent, so it is advisable to be aware, especially because it is a more common health problem than is often thought. Carmen Cuadrado, Doctor in Pharmacy from the Complutense University and Professor of Human Nutrition and Dietetics, helps us in this article to know what symptoms a person has when they lack vitamin B12 and everything necessary about this nutrient.
What is vitamin B12 and why is it important?
Essential for the formation of red blood cells and for body growth and tissue regeneration, vitamin B12 is cyanocobalamin. It helps the production of genetic material inside cells (essential for the formation of new cells), it is necessary for the formation of red blood cells and intestinal cells, and it keeps the nervous system in good condition.
Functions of vitamin B12 in the body.
Among the most notable functions of this vitamin are, in the words of Dr. Cuadrado, «it participates in the production of molecules necessary to manufacture our genetic material (DNA and RNA). In addition, it contributes to maintaining the integrity of nerve cells, that is, it helps produce neurotransmitters and maintain the integrity of neurons, it participates in the metabolism of folate, it intervenes in the hydrolysis of some fatty acids and amino acids and in the metabolism of methionine homocysteine», acting as a factor in the conversion of homocysteine to methionine.
Is it associated with a lack of iron?
“Patients with B12 deficiency usually present an anemic syndrome with macrocytosis (high mean corpuscular volume > 100), often without involvement of other hematological series,” says the expert. And he continues: “They are anemias of very variable intensity and clinical characteristics, although, in general, they are well tolerated.”
Deficit risk groups:
Among the main vulnerable groups, the lack of vitamin B12 in older people stands out, in which case generally «this lack is associated with various deficits due to malabsorption, for example, of B12 and iron, and a multifactorial anemia may occur, with a normal or decreased average corpuscular velocity.» Vegetarians and vegans with a poorly planned diet, without a B12 supplement, are also included, as well as other risk groups such as people who take antacids for a long time, people with chronic alcoholism and people with digestive disorders that affect the absorption of nutrients.
What disease is caused by its lack?
Says the member of the Academy of Nutrition and Dietetics: “The main disease caused by a lack of vitamin B12 is megaloblastic anemia, also known as pernicious anemia, when it is due to an absorption problem.”
This pathology occurs because vitamin B12 is essential for the formation of red blood cells and when it is missing, the red blood cells become large and poorly functional, decreasing the transport of oxygen in the blood.
Symptoms of lack of vitamin B12
Many people wonder how to know if they lack vitamin B12., whose symptoms are divided into anemic symptoms, digestive and neurological alterations, although it must be taken into account that «the manifestations of vitamin B12 deficiency can be very subtle and even go unnoticed.»
Anemic symptoms
People with low levels of this nutrient present symptoms such as fatigue or intense tiredness; In fact, the relationship between a lack of vitamin B12 and fatigue is one of the most common signs along with muscle weakness, paleness, dizziness and shortness of breath. Palpitations, stomach or vision problems and mood changes may also appear, leading to anemia due to low levels of vitamin B12 that accentuates the feeling of weakness.
digestive disorders
“Gradual decrease in appetite, a symptom related to others such as nausea, vomiting or diarrhea, which are due to digestive problems,” alleges Cuadrado.
neurological changes
B12 deficiency can also damage the nervous system, even if there is no anemia: “Tingling or numbness appears in the hands and feet, a manifestation known as paresthesia due to lack of vitamin B12, in addition to balance problems, memory loss or confusion, mood changes or depression and, if the deficiency is prolonged, some neurological damage may be irreversible.”
Other effects that may appear are inflammation of the tongue (glossitis), mouth sores due to lack of vitamin B12, loss of appetite and weight loss.
Common Causes of B12 Deficiency
Although in some cases the lack of this nutrient may be due to aging (the body loses its ability to absorb certain nutrients), the most common causes are related to a poor diet or a medical condition that makes it difficult to absorb vitamins.
“The main cause of vitamin B12 deficiency in people is diets in which they do not consume enough foods of animal origin, or products that are fortified with this vitamin,” declares the professor. And he adds that «eating a varied diet provides us with all the necessary vitamins, but we must keep in mind that vitamin B12 is only found in products of animal origin, such as meat, fish, eggs, dairy products and yeast fortified with B12.»
How to solve a lack of vitamin B12 (include point on blood or urine analysis parameters)
To solve the deficiency of vitamin B12, supplements are administered. These depend on the analytical values and the degree of insufficiency. For example, the expert states that «elderly people with a vitamin B12 deficiency improve, since the deficiency is usually a consequence of difficulties absorbing the vitamin and it is easier to absorb it in high amounts from supplements than from foods such as meat.» If this deficiency is complicated by pernicious anemia, the doses must be high. “Periodic blood tests allow us to verify that the concentration of vitamin B12 returns to normal values,” concludes Cuadrado.
People with very low concentrations of vitamin B12 or symptoms due to nerve damage are usually administered vitamin B12 by intramuscular injection, «which can be self-administered, on a daily or weekly basis over several weeks, until the concentration of vitamin B12 returns to normal. Thereafter, they are administered once a month for an indefinite period of time, unless the causal disorder can be corrected,» the pharmacist suggests.
«Anemia usually subsides in about 6 weeks. However, if severe symptoms due to neurological damage last for months or years, they may be irreversible. In most elderly people with vitamin B12 deficiency and dementia, intellectual functioning does not improve after treatment.»
Frequently asked questions
Carmen Cuadrado answers some of the most common questions from patients and the general population.
Does a lack of vitamin B12 make you gain weight or lose weight?
Vitamin B12 participates in the metabolism of fats, carbohydrates and proteins. For this reason, «some supplement providers maintain that a deficiency of vitamin B12 could promote weight gain. According to this theory, a lack of this vitamin would slow down the metabolism, causing the body to burn calories less efficiently.»
However, this claim is not proven. There is no conclusive research on this matter. “There are some observational studies that show an association between vitamin B12 deficiency and obesity, but it is very difficult to establish a cause and effect relationship.” That is, “it is not clear whether obesity is a consequence of a deficiency of vitamin B12 or if, on the contrary, the deficiency is due to an unhealthy lifestyle.”
How long does it take to notice improvement with supplements?
It cannot be specified because the time may vary depending on the form of administration (oral or injection), the severity of the deficiency and the type of symptom that needs to be improved. “With oral supplements (tablets, capsules or sublingual), energy and tiredness usually begin to improve within 2–4 weeks of daily use, if there is deficiency and other symptoms such as «brain fog» (feeling of confusion and mental slowness) or lack of concentration can also improve in that same period.»
Complete recovery may take several months if the symptoms are more severe or have been present for a long time.
“With doctor-prescribed vitamin B12 injections, by receiving the vitamin directly into the muscle or blood, some people feel more energy in 1–3 days and the rest of the symptoms usually continue to improve over weeks to months depending on the severity.”
Can you get enough B12 from diet alone?
Yes, but it depends on the diet and absorption capacity of each person. “If you regularly consume foods of animal origin, you normally cover your daily needs without a problem.”
On the other hand, the expert warns that «the diet does not cover the nutritional requirements in followers of strict vegetarian diets. In these cases, it is necessary to take a supplement, regardless of taking fortified foods (vegetable drinks, cereals, etc.). At this point, it is also important to note that flexitarian people or people who do not eat meat or fish regularly should pay attention to the concentration of B12 in the analyzes, since there are studies on lower amounts in the blood in these dietary patterns. Nor are they They reach adequate levels in people with absorption problems, with atrophic gastritis, pernicious anemia, gastric surgeries, prolonged use of certain drugs (antacids, metformin), even if they ingest enough vitamin B12,» concludes Carmen Cuadrado, so their blood concentration must be monitored regularly.
The ALDI Council
In vegetarian diets, in addition to your usual B12 supplement, include foods fortified with this vitamin such as vegetable drinks, breakfast cereals, nutritional yeast, etc.).
carmen square. Full Academician and Honorary Member of the Spanish Academy of Nutrition and Dietetics. Doctor in Pharmacy and Professor in the Degree of Human Nutrition and Dietetics Double Degree Pharmacy and Nutrition and in the Degree of Food Science and Technology at the Complutense University of Madrid. Co-director of the Master in Culinary Nutrition and Dietetics in Gastronomy (UCM). His main lines of research include culinary Dietetics and Nutrition and expansion of the Food Composition Tables in Spain, assessment of the nutritional status of various population groups, nutritional epidemiology, study of the diet-health relationship. He is a Member of the Innovadieta Group.
