Vitamin B12: did you know that…?

B12 is a special vitamin

Vitamin B12, like all nutrients classified as “vitamins,” is an essential nutrient. This means that the body cannot produce it on its own and must obtain it from external sources. Almost all vitamins are obtained from the diet. The exception is vitamin D, which is mainly produced, although in insufficient quantities at our latitudes, through sun exposure. Vitamin K is also an exception, as it is produced by the bacteria in our intestines.

Vitamin B12 is generally not obtained in adequate amounts from the diet, even if it contains animal-based foods. Plant foods, on the other hand, are naturally devoid of it, as plants do not need it for their own functioning. Vitamin B12 undergoes a complex absorption process, which primarily depends on the body’s ability to free it from the food it is contained in. It then needs to be transported, protected by a specific protein produced in the stomach (Intrinsic Factor), to the terminal ileum, its absorption site. To ensure efficient absorption, it is therefore not enough for the vitamin to be present in foods; a healthy gastric environment is required. This environment must be capable of providing everything necessary for proper absorption. The Intrinsic Factor-mediated pathway allows only 1.5–2.0 mcg to be absorbed. The rest is absorbed passively from the intestinal lumen, with an efficiency of 1%.

What vitamin B12 is for and how to suspect a deficiency

Vitamin B12 is important for DNA synthesis, the formation of myelin, neurotransmitters, and red blood cells. A deficiency can manifest with various neurological and hematological symptoms. From the age of 50, there is a high prevalence of inadequate “release” of vitamin B12 from the foods that contain it. Furthermore, commonly used medications, such as proton pump inhibitors and metformin, interfere with intestinal absorption. Have you noticed how media campaigns promoting vitamin supplementation are becoming widespread? In fact, vitamin B12 deficiency is estimated to be very common.

Unfortunately, the context in which we live does not allow the average person to suspect the problem. Laboratories define “deficiency” as values below 180–200 pg/ml. However, according to leading experts, deficiency cannot be ruled out below 450–550 pg/ml. This is a “gray zone,” in which vitamin levels may not be sufficient to fulfill their functions. The situation is worsened by the reassuring certainty that only those who do not consume animal foods are at risk.

I regularly evaluate the levels of this vitamin in my omnivorous patients with more or less vague neurological symptoms. I have repeatedly encountered borderline or markedly deficient levels in laboratory results. Often, the primary care physician had not taken effective action to address it. Yet this represents a ticking time bomb, which can manifest at any time with symptoms that are often irreversible.

Practical advice

I would like to conclude with some advice and a message. It is important that, during routine biochemical tests, we ask our doctor to include the following tests:

• • Complete blood count (CBC)
  • Vitamin B12
  • Folate (which may confuse red blood cell volume results)
  • Homocysteine (an indicator of vitamin B12 storage deficiency, which tends to rise when the vitamin is not functioning properly)

Keep in mind that deficiency symptoms are initially vague: fatigueFatigue is a common experience that can manifest in many for... More, depressionDepression is a disorder characterized by persistent sadness... More, tremors, minor forgetfulness. However, it is dangerous to wait for overt symptoms, as these may not be reversible even after correcting the deficiency. Adequate levels are considered above 400 pg/ml, regardless of laboratory reference ranges. Recommendations have been published for supplementing any deficiency. Even if originally intended for pregnant women, they are applicable to all adults, as the requirements are comparable. The guidelines recommend using cyanocobalamin, the most studied and stable form. There is no advantage in using so-called “natural forms” (methyl- and adenosyl-cobalamin).

By also applying prevention at the table, we protect our health, learningIl termine apprendimento - con i sinonimi imparare, assimila... More to adopt ever more sustainable lifestyles. Conscious food choices and attention to critical dietary nutrients are acts of self-education, which contribute to building global health and well-being. Choosing what and how to eat is fundamental to life and evolution, changing both ourselves and the world.

Luciana Baroni is a Neurologist, Geriatrician, Physiatrist, and Nutritionist specialized in plant-based nutritionLife does not take breaks: in every living being, bodily fun... More. Founding member and current President of S.S.N.V. Creator of the PiattoVeg method. IG @dr_luciana.baroni