Consequences of lack of vitamin b12 and folic acid for health

Both B12 and B9 are two key micronutrients for the body. Two B vitamins with a wide range of functions, both jointly and individually, and all extremely important. In the following sections we explain everything about both, focusing on the consequences of vitamin B12 deficiency and folic acid as a key set in well-being and health.

Vitamin B12 and folic acid: differences and similarities

There are not a few people who confuse both micronutrients, so let’s shed some light on them.

Sources of vitamin B12 and folic acid

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One of the main differences between B12 and B9 is that the sources available to them are completely different.

On the one hand, vitamin B12 or cobalamin, which is found in foods of animal origin. However, it is true that there are certain plant foods with this micronutrient in tiny amounts or directly as traces and it is not enough to cover the body’s needs.

That’s why many vegans and vegetarians are deficient if they don’t take the supplements. It is also true that people who follow diets classified as “normal” may suffer from a lack of these vitamins, in short, the important thing is not to follow one diet or another, but to do them correctly.

On the other hand, folic acid is found mainly in green vegetables, seeds, nuts and fruits. The only food in which both micronutrients are found in high amounts is the liver, making it the ideal choice for difficult cases where low levels of both are present.

Basic functions and uses

Both vitamins play a fundamental role in the proper functioning of the body; they are absolutely indispensable in the synthesis of DNA, as well as in the formation of red blood cells in the blood.

In addition, cyanocobalamin is very important for neurons to function properly, so, with vitamin B12 deficiency, some of the most common symptoms are tingling, numbness and weakness.

As for folic acid, it is essential in pregnant women to avoid any type of malformation of the neural tube of the fetus.


Let us now explain how the body absorbs both micro-nutrients:

Vitamin B12, once ingested through food, reaches the stomach, where acid and enzymes break the link between protein and cobalamin, thus preparing the body for absorption. To do this, first of all it had to be linked to the so-called intrinsic factor. Thus, along with intrinsic factor, it is transported to the small intestine, where it is absorbed by the bloodstream.

Folic acid, when it reaches the stomach, is hydrolyzed and directly absorbed in the small intestine, being a very fast absorption step.

What causes a lack of cobalamin in the body?

Vegetarian vegan food

The lack is common in three large population groups:

  • Vegans and vegetarians,
  • People with absorption, synthesis or storage problems of this micronutrient
  • Elderly

We’ll explain everything in detail:

Vegetarians and vegans

As we know, the natural source of vitamin B12 is food of animal origin. While it is true that there are some plant foods that this micro-nutrient, the amount of vitamin B12 is very low, insufficient to cover the necessary dose for the body. Therefore, vegetarians and vegans who do not take B Complex vitamin supplements are at serious risk of suffering from deficiency, a serious pathology.

People with absorption, synthesis or storage problems

The lack of this micro-nutrient is also relatively common in people whose bodies cannot absorb it. It is common in celiac patients, who undergo gastrointestinal surgery or with pathologies such as Crohn’s disease. These people should take cobalamin supplements that come into direct contact with the bloodstream; otherwise, the chances of getting deficiency go up.


After reaching the age of 50, the body’s ability to assimilate B12 is considerably reduced. Added to this is the fact that the vast majority of older people eat less than during their youth and adult life. Therefore, supplements of this vitamin in the B group after age 50 are highly recommended.

Folic acid deficiency: Causes

Certain diseases can cause micronutrient deficiencies in the body.

  • This is the case for those diseases in which folic acid is not absorbed correctly in the digestive tract, such as celiac disease or Crohn’s disease.
  • In addition, there are other causes, such as overcooked vegetables. Vegetables contain a large amount of B9, especially those with green leaves, but the micronutrient is easily destroyed by excessive heat.
  • Of course, a diet without fruits and vegetables of any kind can also lead to a lack of folic acid.
  • This pathology is also common in people who consume excess alcohol as well as those who smoke.
  • Similarly, women who take contraceptives often have lower levels of folic acid, although not always a severe deficiency.
  • In pregnancy, the body absorbs B9 more slowly; the fetus also consumes as much as it needs, and a certain amount can be lost with vomiting. Thus, even if we feed properly we can still have low folic acid, so it is the essential component of supplements for pregnant women.

Consequences of lack of vitamin b12

A low level of cobalamin can lead to relatively serious illness. This nutrient provides energy to the organism; thus, due to its deficiency, one of the main symptoms is weakness and fatigue without apparent cause.

In addition, this B-complex vitamin has a wide range of neurological functions. Thus, some of the main warning signs of a deficiency in the body is weakness and numbness in legs and arms, as well as numbness in both extremities. There are also consequences on the skin, which has a much paler appearance.

In older people, having low levels in the body can speed up the process of certain neurodegenerative diseases, such as Alzheimer’s. A long-term deficiency of this nutrient can cause brain mass loss.

Consequences of low blood B9 levels

The most obvious manifestations of the lack of folate are:

  • Diarrhea
  • Significant loss of appetite
  • Weight loss
  • Weakness
  • Headaches or tongue pain
  • Irritability
  • Tachycardia
  • Conduct disorders of various types

Lack of cobalamin and folate: Consequences and possible diseases

Lack of vitamin b12 and b9 risks in pregnancy

Having low levels of both micronutrients can become a serious pathology that should never be overlooked. In addition, one of the major drawbacks of this disease is that in many cases the symptoms do not appear until 2 or 3 years later.

Cobalamin is mainly stored in the liver, where it has a life span of 2 to 3 years. However, during this time, the deficiency has already caused functional damage to the body. That is why it is so important to avoid receiving the right dose by all means. In addition, the consequences for both physical and mental health can be dire, and may even create irreversible effects.

As for folate, unlike what you might think, it is also stored in the liver; hence many people confuse B9 and B12, because they actually have some similar functions and other similarities, worth the redundancy. Although, for the same reason, it is so dangerous not to count the amount we take, because it is stored for a long time and the body goes using it without us knowing, until we reach a point where we suffer symptoms without knowing it.

Red blood cells

Folic acid and vitamin B12 play a key role in the production of red blood cells, which are essential for the proper functioning of the body as they transport oxygen through the blood to the cells. Therefore, a deficiency of both can lead to anaemia, which causes damage to organ tissue because they do not receive enough oxygen and its serious consequences.


Another function they perform together is the production of DNA. Therefore, if a deficiency of these occurs, this function can be seriously impaired. Having one of the two low vitamins is a serious problem at this level, therefore, suffering from lack of both can be something really serious.


Having good levels of both cobalamin and folic acid in the blood is very important at any stage of life, but especially in pregnancy. Well, the deficiency of both micronutrients during pregnancy can have serious consequences for the fetus, such as deformities in brain development or growth. In addition, they increase the chances of preterm birth.

Also, to indicate that the fetus uses these micro nutrients so it is possible that, by feeding, you suffer from the lack of them and this situation occurs even though at first your levels were good; for this reason, supplements in pregnancy are a necessity.

Cardiovascular diseases

Cyanocobalamin has a fundamental role in the body’s cardiovascular system. It keeps homocysteine at its correct levels; and that is that, if homocysteine is at very high values, the chances of suffering from diseases such as myocardial infarction increase considerably.

Vitamin B9 also acts on this amino acid by participating in the synthesis of lametionin, reducing its levels, so that, in the same way, it helps to reduce the amount and severity of heart problems.

Mental Illness

A lack of the two micronutrients together in the body does not only cause diseases and pathologies at the physical level, but also mental. Vitamin B12 is key for the preservation of the myelin sheath around neurons, as well as for the production of neurotransmitters.

Therefore, at low levels of vitamin B12, the odds of mental illness such as depression increase significantly. On the other hand, it has been proven that adding folate to antidepression treatments improves the effects of these treatments.

Skin and nails

Another consequence is that there are changes in the appearance of hair, skin and nails. On the one hand, hair falls out much more frequently and, on the other hand, more often. On the other hand, the skin becomes paler. And finally, the nails become discolored.

Sources of vitamin B12 and folic acid

As we mentioned, we are fortunate to find natural sources of these micro-nutrients, so if there is no problem, a balanced diet will provide us with good or almost good amounts of them.

Main natural sources of cobalamin

Here are the main foods rich in B12:

  • Meat: Meat is one of the foods with the highest vitamin B12 intake. The loin and tenderloin of beef are one of the pieces that have more quantity; 13 micrograms per 100 grams. Although, without a doubt, it is the animal liver that provides the body with the most contribution, up to 30 micrograms per 100 grams. For low-calorie diets, nothing beats cooked chicken breast, also with up to 30 micrograms per 100 grams.
  • Fish: Fish are also a very healthy food that is worth including in the diet to ensure a good level of this in blood. The species that provides the greatest contribution is salmon; 10 micrograms for an average portion of about 150 grams of grilled salmon. Tuna, mackerel, sardine or herring are also great options, as are fish eggs.
  • Molluscs: Within the mollusks, there are different species that provide the amount that the body needs for its proper functioning. Clams offer 1 microgram of B12 per gram. Equally suitable are mussels and oysters. Also the octopus, with 20 micrograms per 100 grams of food.
  • Eggs: Eggs are a very rich food in cobalamin and, in addition, are present in the vast majority of diets. Virtually all of this micronutrient is found in the yolk. A Class L egg provides 1.3 micrograms.
  • Dairy: A glass of skim milk has 1 microgram of vitamin B12. There are also some dairy derivatives with a large amount of this micronutrient. For example, emmental type cheese provides 3 micrograms per 100 grams of product but any hard or cured cheese has a considerable amount, a matter of taste!
  • Tempeh: Within plant foods, tempeh, a derivative of fermented soybean, is the one that has the highest amount; 0.1 micrograms per 100 grams of dry product.

Main sources of natural folic acid

The main natural sources of B9 are the following:

  • Yeast Extract: Provides no less than 1000 micrograms of folic acid per 100 grams of product. In addition, this food has a wide range of benefits for the body and has significant amounts of other vitamins.
  • Wheat Germ: Another fantastic option to give the body the amount of folic acid it needs. 425 micrograms of this micronutrient per 100 grams. It is also a food very rich in thiamine and niacin, two compounds that protect cell metabolism.
  • White bean: Another plant food very rich in folic acid; 388 micrograms per 100 grams. It also contains a large amount of iron, which, along with folic acid, prevents the body from developing anemia.
  • Agar seaweed: It stands out a great deal in terms of folic acid content by providing 580 micrograms per 100 grams of dry seaweed.
  • Liver: Turkey, followed by chicken and veal, are the richest in folate. In addition, they have many minerals and omega 3 and omega 6.
  • Brown rice: With 49 micrograms per 100 grams of rice, it becomes the ideal resource for children to grow with the right dose of B9.
  • Dark vegetables: Turnip and spinach lead with 194 micrograms at 100; raw cabbage leaf is also an excellent choice.
  • Green asparagus: Asparagus, in addition to having high levels of B9, is a food with lots of benefits, including increasing insulin, detoxifying the body and transporting glucose.


Vitamin B12 Supplements for vegans

As you have been able to see, keeping them at good levels in the body is key to good health, both physically and mentally. Of course, knowing when these levels are correct is by no means simple.

Vitamin B12 supplements

There are many different types of supplements. The most common is to take them in pill or pill form; the most common dosage is to take 1 pill a week of between 1000 and 2000 micrograms, depending on the dosage needed.

People who have problems absorbing vitamin A in their bodies cannot take supplements in pill form because it needs to be absorbed in the same way as any food. Therefore, they need supplements that come into direct contact with the bloodstream, such as nasal gels or injections.

Folic acid supplements

Folate supplements can be used to treat folic acid deficiency, as well as to treat certain menstrual problems and leg ulcers.

For pregnant women, having good levels of folic acid in the body is essential. During gestation, the need for folate in the body is greater because of the cell division that occurs in the fetus.

Well, the recommended daily allowance is 400 micrograms per day to prevent neural tube defects. Thus, all pregnant women should take supplements of this micronutrient from the beginning to 12 weeks of gestation. Then, depending on the follow-up, it is softened or removed.

In any case, it is not only pregnant women who take this type of supplement; anyone who has the symptoms described above or who directly knows that they have low B9 levels should take them. So will those who know they have malabsorption problems.

Vitamin B12 and folic acid supplements

There are also supplements that contain both micronutrients and also those that offer you all the B-complex vitamins and even a mixture with the recommended dose of all the vitamins (and also minerals). If you suffer from a lack of both, the best option is to opt for a multivitamin supplement, more complete and easy to consume.

A note about supplements

It is true that B9 supplements have sometimes corrected anemia caused by a lack of B12, so many people opt for folate pills to “kill two birds with one stone”. However, if they are different it is because they have different functions and folic acid supplements unfortunately cannot correct the nervous system changes that have occurred because they do not have enough cobalamin; therefore, if you have a lack of cobalamin and folate, you have to take both; there is no other option.


By way of conclusion, we would like to stress the importance of following a healthy and balanced diet in order to enjoy a good state of health, both physical and mental; a diet that includes all types of food, i. e. a diet with variety. Both cobalamin and folate are two essential micronutrients for the body whose benefits are seen in both the medium and long term. As we have mentioned, the deficiency of both micronutrients in the body can have very negative health consequences.

Therefore, our recommendation is to supplement the diet with supplements of both vitamins; it is the best way to make sure that the levels of these micronutrients in the body are correct. There are supplements for all kinds of tastes and preferences, in different formats and different coverage, so you can take the quantities you really need.

And finally, to enjoy a good quality of life, it is essential to exercise regularly; 3 or 4 times a week.

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Did you know the problems that can lead to lack of B12 and folic acid? What about their differences? If you have questions, advice or experiences to tell, don’t be shy, share them in the comments.

If you found it helpful or have any questions, please comment and share, thank you! 😉

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