Folic acid and vitamin B12 deficiency: What you should know

In this blog post, we provide an overview of what vitamin B12 and folic acid, or a deficiency in these nutrients, can cause in your body. Vitamin B12 belongs to the cobalamin group of substances. Methylcobalamin is a bioactive and natural form of vitamin B12. Folic acid, or vitamin B9 or folate, is also known by the term pteroylglutamic acid.

It is found in both plant and animal foods. However, it is lost if cooked for too long. In natural food components, folic acid is bound to polyglutamic acids. Within folic acid metabolism, small intestine enzymes convert the polyglutamine form into monoglutamines and diglutamines. These are finally absorbed in the upper part of the small intestine, the so-called jejunum.

In the blood, folates are present exclusively as monoglutamate (the free form of folic acid), mostly in the form of 5-methyltetrahydrofolate, which binds to albumin. High-affinity folic acid receptors of all possible body cells bind to this structure. 5-methyltetrahydrofolate is finally converted by a vitamin B12-dependent enzyme into tetrahydrofolate and eventually into a polyglutamate so that a folate-dependent enzyme reaction can take place.

The excretion of folate and vitamin B12 takes place via the bile, and absorption via the small intestine. However, both nutrients can also be excreted in the urine. So much for folic acid metabolism, but how does a folic acid deficiency actually occur?

Folic acid deficiency: causes, treatment, consequences, and diagnosis

A folic acid deficiency does not happen by chance and entails unwanted risks. As a rule, however, it can be treated well. But what causes it, how can it be diagnosed, and how can it be combated?

What are the causes of a folic acid deficiency?

Usually, a folic acid deficiency is caused by an unbalanced diet and the resulting inadequate intake. Healthy people who eat a balanced diet and do not suffer from impaired intestinal absorption generally do not have a folic acid deficiency. A mixed diet in Germany contains about 200 to 500 µg of folate daily. On average, we lose 50 to 100 µg of this per day. The following groups of people can, among others, still be affected by a folic acid deficiency due to increased consumption:

• chronic alcoholics (excluding beer drinkers, as beer is rich in folic acid and vitamin B12)
• pregnant and breastfeeding women
• elderly people, due to an increased risk of diseases such as dementia and stroke
• people with increased metabolic activity (hypermetabolism)
• people with skin and intestinal diseases
• people suffering from chronic hemolytic anemia, diabetes, or cardiovascular diseases
• those affected by a small intestine disease
• people who take medication such as sulfonamides (chemotherapeutics) or anticonvulsants (antiepileptics)
• people with intolerances such as celiac disease

Those affected who suffer from intestinal diseases or celiac disease also have impaired vitamin B12 absorption in the intestine, which promotes a vitamin B12 deficiency.

Therapy: supplementation of nutrients B9 and B12

The need for B9 increases not only during pregnancy and breastfeeding, but also in elderly people and individuals with specific illnesses. In people with intolerances, the number of tolerable foods is often strictly limited, which can also lead to a folic acid and B12 deficiency. In particular, we therefore recommend that the aforementioned people and those affected by histamine issues take dietary supplements to counteract not only a B9 but also a B12 deficiency. (Provided that the individuals cannot cover their daily requirements through their diet.)

Important: Especially if a nutrient deficiency is suspected or diagnosed, you should clarify the intake of dietary supplements with a doctor and have it tailored to your individual needs.

What happens when there is too little folic acid and B12 in the body?

Single-carbon groups such as methylene, formyl, or methyl groups are transferred by folic acid to various substrates by means of numerous enzymatic reactions. These support the synthesis of proteins, RNA, and DNA. If there is a deficiency of folic acid or inhibited dihydrofolate reductase, there are too few folate compounds in the body cells, which can impair both the growth and maturation of rapidly growing cells, such as bone marrow cells. Folate has a function in cell division and also contributes to the following important processes in the body:

• growth of maternal tissue during pregnancy
• normal amino acid synthesis
• normal blood formation
• normal homocysteine metabolism
• normal psychological function
• normal function of the immune system
• reduction of tiredness and fatigue

A folate deficiency can cause anemia, loss of appetite, weight loss, miscarriages, shortness of breath, heart disease, immune deficiency, or an increased tendency to bleed.

Diagnosis of a folate deficiency

A test that examines the excretion of formiminoglutamic acid after histidine loading can be used to check whether you have a disorder of folic acid-vitamin B12 metabolism. If excretion is increased, this may indicate a folic acid deficiency, but also liver diseases or anemia. Causes can be the following:

• reduced formation of enzymes (tetrahydrofolate synthesis and formiminoglutamic acid degradation) in the liver
• diseases that increase the need for tetrahydrofolic acid and stimulate cell regeneration as well as nucleic acid synthesis
• too little tetrahydrofolic acid due to inhibited dihydrofolate reductase (due to a deficiency of folic acid or vitamin B12 or folic acid antagonists)

Which foods are rich in folic acid and vitamin B12 and fit into a low-histamine diet?

To ensure you receive an adequate supply of folic acid, we have created a list of folic acid-containing and low-histamine foods for you:

• lamb's lettuce
• potatoes
• egg yolk (also rich in B12)
• sour cherries
• kale
• quinoa
• Brussels sprouts
• cauliflower
• endive lettuce
• leek (1)
• asparagus
• fennel
• almonds (1)
• sesame (1)

Vitamin B12 is mainly contained in animal and histamine-rich foods.