Vitamin B5 (pantothenic acid)

What is it

Vitamin B5 or pantothenic acid, water-soluble, is the precursor of coenzyme A, essential for the production of energy from carbohydrates, fats and proteins.From a chemical point of view it can be considered as a molecule of pantoic acid complexed with a molecule of beta-alanine (an amino acid that is not used for protein synthesis).

As mentioned, it is a water-soluble vitamin. It belongs to the so-called “vitamin B2 complex”, a term used in the past to identify some B vitamins except for thiamine (therefore riboflavin or vitamin B2, nicotinamide, niacin or vitamin B3, pyridoxine or vitamin B6, biotin or vitamin B7, folic acid or vitamin B9, cobalamin or vitamin B12 and, precisely, pantothenic acid or vitamin B5) together with para-aminobenzoic acid, choline and inositol.

Food sources

It is no coincidence that vitamin B5 is also called pantothenic acid. In fact, this second name derives from the Greek term “pantothen”, which means “from everywhere”, and in fact vitamin B5 is widely present in several foods:

• some legumes (peas, lentils)
• Grains
• wheat bran and wheat germ
• buckwheat
• brewer’s yeast
• soybean
• Peanut
• ginger
• royal jelly
• beef and chicken
• offal (especially the liver))
• milk and yoghurt
• several other foods of plant origin (such as shitake mushrooms, sunflower seeds, and even fruit, especially avocado)
• fish, especially tuna.

Lobster and eggs (especially egg yolk) also contain significant amounts.

Most of the vitamin B5 contained in food (about 85%) is present in the form of coenzyme A or phosphopantheein.

Both of these molecules are converted into pantothenic acid by digestive enzymes in the gut and intestinal cells.

Pantothenic acid produced in the digestive tract ends up directly in the bloodstream, while panthein derived from phosphopantheein is first absorbed by the cells of the intestine, which convert it into pantothenic acid and then pour the latter into the blood.

The intestinal bacterial flora also produces a little pantothenic acid; however, it is still unclear how much of the vitamin B5 absorbed by the body comes from the activity of bacteria in the gut.

Once in the blood, pantothenic acid is transported by red blood cells to the various tissues of the body, where it is found mainly in the form of coenzyme A and only in smaller quantities as a protein transporter of acyls or free pantothenic acid.

Unfortunately, however, the available data indicate that the body absorbs only a variable amount between 40 and 60% of the vitamin B5 present in food.

Added to this is the fact that the manipulations to which the food is subjected (such as cooking) can cause significant losses of pantothenic acid present in it; The lost share can range from 20% to almost 80%.

Activity

Vitamin B5 is essential for various metabolic reactions and, as a precursor of coenzyme A, is involved not only in the production of energy from nutrients, but also in the synthesis and metabolism of steroid hormones, neurotransmitters and vitamin D.Pantothenic acid also contributes to the reduction of tiredness and fatigue and to maintain normal mental performance.

Vitamin B5 also enters the production mechanisms of fats, corticosteroids and sex hormones (estrogen, progesterone and testosterone, all steroid hormones produced from cholesterol). It is also necessary for the proper functioning of the adrenal glands and nervous system, as well as for normal growth and development.

In addition, vitamin B5 also participates in the synthesis of the acyl transporter protein (Acp), a molecule involved in the synthesis of fatty acids, and is essential for the use of other vitamins, protects cells from damage resulting from oxidation caused by free radicals by increasing glutathione levels.

As far as coenzyme A is concerned, its participation in acetylation reactions (which by modifying the body’s proteins can alter their functioning or their localization within the cell or, in the case of histones, regulate the expression of genes) and those of acylation, involved, instead, in the communication mechanisms between cells, is known.

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Deficiency

Fortunately, since pantothenic acid is present in almost all foods, it is rare to find yourself in situations where the body does not have enough of it. If present, it is associated with deficiency of other nutrients so it is difficult to identify specific symptoms.

Some data suggests that any shortcomings could trigger:

• numbness and burning sensations in the hands and feet
• headache
• fatigue
• irritability
• sleep disorders
• gastrointestinal problems with anorexia.

In general, however, studies have not so far shown symptoms of deficiency related to vitamin B5 alone, which generally occur only in situations of severe malnutrition. It should be remembered, however, that smoking inhibits its absorption.

In addition, there is a particular condition that exposes you to the risk of pantothenic acid insufficiencies: the presence of mutations in the Pank2 gene (pantothenate kinase 2).

Such mutations cause a rare immune disease – pantothenate kinase-associated neurodegeneration (Pkan) – that leads to iron buildup in the brain.

In individuals suffering from this pathology, a deficiency of the enzyme pantothenate kinase, involved in the synthesis of coenzyme A from pantothenic acid, is observed.

Symptoms of PKAN include:

• involuntary and exaggerated muscle contractions (dystonia and spasticity)
• retinitis pigmentosa (a disease that leads to progressive degeneration of the retina of both eyes).

Overdosage

Pantothenic acid can also be taken in the form of food supplements, for example a multivitamin product in which it can be combined with other vitamins of the group or minerals.

At present, no toxic effects or symptoms of hypervitaminosis due to a high intake of vitamin B5 are known.

Exceptions are mild diarrhea and intestinal discomfort found in some individuals after taking high doses of pantothenic acid, equal to 10 grams per day.

The mechanisms underlying these adverse effects are unknown.

Recommended doses

The daily requirement of vitamin B5 ranges between 3 and 12 mg per day, depending on age and gender. Being so widespread, it is not easy to identify a threshold below which specific problems begin to appear. According to the most recent European recommendations, an intake of 4-7 mg per day would be adequate for the majority of the population.As for the Italian guidelines, the scientific data available at the time when the last revision of the LARN (the reference intake levels of nutrients and energy for the Italian population) was developed, dating back to 2014, did not allow nutrition experts to include the average vitamin B5 requirement in the recommendations.

However, adequate intake levels have been established, which vary according to age.

In infants and children up to 3 years of age they are equal to 2 mg per day; They then rise to 2.5 mg between 4 and 6 years, to 3.5 mg between 7 and 10 years and to 4.5 between 11 and 14 years. From the age of 15 they stabilize at 5 mg per day, which is the appropriate intake level for adults, men and women.

In some particular conditions, however, it is better to take more; in particular, according to the LARN the adequate intake rises to 6 mg per day during pregnancy and to 7 mg per day during lactation. published by the Italian Society of Human Nutrition (Sinu) in 2014, adequate intake of vitamin B5 varies depending on the growth phase referred to.