Each B vitamin has its own purpose, but in general they are responsible for the health of the nervous system, eyes, hair, skin, and maintain the body's energy balance. Together with experts, we explain what B vitamins are, why their deficiency is dangerous, and what foods contain them.
- Deficit
- Excess
- Daily norm
- In what products
- Expert commentary
Elena Ostrovskaya, endocrinologist, specialist in preventive and anti-aging medicine at the European Medical Center (EMC);
Tamila Agaeva, endocrinologist at the Family clinic network.
Vitamin B deficiency
Deficiency of B vitamins of varying degrees occurs in approximately 40-60% of people, both adults and children (1), (2). Most often, severe symptoms are caused by a deficiency of three elements of the group – B1, B6 and B12. There are several reasons for B-avitaminosis, here are some (3):
- Unbalanced diet. B vitamins enter the body with food. The absence of foods rich in these substances in the diet leads to a deficiency.
- Bad habits: Smoking, excessive alcohol consumption, and addiction to sweets (added sugars) interfere with the absorption of B vitamins and provoke their destruction.
- Disruption of the digestive and secretory organs. Even if a person eats foods rich in B vitamins, poor digestive system function can impair their absorption and assimilation. This primarily concerns problems with the stomach, intestines and liver.
- Special conditions and diseases. B-deficiency can develop against the background of increased metabolism of vitamins. One of such conditions is pregnancy. For example, the need for folic acid (B9) during this period increases twofold (4). Separately, various diseases can provoke B-deficiencies – Crohn's disease, celiac disease or HIV. In addition, a lack of vitamins, not only B, is typical for older people (5).
Symptoms of a B vitamin deficiency depend on which vitamin is missing. They can range from feeling constantly tired or confused to anemia, skin rashes and weakened immune system.
Most functions of B vitamins are related to the maintenance of the nervous system. Therefore, among the non-specific symptoms of deficiency are weakness, fatigue, increased nervousness, sleep problems, especially in the case of vitamin B5 deficiency, says Elena Ostrovskaya, an endocrinologist, specialist in preventive and anti-aging medicine at the European Medical Center (EMC).
Deficiencies of B vitamins usually occur in those who love refined foods, especially cereals, wheat flour and sweets. The fact is that during the polishing of grains, the source of B vitamins disappears.
A deficiency of B vitamins may be associated with a lack of greens in the diet, such as spinach, a source of folic acid, as well as with gastrointestinal disorders, that is, difficulties with the absorption of these beneficial substances.
Elena Ostrovskaya listed the main signs of deficiency of each vitamin from group B.
Excess of vitamin B
Excess of B vitamins is a rare case, since they do not accumulate in the body, and their excess is excreted in the urine. (7) Much more common are hypervitaminosis, sometimes similar in clinical picture to poisoning, of vitamins A and D with prolonged use.
Overdose in group B is possible with vitamin B12, warns Elena Ostrovskaya. It can occur with long-term uncontrolled use of dietary supplements or vitamin preparations in large quantities. The main symptoms of excess vitamin B12 include:
- general intoxication;
- headache;
- dizziness;
- nausea.
But all these unpleasant conditions quickly end if you stop taking vitamin B12. After that, the level of the element will quickly return to normal.
Daily requirement of vitamin B
The main source of B vitamins is food. The value of a product in terms of the amount of vitamins is expressed through the recommended daily intake (RDI), which should be at least 20% per serving of the product.
But it is important to consider that the daily norm of B vitamins is individual. Therefore, average values are indicated taking into account gender and age. Thus, the physiological needs of children, adult men and women will be different. Here are the recommendations of the European Ministry of Health on the daily norm of B vitamins for adults and children (8):
Recommendations of the Ministry of Health of the European Federation for the daily intake of B vitamins (mg/mcg per day)
| — | V1 | C2 | V3 (niacin) | B5 (Pantothenic acid) | B6 | B7 (biotin) | B9 (folate) | B12 (folic acid) |
|---|---|---|---|---|---|---|---|---|
| Adults | of 1.5 mg | 1.8 mg | 20 mg | 5 mg | 2 mg | 50 mcg | 400 mcg | 3.0 mcg. |
| Children | from 0.3 to 1.5 mg | from 0.4 to 1.8 mg | from 5 to 20 mg | from 1 to 5 mg | from 0.4 to 2 mg | from 10 to 50 mcg | from 50 to 400 mcg | from 0.3 to 3.0 mcg |
There are also separate daily norms for B vitamins for men and women. For example, the US National Institute of Health (NIH) provides them, they are as follows: (9):
The norm of vitamin B for women:
- V1 — 1.1 mg;
- C2 — 1.1 mg;
- B3 — 14 mg;
- B5 — 5 mg;
- B6 — 1.3 mg;
- Biotin — 30 μg;
- Folic acid — 400 μg;
- B12 — 2.4 μg.
The norm of vitamin B for men:
- V1 — 1.2 mg;
- C2 — 1.3 mg;
- B3 — 16 mg;
- B5 — 5 mg;
- B6 — 1.3 mg;
- Biotin — 30 μg;
- Folic acid — 400 μg;
- B12 — 2.4 μg.
Healthy people who do not have a deficiency, to maintain a normal level of B vitamins, replenish the daily requirement through products rich in these elements, says Tamila Agaeva. During pregnancy and lactation, the need increases. In addition, the benefits of some B vitamins are mutual: B1, B6 and B12 are “friends” with each other, so they are prescribed in combination.
What foods contain B vitamins?
B vitamins are found in animal and plant foods. These include different types of meat and fish, legumes, eggs, milk, and greens. Here are some foods that are especially rich in B vitamins:
