Biotin: effects & side effects of vitamin B7

Biotin has experienced a real boom as a dietary supplement in recent years: Capsules and tablets with biotin are said to ensure beautiful hair, strengthen fingernails and counteract inflammatory skin reactions such as acne. But what exactly is the advertised effect of biotin on? Can side effects occur from taking biotin supplements and which foods contain the vitamin?

What is biotin and what effect does it have in the body?

Biotin was originally called vitamin H because its importance for the skin was recognized early on. However  , like folic acid  , biotin is part of the vitamin B complex and is therefore now also known as  vitamin B7  . Biotin is water-soluble and can be bound by the proteins streptavidin and avidin in the body, which makes it more difficult for the vitamin to be used in the intestine.

 Biotin plays an important role in the metabolism of fatty acids,  carbohydrates and proteins, as well as in the cell nucleus. It is also involved in the regulation of blood sugar levels and contributes to the functioning of the nervous system. It is also required for the body’s own production of  creatine  – one of the building blocks for hair and nails.

Vitamin B7 is therefore needed for numerous bodily functions.

What is the daily requirement of biotin?

The exact daily requirement of biotin is not known. However, there are reference values ​​that should serve as a guide for approximate requirements.

According to the German Society for Nutrition, the daily requirement for young people from the age of 15 and adults as well as pregnant women is around  40 micrograms of  biotin, i.e. 0.04 milligrams. Breastfeeding women have a slightly higher requirement of 45 micrograms (0.045 milligrams) per day.

biotin in food

With a balanced diet, the daily requirement of biotin can easily be covered through normal food intake. The vitamin is heat-resistant, but also water-soluble, so that parts of cooked food can migrate into the cooking water.

Some foods are true biotin donors. These include, for example:

• dry yeast
• beef liver
• Eggs, especially yolks (not raw)
• soybeans
• whole grain oatmeal
• walnuts
• Mushrooms
• Spinach
• bananas
• Milch
• Kidneys
• brown rice

The daily requirement can, for example, be almost covered with 200 grams of mushrooms (29 micrograms of biotin) and 50 grams of wholemeal oat flakes (10 micrograms). Two slices  of wholemeal bread  (9 micrograms of biotin) and a boiled egg (12 micrograms) already cover half of the daily requirement.

Biotin: Vitamin B7 deficiency is rare

Biotin is essential for important processes in the body. Unlike some other essential vitamins, the body usually absorbs enough biotin from food. Therefore, healthy people who eat a balanced diet very rarely suffer from a biotin deficiency.

Possible symptoms of a biotin deficiency can be:

• Hair loss, dull and brittle hair
• Skin disorders and skin changes, such as scaly skin, especially in children on the nose, mouth and rectum, as well as excessive sebum production
• brittle nails
• conjunctivitis
• torn corners of the mouth (rhagades)
• Muscle aches
• depressions
• elevated cholesterol levels
• loss of appetite,  nausea  and vomiting
• fatty liver
• hallucinations
• anemia
• movement disorders

Risk groups for a biotin deficiency

Smokers and alcoholics are susceptible to a biotin deficiency due to the poorer utilization of vitamins and the higher requirement. Breastfeeding mothers are also at higher risk of deficiency.

In addition, a biotin deficiency often occurs in people who suffer from certain metabolic diseases (such as a biotinidase deficiency). A biotinidase deficiency is understood as the lack of activity of the enzyme biotinidase. This is required on the one hand to release biotin from chemical compounds that it enters into in the body and on the other hand to make biotin from food available to the body.

Long-term use of antiepileptics and  antibiotics can also  lead to a biotin deficiency  due to impaired utilization and a disruption of the  intestinal flora .

Eating several raw eggs a day over a long period of time can also cause a vitamin B7 deficiency. The reason for this is the protein avidin contained in raw eggs, which binds biotin to itself and thus makes it unusable for the body. However, heating the eggs destroys the protein.

Anyone who has a medically diagnosed biotin deficiency cannot usually remedy it by eating certain foods, but must resort to capsules or tablets with biotin.

Laboratory values: when is there a biotin deficiency?

The biotin levels are determined via the blood serum or a urine sample. In the blood serum, however, changes in the biotin level can only be detected at a late stage. The values ​​in the blood serum should be between 200 and 800 pg/ml (picograms per milliliter). Values  ​​below 100 pg/ml indicate  a deficiency.

In the 24-hour urine collection, i.e. the collected amount of urine that was excreted during this time, there should normally be a value of 18 to 77 nanomoles of biotin. Values  ​​below 18 nanomoles  are referred to as a deficiency.

Preparations with biotin: effect on hair, skin and nails

More and more women in particular are using biotin-containing capsules and tablets as dietary supplements to positively influence the structure or growth of their skin, hair and nails. You can also buy creams or shampoos with biotin.

Basically, it has been proven that biotin is needed to maintain the health of skin and hair. The European Union therefore allows advertising statements such as “Biotin helps to maintain normal skin or normal hair” for food supplements. However, there is no scientific evidence that the additional supply of biotin via dietary supplements can specifically improve the complexion or, for example, stimulate hair growth.

The effectiveness of creams or shampoos with vitamin B7 can also be questioned, since the body can hardly absorb biotin through the skin and hair.

The positive effect of biotin on the nails has not yet been proven. A lack of the vitamin can show up as brittle nails. However, whether the additional intake of preparations with biotin or the use of nail creams containing biotin can contribute to strengthening the nails is controversial. To date, there have been no clinical studies on its effectiveness in humans.

The general rule is: biotin has been proven to help keep hair and skin healthy. It is not clear whether the additional intake of biotin preparations in addition to a biotin-rich diet also provides an additional benefit.

Capsules and tablets as combination preparations

If you are looking for an all-round wellness package from the inside, you will usually come across tablets and capsules in the drugstore, health food store or pharmacy that contain additional active ingredients in addition to biotin. These include selenium,  zinc  or silica. The term silica describes various sediments and minerals that have a high silicon content. Zinc is primarily said to protect the  immune system  , selenium and silica are also said to contribute to healthy skin and healthy hair and nails.

While such benefits have not been demonstrated for silica, selenium does help keep hair and nails healthy. In too high a dose, however, selenium can lead to side effects such as gastrointestinal complaints, blurred vision and skin damage. Overdosing on zinc can also have negative health effects. These include nausea,  diarrhea  and headaches.

Biotin: Overdose Side Effects?

According to the current state of knowledge, there are no side effects from taking biotin preparations  .  Excess amounts are excreted through the kidneys. There is also no evidence of a carcinogenic effect, as has been demonstrated in certain risk groups when taking beta-carotene.

However, biotin is often available in the form of combination preparations with zinc and/or selenium. Both substances can cause side effects in excessive doses.

It’s also important to know that taking biotin supplements can falsify the  results of certain laboratory tests  . These include the so-called immunoassays. For these, the results are determined based on the interaction of biotin with the proteins avidin or streptavidin. Biotin that is additionally contained in the blood can influence these values ​​and lead to incorrect results, for example, when determining troponin to diagnose a heart attack or when determining tumor markers in cancer.

If a medical laboratory test is carried out, it should always be pointed out if biotin preparations have been taken.