Even vitamins can be toxic: what is important to remember when taking dietary supplements

Many people buy various vitamin complexes without consulting a doctor. It seems that such supplements are quite harmless: they are sold not only in pharmacies without a prescription but even on marketplaces. And the label on the bottle stating “Dietary supplement is not a medicinal product” can lull someone’s vigilance, writes “Doctor Peter.”

“People think that since vitamins are natural and can be bought over the counter, they won’t cause harm, but that’s not entirely true,” says American neurologist Baibing Chen on his channel.

According to the doctor, some vitamins can indeed become toxic if dosage guidelines are not followed. Among them are fat-soluble vitamins A, D, E, and K, which accumulate in the body.

For example, vitamin D can cause hypercalcemia — a life-threatening condition where calcium accumulates in the blood. Vitamin A overdose manifests as dry and peeling skin, severe itching, rashes, hair loss, migraines, dizziness, and even joint pain. In severe cases, it can lead to paralysis.

Excess vitamin E leads to headaches, gastrointestinal disturbances, and skin problems. Additionally, bones become brittle, and due to its effect on platelets, there is a risk of bleeding.

Conversely, vitamin K overdose increases blood clotting, which can lead to thrombosis and even strokes. Due to excessive strain on the liver, there is a risk of developing toxic hepatitis.

However, even water-soluble vitamins, which should be excreted in urine, are not always harmless. Here, neurologist Chen particularly highlights vitamin B6, also known as pyridoxine.

This vitamin is necessary for absorbing and storing energy that the body gets from proteins and carbohydrates. Additionally, pyridoxine helps produce hemoglobin, which is responsible for oxygen transport. However, in large doses, this vitamin can be very dangerous.

“As a neurologist, I have often encountered this phenomenon where high concentrations of vitamin B6 become toxic. It disrupts normal neuronal signal transmission, can overstimulate and damage sensory neurons, which then leads to degeneration of these nerve fibers,” explains the doctor.

This can later provoke peripheral neuropathy — a condition where the conductivity of peripheral nerves is impaired.

“Patients develop numbness, tingling, burning, pain, and balance problems, as the brain receives distorted or incomplete sensory information,” says neurologist Chen.

According to the expert, one large dose of the vitamin is unlikely to cause significant harm. The risk arises when vitamin B6 is taken uncontrollably.

“I had a young patient who took multivitamins, energy drinks, an anti-stress supplement, and sleeping pills every day. None of these supplements seemed extreme, but they all contained vitamin B6. The patient was unaware of this, and as a result, he developed neuropathy,” says the doctor.

According to the neurologist, usually, after stopping the supplements, the symptoms of neuropathy disappear. However, in some cases, when people took large doses of vitamin B6 for several months, the effect was already irreversible.

Therefore, it is best to obtain vitamin B6 from your diet. Rich sources of pyridoxine include pork, poultry, peanuts, soy, oats, and bananas.

Experts remind us that even vitamins and dietary supplements require a reasonable approach. People taking blood-thinning medications, as well as patients with heart and kidney diseases, should be especially cautious. Before starting any vitamin complexes, doctors recommend assessing the actual needs of the body and consulting a specialist if necessary to avoid the dangerous consequences of overdose.