A neurologist has issued a stark warning about the dangers of over-supplementing, highlighting three popular options.
Fiona Callingham Lifestyle writer
14:09, 02 Sep 2025Updated 15:30, 02 Sep 2025
Three supplements could be damaging to the brain if taken in excess(Image: Getty)
Brits have been issued a serious warning about dietary supplements, with a neurologist alerting that some could be “toxic” to the brain. Not adhering to the recommended doses of these tablets might lead to damage to your brain and nervous system, the expert has cautioned.
Numerous people rely on daily supplements to ensure they obtain adequate vitamins and minerals that may be lacking in their usual diet. Others struggle to properly absorb these vital nutrients from food sources alone and need extra assistance.
Whilst these supplements can be crucial, they may also present dangers when misused. With this worry in mind, one expert identified three supplements that could “harm” the brain if taken in excess.
Using the social media platform TikTok, neurologist Doctor Baibing Chen – known online as Dr Bing – warned against taking “too much” of these specific supplements.
Zinc
Dr Bing explained that this mineral is frequently used as a supplement to enhance immune system function and prevent colds. He said: “It’s found in multivitamins, lozenges, and even some over-the-counter cold remedies.
“Now, zinc is essential for our bodies and can be found in multiple food sources. But the problem is when people take supplements daily for months, they can easily go over the safe limit.”
According to Dr Bing, taking “too much” zinc can interfere with copper absorption. He said: “Copper is essential for your nervous system. And low copper levels can cause something called myeloneuropathy, which is damage to the spinal cord and your peripheral nerves, leading to things like numbness, tingling and trouble walking.
“And I’ve seen several cases of this where people come in with progressive weakness and sensory loss due to copper deficiency from long-term zinc overuse.” The NHS also warns that high zinc doses reduce the body’s capacity to absorb copper.
“This can lead to anaemia and weakening of the bones,” it explains. As a result, the Department of Health and Social Care recommends not exceeding 25mg of zinc supplements per day “unless advised to by a doctor”.
Content cannot be displayed without consentVitamin A
Vitamin A, also known as retinol, performs numerous crucial roles in the body. These include strengthening your body’s natural defences against illness and infection, aiding vision in dim light, and keeping skin healthy.
Dr Bing said: “Vitamin A is fat soluble, which means that it stores in your liver and it can accumulate over time. Too much of this can lead to a condition called pseudotumor cerebri, which is increased pressure in the brain that mimics a brain tumour, causing headaches, blurred vision and even permanent vision loss.”
The NHS has issued a warning: “If you take a supplement that contains vitamin A, do not take too much because this could be harmful.”
Pregnant women are also advised to avoid vitamin A supplements unless specifically recommended by their GP. According to the health service, consuming an average of 1.5mg daily or less of vitamin A from both food and supplements is “unlikely to cause any harm”.
Vitamin D
This vital vitamin is key in maintaining healthy bones and muscles. Most of our vitamin D intake comes from exposure to sunlight.
In the UK, the Government advises taking a daily vitamin D supplement during the autumn and winter months. However, caution must be exercised regarding the amount consumed.
“Taking too high doses of vitamin D can cause calcium to build up in your blood, which can affect the brain, leading to things like confusion, fatigue, depression, and sometimes even psychosis,” warned Dr Bing. “So while these vitamins and minerals are essential for our bodies to function, moderation is key, like almost everything else in life, and more is not always better.”
The NHS further clarifies: “Taking too many vitamin D supplements over a long period of time can cause too much calcium to build up in the body (hypercalcaemia). This can weaken the bones and damage the kidneys and the heart.
“If you choose to take vitamin D supplements, 10 micrograms a day will be enough for most people.” The health authority warns not to exceed 100 micrograms (4,000 IU) of vitamin D daily, as it could “be harmful”.