Recent studies have observed that high Vitamin B12 levels are associated with increased risk of cancer. What does this mean for people who consume supplements without proper advice? Dr Bhuvan Chugh, lead consultant, medical oncology, Indraprastha Apollo Hospital, Delhi, says: “The first thing to understand is that a high Vitamin B12 level does not automatically mean that Vitamin B12 causes cancer.
In many people, an elevated B12 level may be a marker of something else happening in the body, such as recent injections or tablets, liver disease, kidney disease, inflammatory conditions, blood disorders, or an undiagnosed illness. Supplements should not be taken as a lifestyle habit without a clear need. Many people take B12 or multivitamins for tiredness, energy, immunity, or general wellness, without testing. With a genuine deficiency, B12 replacement is important, but repeated high-dose tablets or injections without indication can lead to persistently high blood levels and may make clinical interpretation more difficult. The practical rule is: supplements should correct a deficiency, not become a mindless habit.”
Vitamin B is water-soluble. Does the body not flush out extra amounts?
Vitamin B12 is water-soluble, and the body can remove some excess through urine. But ‘water-soluble’ does not mean that excess intake is always meaningless. Vitamin B12 is also stored in the body, especially in the liver, which can last for a long time. Also, many supplements and injections contain doses far higher than the daily requirement. Repeated high-dose use can keep blood levels elevated. The point is that taking high-dose B12 without a reason is usually unnecessary, may not provide any benefit, and can confuse the overall health picture.
Which supplements are harmful if taken unregulated and without medical advice?
Vitamin D is one of the most commonly overused supplements. Excessive intake can raise calcium levels and may cause kidney stones, dehydration, weakness, rhythm problems, or kidney injury in severe cases. Excess iron can cause gastrointestinal side effects, can accumulate, and can also delay proper evaluation of the real cause of anaemia, such as bleeding. Calcium unnecessary supplementation may increase the risk of kidney stones in susceptible individuals.
Vitamin A is a fat-soluble vitamin and can accumulate. Excess preformed Vitamin A can affect the liver, bones, skin, nervous system, and pregnancy outcomes. High doses of zinc over time can reduce copper absorption and may cause anaemia, neurological symptoms, and immune imbalance. Biotin may not be toxic in the usual sense, but it can interfere with important blood tests, including thyroid tests and cardiac troponin tests.
Even ‘natural’ or ‘herbal’ supplements are not automatically safe. Some can interact with blood thinners, cancer , diabetes, and heart medicines, or liver function.
How frequently should people on supplements test their levels to adjust dosage and use?
The timing depends on the supplement, the reason it was started, the dose, symptoms, and the person’s medical background. For people taking supplements to correct a documented deficiency, a review after about 8-12 weeks, or around 3 months, is reasonable in many situations. The doctor may repeat the relevant blood test, review symptoms, or adjust the dose.
For long-term supplementation, monitoring every 6-12 months may be enough, especially if they are stable and taking maintenance doses. For high-dose Vitamin D, iron, calcium, or multiple supplements together, monitoring may need to be earlier and more specific. For Vitamin B12 , symptoms, blood counts, the cause of deficiency, diet, medicines such as metformin or acid-suppressing drugs, and absorption issues all matter.
The bigger message is this: Do not start supplements blindly, do not continue them indefinitely without a reason, and do not use blood tests only to chase ‘perfect’ numbers. Use supplements like treatment with an indication, a dose, a duration, and a review plan.
Disclaimer: The information in this article is for educational and informational purposes only and is not intended as medical advice. While the author has incorporated expert medical guidance while producing the story and ensured full authentic information is provided to the reader, you should always seek the advice of a qualified healthcare provider regarding a medical condition or treatment. Never disregard professional medical advice or delay in seeking it because of something you have read here.