The Myths Behind Multivitamins

Many patients start their day with a multivitamin, believing it’s a form of “nutritional insurance.” The supplement industry thrives on this idea, promoting pills as an easy fix for dietary shortcomings. But for most healthy adults, are multivitamins truly necessary — or are they simply expensive reassurance? As clinicians, we need to separate marketing claims from evidence-based practice.

Myth 1: Multivitamins Can Compensate for a Poor Diet

Many believe a multivitamin can fill nutritional gaps from an unbalanced diet. In reality, if a person’s diet is consistently poor, a multivitamin offers limited benefit.
A healthy, varied diet provides nutrients in the right balance and form that supplements can’t replicate.
Without dietary improvement, multivitamins may do little more than create expensive urine.
Key message for patients: Focus on improving food choices first — supplements should only support, not replace, a healthy diet.

Myth 2: More Vitamins Mean Better Health

“More” is not always “better.”
Fat-soluble vitamins such as A, D, E, and K can accumulate in the body and cause toxicity if taken in excess.

• Too much Vitamin A may damage the liver.
• Excess Vitamin D can cause dangerously high calcium levels.
• High iron doses can lead to poisoning, especially in children.

Key message for patients: Always follow recommended doses. If unsure, seek advice from a pharmacist or GP before starting or combining supplements.

Myth 3: ‘Natural’ Means Safe

“Natural” supplements can still have potent effects — and interact with prescription medicines.

• St John’s Wort can reduce the effectiveness of oral contraceptives, antidepressants, and transplant medications.
• Fish oil (Omega-3) can increase bleeding risk when taken with anticoagulants such as warfarin.
• Ginkgo Biloba can interfere with anti-seizure treatments.

Key message for patients: Always bring up herbal and vitamin products during medication reviews. They may affect safety and efficacy.

When Are Supplements Clinically Indicated?

While routine multivitamin use isn’t necessary for most, targeted supplementation is appropriate in specific, evidence-based cases.
Certain long-term medicines can deplete key nutrients:

• Proton Pump Inhibitors (PPIs): may reduce absorption of Vitamin B12 and Magnesium.
• Metformin: can lower Vitamin B12 levels over time.

Clinical approach:

• Review medication history and dietary intake.
• Use blood tests to guide supplementation rather than assuming deficiency.

In Summary

Asking about supplements during medication reviews is essential to ensure you get a full profile. It helps identify areas that may be a priority for patients. E.g. a lot of patients take B12 for low energy or Fish Oils for heart health. Knowing supplements a patient takes may help identify any health concerns a patient has.