May 2022

Megadoses are Megapopular

Since the start of the COVID-19 pandemic, taking megadoses of vitamins has become almost commonplace. There are more products available than ever and they come in all forms and flavors – from tablets and gummies to powders and drinks. With consumers taking more of these products on a regular basis, it’s important to educate them about the potential negative effects of megadoses, and which types of products and vitamins are most concerning.

Fat-soluble vitamins carry the greatest risks. Unlike water-soluble vitamins, the body stores these in fatty tissues and excess amounts are eliminated much slower. Vitamin D is one to keep an eye on. With so much buzz around vitamin D for COVID-19, many people started taking large doses on a regular basis. While toxicity isn’t common, there is concern that long-term intake of very high doses can increase the risk of hypercalcemia, which can cause serious health issues. There are similar concerns for other fat-soluble vitamins as well. Vitamin A is found in acne medications, topical retinoid products, and supplements and multivitamins. Taking high doses of vitamin A long-term can do more harm than good – it’s been linked to increased risk of death from any cause. Similarly, taking regular high doses of vitamin E has led to significant side effects in otherwise healthy people.

Large amounts of water-soluble vitamins aren’t necessarily safe either. Immune health concerns have prompted many people to reach for high-dose vitamin C products. But large doses can increase the risk for gastrointestinal side effects. Vitamin B6 is another good example – taking high daily doses for an extended period of time can cause neuropathy. And taking high doses of folic acid long-term (3-10 years) has been linked to an increased risk of cancer.

High-dose products come in many forms, but gummy products in particular have taken off over the past few years. They typically contain gelatin and added sugars, and are basically made to taste like candy – this can lead to consumers, especially children, taking more than they should. Additionally, many people now take high-dose single-vitamin products along with a multivitamin. Simply taking one of these along with a regular multivitamin could result in regular daily intake exceeding tolerable upper intake levels. Tell patients to focus on consuming a well-balanced diet and getting outside in the sun for around 15 minutes each day. If they still want to take a vitamin supplement, suggest a USP-verified multivitamin that contains doses that don’t exceed the recommended dietary allowance (RDA). And if possible, encourage patients to choose tablet or capsule products over gummies.

The information in this brief report is intended for informational purposes only, and is meant to help users better understand health concerns. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions. Copyright © 2024 NatMed. Commercial distribution or reproduction prohibited. NatMed is the leading provider of high-quality, evidence-based, clinically-relevant information on natural medicine, dietary supplements, herbs, vitamins, minerals, functional foods, diets, complementary practices, CAM modalities, exercises and medical conditions. Monograph sections include interactions with herbs, drugs, foods and labs, contraindications, depletions, dosing, toxicology, adverse effects, pregnancy and lactation data, synonyms, safety and effectiveness.