Questions to Ask Your Clinician or Pharmacist About Mineral Supplements

Why bring questions

The US Food and Drug Administration advises talking to a doctor, pharmacist or other healthcare professional before deciding to buy or use a dietary supplement. [1] MedlinePlus gives the same direction: tell your health care provider about any supplements you use, and check with them if you are going to have surgery. [2] This page is a list of questions, not advice. It does not say whether you need any mineral; only someone who knows your health history can answer that. For label terms used below, see reading a mineral supplement label.

Urgent first. If a child may have swallowed iron or any mineral supplement, do not wait for an appointment. In the US call Poison Help at 1-800-222-1222, or 911 if the child is unwell; other countries are on Poison Help by country. The NHS says very high doses of iron can be fatal, particularly if taken by children. [3] See also iron overdose and child safety.

What to bring

• The product itself, or a photo of the Supplement Facts panel and the ingredient list, so the form, the elemental amount and the added ingredients can be checked.
• A written list of everything you take: prescription and over-the-counter medicines, vitamins, minerals, antacids, herbal products, and any fortified products or drinks you use often.
• Recent blood test results, if you have them.
• Your reason for considering the supplement, in your own words.

Questions about whether you need it

1. Is there a reason to think I am low in this mineral, and how would we know?
2. Is a blood or urine test useful here, and what exactly would it measure? A ferritin test, for example, shows how much iron your body is storing, [4] and for iron deficiency anaemia the NHS says a GP will usually do a blood test (a full blood count). [5]
3. Could my diet cover this instead? For several minerals, the NHS says you should be able to get all you need from a varied, balanced diet. [6][3]
4. If a test is done, what could change the result? MedlinePlus says inflammation from infection or surgery can affect ferritin results and that certain medicines can raise or lower ferritin. [4] The NHS adds that biotin (vitamin B7) can affect thyroid tests. [7]
5. What are the other possible causes of my symptoms? Symptoms alone do not show which mineral, if any, is low; see mineral blood tests.

Questions about the product

1. Which form of the mineral is this, and how much actual (elemental) mineral is in a serving? See units explained.
2. Are there other ingredients I should ask about, such as a second mineral, a vitamin, or a large amount of salt in a dissolvable tablet? The NHS says some dissolvable tablets may be high in salt. [8]
3. Has the product been independently tested? The FDA does not approve dietary supplements for safety and effectiveness before they are marketed. [1] See quality testing and certifications.

Questions about the total amount

1. Counting this product plus my multivitamin, antacids, fortified foods and any other supplements, what is my total from supplements?
2. How does that total compare with the published upper level for my age and sex? Upper levels differ by country and apply to supplements only for some minerals; see intake reference tables.
3. Is this a long-term or short-term plan, and when should we review it? The NHS says high doses of zinc reduce the amount of copper the body can absorb, which can lead to anaemia and weakening of the bones, [9] so combinations and duration are worth discussing.

Questions about medicines (a pharmacist is well placed to check)

Mineral supplements can change how some medicines are absorbed. These examples come from the NHS medicine pages; ask about your own medicines by name and do not stop or change a prescribed medicine without advice.

Questions to ask: Is there any medicine of mine that interacts with this mineral? Does spacing matter, and if so, how should it be arranged for my regimen? See medicine interactions and the mineral and medicine interactions reference.

Questions about health conditions

• Kidney disease. MedlinePlus says people with kidney disease or other long-term illnesses should talk to their provider before taking potassium supplements, [12] and that magnesium excess is uncommon except in people with significantly reduced kidney function. [13] Ask: does my kidney function change which minerals are safe? See minerals and kidney disease.
• Iron overload. The NHS says haemochromatosis is an inherited condition where iron slowly builds up, and that people being treated are usually advised to avoid iron or vitamin C supplements. [14] Ask: should I avoid iron-containing products?
• Thyroid. The NHS says taking high doses of iodine for long periods could change the way the thyroid works. [15] Ask: is any iodine- or selenium-containing product a concern for my thyroid condition?
• Liver disease or other long-term conditions. Ask whether any mineral needs to be avoided or monitored.

Questions about surgery and procedures

NCCIH says certain supplements may raise bleeding risk or affect the response to anesthesia, and to tell providers about all supplements as far in advance of an operation as possible. [16] Ask: which of my supplements should be listed for the surgical team, and should any be paused? See supplements before surgery.

Questions for follow-up

1. What side effects should I watch for, and when should I call? NCCIH says that if you have side effects, stop taking the supplement and contact your health care provider. [16]
2. When should my levels or symptoms be rechecked?
3. If I buy a different product later, who should I check it with?