By a community pharmacist
“Pharmacist, I heard that taking iodine is good for the thyroid. Should I buy some?”
“Is drinking coconut water every day good for potassium?”
“And what about selenium? I see it in so many supplements, but what does it actually do?”
These are reasonable questions. In Malaysia, we have no shortage of health advice from family, friends, social media and the shelves of our local pharmacies. One person recommends a supplement for thyroid health, another swears by coconut water after exercise, while someone else insists that everyone should take a multivitamin containing trace minerals.
But here is something worth remembering: a mineral can be essential to health without needing to be taken as a supplement.
In our previous Health Matters articles, we looked at iron, calcium, magnesium and zinc. This time, we will explore four other important minerals: iodine, selenium, potassium and copper.
They may be needed in relatively small amounts, but they have important jobs to do. The challenge is knowing how to get enough without taking unnecessary or potentially harmful doses.
1. Iodine — The mineral your thyroid cannot do without
Have you ever wondered why iodine is added to certain types of salt?
The answer lies in the thyroid gland, a small, butterfly-shaped gland at the front of the neck. It uses iodine to produce thyroid hormones, which help regulate metabolism, growth and development. Iodine is particularly important during pregnancy and early childhood because thyroid hormones support the developing brain and nervous system. The National Institutes of Health explains iodine’s role in thyroid health and development.
What happens when iodine is lacking?
If the body does not receive enough iodine, the thyroid may enlarge, causing a swelling in the neck known as a goitre. Severe or prolonged deficiency can interfere with thyroid function. During pregnancy, significant iodine deficiency can also affect the baby’s development.
Iodine deficiency is not diagnosed simply by looking at someone’s diet or symptoms. Thyroid problems have several possible causes, and medical assessment may be needed.
Where can Malaysians get iodine?
Seafood, fish, eggs and dairy products can contribute iodine to the diet. Iodised salt is another important source.
Malaysia introduced mandatory iodisation of household salt under its Universal Salt Iodisation programme, with enforcement beginning in January 2021. The Ministry of Health’s Malaysian Dietary Guidelines for Children and Adolescents 2023 explains the role of iodised salt in preventing iodine deficiency.
However, this does not mean we should eat more salt to obtain iodine. Malaysia’s dietary guidance follows the World Health Organization recommendation to keep total salt intake below 5 grams a day for adults. Choose iodised salt where appropriate, but use it sparingly.
Should you take iodine supplements?
Not automatically.
Too much iodine can also disturb thyroid function, particularly in people with existing thyroid disorders. Seaweed and kelp supplements can contain substantial and sometimes unpredictable amounts of iodine.
If you have a thyroid condition, are pregnant or are considering an iodine supplement, ask your doctor or pharmacist first. The NIH iodine fact sheet explains both deficiency and the risks of excessive intake.
A pharmacist’s advice: If you have unexplained changes in weight, unusual sensitivity to heat or cold, a racing heartbeat or swelling in the neck, do not assume you need iodine. Seek medical advice to establish the cause.
2. Selenium — Small amounts, important work
Selenium is a trace mineral involved in the function of enzymes that protect cells from damage. It also supports normal thyroid hormone metabolism and reproductive function. The NIH selenium fact sheet describes its roles in the body.
The word antioxidant appears frequently on supplement packaging, but that does not mean taking extra selenium will automatically improve your health or prevent disease.
Which foods contain selenium?
Fish, seafood, meat, eggs and some other protein-rich foods can provide selenium. The amount in plant foods can vary considerably depending on the selenium content of the soil where they were grown.
For most people eating a varied diet, selenium deficiency is uncommon.
When deficiency does occur, it is more likely to be a concern in people with particular medical conditions, significant malnutrition or problems absorbing nutrients. There is no single symptom that reliably identifies selenium deficiency, so taking a supplement based on tiredness alone is not a sensible approach.
Can too much selenium be harmful?
Yes. Selenium has a relatively narrow safety margin compared with some nutrients.
Excessive intake over time can cause selenosis, which may involve hair loss, brittle or lost nails, a garlic-like breath odour, nausea, diarrhoea or neurological symptoms. The NIH selenium guidance discusses these effects and the risks of excessive supplementation.
Some supplements contain high doses, and selenium may also be included in multivitamins. Taking several products together can increase your total intake without you realising it.
A pharmacist’s advice: Do not take high-dose selenium simply because it is advertised for immunity, thyroid health or anti-ageing. Unless there is a specific reason to supplement, obtaining nutrients through a varied diet is generally the better starting point.
3. Potassium — Important for muscles, nerves and blood pressure
Potassium is essential for normal muscle contraction, nerve signalling and maintaining the body’s fluid balance. It also helps support normal blood pressure. The NIH potassium fact sheet explains its functions and dietary sources.
This mineral deserves particular attention because both low and high potassium levels can be dangerous.
Where can Malaysians get potassium?
Fortunately, potassium is found in many everyday foods, including:
- Bananas, oranges and papaya.
- Potatoes and sweet potatoes.
- Beans and lentils.
- Leafy vegetables.
- Fish, meat and other protein-containing foods.
A varied diet containing fruit, vegetables and legumes can help provide potassium. However, eating a banana or drinking coconut water is not a substitute for treating a medically significant potassium imbalance.
What happens when potassium is too low?
Low potassium, known as hypokalaemia, can cause muscle weakness, cramps, constipation and, in more serious cases, abnormal heart rhythms.
It may develop following prolonged vomiting or diarrhoea, or through the effects of certain medicines, including some diuretics. The risk depends on the person’s health, medicines and circumstances.
What about high potassium?
High potassium, or hyperkalaemia, is also potentially dangerous. It can interfere with the electrical activity of the heart, sometimes without causing obvious early symptoms.
People with chronic kidney disease are at increased risk because their kidneys may struggle to remove excess potassium. Certain medicines, including ACE inhibitors, ARBs and potassium-sparing diuretics, can also raise potassium levels.
This is especially important for anyone taking medicines such as ramipril, losartan or spironolactone. These medicines should not be stopped simply because of a concern about potassium; the appropriate response is to follow the prescriber’s advice and have blood tests when indicated.
The NHS guidance on potassium and the NIH potassium fact sheet explain why both deficiency and excess matter.
Is coconut water a good source?
Coconut water contains potassium, which is one reason it is often promoted as a natural rehydration drink. But its potassium content varies, and it is not suitable for everyone in unlimited amounts.
People with kidney disease or those taking medicines that raise potassium should check with their healthcare professional before regularly consuming large amounts or using potassium supplements.
A pharmacist’s advice: Never start potassium tablets without medical advice. If you have significant weakness, palpitations or fainting, seek urgent medical assessment rather than trying to correct the problem with food or drinks.
4. Copper — More than just a metal
Copper is a mineral the body needs in small amounts. It helps enzymes involved in energy production, iron metabolism, connective tissue formation and normal nervous system function. It also contributes to immune function. The NIH copper fact sheet provides more detail.
Which foods provide copper?
Good sources include shellfish, nuts, seeds, organ meats, wholegrains and some cocoa products.
In Malaysia, a varied diet that includes nuts, seeds, wholegrain foods and suitable protein sources can contribute copper. Most people obtain enough through food without needing a separate supplement.
What happens if copper is too low?
Copper deficiency is uncommon, but it can occur in people with certain absorption disorders, after some types of gastrointestinal surgery or in particular medical circumstances.
A deficiency may contribute to anaemia, low white blood cell counts and neurological problems. These symptoms have many other possible causes, so investigation is needed rather than assuming copper is responsible.
There is also a connection between zinc and copper. Taking excessive amounts of zinc over a prolonged period can interfere with copper absorption and cause copper deficiency.
That is one reason high-dose zinc supplements should not be taken indefinitely without a clear indication.
A pharmacist’s advice: If you are taking a high-strength zinc product for your skin, immunity or another reason, check the dose and how long you intend to use it. More is not always better, and long-term use may create a new nutritional problem.
What about manganese and chromium?
You may have seen these minerals listed on multivitamin labels.
Manganese helps enzymes involved in bone formation and metabolism function normally. It occurs in wholegrains, nuts, legumes and tea.
Chromium is involved in nutrient metabolism, and some supplements are marketed for blood sugar control or weight management. However, evidence that chromium supplements reliably improve these outcomes is limited, and they should not replace established treatment for diabetes or weight management.
For most people, a varied diet provides these trace minerals. Routine supplementation is not necessary for everyone. The NIH collection of vitamin and mineral fact sheets provides further information on these and other nutrients.
Do you need a mineral supplement?
Here is the question I would ask before recommending any product at the pharmacy counter: What problem are we trying to solve?
Are you correcting a confirmed deficiency? Are you pregnant and have a specific nutritional requirement? Do you have a condition that affects absorption? Are you taking medicines that alter mineral levels?
The answers matter.
A supplement may be appropriate in certain circumstances, but it is not automatically beneficial simply because the body needs that nutrient. Some minerals can be harmful in excess, and certain supplements can interact with medicines or complicate existing medical conditions.
If you have persistent symptoms, it is better to establish the cause. Depending on the situation, your doctor may recommend blood tests to assess thyroid function, potassium levels or other relevant markers.
For most people, the foundation remains a varied diet, sensible use of iodised salt, appropriate hydration and regular medical care when needed.
The message from your community pharmacist
Iodine helps the thyroid, selenium supports important enzymes, potassium keeps muscles and nerves working normally, and copper contributes to blood formation and other essential processes.
We need these minerals, but generally in the right amounts — not megadoses.
Before buying another supplement, check your diet, read the label and consider your medicines and medical conditions. If you have kidney disease or a thyroid disorder, take particular care before using products containing iodine or potassium.
And remember: supplements can be useful when there is a genuine need, but they cannot replace a balanced diet, proper diagnosis or appropriate treatment.
In our next Health Matters article, we will bring the series together and answer a question many people ask at the pharmacy: Do you really need vitamin and mineral supplements, which ones are worth considering, and how can you avoid wasting money or putting your health at risk?
Until next time, take care of your health.
Health Matters — practical health advice from a community pharmacist.
Health Matters (zaynp100@yahoo.com) is a content creator under the Newswav Creator programme, where you get to express yourself, be a citizen journalist, and at the same time monetize your content & reach millions of users on Newswav. Log in to creator.newswav.com and become a Newswav Creator now!
The User Content (as defined on Newswav Terms of Use) above including the views expressed and media (pictures, videos, citations etc) were submitted & posted by the author. Newswav is solely an aggregation platform that hosts the User Content. If you have any questions about the content, copyright or other issues of the work, please contact creator@newswav.com.
