Alert over combining supplements, medication

Combining dietary supplements and prescribed medications has been found to put patients at risk of interactions between products or toxicity from high doses.

A new study by University of Otago (Christchurch) researchers showed the use of over-the-counter non-prescribed dietary supplements has increased 72% in New Zealand over the past 15 years, but most people do not need dietary supplements to gain optimal nutrition.

Senior research fellow Dr Geri McLeod said there was no specific legislation governing natural health products in New Zealand, and New Zealanders were able to freely combine dietary supplements and prescribed medications.

Data for the study was from the Christchurch Health and Development Study - a birth cohort of babies born in Christchurch in 1977.

Cohort members were assessed at age 40 on their use of prescribed medications and non-prescribed dietary supplements.

"Among this group of nearly 1000 40-year-old New Zealanders, more than one-third (36.4%) were using a dietary supplement.

"Of this group, nearly half (47.1%) were also taking prescribed medication.

"More females reported using dietary supplements than males," Dr McLeod said.

Of the group taking dietary supplements, she said more than one in three were taking dietary supplements that had no evidence for treating the stated health condition.

A small number of participants reported dietary supplement and medication combinations that could produce an interaction, she said.

"It can sometimes stop prescribed medications from being taken up by the body.

"For instance, iron is a well-known one - it can interfere with thyroid medications.

"You have to be aware - if you’re not, you could actually be harming yourself.

"New Zealanders should be aware that when using dietary supplements without support from their doctor, [it] can at best be a waste of money, and at worst expose them to interactions or symptoms of excessive consumption."

Dr McLeod said clinicians should encourage patients to use diet to attain nutrition and encourage information sharing of supplement consumption by their patients.

"Often, non-prescribed products are a waste of money offering no health benefit."

Ministry of Health clarification:

Current regulation for Dietary Supplements is provided by the Dietary Supplements Regulations 1985, made under the Food Act, which specifies requirements for the composition, dose and labelling requirements for dietary supplements.

The nature of claims in relation to dietary supplements or other natural health products are also regulated under the Fair Trading Act which requires that claims are able to be substantiated and are not misleading.

Products with a therapeutic purpose, regardless of any claims that are made, are medicines as defined by the Medicines Act 1981. Medicines are required to be approved before they are able to be sold in New Zealand.

Last year (July 2021) the Government decided to regulate natural health products under the Therapeutic Products Bill, as a distinct category, separate from medicines.

The Therapeutic Products Bill, expected to be introduced to Parliament this year, will modernise and provide comprehensive regulation of therapeutic (medicines and medical devices) and natural health products.

For natural health products, which include dietary supplements, the Bill will provide assurance of the safety and quality of these products and require any health benefit claims to be substantiated with robust scientific or traditional evidence.

It will also help consumers to make informed decisions about their health.

If consumers have any questions or concerns about any medicines or natural health products they are taking, they should talk to their doctor or pharmacist.

john.lewis@odt.co.nz

 

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