Risks in supplements your patients may be taking

Re-published with permission from NZ Doctor (nzdoctor.co.nz).

Jeni Pearce, head of performance nutrition at High Performance Sport New Zealand, says supplements, particularly for children, should be treated like medications and used only by those who need them, such as people with a nutrient deficiency.

However, the use of supplements, including performance enhancing ergogenics, in the general population is becoming increasingly common, driven by factors such as body image and the desire to bulk up, Ms Pearce says.

As a nutritionist for some of New Zealand's top sporting talent, including shot-putter Valerie Adams and kayaker Lisa Carrington, Ms Pearce knows the pressure athletes are under when performing on the world stage.

But this pressure is felt by junior athletes and masters as well. Just last month, Drug Free Sport NZ announced players at this year's national secondary school rugby tournament in Palmerston North would be subject to antidoping tests.

"My advice to GPs is: please have a conversation with your athletes about what they are doing supplement-wise and where they are buying them from," Ms Pearce says.

Even pharmaceutical-grade dietary supplements are at risk of being cross-contaminated with other drugs, she says, and people should be particularly wary of products which are manufactured outside the Western world; heavy metals and toxic chemicals have often been detected in herbal medicines produced offshore.

She says the Informed-Sport.com website provides a searchable database of supplements certified as free of banned substances.

In her presentation at this year's South GP CME, Ms Pearce stressed the importance of diet over supplements: "Basically, food is better."

She worries about people "stacking" supplements by taking a multivitamin as well as single nutrient supplements, such as those for zinc and magnesium. It is very easy to get an overdose of zinc, she says.

She would like to see a multivitamin that provides a third of the recommended daily intake of essential nutrients, which could provide a boost to people whose diets are lacking.

One delegate noted nutrient deficiencies were common in homeless people who relied on donated food, which Ms Pearce says is a good example of where supplements can be helpful. Vegan teenagers are also likely to benefit from dietary supplements.

Another delegate asked about magnesium supplements, as “every man and his dog" seemed to be taking them. Ms Pearce expressed concern about the trend, “because [magnesium] has become the new cure-all”.

Magnesium is contained in chlorophyll, so green, leafy vegetables are a rich source of the mineral.

It is important for GPs to find out what their patients perceive a diet to actually be, as misinformation can be harmful, Ms Pearce says.

For example, she had two clients recently who told her they had adopted paleo diets, with one eating the foods a paleo diet expressly avoids and the other simply adding a paleo bar to their otherwise unchanged diet.

Orthorexia, obsessively eating foods considered healthy, may also be contributing to the growing demand for dietary supplements, as people strive to "perfect" their diets, Ms Pearce says.

She encourages GPs to report adverse reactions to supplements to Medsafe and check for potential drug interactions.

Dietitians can provide information on what people need to eat to obtain their recommended daily intake of essential nutrients, Ms Pearce says. "Look at your diet first and eat food for energy, rather than stimulants."