Vitamin and mineral supplements can seem like a quick and easy way to ensure health and vitality. In fact, there’s been little quality research to say if they’re helpful or not. Nonetheless plenty of us fork out the cash on the chance the pills will do us some good. What’s often overlooked, though, is the chance they’ll do us some harm.

One of the key concerns is overdosing on supplements. Even vitamin C, widely considered harmless, can cause kidney stones if you take too much. And high doses of one vitamin or mineral can decrease the absorption of others. In short, taking supplements can lead to an imbalance in the body, the very thing they’re supposed to prevent.

In theory, what you’re getting is spelt out on the bottle. But both the name and quantity of ingredients can be listed in a variety of ways, making it hard to compare one kind with another.

And, unlike in other countries, products sold in Australia don’t have to list how the amount of each ingredient in the pill relates to the recommended daily intake or RDI—that’s the amount your body needs.

One way to minimize the risk of overdose is to choose a multivitamin, where each pill contains a bunch of vitamins and minerals. Since the dose of individual ingredients is generally lower in multivitamins, you’re less likely to do yourself any damage. The mix of ingredients and their amounts does vary widely from brand to brand. But research suggests you’re more likely to get too little of something you want than too much.

There are instances though where too little of an ingredient in a multivitamin is a problem. And that’s when specific supplements can be useful.

For instance, there’s good evidence folate (or vitamin B9) supplements, taken in early pregnancy and before, can help prevent nervous system defects in babies. Unlike most vitamins, synthetic folate is actually better absorbed by the body than folate from food.

And it’s thought women who take calcium and vitamin D supplements after menopause have stronger bones and suffer fewer fractures. Athletes too can benefit from specific supplements because of their higher than usual nutrient needs. And you’re less efficient at absorbing nutrients from food if you’re elderly or taking multiple medications.

There’s more information about when specific supplements can be useful on the ABC health and wellbeing website. But it’s always worth trying to improve your diet first. That’s because vitamins and minerals generally work better when we eat them in food rather than in their isolated form. In any case, there’s no pill in existence that can offer all the benefits of a balanced diet.