There have been several alarming stories in the media recently regarding the safety and effectiveness of health supplements. As a nutritional therapist I am often asked about supplements: are they worth the money? Do I need vitamin D when it’s sunny? Will cod liver oil clash with vitamin C?

It has to be said, the world of nutritional supplements is an absolute minefield, so let’s clear up some of the myths and facts about vitamin pills...

Firstly, quality is more important than quantity. A high quality, well absorbed vitamin and mineral formula made by a reputable supplement brand, costing around £10 for a month’s supply (this works out at 36p per day!) is a far better investment than a big pot of cheap vitamin pills bought online.

The ingredients used in cheaper formulas are not absorbed and utilised by your body very well, which means they are passed through your system without giving you any benefit.

For example, calcium carbonate is the form of calcium used in cheap mineral tablets. This is chalk, the same stuff you use to write on a blackboard!

Better quality manufacturers may use calcium citrate, a combination of calcium and citric acid which your digestive system recognises very well and will absorb into your bloodstream. Remember, the only expensive supplement is one that doesn’t work!

Secondly, do check the strength of your supplement. A lot of products are promoted as being ‘one-a-day’ tablets regardless of their strength so have a think about how much of the nutrients you want and whether the strength of the product suits your needs. For instance vitamin C can be 500mg or 1000mg per tablet yet both are sold as one-a-day!

Some of the recent scare stories have linked vitamin supplements with an increased risk of cancer – a terrifying prospect indeed, if it were at all true. What these stories have neglected to share are the real details of the research and dosages used. In some trials, high dosages of one or two vitamins were used whilst in others, influencing factors such as participants’ diets and lifestyles were not taken into account.

Vitamins and minerals are not designed to be taken in high dosages for long periods of time; they are not drugs and the adage of ‘a little is good so more must be better’ does not apply.

In nature, nutrients exist in groups alongside co-factor nutrients which have synergistic effects – a bit like team-mates who have different roles but work together as a whole group.

Vitamin C for instance is found in foods alongside bioflavonoids whilst many magnesium rich foods also contain several B-vitamins. Isolating any nutrient and taking it in high doses is highly likely to trigger some adverse effects - and worrying headlines too!

I frequently recommend clients use certain nutrient pills and powders as they can be supportive to healing and wellbeing. The role of any supplement is to complement a healthy diet, not replace it, and this is the key point to remember.

Sally Duffin is a nutritional therapist and writer based in Holgate, York.