Vitamins again

Vitamins matter – we know that much.

Go without eating fruit and vegetables for six weeks and you will develop scurvy – as sailors did until the 18th century when they learnt to suck lemons on long voyages.

Supplements can be a good idea for the chronically ill or elderly, whose capacity to eat or absorb nutrients may be limited.

But for the rest of us?

There is precious little evidence that vitamin supplements do anything for people eating a healthy diet – except create expensive urine (excess vitamins cannot be stored and must be excreted).

Can they be harmful?

Apparently they can.

Scientists from Monash University have examined the development of insulin resistance, the first stage in the development of diabetes, and found that vitamins mop up molecules known as Reactive Oxygen Species (ROS), which actually enhance insulin action, though they are harmful in other ways.

It seems that the ROS molecules, which include free radicals, are beneficial in the early stages of Type 2 diabetes and shift to be being harmful in the later stages.

The researchers are now trying to find out when they shift from good to bad.

The little-reported study, published in 'Cell Metabolism', has only been done in mice so far.

But the widespread use of anti-oxidants [vitamins] by the general public as a preventative measure is something that should be discouraged, particularly if you are otherwise healthy

Type 2 diabetes is rising so rapidly across the western world it poses a severe challenge for the future.

It would be remarkable if our modern obsession with popping vitamin pills was, in however limited a way, fuelling that rise.

Jeremy Laurance - Independent