Sunday 5 June 2016

Is Manuka Honey great for the immune system?

We are constantly being bombarded with the latest celebrity fad, so I'm grateful to an email from Chelsea asking if Manuka honey is great for the immune system.

The quick answer - no.

This is a honey produced by bees exposed to pollen from the Manuka tree, mostly in New Zealand and Australia. It sold at incredibly high prices for honey - as much as £50 or more for a small jar.

Unfortunately, this is a classic case of assuming something that has a topical benefit - if you use it externally - will have a benefit if consumed. And as is usually the case, there is no link.

Honey in general has a mild anti-bacterial action (as do many substances - washing up liquid, for instance) - and there is reasonable evidence that Manuka honey is amongst the best at this. So applied appropriately to a wound (and I'm not recommending just slapping honey on), it can in principle have a positive effect (though there are many other, cheaper and more effective anti-bacterial agents).

When you eat it, though, it has no impact on your immune system. As discussed in Science for Life:
Your immune system is not a single part of your body but rather a vast network comprising physical barriers like your skin, white blood cells, various different organs and a whole range of complex chemicals with literally thousands of different roles. ‘Boosting’ it by simply eating something is a bit like hoping to redecorate your house by throwing a capsule of paint at the wall.
And in this case there is no evidence that the honey will be anything more than an incredibly expensive sweetener, adding unnecessary sugar to your diet. See the Cochrane report for details on use of honey in treating wounds.

Has it been proved that mobile phones (cellphones) cause cancer?

There has been a certain amount of panic in the news about data from a US National Toxicology Program study where rats were exposed to cellphone radiation and it has been claimed there was evidence of cancer being caused.

The quick answer is no, it hasn't been proved. There is no good evidence to say that mobile phones aren't safe. Keep using them!

There are far more studies suggesting no link at all - so immediately we have to take any findings with a pinch of salt. As is made clear in Science for Life, a single study is never enough to provide useful guidance as any study can be flawed, and it's important to take in the bigger picture. But also the actual findings of this study aren't as negative as the headlines suggest.

First, the study involved exposing rats (with much less brain shielding than humans) to 9 hours of phone radiation a day for the whole of their lives. That's a lot. No females developed any problems, but 3 per cent of the males developed brain cancer. However, experts have pointed out that the number of cancers was small enough to be a statistical occurrence. What's more, most rats were exposed to higher intensity radio waves than are allowed from a mobile phone - and stranger still, the rats that were exposed to the radio transmissions lived longer than a control group that wasn't exposed.

All this strongly indicates that there is nothing negative to be learned from this trial. See the NIH for details.