Should you be thinking twice before you lather your child in sunblock at the beach?
These are the some of the stirrings that I have been hearing lately about sunblock, so after doing some personal research I am happy to summarise here.
One recent concern is with nanoparticles. Remember Zinc back in the 80’s on all of those cricketers?. This worked as an effective barrier against harmful sunrays but alas it was too sticky and hard to apply for the public to get into wholeheartedly. The reason for this was the zinc particles were too big. Nanoparticles of zinc and titanium have recently been created to solve this problem- allow easy application, leaving soft and smooth skin. But are they too small? Do they get into your body, producing toxicity and other effects?
The answer to this is probably not. The studies that have looked at in people (applying nanoparticles for a period of time then biopsying the skin to see how far the metals have got through) show that they stick to the outside layer of the skin, so not absorbed far at all.
Another concern is our Vitamin D. This is a vitamin that we get from the sun. If adequately applied, most sunscreen is very good at blocking vitamin D absorption. In theory this could be a problem, but population studies have not shown this to be a problem in real life. However, if your skin is such that wearing sunblock at all times is a must, then taking vitamin D supplementation is recommended.
One final concern that I am interested in is the coral reefs- could sunblocks leaking off happy snorkelers be killing the reefs?. Sunblock concentrations have been measured in aquatic ecosystems around the world, and some have been shown to harm coral in the lab environment. This question needs to be answered quite urgently but there is not enough information yet to say if it is the culprit.
So overall some interested and potentially concerning issues with sunblock. However, balanced against the harmful effects of ultraviolet rays that are known and well proven (skin cancer, sunburn, global warming) safe use of sunblock still wins out for me and my practice. However, do not forget those other sun protective measures, like staying out of the sun in the hot part of the day and wearing protective clothing and sunglasses.