Sunscreen or Sunblock

It's one of the first lessons I learnt after coming to New Zealand.  The first summer I burnt sooo badly on my trip to Northland enjoying the beaches that I had to change my ways.

I grew up in Croatia, on the seaside.  Rarely, anyone in Croatia used sunblock when I was growing up.  We used Suntanning lotions and potions, but not the sunblock.  And we rarely got sunburnt.

Living in New Zealand and Australia, it's different.  The sun is sooo much stronger, and you can burn so much easier than in Croatia.  It takes 30 min outside on the sun for me to become a lobster.  A few years ago, my cousin from Croatia came for a visit.  She went outside for a smoke and I told her to put some sunblock on, but she did not believe me.  But she also got a sunburn while just sitting outside having a smoke.  She soon started using a sunblock.

Training and working as a surgeon in New Zealand and Australia, you get to see many patients with melanoma as well as other skin cancers.  You do not see this growing up in Europe or visiting the place.  The rates of melanoma in the USA are not as high as they are in New Zealand and Australia.

So my recommendation here is - always use sunblock creams, every day in a year.  It prevents getting skin damage from the harsh sun, it prevents skin cancers and it prevents melanoma.  It also makes your skin not age as quickly. But are there any problems with sunblocks?

This study "Effect of Sunscreen Application Under Maximal Use Conditions on Plasma Concentration of Sunscreen Active Ingredients" published in the JAMA journal tried to answer this.

They investigated if the active ingredient of the sunscreen gets absorbed into our bloodstream and how much.  The active ingredients that were looked at were avobenzone, oxybenzone, octocrylene and ecamsule.  And the sunscreen was applied 4 times per day (as per manufacturers instruction) and tested indoors.  The people were not swimming or going outside, they spent all day indoors.

The US Food and Drug Administration (FDA) is an agency that approves all the medications or medical equipment in the USA. They have a guideline of 0.5nanogram/mL blood limit for the active ingredient in the sunscreen as a safe level for sunscreens.  The sunscreens who have higher blood levels that this should undergo a further assessment of toxicity including carcinogenicity and additional safety studies. 

What this study has shown that all 4 tested brands of sunblock, when used at the maximum levels, had higher than recommended doses of the active ingredient in the blood.

What does this mean for us as users of sunscreen?

1. We do not know what these higher levels mean as companies have not done studies on these sunblocks to see whether these higher levels have an impact on our health

2. Until this is established you should use titanium dioxide and zinc oxide-based sunscreens and wear the protective clothing

3. New Zealand cancer society sunscreen is made out of a mixture of active ingredients, but one of them was octocrylene which was tested in the study above.  It's also the active ingredient in the kids' sunscreen.

4. We need to change the process by which the sunscreens are tested, so we have better knowledge if these products cause medical problems or not.  The process for this should be similar to testing for medications to prove their safety.

5. More studies are needed to look at the safety of sunscreens, not just how effective is the SPF (sunscreen protection).

In conclusion, we should continue using sunscreens as they prevent skin cancers and skin problems.  But we should ask the manufacturers to test them properly so we know that ingredients used in the sunblock do not cause medical problems.

At this stage, the use of titanium dioxide or zinc oxide-based sunscreens (most organic-based sunscreens are made from these ingredients) as these are not associated with high bloodstream levels.