Despite what a lot of marketing suggests, there is no particular reason to suppose that natural ingredients are safer or superior to synthetic ones. It depends on what you are doing with them. It’s horses for courses. You pick the material that has the properties you need for whatever it is you are trying to achieve. But on the whole most of the time I prefer natural oils over mineral oil for skin creams.
I think I have tried enough combinations to be reasonably sure of what I am saying. Vegetable oils like for example capric caprylic triglycerides absorb better and leave the skin feeling better. Natural oils do have some drawbacks of course. They don’t have quite the moisturising power of mineral oil, so for really dry skin they don’t quite cut it. And there is always the greater risk of allergic reactions to be expected from natural ingredients. This isn’t a huge problem but it is not entirely mythical. And you might well end up having to put a ‘may contain nuts’ label on your pack.
But as with a lot of things, it isn’t always easy finding actual evidence of what you believe to be true. So I was very pleased to stumble across a paper in the Lancet the other day while looking for something else. Some doctors at Dhaka Shishu Hospital in Bangladesh had taken the trouble to check out what works best for protecting the skin of premature babies in a maternity ward. Hospitals are very unnatural places and despite the best efforts of the staff when you are in them it is extremely easy to pick up an infection, and this is especially true of premature babies. One of their problems is that their skins have a very poor barrier function, so emollients are used to give them an extra bit of protection. What they looked at was whether a branded product would work better than simple sunflower seed oil. It turned out that the sunflower oil did better than the brand, which was a mineral oil based cream. The infants got fewer skin infections.
I think I should just take a moment to praise the doctors involved. Big headline medical breakthroughs are fine things, but when you tot it all up it is the day to day efforts of people on the ground making steady incremental improvements that really make the difference to our health. Well done for adding a bit to that effort.
But back to cosmetic skin creams. I think I can speculate as to why the sunflower oil did better. The basic structure of all seed oils is triglycerides. These have a pretty reasonable affinity with the kinds of oils that the skin itself produces. So when you apply them to skin they incorporate themselves into the upper layers of the skin, the area known as the stratum corneum, and beef up its barrier properties. Mineral oil on the other hand doesn’t penetrate so well and instead stays on or near the surface. This is pretty good too, and in fact may work better from the point of view of simply holding moisture in. But the skin is a bit more complicated than a simple sponge and has other functions than simply holding your insides in. So the mineral oil treated skin might have been as well moisturised, or perhaps even better moisturised. But the overall protective function of the skin was served better by the sunflower oil.
I don’t say that this study proves anything very profound. It doesn’t mean that natural is automatically good or even that my ideas about the way skin creams work are correct. But it is a good reminder that it always pays to look at the evidence.
Lancet. 2005 Mar 19-25;365(9464):1039-45. Effect of topical treatment with skin barrier-enhancing emollients on nosocomial infections in preterm infants in Bangladesh: a randomised controlled trial. Darmstadt GL, Saha SK, Ahmed AS, Chowdhury MA, Law PA, Ahmed S, Alam MA, Black RE, Santosham M.