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Theme 3: Project 3 - UV radiation effects on vitamin D sufficiency and blood pressure

The blood pressure study was initiated to test the claims that UV can decrease blood pressure; a claim that is potentially very relevant in health protection. Our own investigations revealed that while UVB (which is very much more damaging to DNA) has no appreciable effect on nitric oxide (NO) production from skin cells, UVA, which is much less DNA-damaging, induces skin cells to produce NO, the most potent vasodilator that is purported to mediate the effect of sunlight on blood pressure.

We observed that in addition to keratinocytes, dermal endothelial cells are highly responsive to UVA in this regard and their location which is adjacent to smooth muscle cells suggest that they may be primarily responsible for the reported dilation of blood vessel. The route by which this occurs has been elucidated and published (Holliman et al., (2017) Scientific Reports).

In the coming period (April 1 2018 to March 31 2020) we will determine the optimal UV dose that is effective for inducing NO production in cells and the dynamics of the process of NO production. This is particularly important if exposure to UVA is to be considered when defining a ‘healthy dose’ of sunlight and if ectopic exposure to UVA could offer a potential means to mitigate the seasonal increase in hypertension during winter.

Lead researchers

Dr Ken Raj


Public Health England

Professor Catherine Hawrylowicz


King's College London