Â Â by Carole Jackson, Bottom Line Health
Â Deciding what to wear on a sunny day just got more complicated. Besides how good youâll look or feel, new research suggests the color of your clothing affects your vulnerability to UV radiation.
Â Ascension Riva, PhD, of Universitat PolitÃ¨cnica de Catalunya in Terrassa, led a team studying how a variety of factors — including fabric weave, color intensity and the hue itself — interact with UV light. Their findings may surprise you!
Â The scientists dyed several types of fabric red, yellow and blue (standardizing the dyes for chemical structure and intensity), measuring the ultraviolet protection factor (UPF) of each before and after dying. They used a statistical tool to evaluate the influence of three factors — the UPF of the original, undyed fabric… the color of the dye… and the color intensity — on the final UPF. Hereâs what they learned…
- Â Â Â Â Â Â Â Red and blue fabrics provided significantly more protection than the same fabric dyed yellow at the same concentration.
- Â Â Â Â Â Â Â Intensity mattered as well. Highly concentrated colors were more protective — a brilliant, intense yellow absorbed more UV radiation than a pale blue, for instance.
- Â Â Â Â Â Â Â Density was also a factor — predictably, tight weaves are more protective than looser ones.
Â Is White Still Right?
Â I asked Dr. Riva where white would fall on the scale, because Iâve always heard thatâs the best choice for hot, sunny weather. She told me that optical brightening agents are used to create the commercial white weâre accustomed to wearing. She said this type of white does have both blocking and absorbing properties that are equal to that of pale blue. White reflects more light, she pointed out, so it may feel cooler, but thatâs not to be confused with UV protection.
Â According to Dr. Riva, the differences in protection are significant enough to affect your risk for skin cancer. She suggested that people with reason to be especially worried about the effects of UV radiation, including those with skin cancer, photo-sensitivity and certain dermatological illnesses, might do well to choose tightly woven, deeply colored blue or red clothing when theyâll be outdoors in the sun. For the rest of us, itâs another factor to consider in choosing what to wear — but it need not be the only one.
Ascension Riva, PhD, professor, Universitat PolitÃ¨cnica de Catalunya, Terrassa, Spain.