21 February,2011 10:45 AM IST | | Priyanjali Ghose
At least according to supermodel Gisele Bundchen, who says that she uses sunscreen to avoid looking like a shrimp. the bronze beauty, who came under a lot of flak for dismissing the white potion as 'poison', now claims otherwise. experts on why you need to continue to slap on the sunblock
Types of sunscreen
Sunscreens can be broadly classified into physical and chemical sunscreens. While physical sunscreens contain large particles that reflect and scatter sunlight, chemical sunscreens have nano particles that bind keratin and form a compound that absorbs the sun's rays.
Experts advise that sunscreens should be selected on the basis of SPF (Sun Protection Factor). Typically, an SPF of 15 to 30 is good for Indian climate and skin. The sunscreen should be applied 15 to 30 minutes before going out in the sun. The effects last for two to three hours.
However, there is still some debate over whether or not the presence of nanoparticles in chemical sunscreens is safe. The two most common ingredients for imparting a whitish tinge when sunscreen is applied on the skin are Zinc Oxide (ZnO) and Titanium Dioxide (TiO2).
Nanotechnology, and specifically the use of nanoparticles of ZnO and TiO2, was applied so that manufacturers could reduce the visibility of the cream. Recent studies indicate that ZnO and TiO2 nanoparticles can induce the formation of free radicals when exposed to light. Free radicals are cells responsible for ageing, tissue damage, and certain diseases.
However, most studies claim these nanoparticles do not reach the living cells, a theory that is endorsed by
Dr Chetan Oberoi, consultant dermatologist and cosmetologist. "These particles do not go beyond one or two millimetres of the skin and thus does not get absorbed deep," he says.
Other options
Wearing broad-rimmed hats, full-sleeved clothes and sunglasses are other options for sun protection. Ayurveda specialist Ravi Kothari offers some natural substitutes in place of sunscreen. "Pure coconut oil and coconut milk are the best natural sunscreens. Also, eating colured fruits and vegetables helps. SPFwise they offer the same benefits."
Can't take the heat?
During the recent launch of her line of skincare products, supermodel Gisele Bundchen referred to sunscreen as "poison". She was quoted as saying, "I cannot put this poison on my skin. I do not use anything synthetic."
Claiming that her skin products are natural and do not contain any SPF, the 30-year-old said that she tries to stay out of the sun when it is at its strongest i.e. 9 am to 4 pm.
Her rep later clarified that Mrs Brady was "misquoted" due to a "language barrier" and that she does use sunscreen, but products that are minus harshu00a0 chemicals.