What UV? A, B, C, 3 different UVs with different effects
UVA (320-400 nm): increases seratonin level (1) (feel good neurotransmitter) but also linked to photoaging and likely to cause skin cancer
UVB (290-320 nm): essential for Vitamin D
UVC gets filtered out by the Ozone layer
Vitamin D, the sun hormone and its role
Vitamin D and its metabolites are essential for good health:
-it promotes bone formation by maintaining Calcium and Phosphorus concentrations
-it stimulates immunogenic and antitumor activity
-it enhances Calcium absorption in the intestine and kidneys
Its deficiency is linked to rickets in children, osteoporosis
Dietary intake of vitamin D is very difficult as few foods contain vitamin D (salmon, mackerel, sardines) and at too low concentration to be really effective.
Sunlight is the best way to get vitamin D.
How to get Vitamin D safely
There is not a simple recipe for this: UV emissions change according to the time of the day, the season and the solar elevation (latitude)4! Besides the darker the skin the less UV reaches the deeper skin layers and the longer it takes to produce Vitamin D. People with dark skin need longer sun exposure to get their vitamin D.
Considering location and skin type are major variables the tips below are given for fair skinned people in the UK in the summer:
-Never ever sunburn!
-Get a brief unprotected sun exposure: 10 minutes of sunbathing at midday exposing arms and legs without wearing a SPF (the more skin exposed the more vitamin D is produced) give the highest amount of Vitamin D (5) -Wear a good SPF on the face and hands while sunbathing to prevent photoaging
10 minutes of sun exposure at midday (in the UK) are much more effective than 1 hour between 4 and 5 pm. If you want to find put how much sun you need to get according to your location and skin type please visit the link on NADIR
SPF, unnecessary protection in winter months
In the UK winter sunlight is very weak, meaning that between November and February no vitamin D is produced and no UV protection is required. Applying products with SPF during this period is pointless and it exposes the skin to unnecessary chemicals.
The iRejuvenate 2 steps system by Forest Secrets Skincare
1 Impact of UVA exposure on psychological parameters and circulating seratonin and melatonin, Gambichler, Bader… BMC Dermatology, 2002, 2-6
2 Vitamin D: importance in the prevention of cancers, type 1 diabetes, heart disease and osteoporosis, Micheal Holick, Am J Clin Nutr, 2004, 79:362-71
3 Vitamin D and calcium deficits predispose for multiple chronic diseases, Peterlink M., 2005, Eur. J. Clin. Inv. 35, 290-304
4 Daily duration of vitamin D synthesis in human skin with relation to latitude, total ozone, altitude, ground cover, aerosols and cloud thickness, Engelsen O., Brustad M., Aksnes L., Lund E., Photochemistry and Photobiology, 2005, 81(6), 1287-1290
5 Calculated ultraviolet exposure levels for a healthy vitamin D status, Webb A., Engelsen O., Photochemistry and Photobiology, 2006, 82(6), 1697-1703
DR Barbara Olioso is a chemist who has worked only with natural and organic cosmetics in the last 9 years. She has just launched her own skincare range, Forest Secrets, with the vision of taking naturals to a new level of performance, without compromising on purity and ethics. She writes for trade magazines and she gives talks at International Conferences about achieving sustainability in natural cosmetics
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