Why Vitamin D is so important for people with RA: Part 2

            Sunlight: Your body produces vitamin D when your skin absorbs ultraviolet radiation from the sun and it produces more and more quickly than you can ingest through meals.  Fair skinned people can manufacture as much as 15,000 IU or more in just 30 minutes of optimal sun exposure.

            However, here are some important things to remember about "optimal sun exposure."  First, the sun needs to be higher than 45 degrees above the horizon in order to adequately produce vitamin D, so Noon is the optimal time of day.  Secondly, where you live plays an important factor. For anyone above 35 degrees latitude (think North Carolina to California) the sun shines at such an angle that its rays aren't strong enough to cause vitamin D production for at least one month a year.  Third, people with darker skin pigmentation require longer exposure time than fair skinned people.  Fourth, as we age, the skin's ability to produce vitamin D diminishes, so older people require more time in the sun.  And finally, sunblock eliminates most of our ability to produce vitamin D.  SPF 8 blocks 98% of the UV rays needed for the transformation.  People need to balance their concerns about sun exposure and the risk of developing melanoma with the benefit of sun exposure for producing vitamin D.  10-15 minutes two to three days a week in the mid-afternoon should be plenty of exposure for vitamin D production. (People with RA who take methotrexate should take extra care, though, because of the increased risk of developing melanoma -- the deadliest form of skin cancer.)

            Supplements: Supplements are a way to make sure intake of vitamin D is adequate, especially if one needs to limit sun exposure or doesn't receive enough from dietary sources.  Most daily multivitamins contain 100% of the current recommended AI (400 IU) for people up to age 70.  They are also made using the D3 form, which is the most readily absorbable.  Some multivitamins contain as much as 1,000 IU.