What’s the deal with UVA and UVB?

Vitamin-DThere’s a fine line between soaking up the sun for its health benefits and cooking yourself to a crisp and risking sun damage!  There’s also a great difference between sun that helps your body make vitamin D and the kind that causes damage to cells with no apparent benefit other than helping you look like you’ve gone away to the Caribbean!

There are two types of UV rays (for simplicity sake…): the year-round UVA rays and the beneficial-but-not-always-there UVB rays.  UVB is what forms the precursor to vitamin D on the skin.  From the skin, it travels to the liver where most is then released in the blood – fun fact: this is 25-hydroxyl vitamin D, what they test in your blood to most accurately measure your vitamin D status!  It doesn’t end there though…this 25-OHD3 then goes to the kidneys and gets converted into the active form of vitaminD for your body to use.  So let’s recall that UVB rays are used to all of that… holy macaroni!  That’s a lot of stuff! Unfortunately, these are also the same rays that cause sunburn if exposure is too great.

UVA on the other hand is the more common culprit when it comes to that weathered and leather skin; you know the kind they show you when they want to scare you into lathering yourself up in sunscreen?  UVA is actually more often implicated in cases of melanoma – the worst type of metastasizing skin cancer.

Vitamin D is important in calcium homeostasis, cell differentiation, proliferation and growth!  But it also has important roles in regulating blood pressure, modulating the immune system, and helping those pancreatic B cells function properly (these are the guys that are responsible for insulin secretion and vit. D helps prevent their fatigue!)

You need to be aware of when you can get UBV rays so that your time spent out in the sun can help increase your vitamin D levels and bump up your stores of this great little “hormone”.  Now that it’s October – my gosh, almost November – there is no more vitamin D being made in your skin by the sun because there are no UVB rays reaching the surface of the earth at this latitude (Toronto/GTA among other similar cities).  It’s important to talk to your doctor about finding a good quality vitamin D3 supplement – I prefer Genestra brand!  This supplementation has been clinically indicated in individuals with osteoporosis, psoriasis, and even as influenza prevention!

A deficiency in this neat little “hormone/vitamin” includes muscle weakness, low back pain, fatigue (aren’t we alllll tired?).  You may find you get sick during the winter months, too!  So stop in at the doctor’s office, check your levels, and consider taking a supplement this winter for a nice little boost!

 

References:
http://ajcn.nutrition.org/content/79/3/362.short
http://jcem.endojournals.org/content/67/2/373.short
http://jcem.endojournals.org/content/96/7/1911.short

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