There’s an epidemic going on… and it’s that very few people know they're low in vitamin D!  In today’s episode, Dr. Martin gives 9 major signs you should suspect you’re low in vitamin D. Doctors in Canada and in the United States... and all over the world, really... are 50 years behind when it comes to vitamin D. The numbers used to calculate recommended intake are wrong, as doctors only considered the benefits to bones, and not the immune system. Your immune system needs vitamin D to function properly, and if you’re not getting it from the sun, you need to supplement.