Back in the 1980s, a guy named Edgar Hope-Simpson proposed that a seasonal stimulus was intimately associated with seasonal epidemic influenza. Long story short, winter comes and then all of the sudden viruses become more of a prevalent issue. There was this whole interventional study that showed vitamin D is reducing the incidence of respiratory infections in children. So, this was specifically talking about kids but there are countless of these for adults.
What's happening when the vitamin D levels are sufficient are a multitude of things but in particular, it's helping to reduce Interleukin 6 (IL-6), which is one of those inflammatory cytokines that get people in trouble. So, if you can reduce your cytokines, that’s going to be beneficial. Also, another cool benefit is not only a sort of an antiviral but there's some antimicrobial benefit. It can actually activate your immune cells to produce some antimicrobial like a natural antibiotic if you will by upping vitamin D concentration.
Is it just an ongoing thing? If you think you're getting into trouble with illness, do you go high dose of it? It depends on what your levels are.
So, get a baseline first. I would say the lighter or more fair your skin is, probably the more efficient you are gonna be in converting vitamin D from the sun. The darker your skin is, the more melanin you have. You’ve got different spectrums and for example, a full-on African-American has the highest amount of melanin.
Melanin is like your natural UV block and it helps block your skin from the sun's rays. So, due to evolution and where we evolved, there are people who live closer to the equator and there’s more UV light based on the angle of the sun hitting it. These people naturally evolve with more melanin in the skin. People that evolve further away from the equator get less direct UV light, so there’s less melanin in the skin because it's all about making vitamin D.
So, the more efficient you are at making vitamin D, you probably will be able to get away with not supplementing as much or as frequently. The more melanin in your skin, the more you have to be on top of your vitamin D because unless you're going to be outside 6 to 8 hours a day and you're at a mid to low 30 latitude, you're probably just not going to be able to ever make enough vitamin D. Therefore, you really have to be on top of everything in your testing.
For lighter skin, in general, a good rule of thumb is 1000 IUs per 25 pounds of body weight, especially in the fall and winter months. If you want to take a break in the summer, that's fine. Just make sure you get a test here there to confirm it. The darker your skin is, you may even want to double that in the winter months. Then you may want to follow-up and retest in the early spring to see and to monitor where you're at. If you're someone who works outside, you have to make that adjustment. If you're an office person and you’re inside all day, you also have to make that adjustment, too. So, in general, 1000 IUs per 25 pounds of body weight.
If you have darker skin, you may want to double that for the winter months, and then it's always good to confirm some time in the winter and some time coming off the winter or early spring-summer to see where you're at. We can always adjust accordingly and if there is any risk of autoimmunity or cancer, we probably want to be testing just a little bit more frequently. Once you know where you're at, you can guess based on how well you're doing.