Well, we’re approaching the time of year on this Ireland when the sun makes its annual retreat behind a grey curtain.This absence of sunlight may cause you to consider replacing and replenishing your vitamin D stores.
Below is a brief primer on the subject that hopefully covers many of the bases with regards to this essential vitamin.
What is vitamin D?
Surprise, it’s not really a vitamin — it’s a prohormone or hormone precursor. Like cortisol, estrogen, and testosterone, it’s derived from cholesterol molecules.
How do I get it?
Humans make vitamin D in the bottom two layers of the skin in a photochemical reaction driven by a narrow band of UV light. This means the most significant source is sunlight.
How do I become deficient?
Generally, most people start healthy. Those of us in climates and latitudes with longer winters and extended cloud cover (and 9-6 office jobs!) can take a few months of darkness to become vitamin D deficient. It’s difficult to stay topped up in the midst of an Irish winter and spring (and summer?)
What’s the vitamin D sold in stores?
When you take vitamin D orally, you usually take vitamin D3 as cholecalciferol. It’s absorbed in the gut, carried into the blood, and then makes its way to the liver.
Why should I be interested in vitamin D?
First of all, it strengthens your immune system. It also decreases risk of serious and common autoimmune disorders like Type I diabetes, rheumatoid arthritis, and multiple sclerosis.
Vitamin D replacement improves insulin sensitivity, the ability to secrete insulin, as well as hypertension.
Currently, while vitamin D deficiency does increase the likelihood of diseases of civilization, it’s not seen as a primary cause.
What about the big “c”?
A ton of studies show that exposure to UV light and in some cases vitamin D intake are inversely related to the risk of common cancers, including colon, breast, prostate, esophagus and non-Hodgkin lymphoma.
Okay, I’m sold. Where can I get some vitamin D?
You can get more than 80 percent from sunlight. It’s the only natural source of any significance.
General guidelines suggest that getting whole-body sunlight between 10 and noon for 20 minutes is equivalent to oral dosing with 10,000 IU.
How much do I need?
The current Recommended Daily Allowance is 400 IU a day, which is the bare minimum required to avoid rickets.
If you can get sun at midday — say on lunch-break, with a quarter of your skin uncovered (leave on your pants) for a half hour, and your latitude and the season allow enough UV, you should be fine.
What if there’s no sun? What kind of vitamin D should I buy?
Vitamin D3 only. Almost any brand is good. We will have some in the gym soon.
How much should I take?
It’s best to get plasma 25(OH)D status tested, but if you’re out in the sun a lot, then 5,000 IU daily should maintain.
If you’re low, you’ll need to take much more. Test to know for sure, every 3-6 months.
What if I still eat wheat?
Be aware that wheat will cause you to use up your stores of vitamin D much faster, and also will stop vitamin D from getting into the cells where it can be used.
Any other benefits?
For sure! I’ll leave you with just two: some research shows that having optimal vitamin D levels may reduce your likelihood of getting sunburnt. I have noticed this personally since bringing my D levels up, I never seem to burn.
Also, vitamin D will help you with your gains in the gym. It has been shown as long ago as the 1950s that exposure to UV radiation increases strength. It was also noted that trainability and performance peaked in late summer and was lowest in mid-winter. From a 2009 research article by Cannell, et al:
Methods: We reviewed the world’s literature for evidence that vitamin D affects physical and athletic performance. Results: Numerous studies, particularly in the German literature in the 1950s, show vitamin D-producing ultraviolet light improves athletic performance. Furthermore, a consistent literature indicates physical and athletic performance is seasonal; it peaks when 25-hydroxy-vitamin D [25(OH)D] levels peak, declines as they decline, and reaches its nadir when 25(OH)D levels are at their lowest. Vitamin D also increases the size and number of Type II (fast twitch) muscle fibers. Most cross-sectional studies show that 25(OH)D levels are directly associated with musculoskeletal performance in older individuals. Most randomized controlled trials, again mostly in older individuals, show that vitamin D improves physical performance. Conclusions: Vitamin D may improve athletic performance in vitamin D-deficient athletes. Peak athletic performance may occur when 25(OH)D levels approach those obtained by natural, full-body, summer sun exposure, which is at least 50 ng[middle dot]mL-1. Such 25(OH)D levels may also protect the athlete from several acute and chronic medical conditions.
Workout of the day:
A1: DB Split Squats @ 31X1 x 8 Each Leg (Alt); 3 Sets; 90 Sec (rest/reload)
A2: Neg. pull ups @ 50X1 x 6-8 Reps Total; 3 Sets; 90 Sec
5 rds of
15 overhead squat