Early one morning last week, I awoke to the sound and smell of rain outside my bedroom window. It was a brief shower that came and went, and only left a few traces I could see on my way out the door. It got me thinking about the changing season ahead, and how excited I am for a beautiful fall. It also got me thinking about the vitamin D winter ahead that many of us will experience at certain latitudes. What is this vitamin D winter I speak of, and why should we be concerned with getting enough vitamin D?
Vitamin D is actually a seco-steroid hormone in its active form (1,25(OH)2D), that is necessary for optimal human health. Its role in the body was reevaluated when the vitamin D receptor (VDR) was discovered in tissues having nothing to do with bone metabolism; as it had primarily been known for its role in bone health. We now respect the extensive potential of vitamin D in reducing the risk of type 1 & 2 diabetes, cancer, infectious diseases, cardiovascular disease, and autoimmune diseases.
Vitamin D status of people all over the world is a current hot topic in research and medical communities. It can’t be ignored that widespread deficiency is contributing to numerous health problems for those with soft baby butts to wrinkly old skin. Humans evolved to obtain vitamin D primarily from exposure of their skin to the UVB rays of the sun. We can look to the conditions of modern society, compared to our ancestral lifestyle, as contributing to the development of suboptimal vitamin D status. Most of us have heard anti-sun messages repeatedly, demonizing the rays of the sun. We spend most hours of the day indoors, riding in cars or public transportation instead of walking, and we take measures to protect our skin from the sun with hats, long sleeves, and sunscreen. With all of these factors working against natural vitamin D production, there are no surprises so many of us have deficient or suboptimal blood levels. The following table shows vitamin D levels as defined by the Office of Dietary Supplements (National Institute of Health):
| Serum 25-Hydroxyvitamin D [25(OH)D] Concentrations and Health | ||
|
nmol/L** |
ng/mL* |
Health status |
|
<30 |
<12 |
Associated with vitamin D deficiency, leading to rickets in infants and children and osteomalacia in adults |
|
30–50 |
12–20 |
Generally considered inadequate for bone and overall health in healthy individuals |
|
≥50 |
≥20 |
Generally considered adequate for bone and overall health in healthy individuals |
|
>125 |
>50 |
Emerging evidence links potential adverse effects to such high levels, particularly >150 nmol/L (>60 ng/mL) |
* Serum concentrations of 25(OH)D are reported in both nanomoles per liter (nmol/L) and nanograms per milliliter (ng/mL).
** 1 nmol/L = 0.4 ng/mL
Our skin was designed to produce vitamin D through UVB exposure from the sun, as there are few natural food sources of vitamin D. Modern day folks can also obtain vitamin D from supplements, fortified foods, and some natural food sources. One of the best natural food sources is wild caught salmon, which provides nearly twice the amount of vitamin D as farm-raised salmon and close to the RDA in a 3.5oz serving. Most fortified dairy products usually contribute around 100 IU per serving. If we rely on food alone, most of us are going to fall short of the daily goal and potentially end up with suboptimal or deficient levels. In one study, 32% of healthy physicians, students, and residents at a hospital in Boston who reported drinking a glass of milk daily, eating salmon once a week, and taking a MVI daily had deficient vitamin D levels. The following table shows adequate dietary intake levels set by the Food and Nutrition board assuming little sun exposure. These daily intake levels aim to maintain bone health and normal calcium metabolism in healthy people. We know now that bone health is not the only function of vitamin D in the body; the RDA was recently increased to reflect new knowledge of our daily need. Keep in mind if you have suboptimal levels, you probably need more than the RDA to bring them up (supplementation doses should be individualized).
| Recommended Dietary Allowances (RDAs) for Vitamin D | ||||
|
Age |
Male |
Female |
Pregnancy |
Lactation |
| 0–12 months* |
400 IU |
400 IU |
||
| 1–13 years |
600 IU |
600 IU |
||
| 14–18 years |
600 IU |
600 IU |
600 IU |
600 IU |
| 19–50 years |
600 IU |
600 IU |
600 IU |
600 IU |
| 51–70 years |
600 IU |
600 IU |
||
| >70 years |
800 IU |
800 IU |
||
* Adequate Intake (AI)
If you consume a paleo diet with little or no fortified dairy, you will be doing yourself a favor by regularly eating wild caught salmon; but just like most of the people in the world you still might not be getting adequate vitamin D through your diet. Safe sun is a natural way to get a good dose of vitamin D, however, there are several factors to consider. The Vitamin D Council reports, “If your shadow is longer than you are tall (an indicator of the oblique angle of the sun), you are not making much vitamin D”. Factors that affect vitamin D production from the sun including angle of the sun, time of day, season and latitude where you live, skin type, and others. Check out the Vitamin D Council for more detailed information on these factors, as well as other vitamin D facts. You can also look up the latitude of the town you live in to see if you might be in the “vitamin D winter” zone for the upcoming fall to spring months, I know I am. Enjoy these last weeks of summer and soak up a few rays!
I got a few holes in my understanding of vit D.
D3 is the preferred supplement form. Or is natural form D2 as in fermented cod liver oil. Just as good? I’ve read d2 and d3 both matters and don’t matter this I’m confused.
Also what form of cholesterol becomes vitD. Can the blood markers be affected(gamed) by getting some good sun exposure pre-blood draw?
Would you agree with the NIH table included in the article that states: “Emerging evidence links potential adverse effects to such high levels, particularly >60 ng/mL?” What do you think optimal levels are?
Thanks for this important article! -DJ
Hey robb , love ur shows! Can u please talk a little more on RAW dairy and kefir? Ive got mixed reviews from ur shows! Some times u say its healthy and other times not! im really confused ..thanks robb god bless u
Is it Grass-fed? Have you eliminated it and reintroduced it? I’ve covered this one many, many times amigo.
Love the topic. Here’s where I get my vitamin d blood test for $50 (labcorp), haven’t found a cheaper source yet.
http://www.saveonlabs.com/products/Vitamin-D%2C-25%252dHydroxy.html
I read somewhere to take your vitamin d’s with a fatty meal as it will increase absorption.
I would be curious to read references to this quote “Emerging evidence links potential adverse effects to such high levels, particularly >150 nmol/L (>60 ng/mL)”
Mercola recommends 60 ng/ml for adults which is where my levels are at now.
Here is everything you ever need to know about the most important “vitamin”:
http://www.grc.com/health/vitamin-d.htm
I’m curious what evidence there is that >60ng/ml has any adverse effects. The only evidence I’ve seen of this is from a Canadian study where it is believed that the Vit. D was gotten from cod liver oil, and that the Vit. A in it negated the effects of high levels of Vit D. The Vitamin D Council routinely recommends >60ng/ml if deemed necessary. Also, the RDAs are laughably low.
I’m not too scared about the greater than 60 levels.
Your numbers are too low. The Vitamin D Council recommends levels between 50-80 ng/ml – between 90-100 for cancer survivors. Since toxicity becomes an issue at a bit over 200 ng/ml this makes more sense.
Pay attention to the cofactors. There’s a page here – To read more:
http://www.vitamindcouncil.org
Good article to understand why VD3 is critically important:
New Research on Vitamin D3
http://www.wholefoodsmagazineonline.com/columns/vitamin-connection/new-research-vitamin-d-part-1-vitamin-d-unique
To read about the groundbreaking Study released in February on VD3 and Cancer – concluding that at least 8,000 IU is needed daily to prevent cancers. There are also two videos by the study authors and a summary of the study for the layman:
http://www.grassrootshealth.net.
The above listed organizations are both nonprofits.
How can we determine D requirements based solely on serum 25-D levels without measuring 1,25-D metabolites? Don’t D metabolites block, or are at least more preferential than, cortisol and T cells at the nuclear receptor? They bind to glucocorticoid receptors, thyroid-alpha-1 receptors and androgen receptors, right? With most D requirements studies considering 25-D serum levels only, could we me missing something? I’m a total amateur, just trying to understand more here. Thanks Robb!
Tom
How do we increase the absorption of Vitamin D? Take supplements with a fatty food? Thanks
Yes! Always take vitamin D with a meal and the liquid D drops are your best option.
Sunscreen. What are your thoughts on it? People push it on my like it’s some kind of cult. Help.
Find a good kind with zinc or make your own if you need to use it, but IMO the best way to mitigate sun damage is just get responsible exposure. Personally, I go out in the sun without sunscreen, and if I’m getting too much I just cover up with a shirt, hat, etc, or go in the shade.