YOUR VITAMIN D WINTER
When the sun’s rays enter the earth’s atmosphere at too great of an angle, the atmosphere blocks the UVB portion of the rays. This occurs regularly during the early and latter parts of the day, but also continuously throughout the winter season, increasing as one moves further away from the equator. This is called “Vitamin D Winter”. During this time, due to the lack of sufficient solar UVB rays, the skin is unable to synthesize much, if any, natural vitamin D from the sun.
A healthy individual can typically store around a three month supply of vitamin D in their tissues which means that around this time of year, you may be running low if not already depleted of vitamin D. UVB rays which provide vitamin D are low to non-existent in many areas of the US and Europe by the time that December rolls around. The time of day, season, altitude, and latitude, are amongst the many factors that all determine the amount of UVB that reaches your skin. Don’t think you can go outside and get some vitamin D just because the sun is out. Although being outside on a sunny day is still a good idea!
In this article I want to discuss some interesting signs and symptoms of improper vitamin D synthesis as well as if whether you should supplement, (either prescription or over the counter), with vitamin D. But first let’s talk about how and when your body gets some D from the sun.
Free Vitamin D – At Specified Times
Latitudes above 40 degrees north (New York City & Denver) will experience Vitamin D Winter from around November through early March. Between zero degrees to about 35 degrees north or south will allow for year-round vitamin D production, with higher levels closer to the equator. Here, where I live in central North Carolina we’re just above 35 degrees so we can estimate that our Vitamin D Winter is three months long – December, January, and February – with November and March providing some UVB days. An interesting and fun fact is that 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. So check your shadow!
For optimum vitamin D production, sun exposure should be between the midday hours of approximately 10am-2pm. These hours will also vary slightly according to latitude. The closer to solar noon, the more vitamin D produced. During a summer day around noon in Miami an individual with moderate skin pigmentation would require approximately 6 minutes to synthesize 1000 IU of vitamin D. However, at the same time in Boston it would take that same person ten times longer – 1 hour! Near January and February is typically a great time to take a tropical, (or at least southern), vacation.
Speaking of skin, the amount of skin exposed is important. At least 40% of the entire skin surface should be exposed for optimal vitamin D production. The torso produces the most, legs and arms some, and the hands and face very little or none at all. Go topless!
Melanin is the pigment that determines our skin color; it is nature’s built-in protection against skin damage from excess UV ray exposure. This is why those whose ancestry is native to regions near the equator have darker skin than those native to regions located at higher latitudes. It is also why those with darker skin living at higher latitudes have higher prevalence of vitamin D deficiency, and especially those individuals who also live at low elevation since UVB rays diminish as elevation decreases.
Another factor that affects UVB ray and vitamin D exposure is age. Vitamin D synthesis can take up to four times as long for those over the age of 60 and under the age of 20, apparently due to having less cholesterol in the skin. Some claim that many soaps and lotions can negatively affect skin cholesterol levels and therefore impair vitamin D production. Sunscreen also blocks the absorption of vitamin D; a SPF as low as 8 can block as much as 95% of vitamin D production. Statin medications, (ie: Lipitor, Zocor, Crestor, Prevachol), not only block the production of the important antioxidant CoQ10, but they hinder vitamin D as well.
Glass also significantly limits if not eliminates UVB exposure. So sitting in a sunroom will not increase your vitamin D level much if at all. Indoor tanning beds and sun lamps do provide UVB rays, and therefore can provide vitamin D, but they should be used sensibly due to their direct exposure.
How Does One Actually Make Vitamin D from the Sun?
Once UVB rays from the sun penetrate the epidermal (outer) layers of the skin, cholesterol (7-dehydrocholesterol) in the tissue of the skin then absorbs this UV light to make vitamin D3, also known as cholecalciferol. This further goes on to become 25-Hydroxycholecaliferol, (25(OH)D, also known as calcidiol), in the liver, which happens with adequate niacinamide (vitamin B3) and magnesium levels. The 25(OH)D level is the one that is the best indicator of vitamin D status. Then with some more niacinamide and iron it becomes 1,25-dihydroxycholecaliferol (calcitriol) in the kidneys. This is the most hormonally active form and our most potent steroid hormone which controls the expression of many our genes.
Those hydroxylation (OH) steps just mentioned in the liver and kidney are highly dependent on antioxidants such as vitamin A, C, and E in addition to the niacinamide, magnesium, and iron. Other nutrients such as vitamin K, boron, and calcium are also very important for the absorption and synthesis of vitamin D. Healthy fats play an important role in vitamin D absorption too, especially the fats we recommend in a Paleo Diet – pasture meats, wild fish, eggs, butter, and coconut.
Blood Testing for Vitamin D
The optimum serum level of 25(OH)D is thought to be between 50-80ng/mL although nobody is quite certain and it may very well be specific per individual. In other words, you may be fine if your 25(OH)D is 50ng/mL yet someone else may need 80ng/mL. If your level is much lower than 30 or 40ng/mL you may need to supplement with some Vitamin D3 (not D2) as even an adequate diet and sun exposure may not be enough.
It is not necessarily as simple as what we hear in the news that, “Everyone needs to take vitamin D.” What many do not know is that the 25(OH)D can be converted to a high amount of 1,25(OH)D when there is an infection, (such as those bacterial in nature), as well as with autoimmune diseases such as rheumatoid arthritis and Hashimoto’s. Excess intake of vitamin D is also linked to chronic diseases and obesity.
So if you’re taking vitamin D because your doctor told you to based off your 25(OH)D blood results, you should be aware that your body perhaps wants to keep that 25(OH)D low because if it were to increase it more, you might provoke that infection or illness – and that’s a really bad idea. If your 25(OH)D is low, it can be beneficial to check your 1,25(OH)D level, as well, to make sure it is not too high. Unfortunately you might have to fight with most doctors to get this checked.
Lowdown on Vitamin D
Vitamin D takes calcium from the digestive tract and brings it to the blood where it can then head off to perform many of its functions such as building bones, pumping the heart, and contracting your working muscles. Healthy fats in the diet are required for these functions, especially driving the calcium into muscles to prevent cramping.
If you ever have had a “Charley Horse” type calf cramp at night that is typically due to calcium starvation in the tissues. Usually this is not a need for more calcium but actually those fasts we recommend in a Paleo Diet previously mentioned. Sometimes vitamin D is also needed too. If you’re susceptible to nasty cold sores, that can also be due to a calcium-vitamin D- fat imbalance. Even though the cold sore is caused by a virus, it is the balance of these nutrients that keep the virus in check.
Sunburned individuals are often receiving too much vitamin D and not enough healthy fats, calcium, or antioxidants in their diets (poor hydroxylation). So a diet higher in healthy fats as well as antioxidant-rich foods such as colorful fruits and vegetables will not only help with vitamin D absorption, but also prevent sun damage. People who get thick, leathery skin from too much sun exposure are often dealing with too much vitamin D and a lack of healthy fats in their diet which creates a calcium starvation problem in the tissues.
From my experience, taking the prescription dose of 25,000-50,000IU of vitamin D2, (Deltalin, Drisdol, Calciferol), and especially the calcitriol medications, (Rocaltrol, Calcijex, Decostriol,) is harmful to patients and quickly results in problems with even just one pill a week. Not once have I seen a patient not react to these medications – ranging from muscle aches and headaches to digestive problems and fatigue. Of course I have to say here to check with your prescribing physician – maybe educate him or her if necessary! I, as well as many physicians, have had tremendous success with patients taking 5,000-6,000IU of vitamin D3 once a day and dosing kids at 1,000IU for every 25 lbs of body weight. Some people may need 10,000IU a day for a very short time, but always of D3.
Vitamin D2 (ergocalciferol) is for plants and fungi. Vitamin D3 (cholecalciferol) is for humans! Some studies have shown that you will increase your vitamin D absorption by more than 50% if you take your supplement (D3) with a fatty meal (coconut oil/milk, egg yolks, avocado, and butter).
Vitamin D, along with a host of other antioxidants especially vitamin A, is key to the proper operation of the innate immune system – this is what defends your body against all infections. Yet dietary fats may be the most important factor when it comes to absorbing vitamin D as well as keeping it active in your body. Many people do not eat enough fats, even those following a Paleo Diet. Consuming more fats will help with hormonal production, skin and hair luster, and your overall physical and mental stamina and acuteness. So eat more fat, take a winter vacation, and keep an eye on your D!
See this article in the February 2015 edition of Paleo Magazine Insider!
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