Vitamin D is back in the news in a bigger than life way -- far beyond bone health [osteoporosis, osteopenia, and osteomalacia (soft bones, in children known as rickets), and fractures].  While it has been a constant feature for decades in scientific research circles/reports, the media has recently resurrected the vitamin reflecting its expanding sphere of influence in diverse diseases and near epidemic levels of deficiency.  From cancer, diabetes, periodontal (gum) disease, depression, PMS, Poly Cystic Ovarian Disease, Fibromyalgia, and heart disease, to headache, osteoarthritis, hyperparathyroidism, and various autoimmune diseases such as rheumatoid arthritis, psoriasis, lupus, multiple sclerosis and Hashimoto’s Thyroiditis -- not to mention a healthy pregnancy and delivery/childbirth – vitamin D increasingly is being recognized for its varied vital roles.  The big D is getting bigger!  (Summaries of and links to the original research reports on the role of vitamin D in each of these conditions is posted on the authors website listed at the end of this article.)

Bigger than a vitamin.  Part of vitamin D’s pervasiveness is found in the fact that it is actually more hormone-like in its structure and function (molecular make up) than most vitamins.  It is the only fat-soluble vitamin that is derived from cholesterol [it has a sterol-like structure, called cholecalciferol, hence its double duty nature.  (Cholesterol, by the way, is an important contributor to this portion of the vitamin-hormone compound; sterols are also the core component of most all other hormones in the body.)]  Important not only for calcium absorption from the intestine and the incorporation of calcium into the bone matrix, vitamin D receptors are also found in the pancreas, prostate, stomach, brain, skin, muscle, and breast.

Sourcing vitamin D – it’s not easy to come by.  There are three general sources of this nutrient 1. Sun (more, or less, from certain regions, skin color, and age).  2. A limited number of foods, and  3. Supplements (certain forms are more effective).  Space here will only afford a brief overview of each source; full details may be found on the authors website listed below. 

The “Sunshine Vitamin.”  Many variables determine whether or not your body will produce vitamin D from outdoor sunlight: location, location, location is one of the biggest factors.  In our corner of the country you can’t make vitamin D from sunlight for four months of the year (November through February).  This is true for everyone north of the 35^th latitude (running roughly in this country from Los Angeles to Atlanta.)   Those above the 50^th latitude (north of the Canadian border) are in vitamin D darkness even longer, from September through March.  While direct sun exposure is not necessary (filtered through clouds and trees is fine), 30 minutes of outdoor daylight with hands, forearms and face uncovered, without sunscreen (SPF 8 or higher starts to block D synthesis), eyeglasses, or through glass (U.V. rays do not pass through), is necessary for most people. Caution: a moderate sunburn can produce 10,000 IU of vitamin D per day, a potentially toxic level for individuals whose built-in protection of lumisterol is inadequate.   Note: Because the body can store this fat-soluble vitamin, a deficiency will not necessarily manifest itself during the dead of winter.  It may take six months before a D-ficiency is evident.  Therefore, some of the lowest blood levels are found during Spring time.  At risk individuals are advised to retest every six months (See Testing for D-ficiency, below).  Other risk factors.  The darker the skin, the less vitamin D the body makes.  Vitamin D deficiency is well documented in the elderly.  This is because people aged 22 to 30 make more D than those aged 62 to 80 when exposed to the same amount of sunlight.  Since breast milk contains very little D, and nursing mothers tend to have low levels, infants who are exclusively breast fed often are D-ficient and should be supplemented.  Because fatty tissues sequester vitamin D leaving less in the blood, overweight people tend to be more D-ficient. Additionally, those with malabsorption syndromes, liver congestion, and kidney disease are at increased risk.  Certain drugs also cause D-pletion. (Such drug-nutrient interactions are posted on the website below.)

The current recommended intake of vitamin D of 200 IU for those under 50 years old, 400 IU 51 -70 years old, and 600 IU if you’re over 70, is questionable and not an evidence based guideline, but simply an extrapolation from early observations that 400 IU (the amount in one teaspoon of cod liver oil) would cure rickets in children.  Early researchers made the mistake of applying the same amount to adults.  Given the increased incidence of deficiency and recognition of big D’s ever expanding role in health and various diseases, 1,000 IU is a more reasonable intake.  Up to 2,000 IU per day is considered safe (unless you’re prone to kidney stones), and some experts suggest as much as 4,000 IU daily --  That’s today’s D times 10.

Food, sun, or pills?  Since food sources are few and far between, virtually non-existent if you don’t eat plenty of seafood and fortified (usually more processed) foods daily, and daily exposure to sun is more than challenging here in the great northwest (not to mention that conversion quantities are complicated, highly variable from person to person, and therefore difficult to calculate accurately), it’s easier for most people to insure adequate intake by using a vitamin D supplement.  A note about supplemental sources (R2….D2 or D3?)  Vitamin D3 (cholecalciferol, from animal sources) is the preferred form since it is 25% more potent than D2 (ergocalciferol, from plant sources).  As with any vitamin supplement it is best to test your body tissue level before you take it, and it’s even better to have more than one test result indicator pointing at the same nutrient, before using it for more than a few months.

Testing for D-ficiency:  While D3 is the most potent in food and supplements, it is a precursor to the hormonally active form of vitamin D inside the body.  After the liver and kidneys chemically convert the ingested nutrient it becomes 1,25-dihydroxyvitamin D3 (1,25 DHCC) in the blood, which is 10 times stronger than cholecalciferol (CC).  Appropriate selection, and proper interpretation, of blood/serum vitamin D levels is complex, to say the least, with many conflicting research reports and expert opinions.  It has been proposed that the so-called normal reference range for this nutrient be adjusted for various regions and populations.  Here are some general guidelines that must be weighed on an individual basis.  So called normal blood levels of 1,25 DHCC range from 16 - 57 pg/ml, and for 25-Hydroxy CC 10 – 100 ng/ml, depending on who you talk to.  One size (“normal” range and recommended dose) doesn’t fit all is especially true when it comes to vitamin D.  Always get a second opinion here (including mine), tailored to your individual condition!  While it is not routinely tested for, it should be, and can easily be added to any routine blood chemistry metabolic panel.  Both forms of blood vitamin D should be tested for the clearest meaning, not just one.

Although properly interpreted blood levels are one of the more reliable indicators of vitamin D status, there are other screening methods, early indicators of deficiency, and functional assessment tests that can be done before costly blood work.  One nutrition quick test for D that I perform on patients as part of a nutritional physical examination, and can partially be done at home, is the Joint Popping Index, described on my website.  Hair mineral analysis also is a fair indirect indicator of D status, since it shows how well calcium, magnesium, and other vitamin D-dependent nutrients are being absorbed and metabolized.  Interestingly, both hair and joints are composed of the same ligamentous connective tissue.  When you view the mineral content of hair, you’re actually seeing the mineral make up of all such soft tissues throughout the body.   Hair, nails, and joints are the depository end product of nutritional metabolism after multiple interacting nutrients have been absorbed, converted, distributed (or mis-distributed) and finally deposited into the tissues.  Again, a variety of different test indicators for your particular circumstances is the best assurance of accuracy, safety, and effectiveness.

Given the long history of and recent increased attention to the vital importance of vitamin D in human health, it deserves our continued attention.  As with all nutrients, the best solution to the vitamin D-lemma is threefold: individuality (addressed on an individual, person by person basis), consideration to overall nutrient balance for that individual, and moderation (especially where supplementation is involved).  Testing, reevaluation monitoring, and research updates will prove most useful in all of these regards.  In the meantime, it is my wish that the information in this article will serve as a personal springboard for bigger and better vitamin D balance, and your improved nutritional health.

Note: Ones total daily intake should include cumulative amounts from all sources, including an accurate assessment of food-source intake (comprehensive computer-calculated Dietary Nutrient Analysis), and various supplemental sources.  A no-cost Professional Vitamin Supplement Review is available at www.Nutrition-Testing.com).

Karl Mincin is a clinical nutritionist in practice for over 20 years.  He specializes in nutrition assessment testing.  His office is at 313 W. Section St. near the Mt. Vernon Post Office.  Karl may be reached at (360) 336-2616 or cell 770-8486, and also is available for telephone consultation.  For more information about his professional nutrition services or links to the vitamin D resources mentioned in this article, visit his website www.Nutrition-Testing.com.