I’m not suggesting you spend a weekend (as I did) reading the historically important and game-changing 30-page article in this month’s Mayo Clinic Proceedings entitled “Vitamin D for Health: A Global Perspective.” The study’s authors have written an exhaustive meta-analysis, which means that although they didn’t perform any original research themselves they reviewed the research of others around the world and also looked at previous meta-analyses. In essence, they sat down in front of a computer, typed the words vitamin D supplementation into medically oriented search engines, and read everything. If there’s one single take-away from today’s health tip, it’s that quite likely you yourself are deficient in vitamin D and you’d be wise to do something about it. We all learned in grammar school that D is “the sunshine vitamin” because when our skin is exposed to sunlight, we make our own D. What happens is that the sun’s ultraviolet B (UVB) waves trigger chemical reactions in our bodies so they manufacture a pre-vitamin D that penetrates our bloodstream and then converts to the active form, vitamin D-3.
Your vitamin D status is determined by measuring one of D-3’s metabolic products, 25(OH)D. However, manufacturing D is a lot more complicated than sunshine or my shorthand description above. We also get some limited D from foods (oily fish like wild salmon and fortified milk among them) and from nutritional supplements. Just take a quick glance at this diagram by one of the article’s authors, Michael Holick, MD, which shows the intrepid reader the complete synthesis and metabolism of vitamin D. Low D spells trouble Low levels of vitamin D have been associated with so many seemingly unrelated diseases that it took awhile for doctors to figure out exactly what was going on. How could inadequate levels of a single molecule be responsible for increasing the risk of diabetes, heart disease, many (many!) cancers, autoimmune diseases, cognitive decline, pregnancy complications, bone disease, allergy, and even frailty? Recent studies have also proved that low levels of vitamin D during pregnancy or in a newborn increase the baby’s lifetime risk for susceptibility to schizophrenia, diabetes, and multiple sclerosis and, even more startling, the baby’s late-life risks for chronic illnesses including heart disease, cancer, metabolic syndrome, and premature aging.
This second (and decidedly easier to read) diagram by Dr. Holick shows the various conditions linked to low vitamin D as a person ages. D helps genes function efficiently To understand how vitamin D works, remember that every aspect of you is very much determined by genetics. Each organ and chemical reaction in your body has at its basis a set of genes that govern its operation. If you’re lucky, you come from a family of good genes (aka The Lucky Sperm-N-Egg Club) and unless you throw a wrench in the works with alcoholism or unsuccessful skydiving you’re likely to live a long and healthy life. You can also come from a family with a lot of heart disease, cancer susceptibility, or mood disorders like depression and anxiety. But despite genetic predispositions to certain conditions, no one need capitulate to genetics. In fact, by living a consciously healthy life, you can “up-regulate” your genes so the organ they control functions more efficiently, thereby reducing your genetic health risks dramatically.
In fact, a lot of what we do at WholeHealth Chicago is teaching patients how to thumb their noses at their genetic risks with a combination of good nutrition, exercise, and stress reduction, enhanced by the encouragement (some call it well-intentioned nagging) of our dedicated practitioners. It seems that it’s on a genetic level that vitamin D affects so many apparently unrelated parts of the body. It’s currently estimated that somewhere between 200 and 2000 of our genes are in some way responsive to vitamin D. To rephrase this, if your vitamin D levels are good, your genes function more efficiently. If D is inadequate, they all function poorly, and the genetic expression of poorly functioning genes is the menu of chronic illness. To give you an idea of the numbers involved, it’s estimated that 60,000 Americans die prematurely of cancer every year because of vitamin D deficiency. Add to this premature autoimmune disease (such as multiple sclerosis), heart disease, allergies (like asthma), diabetes, and Alzheimer’s and the numbers become mind-boggling.
Moreover, a pregnant woman’s vitamin D level can “imprint” genetic susceptibilities onto her developing fetus. It was likely quite shocking for researchers to realize that low levels of D during pregnancy increased a newborn’s later risks for autism, schizophrenia, multiple sclerosis, and a variety of chronic illnesses, any of which can shorten longevity and most of which compromise the quality of our lives. So let’s talk about some effective strategies to get your vitamin D to a healthy level. What’s the ideal D level? It’s still open to debate, but current thinking places it between 40 and 70 ng/ml–nanograms of 25(OH)D per milliliter of blood. Levels 20 ng/ml and lower are definitely dangerous. Ironically, I’ve yet to come across a single free wellness screening offered by health insurance companies or large corporations that includes 25(OH)D measurements. Testing is covered by most health insurance, but the cost applies to your deductible.
For those without insurance, the cost is about $60. We’re not entirely sure about this either, but as many as 91% of Americans with dark skin pigmentation are deficient because darker skin requires more sun to generate the same D as fairer skin. Generally, all people who work indoors, wear extensive clothing, avoid the sun (shaded hats, sunblock), live in polluted cities, and get their sunlight only through window glass are also at increased risk for deficiency. Conversely, the East African Maasai tribe, living outdoors with minimal clothing, have the best vitamin D levels on the globe. What about skin cancer? For patients, nothing shakes faith in doctors like opposing points of view. On one hand, dermatologists trying to prevent skin cancers tell us to stay out of the sun, wear big floppy hats, and apply plenty of sunblock. They equate tanning beds with cigarette smoking. Vitamin D researchers say dermatologists have this all wrong. Superficial skin cancers usually occur on the face, are easy to remove, and rarely are dangerous.
Melanomas, which everyone agrees are dangerous skin cancers, usually appear in unexposed areas anyway, so covering every inch of skin as a protection from melanoma is counterproductive and by doing so your vitamin D levels will plummet. There’s no evidence—not a scrap–that sensible sun exposure like our hunter-gatherer ancestors experienced increases skin cancer risk. Interestingly, melanoma is least likely to occur among people with outdoor occupations, indicating that vitamin D is involved here as well. Quick sun-exposure guideline…and a free app In the Northern hemisphere, exposing your arms and legs (and abdomen and back whenever possible) to sunlight twice weekly for about 15 to 30 minutes of June noontime sun produces adequate levels of D. There’s no need to expose the sensitive skin of your face because, ironically, your face is highly inefficient at D production anyway. I hear you thinking, “Doesn’t he remember we live in Chicago? What about the other 11 months of the year?”
Here’s a helpful free app called dminder that provides data on sun exposure based on location, time of day, and skin color. And yes, in the darker months you’re definitely going to need some help. For that there’s always the tanning bed. The Mayo group points out that regular tanning bed users all had robust levels of vitamin D and better bone density than non-users. Moreover, if everyone in the US used tanning beds to boost their 25(OH)D to 45 ng/ml or higher, there would be 400,000 reduced deaths from cancer and heart disease in comparison to 11,000 increased deaths from melanoma and other skin cancers. Or you can take vitamin D3 supplements. In fact, you’ll do better with a supplement than trying to elevate your D by diet alone. Even a generous portion of salmon contains just 400 IU (international units) and it’s one of our richest D food sources. Moreover, the amount of D in a typical one-a-day supplement is also only about 400 IU, not nearly enough to bring you to a good level.