Even though it is normally delivered from a vast distance, this critical vitamin is generally free. Many of us get enough of it automatically in the summer, but most of us run short in the winter and pay a long-term penalty. The penalty can be severe, especially considering how cheaply and easily it can be prevented.
The penalty? Diabetes, stunted growth, high blood pressure, cancer, and fractures … and still counting. The prevention? A few moments in full sunshine for starters, plus milk, orange juice, fish oils, and/or supplements. You can even get a vitamin D injection good for a year for the price of a Big Mac. The ratio of benefit to cost is thus quite astounding; just a daily walk around the block may add health and years to your life if you presently get no sunshine. How do you know whether you need more vitamin D? Just get an evaluation of your blood level of 25-hydroxy-vitamin D next time you have blood drawn for your annual cholesterol evaluation. If it’s not at least 20 ng/ml, get more vitamin D. It makes sense to do this in the winter, when your vitamin D may be at its lowest.
Given a vitamin D deficit’s serious consequences, ease of aversion, and simple detection, prevention is a no-brainer. Let’s see how and why we should prevent its shortage.
We learned nearly a century ago that vitamin D prevents rickets, which stunts children’s growth and deforms adult skeletons. We immediately began advising some daily sunshine and vitamin D-fortified milk, and rickets almost disappeared for decades. But just like Arnold, it’s baaack. In fact, vitamin D deficiency is epidemic, and its known harmful effects increase with almost every new study. It causes far more health problems, in far more people, than we ever thought, to the extent it should concern every one of us.
Is that a fair and balanced statement? We report, you decide:
- Colon cancer climbs steadily as we look further north from the southern U.S. It’s twice as high in the gloomy northeast as in the sunny south. Tests showed the determining factor was the level of vitamin D in the blood, and those tests are being expanded to other common forms of cancer whose death statistics correlate with sunshine exposure. Medical science explains many of these statistical correlations, justifying new trials.
- Finland, with only a few hours of sunshine on clear winter days, has the world’s highest rate of Type I diabetes – the autoimmune form. Giving Finnish infants vitamin D reduces that rate by about 80%, and medical science explains the correlation and the improvement.
- High blood pressure also rises with distance from the equator. Coincidence? Not likely; sun lamps raise vitamin D blood levels and lower blood pressure.
- Osteoporosis increases with age, but a major part of the mechanism may be low blood levels of vitamin D due to decreasing time outdoors and generous application of sunscreen, not just advancing years. Half of the post-menopausal hip fracture patients in one large study had a significant vitamin D deficiency, and we know vitamin D influences bone density.
- Muscle weakness and bone pain in adults can be a symptom of vitamin D deficiency … far more easily treated than a mistaken diagnosis of fibromylagia.
- 10% of young kids in sun-bleached, outdoor-oriented Tasmania, near Australia, already face bone damage because of their national obsession with sunscreen and hats. Teenagers there? 75% deficient. Veiled women in desert climates and the elderly in nursing homes? 80% severely deficient.
Convinced? If not, maybe the simplicity of the cure will push you off the fence: 10-20 minutes a day in full sunlight sans sunscreen – up to two or three hours for very dark-skinned people -- is a great start. Just your bare hands and face will pick up enough sunlight to generate a day’s minimum dose of D except in northern U.S. winters or overcast climates. (Hint: you folks in Seattle don’t know what sunshine is. It’s not the glow that distinguishes day from night; it’s that frightening thing you saw in the sky when you visited your nephew in Albuquerque.)
The next step is foods fortified with D, including milk, OJ, and cereal. A cup of vitamin D-fortified milk contains 100 IU, a noticeable dent in your daily need. By current government minimums, we need at least 200 IU (5 micrograms) a day (400 IU/10 mcg if breast-feeding) up to middle age, then 400/10, then 600/15 by about 70. That’s with sunlight; Dr. Michael Holick of Boston University recommends that adults who don't get any sunlight should probably ingest four times these amounts. When you’re reading food labels to determine the amount you’re consuming – you do read them, don’t you? – remember that the “daily value” (DV) of vitamin D used on those labels equals 400 IU/10 mcg.
Supplementation is also cheap and easy. Vitamin D pills are on your grocer’s shelves, or people with impaired digestion may need an annual injection. Vitamin D3 is proven to be 70% more effective than vitamin D2 (the synthetic form), so take that into account when taking supplements.
[Sidebar: This stuff is so easy; I encountered an unsubstantiated rumor of this difference between D2 And D3, so I asked Google about “vitamin D2 D3”. In 1.2 seconds my screen was full of medical journal data on the issue. If you aren’t using Google, you are looking at the internet through a blindfold. Ask it anything.]Infants under six months need extra vitamin D, partly because they should get no direct sun exposure. Sun exposure at that age correlates even more strongly with skin cancer development than does lifetime skin exposure. They need to ingest 200 IU daily beginning at least by the age of two months.
Nearly half of African Americans may be vitamin D deficient, because dark skin blocks sunlight and because many nonwhite people can't tolerate milk products. The CDC reported in the American Journal of Clinical Nutrition that 42 percent of the African American women in their large study -- compared to only 4.2 percent of white women -- were deficient in vitamin D, and rickets is especially common in African-American infants. This, despite the fact that these African American women were consuming more than the recommended minimum amount of vitamin D!
Do not abuse it; 2,000 IU/50 mcg (1,000 IU for infants) starts producing dangerous calcium excesses with many serious consequences. Vitamin D pills are cheap and readily available, but you should get your doctor’s approval before using them if you have epilepsy, chronic diarrhea, intestinal problems, sarcoidosis, or disease of the kidney, liver, pancreas, heart or blood vessels, or if you're planning to become pregnant.
It’s the uv-B in sunshine that generates vitamin D production, but glass, thick clouds and smog stop it, and the mainland U.S. gets very little of it in the winter anyway. Almost everyone should eat vitamin D in the winter, and even in the summer indoor work prevents most us from getting enough vitamin D from the sun. Just remember that even a little sun-induced reddening of the skin is too much, and begins breaking down the vitamin D produced on our skin. 20 minutes of direct sunshine is plenty except for dark skin.
In summary, vitamin D supplementation is probably necessary for older people, African Americans, people living north of about the mid-U.S. or in overcast climates in general, people whose work or disability or video games keep them indoors most of the day, veiled women, people with any of the many fat malabsorption diseases, exclusively breast-fed infants, and people with certain kidney disorders … and quite possibly all of us if new trials support the experts’ advice to raise the minimum daily values.
So why are we just now hearing about this? Because we thought for decades that its only threat was rickets, and we thought rickets was licked 70 years ago. Only recently have we realized the widespread ill effects of vitamin D deficiency, and the closer we look, the worse the extent and the effects of the deficit appear. This is motivating a flurry of clinical trials, which are snowballing into more clinical trials as new impacts become known. We should all follow this unfolding information, especially if we or anyone we love falls into the previous paragraph.
For references and far more data, ask Google about “vitamin D deficit sun”. In a second, your vitamin D information deficit will cease.