You wouldn't think a roomful of doctors would get excited about vitamin D. But it turns out there's some news about it that is causing quite a stir—at least it did when I presented it at a conference a few years ago. Judging by the reactions I got from other doctors at that conference, this news could turn a whole line of heart health therapy on its ear. So, I think it's important to take a few more minutes to share this information with you, too.

There's actually quite a lot of solid research behind the use of vitamin D as a blood pressure regulator. In fact, it might just rival one of the major blood pressure drug categories in effectiveness—for a whole lot less money out of your pocket.

Is where you live raising your blood pressure?

Epidemiologic studies have shown that people living near the equator are less likely to have hypertension. It's also been observed that blood pressures tend to be higher in the winter, when we get less sunlight, which your body uses to synthesize vitamin D. One recent large study demonstrated a distinct connection between increases in blood pressure and the distance people live from the equator. [1]

Another study, published several years ago in the Lancet, reported that ultraviolet light exposure, which increases the body's internal vitamin D production, lowered blood pressure in individuals with mild essential hypertension. [2] And two other small clinical trials showed that vitamin D supplementation reduces both systolic and diastolic blood pressure. [3,4]

Taken together, these studies and observations strongly indicate that vitamin D is nature's leading blood pressure regulator.

Vitamin D goes one step further than ACE inhibitors—without the dangers

Vitamin D achieves its blood pressure lowering effect by addressing one of the major causes of high blood pressure—a substance called angiotensin II.

Angiotensin II is produced by another substance called angiotensin-converting enzyme, or ACE. When ACE is allowed free rein, it sometimes produces too much angiotensin II. Excess angiotensin II constricts blood vessels, which raises blood pressure. But that's not all that excess angiotensin II does.

Among many other bad effects, excess angiotensin II also leads to abnormal thickening of both the heart muscle and blood vessel walls. It increases output of adrenaline and similar substances, increases the output of another blood pressure raising hormone called aldosterone, and increases salt retention by the kidneys. All of this tends to raise blood pressure.

So blocking ACE, and thereby lowering excess angiotensin II, is actually a logical strategy for lowering blood pressure—and, frequently, it works. But until recently, the best way to block ACE was with patented medications called ACE inhibitors. ACE inhibitor names generally end in the syllable "-pril" (enalapril, captopril, etc.), but they're sold under trade names including Vasotec, Lotensin, Zestril, Altace, Capoten, and others. Like most patent medications and synthetic molecules, ACE inhibitors can cause a number of negative side effects-cough, headache, and dizziness at best; skin rash, kidney problems, and swelling of the face, lips, and throat at worst.

But vitamin D might be able to go one step further-without the added disadvantages of the synthetic ACE inhibitors—by preventing the formation of excess angiotensin II in the first place.

Here's how it works: According to a study published in 2002 in the Journal of Clinical Investigation, one of your genes (a tiny part of your DNA) leads to the formation of a molecule called renin. Renin breaks down another molecule, called angiotensinogen, into angiotension I. Angiotensin I is converted into angiotensin II by ACE. Vitamin D persuades the renin-controlling gene to become less active, and the whole process slows down. [5] The end result is less angiotensin II and lower blood pressure.

Other researchers have found that the higher a person's serum level of vitamin D, the lower his or her blood pressure. [6,7] And in case studies published in the journal Internal Medicine and the American Journal of Kidney Disease, treatment with vitamin D reduced the subjects' plasma renin, angiotensin II, and blood pressure. [8,9]

Vitamin D "clones": coming soon to a pharmacy near you

Of course, with all of this breakthrough news about vitamin D, patent medicine companies see the writing on the wall, so they're racing to develop patentable versions of this potentially blockbuster natural anti-hypertensive therapy. Right now, the patentable versions don't have any specific fancy names—so far, they're just referred to generally as "vitamin D analogues."

The good news is, none of these evil twins of vitamin D has hit the market for hypertension yet. But they're coming-as sure as you can say "patent medicine profits."

Fortunately, supplement companies read medical and scientific research, too, and higher-quantity vitamin D supplements (1,000 IU, 2000 IU, and 5,000 IU) are starting to show up on the shelves of lots of different compounding pharmacies and natural food stores or from the Tahoma Clinic Dispensary. And, even better, these versions are exceptionally inexpensive, with prices ranging from $7 to $9 per 100 capsules, depending on strength.

Just to put that in perspective, ACE-inhibitor prices in my area range from $65 to $145 per 100—even for the generic versions. No wonder the patent medicine companies are frantically researching patentable "analogues."

Safety first

It sounds like an easy solution, and it can be—but only under the proper guidance. Please don't start taking high doses of vitamin D to control your blood pressure on your own. Since the dosage range needed to lower blood pressure isn't yet known, it's a good idea to contact a physician skilled and knowledgeable in nutritional and natural therapies who can work with you in translating this new research into clinical practice. Plus, you'll need to be monitored for vitamin D safety. For a list of natural medicine physicians in your area, contact the American College for Advancement in Medicine at (800) 532-3688 or www.acam.org.

Don't let that scare you off, though: There's actually a much wider range of safe vitamin D doses than health "authorities" generally admit. In 1999, the American Journal of Clinical Nutrition published an article re-examining the upper limits of vitamin D safety. [10] The researchers concluded that the often-mentioned upper limit of vitamin D safety, 2,000 IU daily, "is too low by at least 5-fold." Instead, they suggested that 10,000 IU daily might be a better safe upper limit.

The same journal published a follow-up study in 2001 revisiting that recommendation. [11] This time, the researchers concluded: "We consider 4,000 IU vitamin D3 to be a safe [daily] intake" for adults.

Still, it's smart to have a doctor skilled and knowledgeable in nutritional therapy monitor your vitamin D intake. Back in the 1930s-1950s there were instances of massive vitamin D overdoses. When this happens, calcium is actually leached from bones and appears in the blood in much higher levels than normal—a condition known as hypercalcemia. The initial signs and symptoms of hypercalcemia consist of weakness, fatigue, headache, nausea, vomiting, and diarrhea.

If hypercalcemia persists, calcium is then deposited in soft tissues, most notably in the kidneys. Eventually, this can cause serious kidney damage and osteoporosis.

But you can head these problems off at the pass by keeping a careful eye on your serum calcium level. A doctor skilled and knowledgeable in nutritional therapy will make sure to monitor it, and if your level goes too high, he'll ask you to decrease your vitamin D dosage or stop taking it altogether.

Your doctor should also monitor your serum level of "activated" vitamin D (1,25 dihydroxyvitamin D), though this part is harder to interpret. Your levels are likely to come back as high, but odds are that would have less to do with heading into a danger zone than it would with misunderstandings in this country about what "normal" vitamin D levels really are. "Normal" levels of "1,25 D" in American laboratories are a bit skewed, since they're determined using data from already-deficient people in North America. And, studies of what's "normal" almost always exclude people who take vitamin D supplements. So your levels might come back as "high" when they're really very normal, or even on the low side of what your body actually needs.

Two of the first group of "1,25 D" tests I requested for my hypertensive patients came back "high." Since both individuals had been diagnosed with essential hypertension, both had been taking vitamin supplements—including vitamin D, and neither had any other problems, we decided to "proceed with caution" with the additional vitamin D and continued to monitor their serum calcium levels closely.

If this situation happens to you, you and your doctor should look closely at your individual circumstances and make the decision to use or not use vitamin D accordingly.

My advice, as always, is to go with nature and natural treatment first. If you have essential hyper-tension, find a knowledgeable physician and get his or her help supplementing with vitamin D. Plus, don't forget to get more sunshine—it's the cheapest, most natural way to boost your vitamin D levels. And it's a lot more practical than moving closer to the equator.

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Citations available on the Nutrition & Healing website, www.wrightnewsletter.com.

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