Is it possible for a single vitamin to do everything?

Maybe not – but if I had to pick one all-purpose must-have nutrient, I’d go with that dazzling D. It’s about as close to perfect as a single letter can be.

And now, two new studies add to the already impressive body of evidence for this wonder vitamin: It may help you control your blood pressure, and even lower your risk of dying from heart disease.

The first study, published in Nature Reviews Cardiology, finds that the sunshine vitamin is especially good at helping people who already have hypertension to lower their blood pressure levels.

The second one, carried out by researchers at the University of Colorado, Denver and Massachusetts General Hospital, found that patients who don’t get enough D are three times more likely to die from heart disease and 2.5 times more likely to die from any cause.

That fits in with other studies that have shown that vitamin D can help reduce your overall risk of death. And that’s in addition to research showing how D can help keep your bones healthy and lower your risk of fracture, reduce your risk of cancer, increase muscle strength, improve your immune system, and so much more.

The best source of D is the sun. Our bodies can make it naturally if we get enough of the right kind of sunlight.

But most of our bodies aren’t doing a very good job of it these days.

No, they’re not protesting the sweaty working conditions. We’re simply not getting enough sun – and when we do, it’s often not the right kind.

Your clothes, sunblock, cloud cover, and the seasonal angle of the Earth are all factors in the quality of your sunlight, and whether or not your body is able to turn it into that all- important D.

In most cases, it can’t… and as a result, we’re D-ficient. That means a high-quality supplement is your best chance of ensuring that you get enough of your daily D. Forget the U.S. RDA, which badly understates how much you need of so many nutrients. Follow that pointless chart, and you’ll end up with 400 IUs daily. In reality, we need much more than that.

Even Harvard University – not exactly known for its acts of nutritional rebellion – places the optimal intake at around 2,000 IUs for most of us, and suggests that many people – including folks with darker skin and people who get little direct sunlight – can use up to 4,000 IUs daily.

That’s up to 10 times the U.S. government’s recommendation!

So if you’re not taking a D vitamin, check your multivitamin closely. If it says you’re getting “100 percent” of what you need, you’re simply not getting enough, and you probably want to add a separate D supplement to your regimen.

A lot of companies will try to sell you a miracle pill – but D is the real deal.