I’m sure you’ve heard it said about a million times by now: The best way to avoid skin cancer is to stay out of the sun — and don’t forget to slather on the sunscreen when you do dare to step outside.

But no matter how many times you hear it, it’s still not true.

Simply put, you don’t have to live like a vampire to avoid the deadliest form of skin cancer. In fact, the latest research shows that the best way to slash your melanoma risk has nothing to do with the sun at all.

It’s a simple vitamin — and you might want to go check the label of your multi right now.

If the form of vitamin A used in yours is retinol, you’re golden — because a new study finds that people who get this form of A have a 60 percent lower risk of melanoma. And those who got the most A of all — 1,200 mcg a day — were 74 percent less likely to suffer melanoma, according to the study in the Journal of Investigative Dermatology.

The “catch” here is that vitamin A from food — like liver (calf or chicken), kale, spinach or carrots — didn’t make a bit of difference. The vitamin A precursors such as beta-carotene and lycopene used in many multivitamins didn’t make the cut either.

Only the retinol form of A, and only from supplements — or what the drug industry refers to as “the ‘s’ word” — did the trick.

The new study might fly in the face of what the mainstream has been saying about lowering your melanoma risk, but the research has shown for years now that the sun isn’t the real cause of most of these cancers.

And one of the biggest risk factors of all might be completely out of your control: genetics.

In other words, blame your ancestors — not the sun. And if you have a history of the disease in your family, you might want to make an A supplement your top priority.

Just don’t overdo it, since it’s possible to get too much of a good thing– and too much vitamin A can cause liver damage, hair loss, and skin conditions.

The level used in the study (1,200 mcg a day) is more than what’s recommended by federal guidelines, but perfectly safe for most people.

Is there anything vitamin D can’t do?

I just told you how the sunshine vitamin can help keep pre-diabetes from turning into the real thing — and now, a new study finds it might stop melanomas cold.

Researchers looked at data on 36,282 women between the ages of 50 and 79 who were given either 400 IU of vitamin D and 1,000 mg of calcium, or a placebo, for an average of seven years.

The study actually didn’t reveal a whole lot (more on that in a moment), but one trend stood out: Women on the vitamins who had a prior history of non-melanoma skin cancers had half the risk of melanoma than women who got the placebo.

The study didn’t find any benefit in women without a history of other skin cancers — and the study didn’t include men at all.

But there’s an even bigger problem with this one – and it’s that teensy-weensy 400 IU dose of vitamin D, which isn’t even close to what you need to boost your health and slash your disease risk.

Even the Institute of Medicine, which famously lowballed vitamin D just a few months ago, recommends 600 IUs a day — and mainstream experts agree that number is way too low.

The Harvard School of Public Health, for example, recommends a minimum of between 1,000 and 2,000 IU per day for most — and up to 4,000 IU per day for some.

That’s about as mainstream as it gets — and that’s up to 10 times the levels used in the melanoma study. If researchers ever bothered to test this real dose of D against skin cancer, my guess is that the disease wouldn’t stand a chance.

A growing number of studies have shown how higher levels of D can not only prevent melanoma and other cancers, but also slow the progression of the disease when it does strike.

Studies have also shown how vitamin D can boost the immune system, protect the heart, support the brain, ease allergies, defeat the flu and even help prevent diabetes.

Yet the mainstream tells you to avoid the sun, the single best natural source of D — and even blames it for the very
melanomas it might help prevent.

No wonder we’re sicker than ever — we’re getting awful health advice.

Take charge of your own health — get your hands on a D supplement, and don’t be afraid to spend a little more time outside.

Speaking of addictions, some folks have a real thing for that so-called healthy glow.

They want a tan so badly they’ll even get one when there’s no sun around by spending time in a tanning salon.

But let’s call this what it really is: An unhealthy fascination with an unhealthy skin condition that can lead to cancer. Even tanners who manage to avoid cancer have to face wrinkles, premature aging and skin that resembles beef jerky.

While we’ve known for years that spending too much time unprotected in the sun can lead to cancer, officials now are finally ready to say out loud what many of us have been warning for years: Tanning beds cause cancer, too.

Until now, they would only say these things are a “probable carcinogen.” But a new analysis of 20 studies means they can’t deny it any more. It turns out that skin cancer incidences jump by 75 percent in folks who start using tanning beds before the age of 30.

It’s an absurdly high number – we may as well just count the folks who didn’t get cancer at that point.

Not only that, but the research – which was published in July in the online edition of the journal Lancet Oncology – shows that tanning beds increase the risk of the deadliest form of cancer, melanoma, by 20 percent.

The new classification means tanning beds are now in the same category as smoking and sweeping chimneys.

Skin cancer is often preventable, but in these cases it’s almost always preventable. You can simply choose not to go to the tanning salon and have an instant beneficial impact on your long-term health.

The ironic thing is that most of us can’t seem to get the exact right amount of sun. We do need it. It helps our bodies to make vitamin D, a nutrient we’re sadly deficient in. It’s gotten so bad in recent years that I now recommend a D supplement much more frequently.

But if you really want to be tan, here’s my advice: Wear more khaki.