They’re called “trace” elements for a reason: Tiny amounts of the right stuff can boost your health and save your life… while even a drop of the wrong stuff can end it.

Now, the latest research shows how these same trace elements can play a major role in your risk of getting or avoiding one of the deadliest forms of cancer on the planet — the pancreatic cancer that’s claimed Steve Jobs, Luciano Pavarotti and Patrick Swayze in recent years.

Let’s start with the good stuff: selenium and nickel.

Selenium is already a proven cancer-beater, and it can almost guarantee that you won’t get pancreatic cancer: It can slash your risk by 95 percent, according to the study in Gut.

The best source of selenium is Brazil nuts — but since it’s generally hard to get from diet alone, either take a supplement or make sure it’s included in your multivitamin.

Nickel didn’t quite pack the same punch — but it still managed to reduce the risk of pancreatic cancer by a third, according to an analysis of toenail clippings in 518 people, including 118 who had pancreatic cancer.

Yes, toenail clippings — and while that might sound a little bizarre, that’s actually one of the best ways to measure trace elements… including the ones you already know you should avoid.

We all recognize how dangerous lead is, for example — but the new study finds yet another reason to steer clear: a 600 percent boost in pancreatic cancer risk. Cadmium, another heavy metal, boosted the odds by 350 percent, while arsenic doubled the risk of the disease.

Now, you might not think those last three are worth worrying about. You’re avoiding them already, right?

Don’t be so sure.

All three, for example, can be found in cigarettes. In some areas, they’ve been found in the groundwater. And arsenic and lead have been turning up in apple juice, according to recent tests from Consumer Reports.

Arsenic might even be in your chicken dinner. Until recently, it was considered perfectly acceptable to add arsenic to chickenfeed — in part because poisoning chickens gives their meat that “healthy” pink glow consumers love so much.

The FDA recently issued a temporary ban on the main source of arsenic in chickenfeed — but the poultry industry has been aggressively lobbying for its return, and no one would be too surprised if they got their way on this.

Call it one more reason to go organic.

Exploitation — it’s the only word that comes to mind here.

Even as the mainstream moves away from routine cancer screenings for men and women alike, there’s one group of Americans that are still getting screened regularly for cancers that almost certainly won’t hurt them.

And that’s the elderly.

These are the people least likely to need treatment even if a cancer is detected — and least able to withstand the traumatic surgeries, dangerous drugs, and toxic chemotherapy often used to “treat” those cancers.

But the numbers don’t lie — and the newest numbers show that 57 percent of men between the ages of 75 and 79 were screened for prostate cancer, while 42 percent of men older than 80 were actually given PSA tests.

You have to wonder what the doctors are thinking here: They know these cancers can take decades to develop, decades an 80-year-old doesn’t have. They know that even younger men have nothing to worry about in most cases. They know that the U.S. Preventive Services Task Force recently recommended doing away with the PSA test altogether.

They know all this… yet they’re screening anyway, and not just men.

The same study in the Archives of Internal Medicine found that 62 percent of women between the ages of 75 and 79, and 50 percent of women older than 80 have been given mammograms over the past two years.

And if PSA exams are useless for men, mammograms are every bit as useless for women — so useless that even mainstream docs are backing away from them.

That’s because all the mammograms in the world have barely made a dent in the breast cancer death rate. These screenings have succeeded in finding harmless cancers, which then end up being treated with disfiguring surgeries and dangerous radiation.

Similarly, the study also found that 53 percent of women between 75 and 79 and 38 percent of those older than 80 were given pap smears to test for cervical cancer.

It’s ridiculous — and even the mainstream groups that normally back most cancer screenings agree. The American College of Obstetricians and Gynecologists recommends ending pap smears as early as 65, while the American Cancer Society says there’s no benefit after the age of 70.

In reality, many of these screenings have no benefit at any age. But for seniors, many of whom are already fighting health issues, these screenings, biopsies, and inevitable cancer treatments can turn the golden years into a living nightmare.

Skip ‘em — because in this case, what you don’t know almost certainly won’t hurt you.

It’s outright insane if you stop to think about it: In order to “protect” air passengers, the U.S. government is blasting them all with dangerous levels of radiation from full-body X-ray scanners.

Not exactly how I like my “protection” — especially since the feds won’t provide any honest-to-goodness safety data on these machines.

It seemed like we were finally getting somewhere earlier this year when the TSA told Sen. Susan Collins it would authorize an independent safety study. You’d think they would have done that before they installed these machines at every airport — but better late than never, right?

Well, it might be “never” after all — because TSA administrator John Pistole recently told Congress that the study is off.

The question has to be asked: What are they so afraid of?

I think it’s pretty obvious: Radiation exposure — even the small amounts used in these machines — can cause DNA damage and cellular changes. Over time, that can lead to cancer.

These machines use backscatter radiation, which goes beneath the clothes and concentrates on the skin itself — so TSA agents can view a “naked” picture of you and see what you might be hiding without having to look at your bones, liver, guts, etc.

But since that radiation focuses on the skin, it can build up there and boost the risk of skin cancers, especially among those most often exposed, like regular air travelers.

And who knows what kind of risks these machines will pose to pregnant women, children, and infants.

One expert says he thinks X-ray scanners will cause 100 cancer cases each year — and while that may sound like a small number, why put even a single life on the line in the name of security?

Even if you agree that the government should get a look at everyone’s naked body before boarding an airplane — and I don’t — there are machines that can do it without using a drop of radiation.

The feds even have the machines, and are using them in some airports — but they insist on using the X-ray machines right along with them.

Even Europe has said they’ll only use the radiation-free machines — and they’ve actually banned the X-ray scanners from their airports until they see some actual scientific data proving they’re safe.

I hope they’re not holding their breath.

It’s like a nightmare, except you never get to wake up: A drug used during a common back procedure has been linked to cancer — including one of the deadliest forms of the disease on the planet.

That drug is Infuse, which is supposed to stimulate bone growth after a spinal fusion procedure.

It’s already been linked to everything from infection to sterility — but now, a leading researcher finds that high doses of the drug can boost the odds of cancer by 2.5 times in the first year alone, and by 500 percent in the three years after the procedure.

Dr. Eugene Carragee, editor-in-chief of Spine Journal, told the North American Spine Society that these cancers include breast and prostate cancer — and believe it or not, that’s the good news.

After all, you can fight those cancers and win (although it would be outright insane to deliberately boost your risk of either).

That bad news: The drug was also linked to pancreatic cancer — the same cancer that killed Steve Jobs and claims nearly 95 percent of all patients within five years.

Dr. Carragee said the risk seemed to be greater for Amplify, a high-dose version of Infuse that was rejected by the FDA earlier this year over cancer concerns.

Hey, every now and then the agency gets one right — but in this case, it didn’t matter. If docs want Amplify, all they have to do is up the dose of Infuse — and many of them have been doing just that.

What makes this so much worse is that all of it could have been avoided — because there’s evidence that the researchers behind the studies that were used to get Infuse approved turned a blind eye to its side effects.

As I told you before, these researchers claimed the drug was practically risk-free — and many of those same researchers were also collecting millions of dollars from Medtronic, the company that makes Infuse.

A coincidence? You decide.

A more recent look at the data — including the data from the trials that supposedly found that drug to be so safe — found that up to 50 percent of patients given Infuse experience side effects such as infection, bone loss and excess bone growth.

And for men, the drug may also come with a risk of both sterility and a horrific condition called retrograde ejaculation.

That last one is exactly what it sounds like: You ejaculate backwards, into your bladder instead of out the penis.

There’s no alternative to Infuse — if you need a spinal fusion, just go without. Or better yet, find a way to avoid the surgery in the first place — because you might not even need the procedure at all.