30/11/2016 9:49 AM AEDT | Updated 30/11/2016 4:41 PM AEDT

Avoid Ham Overload This Christmas If You Get Migraines

It's not fair!

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Migraine sufferers beware. Ham is high in nitrates.

Anyone who gets migraines is keenly aware of new research that might point to ways to avoid the debilitating condition.

After all, a migraine can knock you out of action for days, and cause things like blind spots, nausea, slurred speech and of course, a splitting headache.

So when new research came out pointing the finger at gut and mouth bacteria that 'metabolise' nitrates, I'm sure a lot of us read it.

But here's what wasn't spelled out in the fine print -- ham is a trigger.

We know what you're thinking. How could a glazed Christmas ham, dotted with cloves cause anything but happiness?

Almost all hams are high in nitrates but so's kale and other green, leafy vegetables.

Here's what you need to know:

What did the research find?

Our mouths, and guts, and skin are full of microbes. Much of it is positive bacteria that helps to do things like break down food and we call it our microbiome.

The study by the University of California San Diego Health Sciences found people who got migraines had significantly more microbes with the ability to break down nitrates than the rest of the population.

Co author Antonio Gonzalez said they were following a hunch of sorts.

"There is this idea out there that certain foods trigger migraines -- chocolate, wine and especially foods containing nitrates.

"We thought that perhaps there are connections between what people are eating, their microbiomes and their experiences with migraines."

Getty Images/Science Photo Library RF
This is what tongue bacteria looks like up close. Say aaaagh!

What are nitrates (and nitrites and nitric oxide)?

Nitrates are naturally occurring in some foods (like leafy, green vegetables) and are added to others, like processed meat including ham.

Food Standards Australia New Zealand advised nitrates were primarily used to prevent the growth of neurotoxin-producing bacteria Clostridium botulinum -- but they also improve shelf life and colour.

Nitrates become nitrites after bacteria in our mouths gets their hands on them and the body can convert nitrites into nitric oxide, which relax blood vessels.

It may be the case that people with migraines have more bacteria capable of processing nitrates, so we get a sudden rush of nitric oxide to the blood, which in turn affects our blood vessels too dramatically, resulting in a migraine.

What food do you find nitrates in?

Dimitri Otis
Seriously. Since when was lettuce a problem food?

  • Processed meats including: Bacon, ham, pastrami, cocktail frankfurts, csabai, fritz, hotdogs, kabana, knackwurst, kransky, liverwurst, mettwurst, mortadella, Polish sausage, rookwurst, salami, strassburg, viennas, pancetta, prosciutto, chorizo, salami.
  • Vegetables including: Amaranth, lettuce, spinach, celery, white radish, beetroot, cabbage, pumpkin, broccoli, cauliflower, onion, garlic, tomato, mushroom, peas.
  • Fruits have far lower nitrate concentrations, but they can be found in: banana, apple and oranges.
  • Cheese including: Gruyere, feta, casseri, kefalotyri, gouda, and some semi-hard cheeses.

Do I have to avoid these foods all together?

Probably not. While researchers are continuing to look into the relationship between this bacteria and migraines, it's safe to say that a little of the above foods isn't going to trigger a massive migraine because let's face it, we probably all eat some of these foods every day.

Case study: I ate too much ham

After a road test of Christmas hams in the HuffPost Australia office, there were leftovers, and not wanting them to go to waste, I took a hunk of ham home.

I then proceeded to eat ham in roasts, quiches, sliced on sandwiches, in fried rice. Basically, ham was my only meat source for three days.

On the fourth day, I had an epic migraine, that seemingly had nothing to do with stress, sleep, hydration or any of my known triggers.

It seems like one meal of ham was fine, but after a few days, I reached my limit.

But I get migraines from triggers that have nothing to do with nitrates, like stress.

Yep. Migraines are a varied and complex condition that affect different people differently. Nitrates are likely just one trigger.

So can I eat the Christmas ham?

Oh alright. Just don't go overboard.