"No meat, no fish, no eggs, no milk, no bread, no nuts, no seeds, no tofu, no cheese," lists Mark Lavery as he explains the diet restrictions associated with his rare metabolic disease.

The Irish actor, who you may recognise from Handsome Devil (2016), was born with PKU (Phenylketonuria) - a rare genetic disorder that prevents the body from breaking down an amino acid called phenylalanine (phe), a natural substance found in food; a building block of protein.

Off the menu
"They kind of say it's about 85% of foods that aren't available to us (PKUs)," Mark explained. "We can't really say it's similar to a vegan diet because vegans can have pulses and beans and tofu, obviously, so we would just have mostly vegetable, fruits..."

At least the Glengeary man isn't restricted from the nation's favourite vegetable?

"There's actually protein in potatoes, which a lot of people don't really realise. There's protein in rice so we're allowed to have a very small amount. I'm on 6 grams of protein a day, a lot of people would take in about 80 grams or so," he explained.

Protein is essential to the human body; it helps to build and repair tissue, make enzymes and is an essential part of bones, muscles, cartilage, skin, and blood. So how does Mark work around his diet restrictions?

"Obviously we need more protein or we wouldn't be able to function so we take a supplement without that one amino acid (phenylalanine)," he said.

protein
People with PKU must stick to low-protein diets 

Nights Out
As for a night out on the town? The 26-year-old is limited when it comes to both the bar and the chipper afterward. 

"Alcoholic beverages - we can't drink beer, beer is pretty much completely off limits; there are two grams of protein in a Guinness, which a lot of people wouldn't realise either," he said. "I've never had the craving to go wild on a burger or anything like that, I guess it's just not ingrained in me at all."

It's not all bad news though, according to Mark, Ireland is "pretty good overall" when it comes to eating out.

"It's definitely gotten better, particularly with the vegetarian movement and the vegan movement. In terms of myself with my friends, out of the twelve of us, there are six of us now who are vegetarian and they're doing it by choice so that's made a huge difference for me in terms of where I go to eat," he said.

"In terms of cuisine; Indian would be brilliant - it's quite vegetarian-heavy anyway - Thai food would be nice, Chinese. Italian food, not so much because we can't have pizza or pasta. I've gone to Milano's before and brought in my own pizza base, they've been pretty flabbergasted but they've happily cooked it which is nice."

pizza
Pizza and beer are off the menu for those with PKU

Highest in Europe
While the disorder may be considered rare, there are over 700 people in Ireland today living with PKU - that's 1 in every 4,500 people, one of the highest rates in Europe.

"It is rare but Ireland does have the highest occurrence," said Mark.

"In terms of treatment options, Ireland wouldn't be one of the best at the moment which is not great".

Other than the strict low-protein diet and supplement, another treatment option available is Kuvan, a prescription medication specifically made for PKU. Unfortunately, despite being available in many European countries, it is not yet available in Ireland.

The National Centre for Pharmacoeconomics (NCPE) deemed that the drug was not cost-effective and therefore did not recommend the HSE fund it. However, the PKUAI (Phenylketonuria Association Ireland), are currently working to get access to Kuvan in Ireland.

Genetics
Although PKU is a genetic disease, there is no guarantee that the child of two carriers will be born with the disorder. While both Mark and his brother Peter were diagnosed with PKU, their sister Joanne was not.

"I was the eldest child in my family so when I was born, my mum... I think she had heard about it but, obviously, it was quite a shock because there was no family history of it; she just happened to be a carrier of it and so was my dad," said Mark.

If both parents are carriers, there is a one in four chance that the child will have PKU.

Mark and Peter Lavery from Glenageary who have PKU.Picture By David Conachy
Mark and Peter Lavery. Picture By David Conachy.

Serious side effects
While this disorder may be an inconvenience to Mark and others with PKU, the side effects can be much more serious if missed at birth. If untreated or unmanaged, the disorder can result in permanent brain damage. 

"If it's not diagnosed when you're a baby, an amino acid that builds up in your body becomes toxic and can result in brain damage. So, for example, if it's not treated at birth it kind of results in intellectual disabilities and physical disabilities. That's why it has to be picked up at birth. That's what the heel prick test is for," said Mark.

The 'heel prick test' is whereby a sample of blood is taken from a newborn baby and is screened for rare but potentially serious disorders such as PKU, cystic fibrosis, and congenital hypothyroidism.

While the low-protein diet can be difficult to maintain, Mark insists that he feels incredibly lucky to have been diagnosed when he was.

"People may not realise how new the diet is in terms of it [PKU] being treated. It's only been discovered in the last sixty years so there are people, unfortunately, who were born with it [...] who currently are intellectually disabled and in homes and can't look after themselves," he said.

For more information on PKU, click here.