Antonia Terrell loved her morning mug of tea and never suspected it could be causing her extreme vomiting.
For two years the 28-year-old suffered from nausea and was "violently sick" at least twice a day.
Antonia, from south west London, went to her GP for help when she could find no explanation for her extreme symptoms.
But her doctor was unable to pinpoint the cause and the investment banker's nightmare went on.
A simple blood test discovered why Antonia was feeling so ill - she had an intolerance to milk and her beloved cups of extremely milky tea that were making her life a misery.
She said: "I was literally feeling sick all the time. And it got worse and worse and worse until I was being sick most days.
"It slowly crept up on me over a number of months. It would make going to work really difficult as I was always feeling or being sick.
"And I'd get into work, drink my tea - which had lots of milk in it - and I'd think to myself, ‘Urgh, I can't believe I'm already feeling sick and all I've had is a tea with milk’."
It wasn't just Antonia's health that suffered, her personal life was also affected as she couldn't face socialising.
After visiting her GP, Antonia was advised to try and ‘elimination diet’, where certain food groups are removed from her menu to try and monitor symptoms and find a trigger.
Finally she paid for a food intolerance test and the culprit was discovered - cow's milk protein.
Antonia, who took a ‘Food & Drink Scan’ programme from UK firm YorkTest Laboratories, says: "My husband, Richard, had a long-standing dairy intolerance which wasn't great for him as a kid. He'd suffered with it for years.
"So he did a YorkTest - and that's how I found out about it.
"His mum was saying that I needed to take the test as she suspected I also had an intolerance, so I did.
"I was having a lot of dairy in my diet, like milk. And very milky tea turned out to be the main culprit.
"If I’m being honest, I didn't want to believe it. I was refusing to believe it.”
According to YorkTest Laboratories, it’s estimated 45 per cent of people in the UK suffer with a food intolerance - many of which remain hidden.
Symptoms of a food intolerance include irritable bowel syndrome , regular bloating, diarrhoea, constipation or abdominal cramps.
Sufferers can also experience migraines and headaches , tiredness, low mood, depression, anxiety, and even skin problems such as eczema and psoriasis.
And in Antonia’s case her symptoms vanished overnight when she cut milk from her diet.
Antonia - who also discovered intolerances to goat’s milk, sheep’s milk, sesame seeds, nutmeg, vanilla and peppercorn - said: "I’ve found an alternative to milk and it has made such a difference.
"No more nausea, no more vomiting. Life now is good."
Dr Gill Hart, biochemist with YorkTest Laboratories, says a food intolerance test works by identifying ‘IgG antibodies’ in the blood.
She said: "When food particles enter the bloodstream, the immune system can sometimes identify these food protein particles as “foreign” and produces what’s known as ‘IgG antibodies’ to ‘attack’ the food in question.
"This response is your immune system’s natural defence mechanism to ward off harmful invaders in the body which can create inflammation.
"So, essentially, these IgG reactions go hand in hand with gut imbalances and inflammation and are released in the presence of certain ‘trigger’ foods.
"And by monitoring which foods cause food-specific IgG reactions, we can advise people on what they might wish to cut from their diet."
Meanwhile Dr Hart says there’s a big difference between a milk intolerance and a lactose intolerance - where people struggle to digest a certain sugar found in milk- and you should never confuse the two!
She added: "Someone might recognise that they get a reaction after drinking milk, and assume they have a lactose intolerance.
"But it’s actually just as likely you’ve got a milk protein intolerance, which manifests in different ways - and the action that you need to take to make a difference to your lives is different too.
"With a milk protein intolerance, you may be able to tolerate milk in the future after an initial elimination diet.
"You can’t do that with a lactose intolerance - you’ll have that for the rest of your life, and you may benefit from taking lactose enzyme supplements if you want to try and continue to eat food containing dairy."
To add to the confusion, ‘milk’ goes by many other names in food ingredients lists.
Dr Hart said: "If you’re cutting dairy from your diet, you’ll typically ditch milk along with things like yoghurt, cheese, ice cream, and butter. “
"But milk products in foods can also be listed as Lactoglobulin, Lactalbumin, Casein, Caseinate."
