Gwyneth Paltrow once feared she was suffering a stroke.

The 'Iron Man' actress sought medical advice when she suddenly fell ill at her London home in 2011 while serving lunch to friends, and despite her fears, she was found to have been stricken with a migraine and panic attack.

She wrote in her new cook book 'It's All Good: Delicious, Easy Recipes That Will Make You Look Good and Feel Great': ''One sunny afternoon in London, in the spring of 2011, I thought - without sounding overly dramatic - that I was going to die.

''I had just served lunch in the garden at home... I had a vague feeling that I was going to faint, and I wasn't forming thoughts correctly... I got a searing pain in my head, I couldn't speak, and I felt as if I couldn't breathe. I thought I was having a stroke.''

The 40-year-old actress - who has children Apple, eight, and Moses, six, with husband Chris Martin - was also found to be severely anaemic and vitamin D deficient, so had to overhaul her diet, cutting out coffee, eggs, sugar, shellfish, potatoes, wheat and meat.

And the health scare prompted herself and her family to undergo food allergy testing, with ''surprising'' results.

She explained: ''Everyone in my house is intolerant of gluten, dairy, chickens' eggs, among many other surprising foods''.