Claire Foy says she had parasites for five years

The Crown star Claire Foy has said she had parasites for five years after catching an infection, and no longer drinks caffeine as a result.

The award-winning British actress, known for playing Queen Elizabeth II in the hit Netflix royal drama, said she thinks she contracted the bug in Morocco.

Speaking on the Table Manners podcast with Jessie and Lennie Ware, Foy explained: “Quite a few years ago, I had parasites. Gross.

“I kept losing weight and I didn’t know what was going on…”

The 41-year-old, who is also known for the BBC historical drama Wolf Hall and A Very British Scandal, went on to explain that she made changes to her diet, including “giving up caffeine”.

Asked how long she thought she had parasites for, Foy replied: “At least five years.”

There is no evidence that parasite cleanses including dietary changes and cutting out caffeine can cure parasitic infections.

But caffeine can exacerbate pre-existing gastrointestinal conditions, so cutting caffeine may improve gastrointestinal symptoms but without curing any parasite infection.

Revealing more about her gut health and dietary needs, Foy said she had also dramatically cut down on eating gluten or sugar in order to help manage a separate autoimmune condition.

“This is my big secret, I feel like I’m in The Traitors or something, and I’m letting everyone know that I’m related to someone,” she joked.

“I don’t actually eat gluten or sugar… except when I go out for dinner. It doesn’t have an impact on me. It’s just because I have an autoimmune condition, so I should avoid anything which causes more inflammation.”

Foy won two Emmy awards and a Golden Globe for her portrayal of the late Queen, and also starred in the 2022 film Women Talking and the new screen adaptation of H Is For Hawk.

The actress is set to appear in two more forthcoming films: Enid Blyton fantasy The Magic Faraway Tree, and the black comedy Savage House, opposite Richard E Grant.

Last month, she said that when she was younger, she thought she would “never make it past 40” due to “many medical things in my life”.

In medicine, the term parasite usually refers to eukaryotic organisms such as protozoa, parasitic worms and ectoparasites, rather than bacteria or viruses.

Parasitic worms include roundworms, hookworms and tapeworms, while intestinal protists include cryptosporidium and giardia.

According to the NHS website, some types of worms – caught in both the UK and abroad – can infect people in different ways.

Most infections are not serious though and can be easily treated with medicine (antiparasitics).

The NHS suggests contacting your GP if you find a large worm, a piece of worm or worm eggs in your poo; have a red, itchy worm-shaped rash on your skin, or sickness, diarrhoea and/or a stomach ache for longer than two weeks.

Another potential symptom, as in Foy’s case, is losing weight for no discernible reason.

These infections are often caught while travelling, and they can take a long time to show symptoms.

They can be contracted by touching objects or surfaces with worm eggs on them, and by eating or drinking something with baby worms in it – such as under-cooked beef, pork or freshwater fish.

Parasites can, in part, be avoided by thoroughly washing your hands, as well as any fruit and vegetables, before cooking and eating.

Other tips include drinking bottled or boiled water in high-risk areas, and deworming pets regularly.