Dame Alison Holst DNZM CBE QSM, Nine to Noon's longtime resident food expert, has been diagnosed with dementia.
Holst, 77, lives with her husband, a retired doctor, in Orewa.
Having published over 100 books about what she called 'everyday cooking', she had been writing a monthly column for her local Orewa paper but signed off after memory problems became too taxing.
In an editorial for Hibiscus Matters, Terry Moore wrote: "Alison officially "hung up her apron" last year and is enjoying her retirement, painting and walking on the beach with her husband Peter and dog, Lucy.
"While she will always be interested in food, Alison's memory is declining, and the deadlines of developing recipes and writing is a stress that she no longer needs."
Alison Holst, pictured in the 1960s. Photo: Supplied
The news has been met with sadness from home-cooks and high-profile chefs alike.
Born and educated in Dunedin, she lectured on home science at the University of Otago before making her first appearance on national television in 1965, a few years after it was introduced.
She had been planning on being a teacher before the success of the show, Here's How, began her career as New Zealand's first celebrity chef, with her first on-air recipe a meatloaf studded with hardboiled eggs.
In recent years, she has worked with her son Simon Holst. The duo have written 27 books together, as well as building a successful kitchenware and wholefoods brand sold in supermarkets around the country.
Alison Holst Photo: Supplied / Alison's Pantry
Over four million copies of her books, including a memoir, a guide to using mince, and a book aimed at diabetics, have been sold.
She has been credited with introducing New Zealanders to 'exotic' foods such as soy sauce, star anise, filo pastry, and garlic, and was at one stage the most googled name in the country.
She was awarded Dame Companion of the New Zealand Order of Merit in the 2011 New Year Honours.
In the Hibiscus Matters editorial, the Holst family have encouraged people to support the work of Alzheimer's Society and Age Concern and asked for privacy at this time.
What is dementia?
Dementia is a term that encompasses a variety of different conditions characterised by a decline in mental ability, usually in old age. There is no known cause or cure, and usually gets progressively worse as it spreads through the brain.
Common warning signs include memory loss; difficulties with language, time or place; difficulty performing regular tasks; and changes in mood, behaviour and personality.
More information on dementia is available here.