Celebrity nutritionist Dr Libby Weaver forced to recall book after using derogatory word.

Dr Libby Weaver is one of Australia’s most accomplished and recognised nutritional biochemists and authors.

She’s regularly shared the stage with Sir Richard Branson, Tony Robbins and Dr. Oz and is a nine-times number one bestselling author.

But she has been forced to issue a heartfelt public apology and pull her latest book – What Am I Supposed to Eat? – from shelves after she caused offence with a term used to describe Down syndrome up until the mid-1900s.

“I’m here today to issue a public apology,” she said in a video posted to Facebook and her official website.

“In my latest book… I used a word to describe Down syndrome that I thought was a current, medically-used word.

“It has since been brought to my attention that it is a word used in a derogatory way.”

“I am mortified to have caused anyone any distress through my error, in particular children with Down syndrome and their families.”

Dr Weaver confirmed she had instructed her publishing company to immediately recall the book – thought to be around 20,000 copies – from sale and will arrange a reprint where the word will not appear.

In a passage advising pregnant women on what to eat, Dr Libby wrote consuming folate could “reduce the risk of neural tube defects, spina bifida, deformed limbs and mongolism”.

Dr Libby Weaver issues a heartfelt apology for the error. Image via Facebook.

According to The Sydney Morning Herald, the term - coined in the 1860s - was used up until the 1960s, when a group of British scientists determined it was "misleading and derogatory".

Dr Weaver was reportedly notified that the term she had used in her latest book was derogatory by a mother of a child with Down syndrome.

Fans were quick to praise and thank the high-profile nutritional biochemist for her swift and sincere response to the controversy.

"As the mother of a little girl with Down Syndrome, I am in awe of you," one woman wrote on Facebook.

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"The extent you have gone to with your correction and apology for such a small error, will make people realise that our loved ones with special needs are important.

"My daughter is a treasured gift for our family and it is nice to know that derogatory terms are no longer acceptable. It's fantastic that you care, and your heartfelt apology is accepted."

Another wrote: "Words matter, and although it was a mistake in this situation, don't let it overshadow your book accomplishments."

Dr Weaver has also offered a full refund for any customers who have already purchased the book.