It's as Kiwi as hokey pokey and jandals, and Plunket has played a bigger role in Shortland Street actress Beth Allen's life than it has in most people's.

The 24-year-old, who plays Brooke Freeman on the popular TV2 soap, is the great-great niece of Sir Frederick Truby King. The Dunedin man founded the children's welfare society in 1907, and this year Plunket celebrates 102 years of providing support to newborns and their families.

Having an integral part of New Zealand history in her heritage is something the star is extremely proud of and it has prompted her to delve into her family's past to learn more about her famous relative.

'I've discovered he did a lot of work with psychiatric patients, brightening up their environments in the belief that a sound body and healthy surroundings made for a sound mind,' Beth says.

As a result of working in the garden and with animals, he then developed a ground-breaking formula for humanised cows' milk.

'He and his wife [Lady Isabella King] were unable to have kids of their own, so they adopted a little girl called Mary,' Beth explains. 'She was really sickly, which led to Truby creating this instant formula.

'Soon after, he set up the first Karitane nurse and taught the local mothers how to mix the formula so they could feed their babies. Essentially, 12 years later, the formula had halved the infant mortality rate in New Zealand.'

Dedicated to children

Beth laughs when she talks about the type of bloke Frederick was.

'He was eccentric, forgetful and disorganised,' she says. 'But extremely dedicated. I found out that he decided that lactose was better to put into his formula, and because the local grocers had a monopoly on it, he imported about a tonne. He paid for a nurse to be trained, and for her salary. It was all out of his own pocket.'

Despite being reviled by the feminist movement for insisting women should stay at home with their babies, and for enforcing strict schedules, Beth says his research was pivotal for the children of the time.

Frederick tested his theories on his own nieces and nephews, including Beth's grandfather.

'He told my great grandmother she had to feed the baby every four hours and then put him to sleep. One time he just wouldn't stop screaming and she wanted to go in and comfort him but Truby said, "No, you have to stick to the schedule, just leave him." After about 15 minutes of this, she went in to check on him and discovered she'd actually stuck a pin in him when changing his nappy!'

While Frederick's legacy lives on in the Plunket Society, many of his original teachings don't. It's something Beth says is a reflection of the times.

'I think it's great how much it's evolved in the hundred years since it started. Theories about childbearing do change.'

She doesn't have children of her own, but Beth shares a close bond with her eight-month-old niece Olive, and says her brother Oscar and sister-in-law Kim are involved with their local Plunket.

'Olive belongs to the same one I used to go to,' she says.

'I've had no direct experience with Plunket but I know there's so much information out there for mums, from support groups to the internet. From what I can gather, many of them come back to Plunket for the basic things and use it as a great way to meet other mums,' Beth adds.

'It undoubtedly still plays an important role in the lives of New Zealand babies.'