Vitamin D should be added to more NZ foods: Report

Vitamin D levels often dive in people living in southern states including Tasmania and Victoria, and New Zealand, in winter. Photo / Thinkstock

Vitamin D should be added to more Australian and New Zealand foods to prevent widespread insufficiencies, a conference on Tuesday will be told.

About 30 per cent of the Australian population has low levels of vitamin D, which is mostly absorbed through the skin after exposure to direct sunlight.

It is found to a lesser extent in some foods, including fish and eggs.

The key nutrient helps to distribute calcium from food throughout the body.

But with one of the highest skin cancer rates in the world, it's difficult for Australians to absorb the recommended amount without increasing their skin cancer risk, Deakin University researcher Caryl Nowson said.

Vitamin D levels often dive in people living in southern states including Tasmania and Victoria, and New Zealand, in winter, she said.

Ms Nowson said for this reason, Australia and New Zealand should follow the lead of countries like Canada and add more vitamin D to the food supply.

Canada has fortified milk and margarine with vitamin D for 35 years to reduce rickets - a debilitating bone disease in children.

"We should be considering that for Australia," Ms Nowson told AAP.

Vitamin D must be added to Australian margarine but fortification is voluntary for milk, yoghurts and cheese.

Ms Nowson said studies had shown that boosting vitamin D levels could prevent falls and fractures in the elderly and improve mortality rates.

Vitamin D has more recently been linked to a host of diseases including multiple sclerosis, diabetes, cancer and heart disease.

Ms Nowson said most human cells had a vitamin D receptor, which explained the vitamin's widespread association with disease.

A symposium in Melbourne will discuss whether Australia and New Zealand should introduce more vitamin D into foods, and if so, what would be the best foods to fortify.

Migrant communities are often more susceptible to vitamin D deficiencies, so this would need to be taken into account when selecting which foods to fortify, Ms Nowson said.

People with dark skin require longer periods of daylight to absorb enough vitamin D.

A recent Australian study of children with vitamin D deficiency rickets found the majority of sufferers - 75 per cent - were refugee children.

About 60 per cent were African-born and half the parents of the children were Sudanese.

Ms Nowson said only a small amount of vitamin D was needed to prevent rickets.

"That's why having a small amount in the food supply is going to reduce the incidence of rickets," she said.

A study of more than 11,000 Australian men and women found 31 per cent of the population were vitamin D deficient, but only four per cent had a moderate to severe deficiency.

Women had much higher levels of deficiency - 39 per cent, compared to 22 per cent of men.

- AAP