Australian survey to determine vitamin D supplementation guidelines for mothers and babies

07-Aug-2018 - Last updated on 07-Aug-2018 at 03:28 GMT

Australia's CRE will conduct a study measuring vitamin D levels in babies as well as in maternal blood and breastmilk samples. ©Getty Images

Australia's National Health and Medical Research Council's Centre of Research Excellence (CRE) is calling for 100 mothers to enrol themselves and their babies for an upcoming survey as it seeks to help determine if supplements are necessary to lower the risk of bone disease, especially among babies.

The CRE — essentially a partnership between the South Australian Health and Medical Research Institute (SAHMRI), Women's and Children's Health Network (WCHN), SA Health, and the University of Adelaide — will conduct a study called the Vitamin D in Infant Blood and Breastmilk Study (DIBBS), measuring vitamin D levels in babies as well as in maternal blood and breastmilk samples.

WCHN senior dietitian Dr Merryn Netting, who is also SAHMRI's principal investigator, told NutraIngredients-Asia: "The babies should be four to six months of age, and not introduced to solid foods yet. Their mothers also do not have to be exclusively breastfeeding them."

As to whether or not there would be a more in-depth, clinical study in the same vein, Netting said, "That would depend on our results, which would first inform our guidelines for vitamin D supplementation."

Australia may look to countries like Canada and the US, where health authorities recommend vitamin D drops for all breastfed babies.

A bony problem

Sun avoidance and longer screen time are a few of the causes behind an increase in vitamin D deficiency, which could trigger the return of rickets among not just infants, but even pregnant women and nursing mothers.

Rickets, a disease whereby the bones — usually in young children — become soft and weak, is typically caused by a severe and prolonged lack of vitamin D, which is vital for stimulating calcium and phosphorus absorption from the gastrointestinal tract.

A 2012 Australian study reported that an estimated 0.005% of children below the age of 15 had vitamin D-deficiency rickets, which had previously been more common in Asia, the Middle East, and Africa.

It added that vitamin D-deficiency rickets was re-emerging as a serious public health concern in the country, particularly amongst migrants and refugees.

Sun and skin

Infants and children who have darker skin tend to be at higher risk, as their higher melanin levels mean they are less sensitive to sunlight and therefore, absorb less vitamin D from sun exposure.

Netting said, "We are looking at skin colour as part of the study, which is ultimately looking to provide data on vitamin D levels in Adelaide babies to support supplementation recommendations."

Those with limited sun exposure are also at risk, as are infants whose mothers are vitamin D-deficient — even more so if they are exclusively breastfeeding.

In an SA Health press release, Netting said that infants previously got their vitamin D from the sun, but that had changed since more people had learnt how excessive sunlight exposure in the first year of life could increase skin cancer risk in adulthood.

According to the Cancer Council Australia, "the best source of vitamin D is UVB radiation from the sun".

Most people can obtain sufficient vitamin D "just by spending a few minutes outdoors on most days of the week" during summer, while in autumn and winter in South Australia, a short period of midday sun exposure will suffice.

However, for babies, minimal sun exposure is advised — avoidance of direct sunlight, as well as protection via shade, clothing and sunscreen for children are all encouraged.

Dietary dilemma

This means that for babies and young children, dietary vitamin D intake and perhaps even vitamin D supplementation are especially important to obtain adequate levels of vitamin D.

The dilemma, Netting said, came from the difficulty in obtaining sufficient vitamin D through dietary means alone.

"It's a catch-22 for mothers, because while it's recommended that new babies are breastfed exclusively up until six months old, breastmilk is usually a poor source of vitamin D."

Trying to minimise the risk of skin cancer from excessive sun exposure merely adds to the difficulty of maintaining adequate vitamin D levels.

While a growing number of infant formula manufacturers have developed products enriched with vitamins, including vitamin D — as well as ingredients exclusively found in breastmilk, such as oligosaccharides and MFGM (milk fat globule membrane) — Netting declined to comment on whether or not she would recommend such products to raise babies' vitamin D levels.

Furthermore, despite the need for dietary sources of vitamin D, she seemed ambivalent about fortified foods as a solution, saying, "At the moment, we get most of our vitamin D from sunlight exposure, although some foods are fortified with vitamin D, such as margarine.

"But most of the food sold in Australia, including milk, is not fortified with vitamin D. We simply don’t have a lot of fortified foods here.

"If we have a lot of low vitamin D results, we will be making an argument for either uniform supplementation of mothers, or vitamin D drops for babies."