Fish oil finding promising for mums

Animal study suggests supplement may help prevent diabetes in children of overweight pregnant women

Tantalising findings by Kiwi scientists suggest fresh fish oil may prevent children of overweight pregnant women from later developing diabetes. Children of overweight women have nearly twice the risk of developing problems such as diabetes later in life, and at least three in 10 pregnant women in New Zealand are overweight.

Up to one in five New Zealand women currently take fish oil supplements during pregnancy, according to the latest estimate. But it is not known if supplements sold here contain fresh fish oil, as it’s not stated on the label, or oil that has gone off by becoming oxidised.

In research just published in major journal Scientific Reports, an Auckland team were able to show how the approach worked in overweight pregnant rats — and now they hope to prove the same effect in humans.

The rats were fed either a high-fat diet to make them overweight, or a standard diet, and half from each group were also given fresh fish oil.

In the offspring of the high-fat group, the fish oil treatment improved the way insulin works, which is protective against diabetes.

“This is exciting because it raises the question: if overweight women take fresh fish oil in pregnancy, will it lower the risk of their children later developing diabetes?” said Dr Ben Albert, who led the research with Professor Wayne Cutfield, both of the University of Auckland-based Liggins Institute.

But this didn’t mean pregnant women should be taking fish oil — yet.

“The same benefit has not yet been shown in humans, and our earlier study shows New Zealanders cannot be sure the fish oil they buy is fresh.”

The new findings were part of a series of studies by the same team into the potential of omega 3 in fish oil to reduce the risk of diabetes and other obesity-related illnesses.

“Studies by other researchers using adult rats have shown that omega 3 fatty acids in fresh fish oil improve the way insulin works, which protects against diabetes and related diseases,” Albert said.

“We wondered if it could also be protective during pregnancy, particularly for the babies.”

Their hypothesis proved to be correct.

They found that, compared with offspring in the high fat diet-only group, the adult pups of mothers in the high fat diet plus fish oil group had better insulin sensitivity, reducing their risk for diabetes.

“A clinical study we are about to [begin] will reveal whether human babies experience the same benefit.”

Starting later this year, Albert will lead a clinical trial of fish oil supplements in overweight pregnant women to see if the supplements could reduce the risk of their babies becoming overweight and of developing diabetes in later life.

His team has received funding for the first phase from the Health Re- search Council, National Science Challenge A Better Start, and Cure Kids.

In the first of the team’s fish oil studies, published in 2015, the researchers tested 36 brands of fish oil supplement capsules.

Most — 83 per cent — were oxidised beyond international recommended levels.

How “off” they were had nothing to do with best-before date, price, or the country they came from.

Omega-3 fatty acids are known to be chemically fragile or “unstable”, and can easily break down when exposed to natural conditions such as light, heat and oxygen.

In the team’s second study, published last year, highly oxidised, or off, fish oil fed to pregnant rats caused almost 30 per cent of their newborns to die within two days — eight times the death rate of pups in the control group.

Giving pregnant rats the unoxidised or fresh fish oil did not increase mortality rates in their babies.