A recent study from the University of Auckland in New Zealand found that giving fresh fish oil to overweight pregnant rats prevented their offspring from developing diabetes risk factors. Fish oil treatment can improve the way insulin works and prevent diabetes. The study was published in the July 17, 2017 issue of Scientific Reports.

Dr. Ben Albert and Professor Wayne Cutfield of the University of Auckland led the study. Although the results are exciting, the researchers are cautious about pregnant women eating fish oil. First, the results of this experiment have not been clinically validated in humans. Secondly, if the freshness of fish oil cannot be guaranteed, eating fish oil is harmful to pregnant women.

The team has previously conducted a series of studies related to fish oil omega-3 fatty acids. In the new study, the researchers found compared with the offspring of rats in the high-fat diet group, the offspring of the high-fat diet plus the fish oil group had better insulin sensitivity when grown up, which reduced their risk of diabetes.

Beginning later this year, Dr. Albert will conduct a fish oil supplement clinical trial in overweight pregnant women to see if supplements can reduce the risk of overweight and diabetes after babies grow up.

Children with overweight pregnant women have twice the probability of developing diabetes after they grow up. In New Zealand, at least 3 of 10 pregnant women are overweight. According to the latest statistics, up to one in five New Zealand women take fish oil supplements during pregnancy.

The research team tested 36 brands of fish oil supplement capsules in the first fish oil study published in 2015. 83% of the oxidation levels exceeded international standards. Omega-3 fatty acids are very unstable and decompose when exposed to natural conditions such as light, heat and oxygen. Four independent studies from North America, South Africa and Europe also found high levels of oxidation of fish oil supplements.

In the second study published by the group last year, feeding high-oxidized fish oil to pregnant rats resulted in nearly 30% of newborn rats dying within two days—the mortality rate was eight times that of the control group. Feeding pregnant rats with unoxidized (fresh) fish oil did not increase the mortality of newborn rats, which means that the lethal effect on newborn rats comes from chemicals that are broken down when omega-3 fatty acids are oxidized.

Professor Cutfield said: "The consumption of fresh fish oil supplements during pregnancy can improve the health of children who are overweight mothers. However, at this stage, we do not recommend that pregnant women eat fish oil for their baby's health. There are two reasons: First, our research The results need to be confirmed in human studies; secondly, you don't know if the supplement you purchased is fresh, we don't know the safe oxidation of fish oil during pregnancy. Our advice is if you want to add more omega-3 fatty acids. Eating oily fish is a good choice."