Fish oil intake in pregnancy doesn't reduce childhood obesity risk

By Will Chu

- Last updated on GMT

While the study found no significant differences in children’s abdominal fat mass or fat distribution, supplementation may have other benefits. (©
While the study found no significant differences in children’s abdominal fat mass or fat distribution, supplementation may have other benefits. (©

Related tags Nutrition Fat Obesity

Omega-3 supplementation during pregnancy offers no protection for the offspring against obesity during the child’s first year of life, a study has hypothesised. 

Findings that involved supplementing 208 pregnant women with omega-3 fish oils found no significant differences in children’s abdominal fat mass or fat distribution.

Using skinfold thickness (SFT) measurements at four body sites, infants did not show any difference in the sum of their four SFTs in the first year of life. No significance was attached to growth measurements too.

Supplementation with 0mega−3s during pregnancy has become popular because of reported beneficial​ effects on the neurodevelopment of the infant.

However, studies that clarify the role of these oils in influencing fat mass in humans are few in number.

The global rise in childhood obesity over the past decades has caused researchers to target pregnancy and lactation as a window of opportunity to address obesity.

It has been shown​ that the nutritional environment of the foetus in the uterus may have a huge impact on the health of the developing offspring in the long term.

Study details

Foods rich in Omega-3 oils include salmon, flax seeds, and krill.(©

In total 208 women, with an average BMI of 22, took part in the long-term study (INFAT) carried out at the Technical University of Munich (TUM), Germany.

Two groups were established. One ate a normal diet, while the other ate an omega-3 rich diet, which involved a reduction of meat (and hence, a reduction of omega-6 fatty acids).

The experiment started from the twelfth week of pregnancy and ended at the fourth month of lactation.

The mother’s offspring were then invited for a follow up examination every year until they reached the age of five.

“The INFAT study is the first prospective RCT to test the hypothesis that a reduction of the omega−6:3 fatty acid ratio in the maternal diet may cause less-expansive adipose tissue growth in infants,”​ the study claimed.

Similar studies in animals have shown this ratio of oils is critical for adipose tissue growth​, and human observational studies pointed to a link between the fatty acid composition of breast milk and risk of childhood obesity​.

“The end result was negative,”​ said Professor Hans Hauner, head of the Else-Kröner-Fresenius Center for Nutritional Medicine at the Technical University of Munich (TUM). “This special diet had no effect on the weight of the babies and toddlers.”

“This proves that the earlier findings are not translatable onto humans and that the hoped-for benefit of such a diet is questionable as it does not appear to prevent childhood obesity.”

Other benefits?

cognitive brain neuro
There is a case to be made for the beneficial fish oil effects on the neurodevelopment of the infant.(©

The study suggested a mother's diet during early pregnancy has other beneficial effects, which would have to be determined in further clinical studies.

“The most important finding of this RCT was the prolonged gestation by almost five days in the intervention group together with a higher birth weight,” ​wrote the researchers.

“This finding was in agreement with studies that suggested that marine oils and Omega−3 preparations promote a higher birth weight because of prolonged gestation.”

The main mechanism of action attributed to this observation involves interference of the compounds that promote uterine contractions.

This may be due to the inhibition of metabolite production, primarily certain prostaglandins that initiate spontaneous labour.


Source: The American Journal of Clinical Nutrition

Published online ahead of print, doi: 10.3945/​ajcn.111.022590

“Effect of reducing the n−6:n−3 long-chain PUFA ratio during pregnancy and lactation on infant adipose tissue growth within the first year of life: an open-label randomized controlled trial.”

Authors: Hans Hausner et al.

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