Writing in Regulatory Toxicology and Pharmacology the team of academics noted that the consumption of dietary supplements and specifically niche products such as supplements targeting pregnant women is increasing.
While the advantages of dietary supplementation with folic acid during pregnancy have been established, the health effects of many other supplements have not been confirmed, said the team, led by Aliede Boer from the Food Claims Centre Venlo at Maastricht University’s Venlo Campus.
Boer and colleagues warn that while both European and U.S. laws on dietary supplements require a product to be safe for the direct consumer (in this case the mother), the long-term health effects for a child are not taken into account.
Indeed, the Dutch team noted that foetal programming – in which there is an adaptation to the foetal epigenome due to environmental stimuli such as supplementation – can potentially have life-long implications for health.
While many nutrients and supplements could offer a potentially beneficial impact, without appropriate regulations in place there is also a potential for life-long harm to be caused.
“We therefore call for both conducting research in birth cohorts and animal studies to identify potential health effects in progeny of supplement consuming mothers as well as the establishment of a nutrivigilance scheme to identify favourable and adverse effects post-marketing,” said Boer and colleagues.
“The acquired knowledge can be used to create more effective legislation on dietary supplement intake during pregnancy for safety of the child,” they added.
Nutrients in review
The Dutch team cited a variety of scientific reviews that have shown maternal dietary intake has influence on the health status of offspring. They added that micronutrients are well known modulators of the epigenome.
“These reviews however mainly focus on the potential negative effects of deficiencies of the maternal diet or negative consequences following the intake of a sub-optimal maternal diet,” they said.
However the team noted that an increased awareness and focus on preventing deficiencies in women of child-bearing age means there may be less risk of deficiency – coupled with an increasing uptake of supplement use by pregnant women.
“Supplements consumed by the mother before or during the foetal development could however affect the foetal epigenome,” said the authors – who noted that a variety of studies have linked maternal supplementation with folic acid in late pregnancy to an increased risk of developing asthma or other (allergic) diseases in childhood.
While the studies behind these suggestions are ‘of varying quality’ and the results are inconclusive, the team warn they should be followed up by further research – especially when coupled with other studies that suggest maternal intake of methyl-group donors (including folate) can influence infant DNA methylation patterns in genes related to metabolism, growth, and appetite regulation.
“Thus, although maternal folic acid supplementation during pregnancy is undisputed, a follow up at later stages in the child's life is warranted to further optimize the dose of folic acid or to optimally select the time-window during pregnancy at which additional intake of folic acid should be recommended,” the team noted.
Boer and colleagues also noted that animal data has suggested potential epigenetic changes in offspring driven by high-dose intakes of quercetin and phyto-estrogens like genistein during pregnancy.
“The limited epidemiological data available indicate that many pregnant women consume dietary supplements and this number is thought to increase,” said the Dutch team. “Although supplementing the diet with folic acid has proven health benefits, many other supplements used during pregnancy are currently not proven to be beneficial, unless they are used to compensate for deficiencies.”
“With the maternal diet affecting the foetal genome through developmental programming, the consequences of supplementing should not be underestimated,” they said. “We do not suggest that consuming dietary supplements endanger the health of the foetus, yet recognize the current lack of knowledge on the long-term health effects of the maternal diet, and more specifically supplements, on offspring.”
They added that a nutrivigilance scheme set up with currently ongoing birth-cohorts and animal studies could help to identify potential adverse and favourable health effects.
Source: Regulatory Toxicology and Pharmacology
Published online ahead of print, doi: 10.1016/j.yrtph.2018.03.014
“Dietary supplement intake during pregnancy; better safe than sorry?”
Authors: Aliede Boer, et al