When pregnant women suffer from nausea, they are often advised to try ginger as a home remedy. But could too much ginger affect the pregnancy? Þórhallur Ingi Halldórsson, professor at the Faculty of Food Science and Nutrition at the University of Iceland, is now investigating this question with a study entitled: "The use of ginger supplements in pregnancy: Benefit or risk?"
The aim of the study is to find out whether ginger as a dietary supplement could have a negative impact on female fertility. The research looks at existing data on 100,000 pregnant women who gave birth between 1996 and 2004 and answered questions about their diets and use of supplements before and during pregnancy. This study is not just about root ginger like you see in the produce section of the supermarket. When ginger is made into a dietary supplement, the active ingredient is extracted and separated from the fibre and other main ingredients of the root. This process can produce tablets that contain a much higher concentration of the active ingredient than is found in raw or boiled root ginger, which is not always a good thing.
"Generally speaking, it's very different when people are consuming herbs or roots and other foodstuffs as food. Then the active ingredients are generally in such low concentrations that you wouldn't be so worried about it. But dietary supplements are much stronger. And there's nothing wrong with that, per se, but when people take too many supplements, they could end up consuming toxic doses of certain substances," explains Þórhallur.
Follow up of research on rodents
One of the reasons this research is being done is that several previous studies into the effects of ginger on rodents indicated that excessive doses of ginger supplements caused the animals to miscarry. "That doesn't mean that it is harmful to humans. Rats aren't humans," says Þórhallur, stressing that people should not be worried about consuming ginger based on the findings of rodent research. However, it is important to follow up these kinds of results and find out whether there is a comparable risk for women.
The study is conducted in collaboration with Danish specialists and relies on databases that have been under development since the year 2000. The databases contain information about 100,000 pregnant women, including 300 women who took a considerable amount of ginger during pregnancy. The scientists are looking at how long it took the women to become pregnant and whether there is a difference based on whether they took ginger supplements or not. They will also see how long the different groups took to become pregnant again.
This study is not just about root ginger like you see in the produce section of the supermarket. When ginger is made into a dietary supplement, the active ingredient is extracted and all other ingredients are removed. This process is used to make tablets that contain the active ingredient of ginger in much higher concentrations than, for example, boiled root ginger.
Findings from Norway have not shown signs of harm from consuming ginger during pregnancy
Þórhallur says that it is fairly unlikely that ginger affects male fertility, explaining that the main focus here is on miscarriage.
"Nobody wants to limit their fertility by taking supplements and I don't think that is the case. It's important, though, to investigate this in humans rather than rodents."
Þórhallur has worked on risk assessments for food product safety since 2015 and says that the results of research like this are used by authorities and international bodies to evaluate risk, both in terms of use of dietary supplements and official advice.
"How do we use human data in risk assessment?" Interesting video in English: Þórhallur Ingi Halldórsson in an EFSA presentation video from 2018.
Results are expected by the spring, but Þórhallur points out that similar research conducted in Norway has not revealed any indication that the use of ginger supplements in pregnancy is harmful.
Author of the article: Ólína Lind Sigurðardóttir, MA student in International Affairs.