Heat-killed bacteria may boost iron status for young women: RCT

By Stephen Daniells

- Last updated on GMT

© JONGHO SHIN / Getty Images
© JONGHO SHIN / Getty Images

Related tags heat-killed bacteria postbiotics iron status

Supplementation with a heat-killed bacterium may significantly increase iron status for young women, says new study from Japan that creates novel opportunities to address a leading global nutrient deficiency.

According to the World Health Organization (WHO), about 30% of the world’s population may have low red blood cell numbers due to insufficient iron. A 2021 study from scientists at Columbia University​ suggests that we may be underestimating the prevalence of iron deficiency. It is the leading nutrient deficiency in both developed as well as developing countries.

Two main avenues are open to redress the balance in favor of iron: supplementation and fortification. Fortification has been touted as the best way because it is less expensive and can reach a bigger population. Fortification also avoids the gastrointestinal discomfort experienced when supplements containing over 100 mg/d of iron are consumed.

The new study, published in Nutrients​, indicates a potential third avenue: Microbiome modulation.

Data from a randomized, double-blinded, placebo-controlled, parallel-group comparative study indicated that four weeks of supplementation with the heat killed Lactococcus lactis​ subsp. cremoris​ H61 led to significant increases in serum iron, transferrin saturation, and ferritin, with no changes observed in the placebo group.

Commenting on the potential mechanism(s) of action, the researchers noted that this could be related to lactate, which is able to reduce dietary non-heme iron (Fe3+) to divalent iron (Fe2+), which is the form that is absorbed. Heat-killed H61 may boost the abundance of intestinal Lactobacillales, which increase levels of lactate in the intestines to boost iron absorption.

Another possible mechanism could be a direct impact on iron absorption, as has been seen with Lactobacillus plantarum​ 299v, said the researchers.

Study details

Researcher from Juntendo University recruited 50 young Japanese women and randomly assigned them to receive either the 60 mg of H61 or placebo per day for four weeks.

Data from the 29 people who completed the study indicated that H61 led to increases in serum iron of approximately 40%, while transferrin saturation and ferritin levels increased by approximately 15%. No changes were recorded in the placebo group, said the researchers.

The researchers also noted that iron intakes did not change during the course of the study, which indicated that the H61 group’s change in iron status was not due to increased iron intake.

“These results suggest that heat-killed H61 may elevate iron status by enhancing iron absorption,”​ they wrote.

Source: Nutrients
2022, 14​(15), 3144; doi: 10.3390/nu14153144
“Heat-Killed​ Lactococcus lactis subsp​. cremoris H61 Altered the Iron Status of Young Women: A Randomized, Double-Blinded, Placebo-Controlled, Parallel-Group Comparative Study”
Authors: M. Takaragawa et al.

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