EFSA expresses concern over thyroid effects of Moringa leaf extract

By Will Chu

- Last updated on GMT

M. stenopetala nursery in the Gurage Zone of Ethiopia. ©Wikipedia
M. stenopetala nursery in the Gurage Zone of Ethiopia. ©Wikipedia
A technical report by the European Food Safety Authority (EFSA) details safety concerns the Agency has for placing leaf powder of Moringa stenopetala on the market as a traditional food (TF).

Writing in its supporting publication journal, the report​ notes there is not enough information to assess the TF in terms of glucosinolates, isothiocyanates, phytates and tannin content.

EFSA also cite the lack of information on the extent of the leaf powder’s use in Konso, an area in South Ethiopia from where the plant originates.

“The applicant (Laura Manzano Outeiral) did not provide an exposure estimate on the basis of the proposed uses and use levels in the EU, nor can an exposure assessment be performed by EFSA on the basis of the data provided by the applicant,”​ the report states.

“The proposed uses and use levels in the EU are not supported by the information on the use of the TF in the country. Exposure levels in the EU could exceed historical exposure levels in the country (Ethiopia).”

A particular area of concern is the animal studies submitted that report an antifertility and liver enzyme effect observed with the ingestion of M. stenopetala​ leaf extracts.

Along with effects to thyroid function, EFSA scientists say the relevance of these findings for humans at the proposed uses and use levels in the EU market have not been addressed by the applicant.

Waka Waka Moringa Products

Manzano Outeiral is a representative of Waka Waka Organic Moringa Products Exporting PLC, a family based business with offices registered in Bilbao, Spain.  

As well as producing moringa leaf-based flour and powder, the firm also sell moringa capsules as food supplements for malnourished children.

According to Manzano Outeiral, leaves of M. stenopetala​ have been consumed in Ethiopia for more than 25 years.

The TF is proposed to be marketed in the EU as a powder to be added to sauces, sprinkled on meals or used as a herbal infusion.

She ‘recommended’ a maximum ‘average’ daily intake of the TF of 0.2 grams per kilogram body weight (g/kg bw) for adults with this amount to be adapted to different population groups.

In its assessment, EFSA highlighted a number of publications that used human subjects in its observations.

A cross-sectional study​ in 597 children aged 6-18 years, who lived in Goma-Gofa in South Ethiopia, suggests that the consumption of M. stenopetala​ leaves (more than twice per day) was strongly associated with occurrence of goitre (swelling of the thyroid gland).

Here, the authors suggest diet was a factor pointing to isothiocyanates as known goitrogenic chemical substances.

Thyroid function effect

In another study​,​ researchers monitored levels of thyroid stimulating hormone (TSH), triiodothyronine (T3) and thyroxine (T4) in 65 pregnant women in Southern Ethiopia, where M. stenopetalais​ was consumed as a staple food.

Though not statistically significant, median TSH level increased in women grouped as M. stenopetala consumers whereas median T4 level was decreased.

The authors concluded that frequent consumption of M. stenopetala​ may affect the thyroid function.

Another study​suggests that isothiocyantes and thiocyanates, can be formed from glucosinolates, and are known to affect thyroid function.

“Based on the lack of information regarding the quality and quantity of undesirable substances potentially present in the TF and the absence of an exposure assessment, EFSA cannot conclude whether or not the TF may pose a risk for human consumption at the proposed uses and use levels for the EU market,”​ the report concludes.

“Taking into account the points above, EFSA raises safety objections to the placing on the market within the EU of leaf powder of M. stenopetala as TF.”

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