Brazilian review: Body of science so far supports green banana’s health benefits, but more standardized research needed

Bananas of various varieties make up about 15% of the world’s total fresh fruit produced. It is most often transported and consumed in its ripe stage, but researchers from the University of Brasilia argued that this stage is when the fruit is most prone to mechanical damage and perishable during the maturation process, leading to a significant amount of waste.

They make the case that consuming more unripe green bananas can help reduce food waste while still offering health benefits.

“Green bananas seem to be a good source of fibers, vitamins (C, B6, provitamin A), minerals (potassium, phosphorus, magnesium, zinc), bioactive compounds such as phenolic compounds, and resistant starch, potentially contributing to health benefits, classifying green banana as functional food,”​ they wrote in their report​​, published in Nutrients​.

But at their green stage, bananas haven’t developed its sweetness, and they’re not the most pleasant to eat. “People do not usually consume the fresh green banana, mainly due to the typical hardness and its high astringency, caused by the presence of soluble phenolic compounds as tannin,” ​they wrote.

That is why, they added, some food banana growers and food manufacturers are exploring developing products out of green bananas.

There has been some research or evidence on these green banana-derived ingredients, specifically around their nutrient content and how they may benefit human health. To bring the body of science to the next stage, the researchers analyzed existing data on the nutrient contents and potential health benefits of green banana-derived ingredients, such as flour and biomass pulp, and synthesized the results.

Study details and results​

The authors searched through research databases such as PubMed, EMBASE, Scopus, Science Direct, and Google Scholar. Out of 732 articles returned for searches using keywords such as “unripe banana,” “unripe plantain,” “health improvement,” “recovery,” and more, they selected 18 relevant studies to analyze.

The final studies included came from nine different countries: England, Sweden, Bangladesh, Jamaica, Venezuela, Mexico, Brazil, Nigeria, and India, between 1984 and 2019.

Seven studies (40% of the total) came from Brazil, “probably due to the Brazilian banana production corresponding to about 15% of the worldwide banana production,” ​they posited.

Five studies were on animals, one was in vitro ​(on a petri dish), and the rest were human studies (including on healthy adults, overweight women, diabetes patients, rural children with diarrhea, and more).

“Overall, the studies showed the health benefits using green banana products, most of them related to the gastrointestinal symptoms/diseases, followed by the glycemic/insulin metabolism, weight control, and renal and liver complications associated to diabetes, most of the studies using green banana flour,”​ they reported.

In children studies, green banana flour pulp was linked to improvements of both diarrhea and constipation. In studies on healthy adults, the ingredient was linked to increased satiety and blood sugar management.

“However, there is no standardization regarding dose/effect to different age groups and different health effects considering the variety of the green banana, and the ripeness level,”​ they added.

“It is also important to emphasize that few studies well characterized the chemical composition of the green banana product used. Further studies are relevant to evaluate if the health effects of green banana products remain when used as an ingredient of a potential ‘functional food’ after the production of the food product.”​

Source:​ Nutrients
Published 29 May 2019, https://doi.org/10.3390/nu11061222​
Health Benefits of Green Banana Consumption: A Systematic Review​​
Authors: Ana Luisa Falcomer, et al.