Postprandial amino acid, glucose and insulin responses among healthy adults after a single intake of Lemna minor in comparison with green peas: a randomised trial

Abstract

A high protein content combined with its enormous growth capacity make duckweed an interesting alternative protein source, but information about postprandial responses in humans is lacking. The present study aimed to assess the postprandial serum amino acid profile of Lemna minor in healthy adults in comparison with green peas. A secondary objective was to obtain insights regarding human safety. A total of twelve healthy volunteers participated in a randomised, cross-over trial. Subjects received two protein sources in randomised order with a 1-week washout period. After an overnight fast, subjects consumed L. minor or peas (equivalent to 20 g of protein). After a baseline sample, blood samples were taken 15, 30, 45, 60, 75, 90, 120, 150 and 180 min after consumption to assess amino acid, glucose and insulin levels. Heart rate, blood pressure and aural temperature were measured before and after consumption, and subjects reported on gastrointestinal discomfort for four subsequent days. Compared with green peas, significantly lower blood concentrations of amino acids from L. minor were observed, indicating lower digestibility. L. minor consumption resulted in lower plasma glucose and insulin levels compared with peas, probably due to different glucose content. There were no significant differences concerning the assessed health parameters or the number of gastrointestinal complaints, indicating that a single bolus of L. minor – grown under controlled conditions – did not induce acute adverse effects in humans. Further studies need to investigate effects of repeated L. minor intake and whether proteins purified from L. minor can be digested more easily.

A controlled human intervention trial to study protein quality by amino acid uptake kinetics with the novel Lemna protein concentrate as case study

“…Cereals, seeds and nuts are often low in lysine while legumes have an under-representation of the sulphur amino acids, cysteine and methionine (Edelman and Colt 2016). In agreement with the FAO recommendations for children, LPC has an intrinsic good balanced amino acid composition which is in agreement with other publications based on Lemna minor plants (Zeinstra et al 2019) and other species from the Lemnoideae (Edelman and Colt 2016;Appenroth et al 2017;Kaplan et al 2019). As proteins in green leafy plant material can consist up to 50% of RuBisCO (Feller et al 2008), it can be assumed that LPC will contain for a large part RuBisCO proteins.…”

“…More recently, the same group performed a long-term human intervention trial in which up to 100 subjects consumed Wolffia globosa not giving any adverse effects, but instead they showed that it amplified the beneficial cardiometabolic effect of a Mediterranean diet (Tsaban et al 2021). Zeinstra et al 2019 found that oral intake of a single large bolus of Lemna plant material hardly altered glucose and insulin levels of the subjects. Also intake of Wolffia globosa showed smaller changes in glucose responses compared to yoghurt (Zelicha et al 2019).…”

“…Species belonging to the duckweed family (Lemnoideae) are seen as an interesting alternative protein source due to their enormous growth capacity, adaptation to a broad spectrum of growth conditions, balanced amino acid composition, content of vitamins and phytochemicals, and easiness to cultivate on a shallow layer of water allowing cultivation in automated (vertical) farming systems (Appenroth et al 2017;Zeinstra et al 2019). Although plants from the duckweed family are currently consumed in Southeast Asia, Lemna plant material is not yet allowed on the European food market.…”

Exploring Health-Promoting Attributes of Plant Proteins as a Functional Ingredient for the Food Sector: A Systematic Review of Human Interventional Studies

“…Although no studies on the remaining plant proteins were identified in the search, an interest in these alternative protein sources has been growing and gaining increasing attention over the last few years. Beneficial effects on studied health outcomes were observed for pumpkin [ 78 , 79 , 80 ], chia seed [ 81 , 82 ], potato [ 83 ], buckwheat [ 84 ], duckweed [ 85 , 86 ] and sunflower [ 80 ]. However, these interesting studies could not be included in the current review as they did not meet the inclusion criteria.…”

Duckweeds as Promising Food Feedstocks Globally

“…Lemna minor also led to lower plasma glucose and insulin levels in humans [57]. Thus, duckweeds can be a promising alternative for diabetics, reducing blood sugar and benefiting health.…”