Send to

Choose Destination
J Nutr. 2019 Jun 1;149(6):1004-1011. doi: 10.1093/jn/nxy321.

A Green-Mediterranean Diet, Supplemented with Mankai Duckweed, Preserves Iron-Homeostasis in Humans and Is Efficient in Reversal of Anemia in Rats.

Author information

Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
Division of Pediatrics and the Microbiome Research Center, Assaf Harofeh Medical Center, Zerifin, Israel.
Soroka University Medical Center, Beer-Sheva, Israel.
Endocrinology and Diabetes Research Center at Sheba Medical Center, Ramat Gan, Israel.
Harvard TH Chan School of Public Health and Channing Division of Network Medicine, Department of Medicine, Harvard Medical School and Brigham and Women's Hospital, Boston, MA.
Department of Medicine, Nuclear Research Center Negev, Dimona, Israel.
Department of Medicine, University of Leipzig, Leipzig, Germany.



Decreased dietary meat may deplete iron stores, as plant-derived iron bioavailability is typically limited.


We explored the effect of a low-meat Mediterranean (green-MED) diet, supplemented with Wolffia globosa duckweed (Mankai: rich in protein and iron) as a food source for humans, on iron status. We further examined the iron bioavailability of Mankai in rats.


Two hundred and ninety-four abdominally obese/dyslipidemic [mean age = 51.1 y; body mass index (kg/m2) = 31.3; 88% men] nonanemic participants were randomly assigned to physical activity (PA), PA + MED diet, or PA + green-MED diet. Both isocaloric MED groups consumed 28 g walnuts/d and the low-meat green-MED group further consumed green tea (800 mL/d) and Mankai (100 g green shake/d). In a complementary animal experiment, after 44 d of an iron deficiency anemia-inducing diet, 50 female rats (age = 3 wk; Sprague Dawley strain) were randomly assigned into: iron-deficient diet (vehicle), or vehicle + iso-iron: ferrous gluconate (FG) 14, Mankai 50, and Mankai 80 versions (1.7 mg · kg-1 · d-1 elemental iron), or FG9.5 and Mankai 50-C version (1.15 mg · kg-1 · d-1 elemental iron). The specific primary aim for both studies was changes in iron homeostasis parameters.


After 6 mo of intervention, iron status trajectory did not differ between the PA and PA + MED groups. Hemoglobin modestly increased in the PA + green-MED group (0.23 g/dL) compared with PA (-0.1 g/dL; P < 0.001) and PA + MED (-0.1 g/dL; P < 0.001). Serum iron and serum transferrin saturation increased in the PA + green-MED group compared with the PA group (8.21 μg/dL compared with -5.23 μg/dL and 2.39% compared with -1.15%, respectively; P < 0.05 for both comparisons), as did folic acid (P = 0.011). In rats, hemoglobin decreased from 15.7 to 9.4 mg/dL after 44 d of diet-induced anemia. After depletion treatment, the vehicle-treated group had a further decrease of 1.3 mg/dL, whereas hemoglobin concentrations in both FG and Mankai iso-iron treatments similarly rebounded (FG14: +10.8 mg/dL, Mankai 50: +6.4 mg/dL, Mankai 80: +7.3 mg/dL; FG9.5: +5.1 mg/dL, Mankai 50-C: +7.1 mg/dL; P < 0.05 for all vs. the vehicle group).


In humans, a green-MED low-meat diet does not impair iron homeostasis. In rats, iron derived from Mankai (a green-plant protein source) is bioavailable and efficient in reversal of anemia. This trial was registered at as NCT03020186.


Mediterranean diet; iron homeostasis parameters; plant iron sources; vegetarian diet; weight loss


Supplemental Content

Full text links

Icon for Silverchair Information Systems
Loading ...
Support Center