Protein Bioavailability of Wolffia Globosa (Mankai); Acute Test Meal Effects

The investigators aim to test the protein bioavailability of new specific developed strain of duckweed [Wolffia globose, Mankai], an aquatic plant, which might serve as a protein source and contains all the 9 essential and the 6 conditional amino acids. "Mankai" [(Generally recognized as safe (GRAS)] is a cultivated strain of Wolffia globosa, which is an aquatic plant, part of the family of plants known commonly as duckweeds. Duckweeds are very simple flowering aquatic plants which float on or just beneath the surface of still or slow-moving bodies of water. There is a long history of the use of Wolffia species, in particular Wolffia Globosa, as food, especially in Southeast Asia: Burma, Laos and northern Thailand, where it has been used as a vegetable for many generations. There are numerous ways of W. globosa consumption and a variety of recipes, using it either as a main ingredient (such as Wolffia crisps or "kaeng pum" - a popular vegetable dish in northeastern Thailand) or incorporating it in other foods (e.g. Wolffia-meat ball, fermented Wolffia-meat sausage, Wolffia rice noodle, Wolffia cookies, Wolffia bread, and various soups and salads). Along with its long history as a food source in Southeast Asia, it is recognized as an edible vegetable for humans in several databases, including the United States Department of Agriculture (USDA 2014) GRIN database and a database dedicated to tropical species. The nutritional composition of Mankai has been determined and found to be high in protein, containing all the essential and conditionally essential amino acids, dietary fibers and several vitamins and minerals. In a recent safety study, which aimed to test the safety of Mankai administration within and 3 times of the amount approved in the GRAS, 4 groups of female SD rats were orally administered for 4 consecutive days a daily dose of Mankai at three dose levels of 1700, 2500 and 3400mg/kg of Mankai, equivalent to 20, 40 and 60 gr/day human dose, respectively. Clinical (e.g body weight, food intake, morbidity/mortality, toxic signs), pathological (post mortem gross pathology examination) and long list of blood biochemical indicators (e.g liver status biomarkers, stress indicators, minerals) did not show any adverse effects. The results indicate that repeated four day Mankai administration did not cause adverse effects. Unexpectedly, high doses even suggested beneficial results with anti-glycemic effects. Mankai was found to have a high digestibility profile (89%) according to Protein digestibility-corrected amino acid score (PDCAAS) Eurofins tests. However, its human nutrient bioavailability has not been examined yet. For the proposed test, Mankai (grown by Hinoman Ltd., Israel) will be provided as a fresh, whole, product.

Methods: 36 men will be randomized to consume the following food items, which will be equivalent to 30gr protein, after 12h night fasting:

1. Reference group: animal protein food source: White cheese, intact, plus 250ml mineral water
2. Test group 1: plant food source: Green peas, intact, cooked, plus 250ml mineral water
3. Test group 2: plant food source: Wolffia globosa (Mankai), intact, cooked, plus 250ml mineral water

The participants will be asked to maintain a stable diet (according to guidelines that will be provided) for 3 days prior to the test meal. Blood samples will be taken at times 0, 30, 90, and 180 minutes.