Bioavailability Assessment of Copper, Iron, Manganese, Molybdenum, Selenium, and Zinc from Selenium‐Enriched Lettuce

Abstract

Cu, Fe, Mn, Mo, Selenium (Se), and Zn bioavailability from selenate‐ and selenite‐enriched lettuce plants was studied by in vitro gastrointestinal digestion followed by an assay with Caco‐2 cells. The plants were cultivated in the absence and presence of two concentrations (25 and 40 µmol/L of Se). After 28 days of cultivation, the plants were harvested, dried, and evaluated regarding the total concentration, bioaccessibility, and bioavailability of the analytes. The results showed that biofortification with selenate leads to higher Se absorption by the plant than biofortification with selenite. For the other nutrients, Mo showed high accumulation in the plants of selenate assays, and the presence of any Se species led to a reduction of the plant uptake of Cu and Fe. The accumulation of Zn and Mn was not strongly influenced by the presence of any Se species. The bioaccessibility values were approximately 71%, 10%, 52%, 84%, 71%, and 86% for Cu, Fe, Mn, Mo, Se, and Zn, respectively, and the contribution of the biofortified lettuce to the ingestion of these minerals is very small (except for Se and Mo). Due to the low concentrations of elements from digested plants, it was not possible to estimate the bioavailability for some elements, and for Mo and Zn, the values are below 6.9% and 3.4% of the total concentration, respectively. For Se, the bioavailability was greater for selenite‐enriched than selenate‐enriched plants (22% and 6.0%, respectively), because selenite is biotransformed by the plant to organic forms that are better assimilated by the cells.

Selenium and Nano-Selenium Biofortification for Human Health: Opportunities and Challenges

“…The most important nutrients that have been investigated in several biofortification studies include calcium [106], iron [92,107], copper [108], zinc [109][110][111], iodine [29,92], potassium [112], and selenium [66,113]. The use of Se fertilizers is one of the most common methods for Se-biofortification of several crops [105], such as rice [113][114][115], maize [116,117], wheat [92,111,118], cowpea [119], potato [85,120], carrot [90,121], turnip [122,123], shallot [124], beans [125], lettuce [91,126], basil [127], strawberry [32,33], and apple [128,129]. Edible plants that have been biofortified with Se [105] or livestock fed selenium-enriched alfalfa [25,130] are used to support human health as reported by the Finnish experience in biofortification with Se through fertilizers.…”

“…These vegetables are important in biofortification programs due to their importance for human health and short growth period (Table 3). Several vegetable crops have already been used in biofortification programs, including vegetables enriched in Se such as tomato [150,151], potato [85,94,120], lettuce [91,126,152], onion [153], garlic [154,155], cabbage [139], carrot, broccoli [156,157], asparagus [158], radish [66,159,160], and spinach [30,158]. NFT or dry hydroponic method, salicylic acid applied at 0.1 mg•L −1 may increase the leaf content of selenomethionine under enrichment with I and Se Abbreviation: NFT (nutrient film technique).…”

“…For potato crops, foliar applied Se at 100 g ha −1 at the tuber bulking stage led to the highest tuber Se-content [85], whereas a low Se dose (0.75 mg kg −1 as selenate) for pots filled with tropical soil (pH 4.8; clay 71%; total Se content 0.065 mg kg −1 ) was the most efficient source for potato biofortification under tropical conditions [94]. The hydroponic system is a common technique for producing lettuce under greenhouse conditions and the Se-bioavailability in a hydroponic system was higher for selenite (40 µmol L −1 Se) compared with selenate due to its fast bio-transformation into organic forms in plant cells [126]. Under field conditions, a foliar of rate of 100 mg kg −1 may be the proper Se dose for lettuce biofortification in salt-affected soils (pH: 8.65; EC: 4.49 dS m −1 ; [152]).…”

Formulations with microencapsulated Fe–peptides improve in vitro bioaccessibility and bioavailability

“…The cell monolayer was rinsed two times with DPBS solution (Dulbecco’s Phosphate Buffered Saline) incubated with 1.5 mL chyme (0.12 mg/mL of total iron concentration) in AP and with Hanks buffered salt solution (HBSS) in BL for 4 h at 37 °C. The osmolality of the chyme was measured (semi-micro osmometer, model K 7400, Knauer, Berlin, Germany) and presented a mean value close to 310 mOsm/kg, which is the recommended value of solutions used with Caco- 2 cells ( Do Nascimento da Silva and Cadore, 2019 ). At the end of the experiment, the resulting liquids of the AP and BL compartments were aspirated and reserved for analysis by ICP OES.…”

“…The measurements of iron bioavailability were done considering its concentration at the BL compartment. Before the experiment, the TEER was verified as being greater than 250 Ω cm 2 ( Do Nascimento da Silva and Cadore, 2019 ). The cell monolayer was rinsed two times with DPBS solution (Dulbecco’s Phosphate Buffered Saline) incubated with 1.5 mL chyme (0.12 mg/mL of total iron concentration) in AP and with Hanks buffered salt solution (HBSS) in BL for 4 h at 37 °C.…”