Selenium bioavailability from naturally produced high-selenium peas and oats in selenium-deficient rats

Authors: Yan, Lin; JOHNSON, LUANN - University Of North Dakota

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/9/2011
Publication Date: 5/9/2011
Citation: Yan, L., Johnson, L.K. 2011. Selenium bioavailability from naturally produced high-selenium peas and oats in selenium-deficient rats. Journal of Agricultural and Food Chemistry. 59:6305-6311.

Interpretive Summary: Selenium is an essential nutrient. The soil selenium contents among the agricultural states in the United States vary widely, and states in the Northern Plains, e.g. Dakotas, have sufficient or adequate selenium in soil. The Selenium concentrations of agricultural crops reflect the selenium contents of the producing soil, and those produced in the Northern Plains are high in selenium. We determined the bioavailability of selenium from yellow peas and oats that were naturally produced from the high-selenium soil of South Dakota.We produced low-selenium status in rats by feeding them a Torula yeast-based selenium-deficient diet, which was very low in selenium, and then replenished of selenium by feeding rats diets supplemented with high-selenium peas or oats at various concentrations.The selenium bioavailability was determined on the ability of selenium from peas or oats to restore selenium-dependent enzyme activities and tissue selenium contents in these rats. Selenomethionine, a selenium-containing amino acid commonly from plant foods, was used as a reference. Dietary supplementation with peas or oats resulted in dose-dependent increases in selenium-containing enzyme activities in blood and liver and selenium contents of plasma, liver, muscle and kidneys. These responses indicated an overall bioavailability of approximately 88% for selenium from yellow peas and 92% from oats, relative to selenomethionine. These results demonstrate that selenium from naturally produced high-selenium yellow peas and oats is highly bioavailable in this model and that these foods can be a good dietary source of selenium.

Technical Abstract: We determined the bioavailability of selenium (Se) from yellow peas and oats harvested from high-Se soil of South Dakota, United States. The Se concentrations of the peas and oats were 13.5 ± 0.2 and 2.5 ± 0.1 mg/kg, respectively. Male weanling Sprague-Dawley rats were depleted of Se by feeding them a 30% Torula yeast-based diet (4.1 µg Se/kg) for 56 days, and then they were replenished with Se for an additional 50 days by feeding them the same diet supplemented with 20, 30 or 40 µg Se/kg from peas or oats, respectively. L-selenomethionine (SeMet) was used as a reference. Selenium bioavailability was determined on the basis of the restoration of Se-dependent enzyme activities and tissue Se concentrations in Se-depleted rats, comparing those responses for yellow peas and oats to those for SeMet by using a slope-ratio method. Dietary supplementation with the pea or oats resulted in linear or log-linear, dose-dependent increases in glutathione peroxidase activities in blood and liver and in thioredoxin reductase activity in liver. Supplementation with the peas or oats resulted in linear or log-linear, dose-dependent increases in Se concentrations of plasma, liver, gastrocnemius muscle and kidneys. The overall bioavailability was approximately 88% for Se from yellow peas and 92% from oats, compared to SeMet. We conclude that Se from naturally produced high-Se yellow peas or oats is highly bioavailable in this model and these high-Se foods may be a good dietary source of Se.