Date Full Report Received03/28/2019
Date Abstract Report Received03/28/2019
InvestigationInstitution: Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University
Primary Investigator: Xueyan Fu
Funded ByIowa Pork Producers Association
a. Determine if vitamin K forms found in pork are absorbed and contribute to vitamin K function in the body.
b. Determine if there is sex difference for vitamin K forms absorption.
c. Determine if tissue accumulation of vitamin K forms are independent of gut microbiota (the microbe population living in our intestines) production of menaquinones. Menaquinone forms are also produced by the gut bacteria.
2. How research was conducted: Male and female mice were fed a diet containing (1) pork; (2)purified forms of menaquinones (vitamin K2) found in pork; or (3) a vitamin K deficient diet. Vitamin K forms in blood, tissues, and feces were measured. As vitamin K is essential for blood clotting, a blood clotting time test was conducted to test vitamin K function.
3. Research findings: Our results show that menaquinones found in pork are absorbed. Female mice has higher vitamin K concentrations than male mice in most analyzed tissues. Vitamin K forms in the liver and feces reflect the forms provided in the diet, both from pork and from the purified dietary forms. No vitamin K forms were found in blood. Although the blood clotting time test did not show differences between the mice on different diets, all mice fed pork or purified vitamin K forms were healthy, whereas several mice on a vitamin K deficient diet died prior to the end of the study. Despite an abundance of menaquinones produced by the microbiota (as indicated by measurement in feces) independent of diet, animals on the vitamin K deficient diet contained minimal vitamin K in tissues. These results together demonstrate multiple dietary vitamin K forms contribute to tissue accumulation of vitamin K independent of gut microbiota.
4. What these findings mean to the industry: Fresh pork cuts and processed pork products are a rich dietary source of menaquinones, which are forms of the essential nutrient vitamin K. We have demonstrated in a mouse model that menaquinone forms in the pork products can be absorbed and effectively metabolized. Vitamin K is considered a shortfall nutrient for older adults, which means that many older adults consume less vitamin K than consumed by other age groups. These data suggest that pork may have a role in increasing vitamin K intakes. However, these findings generated in a mouse model must be extended to human populations prior to promoting pork as a vitamin K-rich food.