Vitamin K is a general term used to describe several related compounds. vitamin K1 or phylloquinone is the form found in plants—predominately leafy greens and vegetable oils. Vitamin K2 is referred to as menaquinone and is found in animal foods—egg yolks, meats, cheese curds, and fermented foods like natto (fermented soybeans) .
Vitamin K deficiency can lead to major bleeding problems since green vegetables, salads, and fat sources are significantly reduced in the bariatric diet. Vitamin K2 loss may result in bone loss or osteoporosis .
Vitamin K1 deficiency can be identified by an elevated International Normalization Ratio (INR) or prothrombin time. Although deficiency is seldom severe enough to cause bleeding, lack of adequate food intake in conditions like inflammatory bowel disease and celiac/ gluten sensitivity have been reported to lead to malabsorption . The bariatric diet results in low intake, which may contribute to malabsorption issues.
Selenium functions as a cofactor for glutathione peroxidase for detoxification and immune enhancement in addition to treatment of congestive heart failure, hepatitis, lymphedema, thyroiditis, and cancer [7, pp. 166-168]. The selenium content of foods depends on the selenium content of the soil where it is grown. Vegetarians have significantly lower selenium status than omnivores probably related to protein quality and methionine levels in their food choices .
Alasfar et al. report selenium status needs review presurgery . Food sources of selenium include meat, fish, legumes, and Brazil nuts but since consumption is limited by bariatric surgery, supplementation beyond multivitamins and minerals may be needed for those with thyroid disorders.