Beef Beef is an excellent source of vitamin B12. One grilled flat iron steak (about 190 grams) provides 467% of the DV for vitamin B12 (). Also, the same amount of steak contains reasonable amounts of vitamins B2, B3, and B6, as well as more than 100% of the DVs for selenium and zinc . If you’re looking for higher concentrations of vitamin B12, it’s recommended to choose from low fat cuts of meat. It’s also better to grill or roast it instead of frying. This helps preserve the vitamin B12 content.