men over age 18 the adequate intake (AI) is set at 4.0μg/day. AI for pregnancy is 4.5 μg/day, for lactation 5.0μg/day. For children aged 1–17 years the AIs increase with age from 1.5 to 3.5μg/day. These AIs are higher than the U.S. RDAs. The EFSA also reviewed the safety question and reached the same conclusion as in the United States—that there was not sufficient evidence to set a UL for vitamin B. The Japan National Institute of Health and Nutrition set the RDA for people ages 12 and older at 2.4μg/day. The World Health Organization also uses 2.4μg/day as the adult recommended nutrient intake for this vitamin. For U.S. food and dietary supplement labeling purposes the amount in a serving is expressed as a "percent of daily value" (%DV). For vitamin B labeling purposes 100% of the daily value was 6.0μg, but on May 27, 2016, it was revised downward to 2.4μg. Compliance with the updated labeling regulations was required by 1 January 2020 for manufacturers with US$10 million or more in annual food sales, and by 1 January 2021 for manufacturers with lower volume food sales. A table of the old and new adult daily values is provided at Reference Daily Intake. Sources Bacteria and archaea Vitamin B12 is produced in nature by certain bacteria, and archaea. It is synthesized by some bacteria in the gut microbiota in humans and other animals, but it has long been thought that humans cannot absorb this as it is made in the colon, downstream from the small intestine, where the absorption of most nutrients occurs. Ruminants, such as cows and sheep, are foregut fermenters, meaning that plant food undergoes microbial fermentation in the rumen before entering the true stomach (abomasum), and thus they are absorbing vitamin B12 produced by bacteria. Other mammalian species (examples: rabbits, pikas, beaver, guinea pigs) consume high-fibre plants which pass through the intestinal system and undergo bacterial fermentation in the cecum and large intestine. The first-passage of feces produced by this hindgut fermentation, called "cecotropes", are re-ingested, a practice referred to as cecotrophy or coprophagy. Re-ingestion allows for absorption of nutrients made available by bacterial digestion, and also of vitamins and other nutrients synthesized by the gut bacteria, including vitamin B12. Non-ruminant, non-hindgut herbivores may have an enlarged forestomach and/or small intestine to provide a place for bacterial fermentation and B-vitamin production, including B12. For gut bacteria to