Some research shows that most people in the United States and the United Kingdom consume sufficient vitamin B12. However, other research suggests that the proportion of people with low or marginal levels of vitamin B12 is up to 40% in the Western world. Grain-based foods can be fortified by having the vitamin added to them. Vitamin B12 supplements are available as single or multivitamin tablets. Pharmaceutical preparations of vitamin B12 may be given by intramuscular injection. Since there are few non-animal sources of the vitamin, vegans are advised to consume a dietary supplement or fortified foods for B12 intake, or risk serious health consequences. Children in some regions of developing countries are at particular risk due to increased requirements during growth coupled with diets low in animal-sourced foods.