 Universal improvement of B12 status appears to be a nutritional imperative, with possibly profound beneficial effects, particularly at the bookends of life at old age and infancy. I've explained the rationale for my recommendations to take vitamin B12 supplements once a week, once a day, or alternately eat sufficient daily vitamin B12 fortified foods. But for those over age 65, those guidelines go out the window. The recommendations change to everyone taking a high daily dose of 1,000 micrograms every day. Starting at age 50, everyone, meat-eaters and vegans alike, should be taking B12 supplements or eating B12 fortified foods, but over age 65, 50 a day may not do it. Even 100 a day doesn't seem sufficient. Researchers investigated three doses and found that most didn't normalize their MMA until after the 1,000 microgram dose MMA suppression is a measure of B12 sufficiency. But they just tested 2,500 and 1,000, maybe 250 or 500 would do it. Researchers set out to find an adequate dose at that age, and it seems we need at least about 650 to 1,000 a day in most people, hence my 1,000 a day recommendation after age 65. Okay, what about the other end of the life cycle? The consequences of B12 deficiency and insufficiency can be devastating. In infancy and childhood, and this is not just a problem for plant-based pregnancies, vitamin B12 insufficiency during pregnancy is common. Even in non-vegetarian populations, about a quarter of all pregnant women aren't getting enough B12, and that number rises to nearly 1 in 3 by the third trimester. But insufficiency isn't as bad as frank deficiency, which can manifest in cases like cerebral atrophy, meaning brain shrinkage in a vitamin B12 deficient infant of a vegetarian mother. Thankfully, even severe brain atrophy can be substantially reversed with B12 supplementation, but better not to become deficient in the first place. The solution proposed by a group of French pediatricians is to recommend against raising vegan kids at all, since B12 supplementation is necessary. And they're not alone, to vegan or not to vegan. In 2016, two professional organizations, the US Academy of Nutrition and Dietetics, and the German Nutrition Society, issued conflicting statements. The US Academy said that even strictly plant-based diets are appropriate for all stages of the life cycle. Whereas the German group echoed the French group, saying, since you have to take B12, we can't recommend a vegan diet for pregnant women, lactating women, infants, children, or adolescents. To confuse the matter further, the American Academy of Pediatrics appeared to have it both ways. In one place, repeating the US Academy's position while in another place is stated that vegan diets should not be recommended for children. But I think they're just saying the same thing. Everyone agrees that a non-B12 supplemented plant-based diet is a bad idea. That's part of what the US Academy means by well-planned. Everyone, eating plant-based, but especially pregnant and breastfeeding women, must ensure a regular, reliable source of vitamin B12, meaning B12 supplements or B12 fortified foods. But then you may be able to get the best of both worlds. That's why there are reviews with titles like this. Plant-based pregnancy is danger or panacea. Danger, if you don't take your B12. But following a plant-based diet during pregnancy may be protective against the development of preeclampsia, pre-gravid obesity, and minimize exposure to DNA-damaging agents. It may also protect our newborns from the onset of pediatric diseases such as pediatric wheezing, diabetes, neural tube defects, oral facial clefs, and some pediatric tumors. Vegan pregnant women have a lower-than-average rate of caesarean section, less postpartum depression, and lower neonatal and maternal mortality, with no complications or negative outcomes that are higher than average. In addition, a lower incidence of what used to be called toxemia, potentially dangerous pregnancy complication known as preeclampsia. Overall, plant-based diets seem to confer protection to both mothers and newborns, by not only reducing the risk of several pregnancy-related issues, but decreasing the risk of childhood disease. Children following plant-based diets might have a low risk of developing obesity, obviously less exposed to drugs used in animal production, and a favorable anti-inflammatory profile of cell signaling factors. But again, everyone on a plant-based diet has to get enough B12. Pregnant breastfeeding women can just follow my 50 micrograms a day recommendation for non-pregnant adults, or 2,000 a week, though they suggest breaking up those doses into two halves to boost absorption. After infants are weaned, they can start on 5 micrograms a day. From ages 4 through 10, they can eat half the adult dose of 25 a day, and then at age 11 they can do 50 a day or 2,000 a week. You don't have to worry about taking too much. It's water soluble, and you'll just end up with expensive pee.