Vitamin B12 requires extra attention on a plant-based diet. This post covers how it’s made, where it’s found, and how to get enough vitamin B12 for kids. Plus vegan B12 supplement recommendations.
What is Vitamin B12?
B12, also called cobalamin, is one of the eight water-soluble B vitamins.
It’s needed for:
- DNA synthesis
- Cell metabolism
- Red blood cell formation
- Keeping nerves and blood vessels healthy, and
- Supporting growth and development.
It’s essential to get enough vitamin B12 for all of these processes to occur as they’re supposed to – and it does need some extra attention when following a plant-based diet.
Where Does B12 Come From?
Vitamin B12 is made by bacteria that live in the soil. It’s the only essential micronutrient for humans that is exclusively made by bacteria.
The predominant dietary sources of B12 are animal products, like beef, fish, and dairy. But there are also B12-fortified brands of nutritional yeast and non-dairy milks.
The reason animal products contain B12 is that most of them are eating plants that grow in B12-rich soil. Farmed animals also get it from eating B12-fortified feed, as well as being exposed to bacteria-rich manure and unsanitized water.
Humans produce some B12 in our intestine, but this occurs below the ileum where it’s not available for absorption.
The same is true for animals. There’s further evidence of this when you watch mostly or totally vegetarian animals in nature. Many of these eat their own poop – as this is an important way to obtain B12 on their plant-based diet.
Because humans (thankfully) don’t practice this same behavior, this is why supplementation is essential when there are not enough B12-rich sources of food consistently meeting needs in the diet.
Plants neither use nor store B12 and therefore aren’t a reliable source of the nutrient. You may have heard claims that plants like seaweed, algae, and fermented foods naturally contain B12 but those are inactive analogs that won’t contribute to B12 needs. The same is true of unwashed produce (but who is eating their produce straight from the ground and unrinsed, anyway?).
While fortified foods can provide some B12, the amounts can be inconsistent and possibly unreliable as B12 is light and heat-sensitive, and therefore broken down during storage of cooking. It’s why we believe that a supplement is the most reliable source for anyone who follows a plant-based diet: vegan, vegetarian or flexitarian.
So, supplements are best.
Vitamin B12 for Kids: Dosing Recommendations
Plant-based babies will get enough vitamin B12 from formula or breastmilk as long as mom is supplementing herself adequately. We recommend 250mcg a day of B12 during this time. Children should start receiving their own supplement at around 12 months. But how much do they need?
Understanding the RDA for vitamin B12 is a good start, but meeting your child’s needs requires looking beyond this number. This can be a little confusing, so let’s break down what influences B12 absorption and how to dose it accordingly for kids.
B12 absorption is a complex process that becomes less efficient with age.
Vitamin B12 requires a protein called intrinsic factor (IF), made by cells in the stomach lining, to be fully absorbed. After it binds to B12, this travels to the intestines where B12 is absorbed into the bloodstream.
But IF can only help absorb so much B12 at a time. And B12 absorption decreases significantly when the capacity of IF is exceeded.
In other words, the percentage of B12 our body can absorb in one sitting – like with a supplement – wanes as the dose increases. For example, about 50% is absorbed in a dose of 2 mcg but only 1-2% is absorbed in a dose of, say, 2000 mcg.
IF capacity becomes saturated at about a 1.5-2 mcg dose of B12. At doses of up to 2 mcg, about 40-50% of B12 is absorbed. After IF has reached saturation, the remaining B12 can be absorbed through a process called passive diffusion at a rate of about 1%.
The bottom line here is that while we only need a small amount of B12 daily if we’re going to get it all from one single supplement, we need to take a much larger amount than the RDA – or take it in multiple doses.
How to Dose
The B12 RDA for kids 1-3 years old is 0.9 mcg. But in order to absorb enough to meet daily needs given the factors above, kids should take a single 10 mcg supplement.
To complicate things further, if you’re giving B12 a couple of times a day, the amount that should be taken at once goes back down, since you absorb more when you take less.
So the same 1-3-year-old could either take a single 10 mcg supplement or two doses spread out ranging from about .5-1 mcg.
For more examples of B12 supplement dosing for kids, see this table, which outlines dosing guidelines ranging from once per week to up to three times daily.
Best Vitamin B12 for Kids Supplement
Unfortunately, most B12 supplements on the market don’t offer these low amounts as they’re usually created for adults. And while B12 is a water-soluble vitamin and there isn’t an upper limit, we’d prefer to stick to a level closer to kids’ needs than have to titrate doses ourselves.
That’s why we’re SO excited that after sharing these concerns with LiveWise Naturals (affiliate link), they developed a product with us in mind for the perfect dosing for toddlers! A single drop of their product provides 2.5 mcg or 5 mcg in 2 drops.
Forms of Supplements
B12 supplements come in 4 different forms:
1. Cyanocobalamin: This is the manmade form of B12. It’s also the most common, well-studied, stable, and inexpensive form. It’s made up of a cobalamin molecule attached to a cyanide molecule. But as scary as this may sound, the amount of cyanide in a supplemental dose of B12 is actually less than most people consume on a daily basis.
2 and 3. Methylcobalamin and Adenosylcobalamin: These two are the “active” coenzyme forms of B12 that are used in chemical reactions.
4. Hydroxocobalamin: Both this form of B12 and cyanocobalamin are converted to the methyl- and adenosyl- forms in the body.
When it comes to the best form, cyanocobalamin and methylcobalamin are the most common ones used in supplements. And either one will do, as there’s not sufficient evidence to recommend one form over another for prevention or treatment of B12 deficiency.
For More Information:
For more guidance on supplements for predominantly plant-based kids, get your FREE copy of the Plant-Based Juniors’ Supplement Guide here!
Chime In: Do you have a favorite B12 supplement for your family?
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