How Much B12 Should I Take? Vitamin B12 Supplements

How Much B12 Should I Take? Vitamin B12 Supplements
Heather Nicholds, C.H.N.

How much B12 should I take?” Or even: “Do I really need to take B12 supplements?”

Vitamin B12 supplements are really important for vegans, for anyone with digestive issues and for older adults.

Vitamin B12 is a pretty difficult vitamin for our digestive systems to break apart from food and absorb. For people who have less-than-perfect digestion, supplements are often a good thing to take.

As we age, our digestive system becomes less effective, so older adults are prone to B12 deficiency. Interestingly, B12 deficiency symptoms are similar to senility and dementia, so it might be passed off as just part of the aging process.

If you think you might be low, you can check yourself for vitamin B12 deficiency symptoms and it’s a good idea to have your urine or blood tested for an objective and quantitative look.

Isn’t there Vitamin B12 in plant foods?

Although I would love nothing better than to tell you that all the nutrients you need are easily available from fresh, whole plant foods, Vitamin B12 is unfortunately one nutrient that vegans in the developed world should be getting from supplements.

There are some plant foods (algaes, tempeh, etc) that list Vitamin B12 in the nutritional info, but the trouble is these foods have a form of B12 that’s called an analogue, and haven’t been shown to prevent or correct a B12 deficiency.

(Click for a more detailed look at studies of B12 in plant foods by Jack Norris.)

I certainly spent a lot of time wondering how much Vitamin B12 should I take before I became a holistic nutritionist. Now I’ve got it figured out and my blood tests tell me I’m right on.

*Click here for deficiency symptoms to watch for.

If someone suggests eating eggs or other animal foods to correct a vitamin B12 deficiency, keep in mind that B12 isn’t created by animals – it’s generated by bacteria.

Supplements made from bacterial sources of B12 are a more direct form of B12. Also, the amount of animal foods you’d need to eat in order to absorb enough B12 is pretty huge.

With the health downsides of animal foods (hormones, antibiotics, cholesterol, saturated fat) along with the environmental impact and ethical considerations, supplements seem to me to be the best option. (Click for more info on why supplements are the safest source of B12 in Michael Greger’s video.)

For anyone who wants a detailed look at the science and studies of vitamin B12, Jack Norris has put together a very comprehensive series of articles in his vitamin B12 summary.

What I really want to go over here is the specifics of taking vitamin B12 supplements.

Vitamin B12 Supplements For Maintenance

Getting enough Vitamin B12 on a regular basis is really important, and the best plan is to take B12 along with all of the other B vitamins as a “complex”. Most good multivitamins include all of the B complex, including enough B12 for daily maintenance.

There are plenty of foods that are fortified with B vitamins, and they’re fine as a source of B12 but are often processed foods that you may want to minimize for other reasons.

Another thing to consider is that the manufacturer might use a low-quality version that’s not as active as a high-quality supplement. They also might not say exactly how much B12 you’re getting from a serving of the food.

Vitamin B12 Supplements For Correcting A Deficiency

If you have a Vitamin B12 deficiency, you’ll need to get the vitamin in higher levels than what’s in a multivitamin until you catch up.

If you have a slight deficiency, or if your multivitamin doesn’t have enough B12 and the other B vitamins, your best best is to take a full vitamin B complex. The B vitamins all work together in your body, so taking them together is a good idea.

Sublingual vitamin B12 supplements are often recommended if you have a more serious deficiency, and especially if you have an issue absorbing B12 through your digestive system.

Sublingual is a fancy name for a supplement that you hold under your tongue. The idea is that the vitamin gets absorbed directly into your blood stream through the thin skin on the underside of your tongue. You can get sublingual vitamin B12 as a liquid or a tablet.

But according to a study Jack Norris shared on his blog, sublingual supplements weren’t any more effective than regular supplements taken orally at the same dosage. So if you do have a deficiency, the most important thing is to make sure you get the dosage high enough and not rely on sublingual having any higher absorption rate.

Having said that, I do like liquid supplements in general because they’re easy to take and should be easier for your system to absorb. I don’t think studies have shown anything conclusive on the difference, but it makes some sense.

The best way to get B12 is paired with some of the other B vitamins. The most important one is folic acid, which shares deficiency symptoms with B12 so it can be hard to tell which one you’re low in.

*Click here for my supplement recommendations.

Sometimes people with a severe deficiency need to get B12 by injection. This would be something to discuss with a doctor after having your blood or urine levels tested.

How Much B12 Should You Take?

The US RDA minimum for Vitamin B12 is 2.4 mcg per day for adults, and 2.8 mcg for pregnant or nursing women. More recent studies put the ideal intake at 4-7 mcg per day. (Click for more info on optimum levels.)

The trouble is our bodies don’t absorb all of the B12 we take, and there’s kind of a cap on how much we absorb at one time. (Click for more info on how to calculate our body’s absorption rate.

The ideal would be to take smaller doses throughout the day. Since B vitamins stimulate energy and the nervous system, it’s better to take them in the morning and early afternoon so that you don’t get wired before going to sleep.

A B Complex that includes 250 mcg of B12 as cyanocobalamin daily should be enough for you to absorb what you need to maintain healthy levels. (As per Dr. Michael Greger’s latest recommendations.)

Methylcobalamin is reported to be a more active form of B12 and more effective than cyanocobalamin for smokers and for certain conditions like chronic kidney failure. The methyl form of B12 is found in higher quality supplements, but you need a higher dose of it (1000-2000 mcg) to make sure enough is absorbed.

If you’re trying to correct a vitamin B12 deficiency, you’ll need more than those amounts. The exact amount will depend on how low your levels are. It’s best to work with a doctor, naturopath or nutritionist to find the right dose to get you back on track.

If you get a good multivitamin, it should have enough of the most active form of vitamin B12 (methylcobalamin). If it doesn’t, or if you get deficient in B12 or any of the B complex of vitamins, you should take an extra supplement.


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