Here are my recommendations for brands of vitamin B12 supplements, with links to order online. If you have one that you like, email me to let me know and I'll check if it's a good one.
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.
Some people don’t absorb B12 very well through their digestive system, and should take a supplement that you dissolve under your tongue (called sublingual), sending the vitamin directly into your blood stream, skipping the digestive system.
Jarrow Formulas B Complex
This supplement uses high-quality forms of all the B vitamins (including B12 as methylcobalamin) and in quantities that will help maintain healthy blood levels of B vitamins to keep energy levels up. It includes choline and PABA, which are important for vegans since they may not eat enough foods rich in those nutrients.
Ultra B12 Liquid
This liquid supplement gives you B12 in the more effective methylcobalamin form, along with a boost of the other B vitamins. You need to hold the liquid under your tongue for 30 seconds, and it'll be absorbed directly into your blood stream.
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.)
To correct a deficiency, take something in the range of 1000-2000mcg per day. Your body will flush any excess in your urine (you'll notice it being overly yellow) so there's no danger of overdosing.
When taking supplements to correct a deficiency, they should only be taken in higher doses for 4-6 weeks, then reevaluate to see if you've gotten back to balance and can move to a maintenance level.
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.
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