Important to take just in case we don’t have the right bacteria in our bodies.
What form of B12 is best absorbed or does it matter?
A common question. Short story first, details will follow....
Methylcobalamin is the more natural and easily absorbed form of the cobalamins. B12 supplements are primarily produced by bacteria, from bacteria cultures not from animal products. For vegetarians and vegans please check the bottles as some supplement capsules are made from gelatin. Now, what does that tell you about a natural source for B12.
Lets see what the research says:
Dec 22, 2022, Vitamin B12 - Health Professional Fact Sheet, National Institutes of Health (.gov)
https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/Vitamin B12 contains the mineral Cobalt and the various forms carry the general category of cobalamins. The most common form of vitamin B12 in dietary supplements is cyanocobalamin. Other forms of vitamin B12 in supplements are adenosylcobalamin, methylcobalamin, and hydroxycobalamin [22]. No evidence indicates that absorption rates of vitamin B12 in supplements vary by form of the vitamin.
The literature does a good job at describing how B12 is released and absorbed. The process of releasing Vitamin B12 from food starts with saliva in the mouth, hydrochloric acid in the stomach and digestive enzymes in the duodenum. The "free" Vitamin B12 then combines with intrinsic factor (protein secreted by the stomach). It is said that vegetarians have low intrinsic factor but yet the paper shows the sources of B12 as mostly external sources of meat.
Table 1: Recommended Dietary Allowances (RDAs) for Vitamin B12 [1]
Age Male Female Pregnancy LactationBirth to 6 months* 0.4 mcg 0.4 mcg
7–12 months* 0.5 mcg 0.5 mcg
1–3 years 0.9 mcg 0.9 mcg
4–8 years 1.2 mcg 1.2 mcg
9–13 years 1.8 mcg 1.8 mcg
14–18 years 2.4 mcg 2.4 mcg 2.6 mcg 2.8 mcg
19+ years 2.4 mcg 2.4 mcg 2.6 mcg 2.8 mcg
Now look at the table showing the amount per serving with percent DV (Daily Volume).
Food Micrograms
per serving PercentDV*Beef liver, cooked, pan fried, 3 ounces 70.7 2,944
Clams (without shells), cooked, 3 ounces 17 708
Nutritional yeast, fortified, from several
brands (check label), about ¼ cup 8.3 to 24 346 to 1,000Salmon, Atlantic, cooked, 3 ounces 2.6 108
Tuna, light, canned in water, 3 ounces 2.5 104
Beef, ground, 85% lean meat/15% fat,
pan browned, 3 ounces 2.4 100
Milk, 2% milk fat, 1 cup 1.3 54
Yogurt, plain, fat free, 6-ounce container 1.0 43
Breakfast cereals, fortified with 25%
of the DV for vitamin B12, 1 serving 0.6 25Cheese, cheddar, 1½ ounces 0.5 19
Egg, whole, cooked, 1 large 0.5 19
Turkey, breast meat, roasted, 3 ounces 0.3 14
Tempeh, 1/2 cup 0.1 3
* Adequate Intake (AI)
The food sources are primarily shown as various meats. However, Brewers Yeast has a very high amount of B12 and would be a recommended supplement. You should note that the daily requirement for B12 is in the range of "micro-grams" or millionth of a gram. So though the vegetable sources are few and show small amounts the amounts needed are also small. Vegetable sources also have higher bioavailability (easier to digest, rate of absorption).