What it is
Vitamin B12 is a water-soluble vitamin.
What it does
Vitamin B12 is a cofactor for two major enzymes that are important for central nervous system function, DNA synthesis, and red blood cell formation.
The recommended intake for vitamin B12 is 4mg per day for men and women who aren’t pregnant or lactating. Pregnancy and lactation can increase intake requirements for vitamin B12.
Likelihood of tracking completeness: Very low
Vitamin B12 is not a nutrient that food manufacturers are required to disclose on nutrition labels. The vast majority of food and beverage manufacturers do not voluntarily list vitamin B12 content on nutrition labels, so most branded products in the MacroFactor database lack information on vitamin B12. So, if you’d like to accurately track your vitamin B12 intake, you’ll need to make a point of mostly tracking “common foods,” which come from research-grade databases that have full nutrient reporting.
For more on when you can track using branded foods versus common foods when you’re trying to accurately monitor your intake of particular nutrients, you should check out this article.
Likelihood of insufficient intake: Moderate
Most adults generally consume adequate amounts of vitamin B12, but the likelihood of insufficient intake and low blood B12 levels is considerably higher for vegans and elderly individuals. Certain drugs and medical conditions can also interfere with vitamin B12 absorption, which increases intake requirements.
For more on nutrients with a greater likelihood of insufficient or excessive intake, you should check out this article.
Signs of deficiency
Signs of a vitamin B12 deficiency include megaloblastic anemia, low blood counts generally (including red blood cells, white blood cells, and platelets), tongue swelling, fatigue, numbness and tingling in the extremities, and depression.
Great sources of vitamin B12 include shellfish, liver, fatty fish, beef, and dairy products. Plants don’t synthesize vitamin B12, so most vegans will need to use B12 supplements in order to achieve an adequate intake, though algae and seaweed (like nori) can be a good vegan source of B12.
If you’d like to learn more about micronutrients generally, there’s a five-part series on the MacroFactor website you might enjoy.