Vitamin B12, also known as cobalamin (this name is due to the mineral cobalt found in this vitamin), is the last member of the B vitamin family. Now, let me emphasize 3 things before we go further. First, the only plant-based products that contain vitamin B12 naturally are (1) mushrooms and (2) yeast. Second, not all yeast brands are rich in vitamin B12; hence, you must check nutritional label or contact the manufacturer for information. Third, vitamin B12 can be stored in large amount, unlike other B vitamins. So, if you have not been vegans all your life, have consumed good amount of animal-based foods, and just started picking up this new diet, you may have a good few years of vitamin B12 stored before you run out of it and suffer vitamin B12 deficiency.
1/ Functions of vitamin B12:
One: Prevent anemia
It works closely with vitamin B6 and B9 to participate in hemoglobin production. Each of these 3 vitamin works in different way to ensure the proper production of hemoglobin: vitamin B6 has something to do with the heme component of hemoglobin; vitamin B9 does the general support task, and vitamin B12 helps create succinylCoA (a building block of hemoglobin). So, if you lack vitamin B12 in your system, production of succinylCoA may be compromised, which may interfere with hemoglobin synthesis eventually.
Two: Vitamin B12 and its affect in cardiovascular system by lowering homocysteine level.
Vitamin B12 can lower homocysteine-which is one of the markers of heart diseases. Most cardiovascular patients have elevated homocysteine.
Three: Participate in DNA synthesis and prevent megaloblastic anemia
Blood cells have their own DNA. After DNA synthesis is complete, DNA molecules need to be released so that they can do its job. However, when we do not consume enough vitamin B12, the red blood cells can’t release it own DNA. Over time, the red blood cells become “inflated” and huge; which is the onset of the condition called megaloblastic anemia?
Four: Central Nervous system
When vitamin B12 is wanting, it may affect nerves (the nerve sheaths are stripped off). When the nerves are damaged, they can’t do what they’re supposed to do: sending incoming and outgoing signals to and from the brain. Usually, the nerves in the limbs will be the first to be affected.
Five: Maintain steady supply of energy for aerobic activities
Vitamin B12 helps produce succinylCoA, which is also participating in the Krebs cycle-the energy production cycle. This cycle is one of a few energy metabolism pathways that provide energy for many activities, mostly aerobic activities. When you suffer vitamin B12 deficiency, you may experience chronic fatigue because the body can’t generate enough energy to carry out even daily living activities.
2/ Recommended Daily Intake (Daily Value) microgram per day
Let me give heads up: there’s no record of people suffering toxicity from overdosing vitamin B12. Actually, when you’re diagnosed with vitamin B12 deficiency, they will give you large doses of vitamin B12 through shots or IV. Besides, most Western countries where meat and seafood are consumed about 8 oz ( about 240 g), they consume at least 300% daily value of vitamin B12 on a daily basis; yet, nobody has reported toxicity.
- 0-6 months: 0.4 mcg/day
- 6-12 months: 0.5 mcg/day
- 1-3 years: 0.9 mcg/day
- 4-8 years: 1.2 mcg/day
- 9-13 years: 1.8 mcg/day
- Pregnant women: 2.4 mcg/day
- Lactating women: 2.8 mcg/day
3/ Diseases caused by vitamin B12 deficiency
- Pernicious anemia
- Megaloblastic anemia
- Multiple Sclerosis
- Nerve damages
- Poor memory
- Muscular atrophy (degeneration)
- Alzheimer’s Disease
- Shingles (due to weakened immune system)
4/ Signs and symptoms of vitamin B12 Deficiency
Before the deficiency is left to exacerbate and/or cause such diseases listed above, you may have a chance to catch it before too late if you see some of the following signs:
- Memory loss
- Sore mouth
- Loss of appetite
- Abnormal gait
- Loss of sensation or tingling feelings in the hands and feet (very important sign, indicating nerve damages)
5/ Who’s at risk of developing vitamin B12 deficiency?
- Alcoholics (poor liver function and digestive function)
- Vegans or Vegetarians who do not consume dairy products and/or eggs or nutritional yeast
- People with poor absorption ( such as problems with bile, pancreas, lining of the stomach and/or the intestines)
- People above 50 years of age (psychological reasons causing loss of appetite, and also natural decrease in GI function)
- People with tinnitus
6/ Factors affecting vitamin B12 contention
Vitamin B12 is considerably stable compared to many other B vitamins. Except for boiling, vitamin B12 has higher retention rate than many B vitamins when being cooked with the same cooking method and similar cooking time.
Boiling destroys about 50% of the original vitamin B12
Steaming destroys 10-25% of the original vitamin B12
Sauteing foods in 10 minutes can destroy 20% of the original vitamin B12
Grilling or frying in 30 minutes can destroy 40% of the original vitamin B12.
7/ Foods rich in vitamin B12
There are four things to remember. First, animal based products have the highest concentration of vitamin B12. Second, mushrooms or fungi can make their own vitamin B12 in small amount. Third, fungi do not belong to plant kingdom; therefore, practically no plants (vegetables and fruits) contain any vitamin B12 (not even the super kale). And finally, nutritional yeast contain good amount of vitamin B12.
Of all animal meats, chicken is the least ideal source for vitamin B12. However, liver and giblet of chicken (and others such as pigs and cows) contain very high level of vitamin B12, although that comes with high cholesterol as well.
Mushrooms, 100 g, 3-4% vitamin B12
Cheese, sliced, 28 g (1 oz), 10% vitamin B12
Egg, cooked, 1 large, 23% vitamin B12
Cow’s milk, 250 mL (1 cup), 46% vitamin B12
Yogurt, 170 g, (6oz), 26% vitamin B12
Beef, cooked, 100 g( almost 4 oz), 53% vitamin B12
Lamb, cooked, 100 g (almost 4 oz), 90% vitamin B12
Pork loin, cooked, 100 g (almost 4 oz), 12% vitamin B12
Ham, boneless, cooked, 100 g, 10% vitamin B12,
Pork, ground, cooked, 100 g, 18% vitamin B12, 33% cholesterol!
Pull pork, 100 g, 6% vitamin B12.
Chicken breast, skinless, cooked, 100 g (almost 4 oz), 6% vitamin B12
Chicken drumstick, skinless, cooked, 100 g, 5% vitamin B12
Chicken wings, cooked, 1 wing, 1% vitamin B12,
Chicken liver, cooked, 100 g (almost 4 oz), 350% vitamin B12, 71% iron, and 188% cholesterol!
Chicken giblets, cooked, 100 g, 190% vitamin B12, 32% iron, 87% cholesterol!
Shrimp, cooked, 100 g (almost 4 oz), 70% vitamin B12
Yellow fin tuna, cooked, 100g, (almost 4 oz), 100% vitamin B12
Salmon, cooked, 100 g (almost 4 oz), 210% vitamin B12
Cod, cooked, 100 g (almost 4 oz), 90% vitamin B12
Sardines, canned, 100 g (almost 4 oz), 350% vitamin B12