Vitamin B12 is a water-soluble B vitamin that is essential for the healthy functioning of the brain and the nervous system. It also plays a major role in forming red blood cells, creating the genetic material RNA and DNA, and breaking down the amino acid homocysteine. B12 is critical to the body’s ability to turn the carbohydrates it gets from food into energy, and also promotes healthy hair, skin, and eyes.
Vitamin B12 is found in animal products and fortified foods. Those who eat a vegan or vegetarian diet must watch their vitamin B12 levels in order to avoid becoming deficient. Additional populations who might require additional supplementation include pregnant or lactating people, older people, people who drink alcohol, those who have had digestive issues, and people on certain medications like Proton pump inhibitors.
Your vitamin B12 levels can easily be determined with a blood test from your physician. Normal values are 160-190 picograms per milliliter (pg/mL) or 118-701 picomoles per milliliter, though these values may vary slightly among laboratories. The recommended dietary allowance (RDA) of vitamin B12 for healthy adults is 2.4 mcg/day. There is no tolerable upper intake level (UL), and there are a number of reasons someone might take more than the RDA. The amount needed is largely determined by how much of the nutrient is absorbed by a person. Factors affecting absorption include overall health, age, amount of stomach acid one has, medications, prior intestinal surgeries, oxidative stress, and alcohol consumption.
Vitamin B12 deficiencies are rare in most healthy people who have a balanced, varied diet. But since the source of B12 is animal products, vegans, vegetarians, and those who have certain medical conditions may also be deficient. Some of the signs of vitamin B12 deficiency symptoms may include constant fatigue, shortness of breath, not feeling as hungry as you typically are, poor balance, being forgetful, and tingling of hands and feet. Long-term deficiency can impact the normal function of the nervous system and lead to more serious, and sometimes irreversible, symptoms including disorientation.
Organ meat is cheap and loaded with nutrients. Beef liver is one of the highest food sources of vitamin B12. A 3 oz. serving of beef liver contains 70.7 mcg, which is nearly 3,000% of the recommended daily value (DV) of vitamin B12. Lamb and veal liver are similarly high in B12, but it is beef liver that is the most nutrient dense.
Beef is an excellent source of vitamin B12. A 3 oz serving of ground beef contains 2.4mcg, or 100% of the DV of B12. An average flank steak provides 467% of the DV for B12. For higher concentrations of vitamin B12, choose low fat cuts of meat and grill rather than fry the meat in order to retain its B12 content.
Lamb liver is especially high in Vitamin B12, but if liver is not appealing to your taste buds, lamb meat is another great choice. A 3 oz serving of lamb contains 2.2 mcg of vitamin B12, slightly under the DV. It also boasts nearly 10% of the DV of iron.
For those who can tolerate dairy products, this can be a wonderful source of vitamin B12. The amount of B12 present is usually listed on the nutrition label. One cup of whole milk 1 will provide 1.3 mcg of vitamin B12. A general rule of thumb for cheese is that 1.5 oz will provide 0.5 mcg of B12.
Eating two large eggs will give you approximately 0.9 mcg (or 38% DV) of vitamin B12. A substantial amount of the B12 comes from the yolk, so make sure to eat the whole egg. Two eggs will also provide you 12g or protein and vitamins A, D, E, K, and other Bs. Not all eggs are created equal, however. According to this abstract, the B12 status of an egg can depend on the B12 status of the hen laying the egg.
A 3 oz serving of canned white tuna contains 2.5mcg of vitamin B12. Not bad at just over 100% of the DV. But if you go upscale, Bluefin tuna, the pricey tuna eaten raw in sushi and sashimi, provides 9.1 mcg, a whopping 385% of the DV of B12. Sushi or sandwich? Either way you can’t go wrong with tuna. When eating fish it is important to stick to wild caught as much as possible and be cautious with the heavy metal content in large fish like tuna. And if you are pregnant be sure to follow food safety guidelines from your doctor.
Salmon is a healthy, fatty fish that contains very high amounts of vitamin B12. At 2.6mcg in a 3 oz serving, salmon provides you with more than 100% of the DV of B12. The popular pink fish is also a good source of omega-3 fatty acids and is high in vitamin D and selenium.
Rainbow trout is an especially good source of vitamin B12. The freshwater fish boasts 7.5 mcg of B12, which is 312% of the DV.
Shellfish can also be a source of vitamin B12. A 4 oz serving of clams provides almost 15 mcg of vitamin B12, which is more than 600% of the DV. Clams are also high in protein and a good source of iron. Who knew a bowl of New England clam chowder could be so good for you?
Sardines are nutrient packed and provide 7.6 mcg of vitamin B12 in a 3 oz portion.
Some of the best food sources of vitamin B12 for vegans and vegetarians include nutritional yeast, marmite and yeast spreads, fortified milks such as soy, almond, hemp, and oak, and plant-based meats with up to 100% of the DV per serving. Tempeh, chlorella, nori seaweed, and cremini mushrooms are also excellent sources of B12.
Fortified cereals are also a rich source of vitamin B12 and most brands are available at any grocery store. The best way to determine how much B12 you are getting per serving is by reading the nutrition label on the package.
Nutritional yeast is a deactivated form of yeast commonly used in baking and as a vegan alternative to cheese and cheese flavoring. Fortified with B12 and other Bs, the flakey yellow protein source is packed with B12 at 17.6 mcg or 730% of the DV for a ¼ cup serving.
Each brand and type of plant-based milk has a different nutrient profile, though they are all fortified with vitamin B12. Almond milk contains 3 mcg per cup, while oat milk offers 25-100% DV depending on the brand. According to this source, approximately 1 in 5 plant based yogurt brands have adequate vitamin B12 and vitamin D fortification. Some may contain very little B12 or even none at all.
There is no UL for vitamin B12 because it is a water-soluble vitamin. If your body does not absorb excess B12, it will be excreted through your urine. If you are thinking about megadosing, it is best to consult your physician for the best dosage and protocol for you. It is possible, though not common, that you may experience some side effects if taking high doses of B12. Gas, bloating, headaches, fatigue, diarrhea, tingling hands and feet, and skin rashes are among the most frequent side effects. These symptoms are easily remedied, but do not let them go unaddressed.
Taking a vitamin B12 supplement, or any supplement for that matter, is a decision that is best made in conjunction with your physician or a registered dietician. Ideally, it is best to get your B12 from a healthy diet that contains a variety of animal products including fatty fish, shellfish, meat, dairy, eggs, nutritional yeast, and fortified foods. If you are unable to meet all of your body’s B12 needs, supplementation is an excellent, reliable way of doing so. Care/of has a premium brand of B12 The Energizer that provides several forms (methylcobalamin, adenosylcobalamin, and hydroxocobalamin) of B12 to help with absorption of B12 in a vegan formula.
Vitamin B12 is critical for your body’s overall health and wellness. Ideally, you could get enough of it from your diet, but there are some who will need supplements to fill the nutrient gap caused by digestive issues, plant-based diets, pregnancy, lactation, use of medication, or aging. B12 is a water-soluble vitamin so any that your body doesn’t use will be excreted through your urine. Absorption is a critical element in ensuring your vitamin B12 levels are within normal range. The best way to monitor your B12 levels is with a blood test that can be taken by your physician. While deficiencies are rare, they are important to remedy.