Vitamin B12 is one of many vital nutrients and minerals the body needs in adequate supply to perform its best each day. Also called cobalamin, vitamin B12 is a water-soluble vitamin that helps support a number of processes and functions in the body including:
— Metabolic processes and energy generation.
— Brain and nervous system function.
— Creation and maintenance of red blood cells.
— Creation and maintenance of DNA.
You need a certain amount of vitamin B12 each day to maintain all these vital functions. The National Institutes of Health’s Office of Dietary Supplements reports that depending on your age, you’ll need the following amounts of vitamin B12:
— Birth to 6 months: 0.4 micrograms.
— Infants aged 7 to 12 months: 0.5 micrograms.
— Children aged 1 t 3 years: 0.9 micrograms.
— Children aged 4 to 8 years: 1.2 micrograms.
— Children aged 9 to 13 years: 1.8 micrograms.
— Teen aged 14 to 18 years: 2.4 micrograms.
— Adults: 2.4 micrograms.
— Pregnant teens and women: 2.6 micrograms.
— Breastfeeding teens and women: 2.8 micrograms.
“This is the minimum amount someone needs of any given nutrient to stay healthy,” says Joy Stephenson-Laws, founder of the non-profit health information company Proactive Health Labs and author of “Minerals – The Forgotten Nutrient: Your Secret Weapon for Getting and Staying Healthy.” But your specific needs might be different. “How much any person really needs is determined by age, gender, physical condition, comorbidities and how well his or her body absorbs B12.”
To absorb vitamin B12 from the foods you eat, your body must have an adequate supply of a protein made in the stomach called intrinsic factor. However, people who have pernicious anemia, a condition that’s typically associated with an autoimmune disorder, don’t make this protein. They have difficulty absorbing vitamin B12, whether it’s coming from food or a dietary supplement. This condition requires medical attention and no amount of eating more vitamin B12 can make up for the missing intrinsic factor.
“Usually, after we ingest water-soluble vitamins, leftover amounts leave the body through urine. But B12 is different in that it can be stored for years in the liver. It’s perhaps the only water-soluble vitamin that can be stored in the body,” Stephenson-Laws says.
Vitamin B12 Deficiency
Because vitamin B12 can be stored in the liver, it can take a while for a nutritional deficiency to become apparent. But vitamin B12 deficiencies can and do occur. Vitamin B12 deficiencies can lead to a range of issues including:
— Fatigue and weakness.
— Problems with balance.
— Mood changes, including irritability and depression.
— Cognitive problems such as poor memory, confusion, disorientation, paranoia or dementia.
— Damage to the brain and central nervous system.
Vitamin B12 deficiencies tend to be more common in older adults and those following a strict vegetarian or vegan diet that eliminates a lot of the animal-based foods that can provide this nutrient in large quantities.
However, “it can occur occasionally in infants too, potentially leading to failure to thrive, weakness and lack of muscle tone,” Stephenson-Laws says. You can find out whether you’re deficient in vitamin B12 via a simple blood test ordered by your doctor.
[Read: Foods High in Magnesium.]
Foods High in Vitamin B12
Vitamin B12 comes from bacteria that’s found naturally in animal products, but many processed foods, such as breakfast cereals, are also fortified with it. The following foods are rich sources of vitamin B12:
— Shellfish. Clams in particular are very high in vitamin B12. A 3-ounce serving of cooked clams contains a whopping 84.1 micrograms of the stuff.
— Liver. Organ meats and liver in particular are great sources of vitamin B12 because other animals, like humans, accumulate extra vitamin B12 in those tissues. A 3-ounce serving of beef liver contains 70.7 micrograms.
— Red meat. A 3-ounce portion of top sirloin beef contains 1.4 micrograms, and a double patty cheeseburger contains 2.1 micrograms.
— Fish. A 3-ounce portion of wild rainbow trout contains 5.4 micrograms of vitamin B12 and 3 ounces of sockeye salmon contains 4.8 micrograms. Even canned tuna fish can cover all or nearly all of your vitamin B12 needs for the day, clocking in at 2.5 micrograms per 3 ounces.
— Dairy products. One cup of low-fat milk contains 1.2 micrograms of vitamin B12, which gets you about half way to your daily goal.
— Eggs. A single large egg contains 0.6 micrograms of vitamin B12.
— Fortified foods. Breakfast cereals, tofu, rice milk and soymilk can all be good sources of vitamin B12. Check the product label for the specific amounts each contains.
— Fortified nutritional yeast. Nutritional yeast is a strain of yeast called Saccharomyces cerevisiae. It’s a powdery substance that’s sometimes added to vegetarian or vegan dishes to provide a cheesy, nutty, umami flavor that makes up for missing meat. Many brands are fortified to provide 100% of your RDA, while some offer way more.
— Yeast extract. Yeast extract is that brown sticky stuff that Brits and Australians love to smear on toast. It might not be the most appealing thing to Americans, but products like Bovril and Marmite contain high levels of vitamin B12. Just be cautious with how much you use, as these products can contain high levels of sodium. Per 100 grams of Marmite you’ll get 25 micrograms of vitamin B12. (The Australian version of yeast extract, called Vegemite, does not contain B12.)
[SEE: Foods High in Calcium.]
Should I Use a Supplement?
Meeting your nutritional needs through whole foods is generally considered best for all the various vitamins and nutrients our bodies need.
Stacey Pence, a registered dietitian with the Ohio State University Wexner Medical Center, says that “according to the National Health and Nutrition Examination Survey, most children and adults consume recommended amounts of B12 in their diet.”
Because of this, she says she wouldn’t recommend a B12-specific supplement “unless you’ve had a prior gastrointestinal surgery that’s reduced your ability to absorb B12 or if you have pernicious anemia,” the condition in which your body doesn’t make the intrinsic factor necessary to absorb B12. People with gastritis, ulcerative colitis or Crohn’s disease might also benefit from vitamin B12 supplementation, but talk to your doctor first.
Pence also notes that for most of us, it’s probably overkill and we may end up just flushing our money down the toilet when taking a B12 supplement. “Many B12 supplements provide greater than 100% of RDA of vitamin B12, therefore our bodies are excreting most of the unused B12 in these supplements.”
While there are no known adverse effects of excess supplementation with B12, if you don’t actually need it, it’s probably best to just skip it. “I wouldn’t recommend using excessive amounts unless there’s a medical reason or deficiency as most people don’t need it,” Pence says.
All that said, “if your diet is lacking in B12-rich food sources, then a B12 supplement may be beneficial,” she adds. Dietitians who work with people following a vegetarian or vegan diet do sometimes recommend vitamin B12 supplementation for these clients.
Stephenson-Laws adds that people who’ve been on an antibiotic for a long time and those who take other medications that can cause vitamin B12 deficiency, such as certain blood thinners, heartburn medications and anti-seizure medications, may want to consider supplementation. Talk to your doctor if you are in any of those categories.
Also, if you drink a lot of alcohol or are a smoker, those activities can also impact your vitamin B12 levels, so talk to your doctor about whether you should supplement.
Bottom line, if you’re concerned about your vitamin B12 status and are considering a supplement, be sure to talk with a health care provider. “I would recommend discussing any supplementation with your physician and registered dietitian,” Stephenson-Laws says. “People should not just decide to take supplements and then dose themselves on their own. It’s very important to take vitamin B12 or other supplements with the advice of a competent healthcare professional.”
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