A vitamin B12 deficiency is thought to be one of the leading nutrient deficiencies in the world, with a 2004 study showing that it’s a major health concern in many parts of the world, including the U.S, India, Mexico, Central America, South America and certain areas in Africa. (1)
Vitamin B12 benefits your mood, energy level, memory, heart, skin, hair, digestion and more. Vitamin B12 is also an essential vitamin for addressing adrenal fatigue, multiple metabolic functions — including enzyme production, DNA synthesis and hormonal balance — and maintaining healthy nervous and cardiovascular systems.
Because of its wide-reaching roles within the body, a vitamin B12 deficiency can show up in many different negative symptoms, many of which are very noticeable, such as potential chronic fatigue, mood disorders like depression, and chronic stress or feeling run down.
Vitamin B12 Benefits, Deficiency Symptoms and Food Sources
Vitamin B12 benefits the central nervous system in many important ways: It helps maintain the health of nerve cells — including those needed for neurotransmitter signaling — and helps form the protective covering of nerves, called the cell’s myelin sheath. This means that when vitamin B12 levels are low, almost every cognitive function can suffer.
Vitamin B12 — sometimes also called cyanocobalamin, hydroxocobalamin, cobalamin or methylcobalamin — also helps with digestion and heart health, so a deficiency can lead to both digestive disorders and an increased risk for heart disease. It can come in food sources, hydroxocobalimin vitamin B12 injections or as an intramuscular vitamin.
The National Institute of Health’s (NIH) Dietary Office estimates that somewhere between 1.5–15 percent of people in the U.S. are deficient in vitamin B12. (2) Other studies, like one done by the American Journal of Clinical Nutrition in 2000, indicate that this number might be even higher, with up to 39 percent of the population possibly suffering from a vitamin B12 deficiency. (3)
Animal foods are the best food sources of vitamin B12, including organic grass-fed dairy products, cage-free eggs, grass-fed meat, wild-caught fish, organic poultry and organ meats. According to the NIH, plant foods do not naturally contain vitamin B12 unless they are synthetically fortified.
Vitamin B12 can be found to some degree in fortified plant foods like nutritional yeast, fortified grain products and algae sea vegetables. However, most of these are not thought to be nearly as absorbable as natural animal sources are.
Vitamin B12 Deficiency
Vitamin B12 deficiency can be hard to detect, especially considering how common the symptoms of a vitamin B12 deficiency can be, such as feeling tired or unfocused. A diagnosis of vitamin B12 deficiency is typically based on the measurement of serum vitamin B12 levels within the blood. However, alarmingly, studies show that about 50 percent of patients with diseases related to vitamin B12 deficiency have normal B12 levels when tested. (4)
There are more precise screening options available to detect a deficiency, but these are usually not given to patients unless they have a known case of anemia or heart disease-related symptoms. (5) So if you suspect you might have a deficiency but your initial blood test shows that your levels are normal, you may want to talk with your doctor about performing secondary tests, especially those that check for high homocysteine levels.
Symptoms of a vitamin B12 deficiency can include: (6)
- Constantly feeling tired or chronic fatigue
- Muscle aches and weakness
- Joint pain
- Difficulty breathing or shortness of breath
- Feeling dizzy
- Poor memory
- Inability to concentrate well
- Mood changes, like increased depression and anxiety
- Having abnormal heart problems, such as palpitations
- Poor dental health, including bleeding gums and mouth sores
- Digestive problems like nausea, diarrhea or cramping
- A poor appetite
- A more serious deficiency can also cause a form of anemia called pernicious anemia, a serious condition that can cause memory loss, confusion and even long-term dementia
Who is most at risk for having a vitamin B12 deficiency? Elderly people who tend to have impaired digestion are one of the most susceptible populations. This is because older people tend to produce less stomach acid that is needed to convert vitamin B12 properly.
Since animal foods are usually the best sources of vitamin B12, those who follow a vegan diet and don’t eat any animal products are also most likely to have a deficiency. Therefore, both older adults and plant-based eaters are advised to take a daily vitamin B12 supplement. (7)
Other groups that are at a higher risk of having a vitamin B12 deficiency include smokers (since nicotine can block absorption), alcoholics, those with anemia, and anyone with a digestive disorder like celiac or Crohn’s disease.
I would recommend taking vitamin B12 as part of a whole foods-based B-Complex supplement, or a high-quality whole foods-based multivitamin. These will contain the full spectrum of B vitamins that all work together within the body to carry out functions and balance one another, hence the “complex” name this group is given. Within a vitamin B complex supplement, you’ll find other important B vitamins — like biotin, thiamine, niacin and riboflavin — that require one another to be present for the best results.
Recommended Daily Amount of Vitamin B12
According to the NIH, the Recommended Dietary Allowance (RDA) for vitamin B12 is: (8)
- Infants 0–6 months: 0.4 micrograms
- Infants 7–12 months: 0.5 micrograms
- Toddlers 1–3 years: 0.9 micrograms
- Children 4–8 years: 1.2 micrograms
- Children 9–13 years: 1.8 micrograms
- Adult men and women over age 14: 2.4 micrograms
- Women who are pregnant: 2.6 micrograms
- Women who are breastfeeding: 2.8micrograms
Compared to other vitamins, we don’t need a very large amount of vitamin B12 — but we do need to replenish our supply just about every single day. B vitamins are water-soluble and flushed out of the body somewhat easily, so to maintain levels of the recommended amount within our bloodstream and prevent a vitamin B12 deficiency, we need to eat food sources of B vitamins often.
The NIH recommends that adults over 50 years take a daily vitamin B12 supplement, or that they consume foods fortified with vitamin B12. The recommendation is to take between 25–100 micrograms per day, as this amount has been shown to maintain healthy levels of vitamin B12 levels in older people.
Vitamin B12 can be taken in tablet form, in drops that you place under on the tongue or in oral spray form. Sometimes seniors do better with drops and oral spray forms of vitamin B12 because they have trouble absorbing the vitamin from the stomach.
Because vitamin B12 is a water-soluble vitamin, the body has the ability to flush out (through our urine) any excess that it doesn’t need. As a result, vitamin B12 is considered safe and non-toxic, although it’s still always best to stick to the recommended amount and not take large doses of any supplement without consulting with a doctor first.
Top 9 Vitamin B12 Benefits
Wonder how vitamin B12 functions as a health-promoting vitamin? Vitamin B12 functions as a beneficial substance in the following ways:
1. Helps Maintain Energy Levels
Vitamin B12 benefits your metabolism because it’s needed to convert carbohydrates into useable glucose in the body. Glucose from carbohydrate foods is used as a form of energy, so this is the reason why people with vitamin B12 deficiencies often experience fatigue. Vitamin B12 is also needed for neurotransmitter signaling that helps your muscles contract and gives you energy to go about your day without feeling tired and run down.
2. Prevents Memory Loss and Lowers Risk of Neurodegenerative Disease
A vitamin B12 deficiency may cause various neurologic and psychiatric disturbances. Because of its role in nerve health and neurotransmitter signaling, vitamin B12 benefits cognitive function and is used to lower the risk of neurodegenerative diseases, including Alzheimer’s disease and dementia. (9) (10)
3. Boosts Mood and Helps the Nervous System to Properly Function
One of the most researched vitamin B12 benefits is its ability to help in healthy regulation of the nervous system, including reducing such mood disorders as depression and anxiety. Vitamin B12, along with folate, is needed as a major determinant of one-carbon metabolism, which produces the compound called SAM (S-adenosyl methionine). SAM is crucial for neurological function, dealing with stress and mood regulation. (11) (12)
Vitamin B12 is needed for concentration and cognitive processes, such as learning, so a vitamin B12 deficiency can result in difficulty focusing and an increased risk for attention disorders.
4. Plays a Role in Maintaining Heart Health
Vitamin B12 benefits cardiovascular health in several ways, which is important considering the fact that heart disease is currently the number one cause of death worldwide. Vitamin B12 helps to reduce elevated homocysteine levels, which is now considered a major risk factor for heart disease. (13) Homocysteine is an amino acid and its levels in the blood are influenced by blood levels of B-complex vitamins, including vitamin B12.
Vitamin B12 helps to protect against heart disease like a heart attack or stroke by lowering high homocysteine levels in the blood. There is also some evidence that B12 can help control high cholesterol and high blood pressure levels. B vitamins are also able to control atherosclerotic diseases, in which someone experiences a dangerous build-up of plaque in the arteries. (14)
5. Needed for Healthy Skin and Hair
Vitamin B12 is essential for healthy skin, hair and nails because it plays a major part in cell reproduction. Vitamin B12 benefits skin health by reducing redness, dryness, inflammation and acne blemishes — and can be applied to the skin for psoriasis and eczema. It can also reduce hair breakage and help nails to become stronger.
6. Aids in Digestion
Due to its role in helping with digestive enzyme production, vitamin B12 is needed to support a healthy metabolism and the breakdown of foods within the stomach. One of the ways that vitamin B12 benefits digestion? It helps foster healthy bacteria within the gut environment. The elimination of harmful bacteria in the digestive tract — and simultaneously the presence of beneficial bacteria — is what prevents digestive disorders like inflammatory bowel disease (IBS) or Candida.
7. Needed for a Healthy Pregnancy
Vitamin B12 is needed to create nucleic acid, or DNA — the basic genetic material that’s used to create the entire body. Therefore, vitamin B12 is not only a key nutrient for growth and development, but a vital component of a healthy pregnancy. Vitamin B12 also interacts with folate in the body, so it may help lower the risk of birth defects, such as neural tube defects.
8. May Help Prevent Cancer
Vitamin B12 supplementation is now being studied as a way to help lower the risk of certain kinds of cancers, especially when taken with folate. (15) Some preliminary research shows that vitamin B12 benefits the immune system enough to potentially help prevent cancer, including cervical, prostate and colon cancers.
9. Helps Produce Red Blood Cells and Prevent Anemia
Vitamin B12 is needed to help produce a healthy level of red blood cells. It helps prevent a type of anemia called megaloblastic anemia, which results in symptoms like chronic fatigue and weakness. (16)
Best Sources of Vitamin B12
According to the National Institute of Health, two steps are required for the body to absorb vitamin B12 from foods and experience the vitamin B12 benfits mentioned above.
First, hydrochloric acid in the stomach separates vitamin B12 from the protein to which vitamin B12 is attached in food. After this, vitamin B12 combines with a protein made by the stomach called intrinsic factor and is absorbed by the body. (17)
So, essentially, the health of your digestive system is just as important in absorbing and using adequate levels of vitamin B12 as the foods you’re eating are!
According to a 2007 done by the Experiential Biology and Medicine group, vitamin B12 is a difficult nutrient to absorb, with healthy adults only being able to actually absorb and use about 50 percent of the vitamin B12 present within food sources, and sometimes much less. (18) The vitamin B12 present in foods like chicken, meat and fish were found to be the most absorbable, while eggs were shown to be somewhat poorly absorbed, with only about 9 percent of its vitamin B12 being used by the body.
Another unfortunate finding was that algae foods, such as blue-green algae that is a popular “superfood” among vegans and vegetarians, was not a very absorbable source of vitamin B12 at all. This is another reason why many vegans are told to take vitamin B12 supplements daily, even if they believe they are acquiring enough from certain plant foods, in order to prevent a vitamin B12 deficiency. (19)
Although the exact rate of absorbability depends on the person’s digestive health, here are the top food sources that provide vitamin B12 (with percentages based on 2.4 milligrams daily for adults):
- Beef and chicken liver (20) — 3 ounces: 81 milligrams (3,375% RDA)
- Salmon (21) — 1 filet (108 grams): 19.5 milligrams (812%)
- Herring (22) —1 filet (143 grams): 18.7 milligrams (779%)
- Mackerel (23) — 3 ounces: 15.3 milligrams (637%)
- Sardines (24) — 1 cup: 13.3 milligrams (554%)
- Tuna (25) — 3 ounces: 9.3 milligrams (385%)
- Trout (26) — 1 filet: 9.1 milligrams (379%)
- Organic yogurt (27) — 1 container of plain Greek yogurt (170 grams): 1.3 mg (53%)
- Turkey (28) — 3 ounces: 1.1 milligrams (43%)
- Raw milk (29) — 1 cup: 1 milligrams (41%)
- Beef tenderloin (30) — 3 ounces: 0.9 milligrams (38%)
- Lamb (31) — 3 ounces: 0.8 milligrams (34%)
How to Add More Vitamin B12 to Your Diet with Food
It’s always best to try and get vitamin B12, and all other nutrients as well, from natural food sources whenever possible. Foods provide a complex network of vitamins, minerals, dietary fiber and other substances that benefit health in ways that supplements usually cannot. Dietary supplements might help in some serious situations to alleviate a deficiency, but it’s not a good idea to rely on them solely for your nutrient needs.
You can prevent a vitamin B12 deficiency and get the most vitamin B12 benefits by adding more vitamin B12-rich foods to your diet. Try increasing your intake naturally by including some of these recipes:
Concerns and Interactions of Vitamin B12
Vitamin B12 absorption can be hindered when someone has a history of alcoholism or heavy smoking. In addition to alcohol and nicotine, long-term antibiotic use can also reduce the ability of the stomach to absorb and use vitamin B12. For this reason, anyone who has used stomach-acid controlling drugs may want to talk to their doctor about needing vitamin B12 supplements.
Potassium supplements can also reduce absorption of vitamin B12 benefits, so if you take large amounts of potassium in supplement form, you should watch out for a possible vitamin B12 deficiency. Potassium from food sources shouldn’t cause a problem, but very high amounts may set someone up for a vitamin B12 deficiency.
The recommended dosage for vitamin B12 varies, but according to the Mayo Clinic, it is as follows: (32)
- 0–6 months: 0.4 micrograms
- 7–12 months: 0.5 micrograms
- 1–3 years old: 0.9 micrograms
- 4–8 years old: 1.2 micrograms
- 9–13 years old: 1.8 micrograms
- 14+ years old: 2.4 micrograms
- pregnant females: 2.6 micrograms
- breastfeeding females: 2.8 micrograms
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