September 18, 2021 Glynis Kennedy
VITAMIN B12 DEFICIENCY
Why vitamin B12 is important
The human body needs vitamin B12 to make red blood cells, nerves, DNA, and carry out other functions. The average adult should get 2.4 micrograms a day. Like most vitamins, B12can’t be made by the body. Instead, it must be gotten from food or supplements.
And therein lies the problem: Some people don’t consume enough vitamin B12 to meet their needs, while others can’t absorb enough, no matter how much they take in. As a result, vitamin B12 deficiency is relatively common, especially among older people.
Deficiency can result when levels of vitamin B-12 are too low. This can lead to irreversible neurological symptoms. In the United States (U.S.), between 1.5 and 15 percent of the population are currently diagnosed with vitamin B-12 deficiency.
Facts about vitamin B-12
- Vitamin B-12 is important for brain function and the synthesis of red blood cells.
- Deficiency of vitamin B-12 can lead to neurological difficulties and anemia.
- People over the age of 14 should consume more than 2.4 micrograms (mcg) of vitamin B-12 daily.
- Vitamin B-12 is naturally available in meats, but people who do not eat meat, such as vegans, can obtain vitamin B-12 in supplement form.
What is vitamin B-12?
Vitamin B-12 is a water-soluble vitamin, like all other B-vitamins. This means it can dissolve in water and travel through the bloodstream. The human body can store vitamin B-12 for up to four years. Any excess or unwanted vitamin B-12 is excreted in the urine.Vitamin B-12 is the largest and most structurally complicated vitamin. It occurs naturally in meat products and can only be industrially produced through bacterial fermentation synthesis.
Vitamin B-12 is crucial to the normal function of the brain and the nervous system. It is also involved in the formation of red blood cells and helps to create and regulate DNA. The metabolism of every cell in the body depends on vitamin B-12, as it plays a part in the synthesis of fatty acids and energy production. Vitamin B-12 enables the release of energy by helping the human body absorb folic acid. The human body produces millions of red blood cells every minute. These cells cannot multiply properly without vitamin B-12. The production of red blood cells reduces if vitamin B-12 levels are too low. Anemia can occur if the red blood cell count drops.
What is vitamin B12 deficiency?
Vitamin B12 deficiency occurs when there are inadequate levels of the vitamin B12 in the body. This important vitamin is necessary for the production of red blood cells and the healthy functioning of the nervous system. A lack of vitamin B12 can cause anemia and other health problems.
Anemia is a condition where the body either cannot make enough healthy red blood cells or cannot produce enough of the substance hemoglobin that allows red blood cells to transport oxygen around the body. There are several different types of anemia, each with their own causes and symptoms. For example, vitamin B12 deficiency can cause megaloblastic anemia, a condition where the red blood cells are larger than normal and cannot function properly.
For many people, a balanced and varied diet provides all the vitamin B12 they need. Good sources of vitamin B12 include meat, fish, eggs and dairy products. Despite the availability of vitamin B12 in a balanced diet, deficiency is not all that uncommon, particularly among people over 50 years of age, premenopausal women and people who follow strict vegan diets.
Low levels of vitamin B12 may be the result of a number of different factors and conditions. One of the most common causes of vitamin B12 deficiency is pernicious anemia, a condition where a person’s immune system mistakenly reduces their ability to absorb the vitamin. Less common causes of deficiency include conditions affecting the stomach or intestines that interfere with absorption of vitamin B12, inadequate dietary intake, and certain medications.
Symptoms of vitamin B12 deficiency usually develop gradually and can be wide-ranging. These may include general symptoms of anemia, such as fatigue and lethargy, as well as the symptoms specific to the deficiency, such as yellow tinge to the skin and a sore tongue. If left untreated, the symptoms of vitamin B12 deficiency tend to worsen and irreversible problems involving the nerves and brain may develop. The risk of experiencing a number of serious complications, including heart failure, may also increase. For this reason, it is important to seek medical advice without delay should any of these symptoms be present.
According to the National Health Service (NHS) in the United Kingdom, a person with vitamin B12 deficiency may develop anemia and other symptoms.
Low levels of B12 can lead to:
- fatigue and weakness
- loss of appetite and weight loss
- problems with balance
- problems with thinking
- a sore mouth or tongue
In infants, signs of a deficiency include:
- not growing or developing at the expected rate
- problems with movement
- megaloblastic anemia
Anemia and neurological problems can lead to further symptoms and complications.
Common symptoms of anemia are:
- shortness of breath
- feeling faint
- pale or yellowish skin
- heart palpitations
- tinnitus (ringing in the ears)
- reduced appetite and weight loss
A vitamin B12 deficiency can also lead to neurological symptoms, such as:
- numbness and tingling in the hands and feet
- problems with thinking and memory
- problems with balance
- changes in gait and other movements
Long-term B12 deficiency may increase the risk of various health problems. One reason for this may be that the body needs vitamin B12 to process homocysteine. Experts have found links between high levels of homocysteine and some health conditions, such as dementia and cardiovascular disease.
Dementia and Thinking
Low levels of vitamin B12 may affect brain health in the long term and increase the risk of cognitive decline. Depending on the person’s age, it may lead to
- reduced school performance in children
- memory loss
Some research has found higher levels of homocysteine in people with Alzheimer’s and dementia. In 2012, researchers published the results of a study involving 121 people aged 65 years and over. First, they tested the participants’ blood to identify levels of vitamin B12 and other markers of B12 deficiency. They also assessed their memories and other thinking skills. After 52 months, they carried out MRI scans of the participants’ brains. They checked for brain size and any signs of brain damage.
Results showed that those with the strongest signs of vitamin B12 deficiency in the initial tests were much more likely to have lower cognitive test scores and smaller total brain volumes after 52 months.
Studies have shown that 20–30% of people with B12 deficiency have neurological damage, such as:
- nerve damage
- damage to the spinal cord
- neurological problems that affect mental health
Experts have also found high levels of homocysteine in people with coronary heart disease and stroke. However, there is not enough evidence to recommend B12 supplementation to prevent heart disease.
Some people use B12 supplements to boost energy levels and athletic performance. However, supplements only appear to help if a person already has a deficiency.
What causes B12 deficiency?
A B12 deficiency can occur if a person does not consume enough of the vitamin in their diet or if their body cannot absorb it effectively during digestion. When a person consumes food that contains vitamin B12, the body takes two steps to absorb it. First, hydrochloric acid in the stomach separates it from the protein it binds to in food. Then, vitamin B12 combines with another protein that the stomach produces, called intrinsic factor. Then, the intestines can absorb it. Here are some possible causes of vitamin B12 deficiency.
1) Pernicious anemia
Pernicious anemia is an autoimmune disease that affects the gut’s ability to digest vitamin B12. When a person has pernicious anemia, their immune system creates antibodies that attack the stomach’s lining. There, they damage cells that produce intrinsic factors. If the stomach cannot produce intrinsic factors, the intestines will be unable to absorb vitamin B12.
2) Bowel problems
Some people may have problems absorbing vitamin B12 into their bloodstream because of a condition that affects their stomach or small intestine. Possible causes include:
- Crohn’s disease
- celiac disease
- surgery that reduces the size of the stomach or the length of the intestine
These people can experience malnutrition because they cannot absorb enough vitamins, water, and other nutrients.
People who follow a vegan or vegetarian diet may have a higher risk of B12 deficiency. During pregnancy, this may increase the risk of neurological damage in a fetus. While some plant foods contain vitamin B12, it is often in a form that the body cannot absorb efficiently, according to research published in 2013. People who follow a plant-based diet can supplement their B12 intake by eating fortified foods, such as nutritional yeast products.
Some medications can affect the body’s ability to digest vitamin B12, leading to a deficiency. Examples include proton pump inhibitors (PPIs) and Histamine H2 receptor agonists (H2 blockers), which doctors prescribe to treat indigestion, heartburn, and gastroesophageal reflux disease (GERD). PPIs prevent the stomach from producing acid, but the body needs acid to absorb vitamin B12.
5) Functional vitamin B12 deficiency
Some people appear to have enough vitamin B12 in their blood, but they do not have the proteins they need to transport it between cells. This means the body cannot use it effectively. They can develop neurological symptoms related to B12 deficiency.
Treatment will depend largely on the cause of a deficiency. Options include increasing vitamin B12 intake through:
- intramuscular injections
- oral medicine
- adding foods that are rich in B12 to the diet
Some people may need regular injections for the rest of their life.
Preventing B12 deficiency
Most people can prevent B12 deficiency through dietary choices, but this is not always the case.
People following a plant-based diet
People whose diet is largely or wholly plant-based should ensure their B12 intake is adequate.
Dietary options include:
- fortified breakfast cereals
- fortified nutritional yeast
- fortified soy milk
People who eat meat or fish
For those who eat meat or fish, a balanced diet containing fish, meat, and dairy foods should have enough B12 for human requirements.
Other conditions and medical treatments
Anyone who has a chronic gastrointestinal condition or believes they may have symptoms of B12 deficiency should seek medical advice. The doctor will seek to identify the cause and treat it accordingly.
Good sources of vitamin B12 include the following:
- beef liver
- fish, such as trout, salmon, and tuna
- nutritional yeast
- dairy products
- fortified yeasts and other foods
List of B-12 foods for vegetarians
For vegetarians looking to increase their vitamin B12 intake, there are a variety of options. Some good choices for B-12 include:
- low-fat milk
- fortified plant-based milk
- eggs (ovo-vegetarian option)
- fortified cereals
- nutritional yeast
While seaweed, algae, and certain mushrooms all contain vitamin B-12, they are not reliable sources because they do not act the same way in the human body. Studies have found that consuming these foods does not significantly increase a person’s vitamin B-12 levels and can still lead to a deficiency. A vegetarian should be sure to consume enough of the following foods on a regular basis. It is vital to understand how much vitamin B-12 these foods contain:
- 8 ounces (oz) of yogurt contains about 1.1 mcg of vitamin B-12
- 1 cup of low-fat milk can provide 1.2 mcg of vitamin B-12
- 1 oz of Swiss cheese can contain 0.95 mcg of vitamin B-12
- 1 large egg contains 0.6 mcg of vitamin B-12
Fortified cereals are a good choice as they have high bioavailability. This means that the vitamin B-12 does not have to break down before the body absorbs it. Nutritional yeast is popular with both vegetarians and vegans because it is easy to add to dishes while cooking and has a rich, cheesy, nutty flavor. Nutritional yeast can be added to cooked meals or sprinkled on food and snacks.
To use nutritional yeast, a person can:
- sprinkle it on popcorn
- mix it into cheese sauces
- mix it into mashed potatoes
- sprinkle over scrambled eggs or tofu
- stir into a creamy soup
- add to pasta dishes
- put it on salads
B-12 foods for vegans
Because vegans avoid all animal-derived products, they may rely on vitamin B-12 fortified foods, such as certain breakfast cereals and nutritional yeast. Plant foods do not produce vitamin B-12, so it is vital that vegans find alternative sources of vitamin B12 to remain in the best health.
Some foods that can be fortified with vitamin B-12 include:
- fortified non-dairy milk
- meat substitutes
- breakfast cereals
- nutritional yeast
- vegan spreads
It is essential to read the labels on all of these foods, as some may not be fortified with vitamin B-12. For those who are already B-12 deficient, supplemental B-12 in the form of capsules or injections may be required.
The Bottom Line
Vitamin B12 deficiency is common and can present itself in various ways, making it difficult to identify. If you’re at risk and have any of the symptoms above, speak to your doctor. For most people, a B12 deficiency should be easy to prevent simply by ensuring you are getting enough B12 in your diet.