Adequate levels of vitamins and nutrients are important for keeping all systems in your body functioning properly — including functions related to weight and metabolism. Vitamin B12, also known as cobalamin, plays a vital role in many of these processes. Vitamin B12 helps boost your metabolism, improves oxygenation, increases energy, and is often included in many comprehensive weight-loss and wellness programs.
What is vitamin B12?
B12 is one of the eight B vitamins that help the body convert food into energy. B vitamins are necessary for maintaining healthy skin, hair, and eyes, as well as a healthy liver. B vitamins are water soluble — meaning they dissolve in water and are not stored in the body, and must be replenished every day as a result.
How vitamin B12 works in the body
Vitamin B12 works differently than other vitamins, in that a substance called intrinsic factor must be present in the intestinal tract in order for the body to absorb B12. People whose stomachs are unable to produce intrinsic factor generally suffer from vitamin B12 deficiency — a health condition known as pernicious anemia. However, those whose stomachs do produce intrinsic factor can properly absorb vitamin B12 and benefit from more optimal health.
Vitamin B12 helps the body maintain healthy nerve cells and aids in the production of DNA. Along with vitamin B9, or folate, B12 helps create red blood cells, aids in the function of iron in the body, and produces a compound that supports the mood and immune system. Vitamin B12 also removes a dangerous protein in the blood called homocysteine that could otherwise damage arteries and contribute to inflammation, osteoporosis, and heart disease.
Symptoms of B12 deficiency
Vitamin B12 deficiency is relatively common, especially among older people. As we age, our ability to absorb the nutrients in our foods decreases. Older people tend to have lower amounts of stomach acid, which the body needs to absorb B12.
Others who have difficulty absorbing nutrients may also have low B12 levels — such as individuals who have had gastric bypass surgery or who have certain digestive disorders. Excessive alcohol consumption can also interfere with the body’s absorption of B12. Low levels of B12 can lead to:
- Digestive issues
- Shortness of breath
- Numbness or tingling in the fingers and toes
- Difficulty walking / balance problems
- Cognitive impairment or memory loss
A person can also have low levels of vitamin B without exhibiting any obvious symptoms. A severe prolonged B12 deficiency can lead to joint pain, depression, and loss of taste and smell.
How does vitamin B12 help with weight loss?
Vitamin B12 does not directly cause weight loss, but it does help with many functions throughout the body related to weight and metabolism. First, B12 helps the body break down the food we eat and use it for energy. Also, because B12 is necessary for proper cellular respiration and the formation of red blood cells, this vitamin can help your body transport oxygen and use it more efficiently, resulting in an increased metabolism.
By helping restore energy levels, balance, concentration, and mood, B12 can foster a general sense of increased wellness and help motivate people to exercise more frequently.
Does vitamin B12 help with depression?
Vitamin B12 plays a role in producing brain chemicals, such as serotonin, that help control mood and other brain functions. Low levels of serotonin have been linked to depression. Taking vitamin B12 can help restore and boost levels of serotonin and other neurotransmitters to improve mood and ward off depression.
Does vitamin B12 help with memory?
In addition to controlling mood, vitamin B12 also plays an important role in memory and cognition. Low levels of B12 have been linked to a higher risk of dementia and Alzheimer’s disease. Studies haven’t been able to prove whether B12 can improve or reverse memory loss once it becomes problematic; however, being proactive with taking B12 throughout your life may help prevent the onset of cognitive decline.
Can vitamin B12 cause anxiety?
Being deficient in vitamin B12 has been linked to anxiety due to the way B12 deficiencies trigger symptoms in red blood cells and the nervous system, and interfere with brain chemistry. But taking B12 can actually improve symptoms of anxiety and help individuals feel less stressed, less anxious, and more relaxed.
Can vitamin B12 cause acne?
Recent studies show that B12 could make those with acne-prone skin more susceptible to acne breakouts. In some instances, vitamin B12 can alter the metabolism of bacteria on the skin to promote inflammation and the development of acne. However, acne triggered by vitamin B12 is rare, and doesn’t necessarily affect everyone with acne-prone skin. To counteract the effects of B12 on acne-prone skin, drink plenty of water to flush toxins from the body and eat lots of fresh fruits and vegetables to keep your skin as hydrated and as clear as possible.
Can vitamin B12 cause nausea?
Deficiency in vitamin B12 can lead to problems with the digestive tract including heartburn, abdominal bloating, constipation, diarrhea, loss of appetite, and nausea and vomiting. B12 can help improve these symptoms and overall digestive health.
In some instances, B12 and other vitamins may cause nausea if you take them on an empty stomach, or if you take more than what your body needs. Talk to your doctor about the exact amount of B12 you need and about methods of use so you can benefit from improved overall health and reduced nausea.
Sources of B12
B12 is naturally found only in foods that come from animals, such as meat, eggs, poultry, and dairy. This means vegetarians and vegans may be at risk of having low levels of B12. Some foods such as plant-based milk substitutes and cereals may be fortified with B12.
Because B12 from food and pills may not be fully absorbed by the body, many health experts recommend taking B12 as a sublingual (under the tongue) spray. This allows the vitamin to be absorbed directly into the bloodstream without having to go through the digestive system, reducing the risk of malabsorption in the stomach.
What foods have vitamin B12?
Animal organ meats such as liver and kidneys contain high amounts of vitamin B12 — especially those from lamb. Seafoods including clams, sardines, tuna, trout, and salmon are also all high in B12. Beef is an optimal source of B12 and provides the highest amount of this vitamin when grilled or roasted, since frying beef is shown to deplete some of its nutritional value.
Cereals, non-dairy milk, and nutritional yeast may be fortified with vitamin B12, but make sure you fully read the nutrition labels before relying on these sources for B12. Eggs are also high in vitamin B12, but yolks have higher amounts of B12 than egg whites, with the B12 in yolks being more easily absorbed by the body. Eat whole eggs instead of just the whites if your goal is to boost B12 intake through food.
Should vitamin B12 be taken with or without food?
B vitamins, including B12, are water-soluble and don’t necessarily need to be taken with food for absorption. In fact, B12 is often best absorbed by the body when taken without food. However, some people may experience nausea or indigestion when taking vitamin B12 on an empty stomach. If you experience discomfort when taking B12 on its own, try taking it with healthy, non-greasy foods that won’t worsen symptoms like nausea and heartburn.
Are vitamin B12 shots safe?
B12 injections are another way for this essential vitamin to bypass the digestive process and be more readily absorbed by the body. Using B12 sprays or injections can help boost energy levels in those who have low levels of vitamin B12. Many B12 injections are also combined with other beneficial compounds that help increase energy, reduce stress, improve sleep quality, strengthen the immune system, and help the body burn fat.
When to get vitamin B12 shots
B12 shots are usually prescribed by a doctor to treat vitamin B12 deficiency. The frequency at which you should receive B12 shots is normally determined by your doctor. When you first start getting B12 injections, you may be required to visit your doctor as often as once or twice per week during the first few months, after which you may receive shots once per month. Your doctor will usually perform assessments during your appointments to determine your need for future B12 shots.
Garcia Weight Loss and Wellness Centers offer therapeutic B12 injections as part of UltraWellness labs, which help uncover chemical imbalances in the body that may be preventing you from achieving optimal health. Request a no-cost consultation today to discover how we can help you reach your goals and achieve improved physical well-being!
This post was originally published in May, 2017, and has been updated for freshness, accuracy, and comprehensiveness.
Medically reviewed by Jay J. Garcia, MD on November 5, 2018