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Vitamin B12 Weight Loss Benefits and Beyond

By Fitoru | 18 December 2018
b12 vitamin and meat shellfish cheese mushrooms

Have you heard that vitamin B12 is the secret to weight loss? That message has been making the rounds on social media for quite some time. If you are looking for the truth about vitamin B12 weight loss benefits, you’ve arrived at the right place.

Vitamin B12 Facts and Deficiency

Vitamin B12 is a water-soluble vitamin required for red blood cell formation, neurological function, and DNA synthesis. Two forms of vitamin B12—methylcobalamin and 5-deoxyadenosylcobalamin—both support healthy human metabolism activity.

The human body does not store vitamin B12, making it necessary to consume vitamin B12 foods daily. Vitamin B12 helps to protect against anemia, pregnancy problems, and heart disease, and provides energy. Sadly many people don’t absorb enough vitamin B12 and become deficient.

Vitamin B12 is a vital nutrient considered an essential vitamin for women. The human body cannot produce it—vitamin B12 must be consumed from animal proteins, fortified foods, or through supplementation.

Globally vitamin B12 deficiency is a growing problem. Foods naturally rich in vitamin B12 are shellfish, meat, and fish—making it challenging for vegetarians and vegans to get enough without some type of supplementation.

Research indicates that anywhere from 5% of the global population to 40% of the global population has a vitamin B12 deficiency, and emerging research shows genetics may be partially to blame. If you have certain digestive diseases or low stomach acid, you are at a higher risk of developing a deficiency.

If you are deficient, it is vital to act quickly. The longer the deficiency persists the higher the likelihood of permanent damage.

Signs of vitamin B12 deficiency include:

  • Difficulty losing weight
  • Fatigue
  • Dizziness
  • Shortness of breath
  • Heart palpitations
  • Constipation
  • Diarrhea
  • Gas
  • Anxiety and stress
  • Pale skin
  • A smooth tongue
  • Pernicious anemia
  • Tingling or numbness
  • Muscle weakness

Vitamin B12 deficiency causes include:

  • Heavy smoking
  • Alcoholism
  • Antibiotics
  • Potassium supplements
  • Anti-seizure medications
  • Chemotherapy medications
  • Colchicine
  • H2 blockers
  • Metformin (Glucophage)
  • Proton pump inhibitors
  • Celiac disease
  • Crohn’s disease
  • Lupus
  • Grave’s disease
  • Weight loss surgery
  • Vegetarianism/veganism

Vitamin B12 deficiency dangers include:

Vitamin B12 Weight Loss Claims

Clinical research has not proven that vitamin B12 is a cure for obesity or that it helps you lose weight. There are small studies that link vitamin B12 with weight loss due to its ability to improve mood and boost energy levels, but this is mostly incidental.

However, if you are clinically deficient in vitamin B12 weight loss can be challenging. A quick blood test is necessary to determine your vitamin B12 levels and whether you need to eat more vitamin B12 foods, take a supplement, or consider having monthly vitamin B12 injections.

Vitamin B12 Benefits

What is vitamin B12 good for? This essential nutrient is central to many processes in the human body. Vitamin B12 has been shown to protect against many chronic health conditions, and it may even defend against certain types of cancer.

1. Fight Osteoporosis

According to the United States Department of Agriculture, a vitamin B12 deficiency is linked to low bone mineral density in both men and women. Citing the Framingham Osteoporosis Study, the USDA notes that individuals with a vitamin B12 level lower than 148 pM/L are at a greater risk for osteoporosis than individuals with higher levels.

2. Protect Against Cognitive Decline

Vitamin B12 can lower homocysteine levels in the body. Elevated levels of homocysteine are often found in people with dementia and Alzheimer’s disease.

3. Protect Against Breast Cancer

In a small case-controlled study of postmenopausal women, an association between vitamin B12 levels and breast cancer has been indicated. In fact, the risk of breast cancer was more than doubled in women with low vitamin B12 levels.

Another study published in the British Journal of Cancer found that the risk of breast cancer decreased by 23% in women who took a supplement containing the amino acid methionine, vitamin B6, and vitamin B12.

4. Protect Against Age-Related Macular Degeneration

According to a study published in the journal Nutrients, age-related macular degeneration is the leading cause of blindness in the elderly. Women at risk for vascular disease had a 34% reduction in risk for age-related macular degeneration after daily supplementation of folate, vitamin B6, and vitamin B12. The prescribed dosing for this study was 2.5 milligrams of folate, 50 milligrams of vitamin B6, and 1 milligram of vitamin B12.

5. Guard Against Depression

Researchers from Singapore have identified through a cross-sectional study that low levels of folate and vitamin B12 can lead to depression in older adults. The study published in the Journal of the American Geriatrics Society highlights that vitamin B12 deficiency is significantly associated with depression symptoms.

In a study published in the Journal of Psychopharmacology, researchers recommend 1 milligram of vitamin B12 daily and 800 micrograms of folic acid daily to fight depression symptoms. The authors of the study note that previous research indicates that low folate levels are linked to “poor response to antidepressants” and supplementation with folate improves prescription antidepressant efficacy.

Vitamin B12 Weight Loss Benefits

Weight loss clinics and many in the wellness community support vitamin B12 injections for weight loss, even for individuals that do not have a confirmed vitamin B12 deficiency. Conventional doctors rarely prescribe vitamin B12 shots unless blood tests show a deficiency or the patient has difficulty absorbing vitamin B12.

Research has produced mixed results and frankly the jury is still out as to whether vitamin B12 benefits weight loss. If you have symptoms of a vitamin B12 deficiency ask your physician to order a blood test. Many individuals can improve their levels of vitamin B12 by eating more vitamin B12 foods and taking an oral supplement.

Vitamin B12 Injections

If you have a significant vitamin B12 deficiency your physician may recommend vitamin B12 injections. The most significant benefit to injection is that it bypasses the digestive tract, allowing the vitamin B12 to be absorbed quickly through the bloodstream. This type of supplementation can be ideal for individuals with digestive diseases or those with an absorption problem.

Physicians believe that many individuals with vitamin B12 deficiencies are actually getting “enough” vitamin B12 through their diet but that they can’t correctly process and absorb this critical nutrient. Natural healthcare providers may recommend vitamin B12 injections as a regular course for those having a difficult time losing weight or showing other symptoms of vitamin B12 deficiency.

The good news is vitamin B12 is considered safe and nontoxic. Proponents of vitamin B12 for weight loss say that injections reduce food cravings, boost energy, increase mental focus, and improve mood—all things that may help you lose weight. If recommended, a vitamin B12 shot is generally considered safe and may help you lose weight when partnered with a healthy diet and exercise.

Vitamin B12 Foods

Vitamin B12 is primarily found in animal products including meat, poultry, fish, and shellfish. Today, many breakfast cereals, breads, and other processed foods are fortified with B12 to help the population get the daily value of vitamin B12 each and every day.

The best vitamin B12 foods include:

Clams 3 ounces 84.1 micrograms

Beef liver 3 ounces 70.1 micrograms

Mackerel 3 ounces  7.4 micrograms

Sardines 3 ounces  6.6 micrograms

Salmon 3 ounces  4.8 micrograms

Trout 3 ounces  3.5 micrograms

Lamb 3 ounces  2.7 micrograms

As you can see from this list of the top vitamin B12 foods, it is virtually impossible for vegetarians and vegans to get their DV of vitamin B12 through diet alone. The Vegan Society explains that most vegans consume just enough vitamin B12 to avoid nervous system damage and anemia but that many vegans don’t get enough vitamin B12 to protect against pregnancy complications and heart disease.

The Vegan Society suggests these three different ways to get the DV of vitamin B12:

  1. Take a single weekly dose of at least 2000 micrograms of vitamin B12.
  2. Take a daily dose of at least 10 micrograms of vitamin B12.
  3. Eat two or three servings daily of vitamin B12 fortified foods.

Vegan-friendly vitamin B12 fortified foods include:

  • Cereals
  • Soy milk
  • Almond milk
  • Rice milk
  • Hemp milk
  • Coconut milk
  • Nutritional yeast
  • Protein bars
  • Cremini mushrooms
  • Whole grain breads
  • Soy-based products including tofu, sausage, and burgers

The above list is not complete, and it is very critical to read nutrition labels carefully to determine the prepared foods that are fortified and the amounts of vitamin B12 they provide in each serving. A monthly vitamin B12 injection may be a good way for vegans and vegetarians to guarantee they are getting enough B12 and that it is being absorbed properly.

Vitamin B12 Side Effects and Precautions

Vitamin B12 is generally considered safe and nontoxic. However, vitamin B12 supplements and vitamin B12 injections can interfere with certain medications including:

  • Chloramphenicol (Chloromycetin)
  • Omeprazole (Prilosec)
  • Lansoprazole (Prevacid)
  • Cimetidine (Tagamet)
  • Famotidine (Pepcid)
  • Ranitidine (Zantac)
  • Metformin
  • Chlorambucil (Leukeran)
  • Colchicine (Colcrys and Mitigare)
  • Goldenseal
  • Grapefruit and grapefruit juice

Most people don’t experience adverse events from vitamin B12, but side effects can occur. Watch out for:

  • Headache
  • Itching
  • Swelling
  • Nervousness
  • Anxiety
  • Involuntary movements
  • Low levels of potassium
  • Congestive heart failure
  • Clots in the arms and legs
  • Anaphylaxis
  • Fluid buildup in the lungs

Are Vitamin B12 Injections the Answer to Weight Loss?


    1. Hi Jeannie! It’s better to seek professional advice regarding this matter. If you can’t visit any of the professional, you can try this food for boosting Vit B12 like shellfish, meat, and fish. 🙂

  1. I would go them I have most of the problems like headaches light headed ever since I broke my back in 2017 and still have a brace on so don’t do much and getting so big nothing works just lost my mum everything is just shitting me

    1. Hi Cheryl! I’m sorry for your lose. Also thanks for sharing your thoughts. It’s also wise to seek professional advice to get the best treatment. Please know that we care about you.


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