Weight Loss

Does B12 Help You Lose Weight?

Hiral Patel

March 3, 2023

The prevalence of overweight and obesity is on the rise nowadays. As per a report by WHO, about 39% of adults worldwide were overweight in 2016.

These include obese adults amounting to 13% of the world population. Thus the problem of excess weight is quite common. It can lead to health complications such as heart problems, diabetes, orthopaedic problems, etc. The obesity issues widespread as a pandemic make several researchers look for healthy dietary components to help lose weight. 

In the modern era, where many people are keen on maintaining healthy body weight, they follow numerous diets and exercise regimes to shed those extra kilos.

In addition, there are other measures to aid in weight loss too. These include acupuncture, acupressure, hypnotherapy, massage therapies, slimming creams, weight loss pills, dietary supplements, etc.

However, your foods and physical activity regimes are of prime importance. Therefore, when you follow any diet or food plan, it is essential to understand the role of various nutrients and vitamins in your weight loss journey. 

Previous studies show that some minerals and vitamins aid in weight loss. These include calcium, magnesium, iron, vitamin B complex, vitamin C, and vitamin D.

As per recent studies, vitamin B12 has an association with obesity. That is primarily because It plays a role in improving metabolism, energy provision, etc. However, whether vitamin B12 helps lose weight or not is still confusing for many people. Therefore, this article will help you know vitamin B12’s association with weight loss.

Understanding Vitamin B12 and its Functioning

Vitamin B12 is a water-soluble vitamin naturally present in some foods, added to others, and available as a dietary supplement and a prescription medication. Since vitamin B12 contains the mineral cobalt, research suggests that compounds with vitamin B12 activity are collectively called “cobalamins”.

Vitamin B12 is essential for your body in many ways. For example, your body requires vitamin B12 for the central nervous system’s development, myelination, and function.

In addition, it is essential for healthy red blood cell formation and DNA synthesis. Furthermore, it helps break down the food for energy provision. Also, it can boost metabolism and help fight fatigue. Moreover, it is also involved in breaking down a protein called homocysteine. Therefore, it reduces the risk of heart disease associated with high homocysteine levels.

The recommended daily allowances for vitamin B12 depend on an individual’s age. However, the allowances slightly differ for pregnant and lactating mothers. As per the recent research, the RDAs are:

Birth to 6 Months

  • Boys: 0.4mcg
  • Girls: 0.4mcg

7 to 12 Months

  • Boys: 0.5mcg
  • Girls: 0.5mcg

1 to 3 Years

  • Boys: 0.9mcg
  • Girls: 0.9mcg

4 to 8 Years

  • Boys: 1.2mcg
  • Girls: 1.2mcg

9 to 13 Years

  • Boys: 1.8mcg
  • Girls: 1.8mcg

14 to 18 Years

  • Boys: 2.4mcg
  • Girls: 2.4mcg

19 Years and Above

  • Men: 2.4mcg
  • Women: 2.4mcg
  • Pregnant Women: 2.6mcg
  • Lactating Women: 2.8mcg

As per the Institute of Medicine (IOM), the main criteria that help establish the RDAs for adults are the amount needed to maintain a healthy haematological status and serum vitamin B12 levels. At the same time, the adequate intake for infants aged 0 to 12 months is equivalent to the mean intake of vitamin B12 in healthy, breastfed infants.

Vitamin B12 for Weight Loss – The Relationship

Although only a few human studies prove vitamin B12’s role in obesity and weight loss, some studies showcase its positive effect on body fat and weight.

For example, a study on rats suggests that vitamin B12 deficiency can increase total body fat. Another cross-sectional study shows that obesity and overweight are risk factors for vitamin B12 deficiency. However, researchers and experts believe that more studies are needed to establish a direct link between vitamin B12 and obesity or weight loss.

Based on the analysis of the current studies, it is evident that vitamin B12 can influence weight in several ways. Some ways can be more direct such as boosting metabolism and energy level. On the other hand, some can be indirect, such as reducing stress. So, let us look at the relationship between vitamin B12 and weight loss.

Role in Metabolism

Your metabolism plays a crucial role in weight management. As per Harvard Health, if your metabolism is “high” (or fast), you will burn more calories at rest and during activity. In contrast, a person with a “low” (or slow) metabolism will burn fewer calories at rest and during activity. 

Vitamin B12 acts as a key in activating the succinyl-CoA, an essential part of the Krebs cycle. The Krebs cycle is a cellular process that produces energy during aerobic respiration. It allows for oxygen consumption and the production of consequent carbon dioxide and water in the cells. As per studies, vitamin B12 deficiency disrupts the process, increasing your body’s fat reserves for energy and causing excess fat gain.

Studies also suggest that vitamin B12 also aids in the metabolism of fatty acids and proteins. Therefore, a deficiency in Vitamin B12 leads to low energy levels, thus hindering weight loss efforts.

Provides Energy

Vitamin B12 helps form haemoglobin in the red blood cells. Hence, its deficiency may lead to anaemia, a condition with low levels of red blood cells.

As a result, the body may have difficulty transporting oxygen to different parts of the body. Consequently, it will lead to fatigue, weakness, and shortness of breath. That will hamper the efforts that you put into your weight loss journey.

Role in Mental Health

Vitamin B12 helps maintain brain health and nerve function. Its deficiency may trigger existing conditions such as anxiety and depression. 

Your nerves have a protective covering called myelin sheath. Vitamin B12 is essential for the formation of myelin. As per research, vitamin B12 deficiency causes damage to the myelin sheath. A severe deficiency can even cause permanent damage.

Vitamin B12 can also help in reducing stress. Research states that adequate vitamin B12 levels can positively impact patients with depression.

Effect on Your Weight Loss Efforts

Vitamin B12 deficiency leads to fatigue and weakness. In addition, it affects the respiratory and circulatory systems, which play a vital role in exercise. Hence, vitamin B12 deficiency will make your exercises and physical activity less effective. Also, it can be difficult to do physical activities and exercises for extended periods.

Moreover, prolonged inactivity can cause metabolic issues. It can affect the body’s metabolic flexibility. It refers to how effectively the body shifts from using carbohydrates to using fat as energy for the body. Furthermore, when the body has a healthy metabolism, it will utilise fat for energy.

Otherwise, it will have difficulty mobilising fat stores, leading to muscle reduction and fat storage. Therefore, a deficiency of vitamin B12 can sabotage weight loss efforts.

Other Significant Health Benefits of Vitamin B12

Improves Skin, Hair and Nails

Since vitamin B12 plays a crucial role in cell production, it helps promote skin, hair and nail health.

In addition, low vitamin B12 levels can cause various dermatologic symptoms, including hyperpigmentation and nail discolouration. Furthermore, it can lead to hair changes, vitiligo (the loss of skin colour in patches) and angular stomatitis (inflamed and cracked mouth corners) 

Eliminates Anaemia

Vitamin B12 plays an essential role in producing red blood cells. Studies suggest that low vitamin B12 levels reduce red blood cell formation and prevent them from developing.

In case of vitamin B12 deficiency, your red blood cells become larger, making it difficult to move from the bone marrow to the bloodstream, causing anaemia.

Anaemia hampers the red blood cells’ capacity to transport oxygen to your vital organs. As a result, it can lead to fatigue and weakness. In addition, it can lead to difficulty breathing. However, vitamin B12 can improve the condition by increasing red blood cells.

Supports Bone Health and Prevents Osteoporosis

Vitamin B12 helps support bone health. A study of 2500 individuals shows that people with vitamin B12 deficiency had low bone mineral density. 

Bones with decreased mineral density can become delicate and fragile over time, leading to an increased risk of osteoporosis. Furthermore, other studies show an association between low vitamin B12 levels and poor bone health, especially in women.

Improves Eye Health

Macular degeneration is an eye disease that mainly affects your central vision. Maintaining adequate vitamin B12 can help prevent the risk of age-related macular degeneration. 

A study involving 5,000 women aged 40 or older concluded that supplementing with vitamin B12 and folic acid, and vitamin B6 may reduce this risk. But further studies are needed to fully understand vitamin B12’s role in promoting vision health and preventing macular degeneration.

Enhances Mood

Vitamin B12 plays a vital role in synthesising and metabolising serotonin, a chemical responsible for regulating mood. Hence, vitamin B12 deficiency can lead to low serotonin levels, causing depression.

Vitamin B12 Deficiency

The daily requirement of vitamin B12 for average adults is 2.4 mcg. It is 2.6 mcg for pregnant women and 2.8 mcg for lactating women. Excess vitamin B12 gets stored in the liver for future use.

A tiny amount gets lost through excretion. Thus, it can take up to a year of insufficient intake to cause deficiency symptoms.

As per a report, several factors that increase the risk of vitamin B12 deficiency are:

  • Immune system disorders such as HIV
  • Medical disorders such as atrophic gastritis and pernicious anaemia lead to absorption issues.
  • Conditions affecting the small intestine like Crohn’s disease or celiac disease
  • Certain medications such as metformin
  • Vegan and vegetarian food preferences
  • Surgery on the digestive tract
  • Certain genetic mutations

Also, older people are more likely to have a deficiency as they do not produce enough hydrochloric acid to absorb vitamin B12 in food sources.

Common symptoms of vitamin B12 deficiency include:

  • A feeling of fatigue or weakness
  • Shortness of breath
  • Headache
  • Diarrhoea
  • Anxiety or nervousness
  • Numbness
  • Anaemia

You may also have a deficiency without showing any of the above symptoms. Also, a prolonged deficiency can lead to loss of taste & smell, joint pain, etc.

Natural Sources of Vitamin B12 for Weight Loss

Research suggests that vitamin B12 is naturally present in foods of animal origin, including fish, meat, poultry, eggs, and dairy products.

In addition, fortified breakfast cereals and fortified nutritional yeasts are readily available sources of vitamin B12. Some of the healthy foods that contain vitamin B12 are:

  • Milk
  • Yoghurt
  • Fortified foods such as breakfast cereals and plant-based milk
  • Organ meats such as liver and kidney meats
  • Salmon
  • Trout
  • Clams
  • Oysters
  • Shrimp
  • Chicken
  • Eggs

Most of the sources of vitamin B12 are animal-based. Therefore, vegans and vegetarians may need supplements to fulfil their vitamin B12 requirements.

Other Sources of Vitamin B12

Other than the natural sources of vitamin B12, you can also take its supplements and injections. In these, vitamin B12 is available in free form, making it easier to absorb.

Vitamin B12 Pills

You can buy them over the counter in pharmacies. You do not require a prescription to buy them.

Vitamin B12 Injections

It has a more concentrated form of Vitamin B12. It provides the fastest way to overcome a vitamin B12 deficiency. Here, the vitamin goes directly into the bloodstream. It is helpful for people with severe anaemia. The assistance of a licensed medical practitioner is required to administer this form of medicine.

Vitamin B12: Precautionary Measures

Vitamin B12 has low toxicity. A large dose of this vitamin is also safe as the body does not store excess amounts. Some precautions that you should take while consuming vitamin B12 include:

  • Avoid taking vitamin B12 if you are allergic to cobalt or if you have Leber’s disease.
  • Consult your doctor if you have existing conditions such as diabetes, liver problems, etc.
  • Vitamin B12 may interact with other medications like chloramphenicol, colchicine, aminosalicylic acid, etc.
  • Discuss with your doctor regarding permitted food, alcohol, and tobacco consumption while taking vitamin B12.
  • Avoid taking Vitamin B12 after receiving a coronary stent. It can contribute to the narrowing of blood vessels.

The Bottom Line

The deficiency of some nutrients can hinder weight loss efforts. One such nutrient is vitamin B12. Although it does not directly impact weight loss, its deficiency can impair your weight loss process. That is because it assists in multiple body processes.

Its deficiency can lead to low energy levels, poor metabolism, etc. However, you can overcome it through natural sources or shots and supplements.

Correcting this deficiency improves energy levels and boosts metabolism, thus assisting in weight loss. However, it has shown no such effect on individuals with sufficient levels of the vitamin so far.

While vitamin B12 may help in some weight loss in deficient individuals, it cannot replace diet and exercise. Lifestyle changes are necessary to lose weight and keep it off.

You must follow a healthy diet and habits for long-term, sustainable weight loss. Other measures that You can adopt include stress management, proper sleep, adequate water intake, goal setting, calorie tracking, etc.

Frequently Asked Questions (FAQs)

Q. Does B12 help lose belly fat?

A. Spot reduction does not work. However, you can reduce belly fat when you lose overall fat. In addition, vitamin B12 can aid in weight loss efforts by boosting metabolism, improving energy levels, etc., for individuals having vitamin B12 deficiency.

Q. Is it ok to take 1000 mcg of B12 a day?

A. It is ok to take 1000 mcg of vitamin B12 daily if you have a deficiency. Your doctor will determine the correct dosage for you according to your medical condition.

Q. How quickly does the B-12 shot work for weight loss?

A. A vitamin B12 shot may show results in weight loss as early as within the first week of treatment. However, it only works if you have a deficiency. Studies show no effects on weight loss in normal individuals.

Q. Which vitamin helps with weight loss?

A. Vitamin B complex and vitamin D help in weight loss. Vitamin B plays a crucial role in our metabolism. It is also responsible for energy provision. On the other hand, vitamin D may prevent depression. In addition, it works with calcium to reduce cortisol levels. Consequently, it is linked to lower belly fat.

Q. Does B12 affect appetite?

A. Yes, studies suggest that a deficiency in vitamin B12 can cause appetite loss. However, the appetite may return to normal after restoring optimum vitamin B12 levels.

Q. Is it better to take B12 daily or weekly?

A. Vitamin B12 can be taken both daily and weekly. It depends on the type of treatment and the underlying condition. Your doctor will guide you regarding the frequency and amount of dosage required.

Q. When should I take B12 in the morning or night?

A. It is advisable to take Vitamin B12 in the morning as it provides energy. However, you can take it after breakfast. Also, taking it at night may disrupt sleep.

Q. Can you overdose on B12?

A. No, you cannot overdose on vitamin B12. There is no prescribed upper limit for its consumption. It is a water-soluble vitamin that gets absorbed quickly. Our liver stores some amount, and the excess gets flushed out through excretion.

Q. Does low vitamin D cause weight loss?

A. No, low vitamin D does not cause weight loss. On the contrary, vitamin D deficiency may lead to weight gain. Studies also suggest that individuals with optimum vitamin D levels lose more weight than deficient individuals. It may also impact weight indirectly as it leads to low mood, sleep disorders, etc.

Q. How much B12 does a female need daily?

A. A report indicates that the recommended dietary allowance for an adult female is 2.4 mcg/day. However, this requirement increases to 2.6 mcg/day for pregnant women. Moreover, lactating women need 2.8 mcg/day.

About the Author

According to Hiral, “Striving to be better than yesterday, is the key to achieving any goal that is ahead of you”. As a diet and lifestyle consultant, Hiral intends to help her clients inculcate habits such as healthy eating and regular exercise to improve their lifestyle holistically for a better tomorrow. She also aims to make her clients feel good from the inside-out and bring about a positive change to their overall life.

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