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Health Hub

B12 deficiency and weight gain: Is there a connection?

How does a B12 deficiency impact our health?

Can a B12 Deficiency Cause Weight Gain?

Vitamin B12, also known as Cobalamin, is an essential nutrient and a type of vitamin B found in animal-based products such as meat, fish, eggs and milk, as well as certain foods fortified with vitamins and minerals, such as cereals and grains [3].

Like many other vitamins, vitamin B12 is the sort of multi-function nutrient that sustains your body.

It helps to produce and maintain the insulating layer surrounding nerve cells, helps to form red blood cells, and breaks down some of the fatty acids and amino acids that produce energy [6].

It’s also essential for DNA synthesis and cellular energy production [7].

With vitamin B12 playing such a crucial role in the function of a healthy body, what does it mean when we don’t get enough?

How does a B12 deficiency impact our health? And more specifically, how does it affect our weight?

How much vitamin B12 do you need?

Like with many vitamins, vitamin B12 can’t be made in the body, and as a result, it needs to be consumed either through food or supplements.

Luckily, the understanding of how much vitamin B12 we need is pretty standard, with medical professionals recommending that the average adult should get at least 2.4 micrograms per day [1].

What causes a vitamin B12 deficiency?

As vitamin B12 is bound to protein in food, it’s found almost exclusively in animal-based food or animal products such as milk, dairy and eggs [7][2].

As a result, vegetarians or those on a vegan diet can be particularly susceptible to a vitamin B12 deficiency.

That said, how much vitamin B12 we eat or drink isn’t always the culprit of a deficiency.

There are many reasons why our bodies may not absorb nutrients such as vitamin B12 in the way that they should.

In particular, pre-existing health conditions that interfere with nutrient absorption such as anaemia, Crohn’s disease, celiac disease, hypothyroidism, pregnancy, or genetic defects can all contribute to a vitamin B12 deficiency, as can the use of certain medications such as commonly prescribed heartburn drugs, which reduce acid production in the stomach which is needed to absorb vitamin B12 [5][1].

The latter condition is more likely to occur in older adults over the age of 50 due to the cutback in stomach acid that the body stores, something that often occurs with ageing.

Recent research has shown that weight loss surgery can also put people at risk of a vitamin B12 deficiency as the operation interferes with the body’s ability to extract vitamin B12 from food [1].

Symptoms of B12 deficiency

With so many likely causes for a vitamin B12 deficiency, understanding the symptoms can be vital to ensuring you address it before it gets severe.

After all, like with many vitamin deficiencies, issues with your B12 levels can take time to develop, with symptoms often being slow to start and intensifying over time.

That said, those more intense symptoms can strike hard when they want to, so if you're worried that you're at risk for a deficiency in vitamin B12, ensure you’re on the lookout for:

  • Tiredness and fatigue
  • Headaches
  • Mood changes
  • Weakness, low energy levels and reduced physical activity
  • Sensations of numbness or tingling in the hands, legs or feet
  • Difficulty walking, including staggering or balance problems
  • A swollen and inflamed tongue, or tongue fatigue
  • Anaemia
  • Cognitive difficulties such as difficulties in thinking, confusion or memory loss.

In extreme cases, a vitamin B12 deficiency can also lead to depression, paranoia and delusions, memory loss, incontinence, loss of taste and smell, and more [1].

If you suffer any of the above symptoms, speak to your doctor or healthcare provider as soon as you can.

Can B12 deficiency cause weight gain?

Of all the health issues a vitamin B12 deficiency raises, weight gain is still one that experts are unsure about.

There have been a few recent studies that have indicated a link between excess weight and a higher body mass index and lower vitamin B12 levels, a fact that some believe to be supported by the role vitamin B broadly plays in your body maintaining your metabolism [8].

However, this area of research is still too new to offer any conclusive findings [3].

Can it make it harder to lose weight?

No research has indicated that a vitamin B12 deficiency makes it harder to lose weight.

That said, vitamin B does assist your metabolism to function properly, and having a healthy level of vitamin B12 in your diet has been suggested to suppress appetite and, along with folate, improve insulin resistance [9].

Regardless of whether you gain weight or lose it though, no vitamin deficiency is ever something to endure.

Vitamin B12 is a crucial part of a healthy diet, and ensuring you’re getting enough of it helps your body function well beyond maintaining a healthy weight.

Ways to ensure you're getting enough B12

When it comes to maintaining a healthy diet and a healthy body, making sure you’re getting enough vitamin B12 is vital.

As one of the vitamins responsible for ensuring you have enough red blood cells, ensuring the proper functioning of cellular energy production and protecting the nervous system, it needs you to support it, so that it can support you.

One of the simplest ways to do this is to maintain a diet high in B vitamins.

You can do this by eating a wide and diverse range of unprocessed foods such as fish, poultry, red meat, eggs, dairy products, fortified cereals, fruits and vegetables [3].

If you are a vegetarian or a vegan, you may be more susceptible to a vitamin B12 deficiency and may need to consume more fortified foods and dietary supplements to get enough B vitamins.

A serious vitamin B12 deficiency can be diagnosed with a blood test and may need to be addressed with physical medicine in the form of either weekly shots of vitamin B12, or daily high-dose vitamin B12 pills. These can come in the form of a water-soluble vitamin.

A standard multivitamin, however, delivers 6 micrograms of vitamin B12, which is more than enough to cover the average body’s daily needs and would be a more suitable treatment for a mild deficiency [1].

Understanding how to navigate the different vitamins and minerals your body needs can be a complex undertaking, particularly when trying to obtain or maintain a healthy weight.

To best achieve your health goals, and get to know your vitamin A, Bs and Cs, why not take a look at Juniper’s Weight Reset Programme?

This supportive weight loss programme connects you with medical professionals to guide you on your journey to a better, healthier you.

If eligible, you may get access to weight loss medications (Wegovy or Mounjaro) to help you reach your weight goal, along with ongoing support from clinicians, health coaches and dietitians, and access to a community of other women on the same journey as you.

In the meantime though, eat well, ensure you consume sufficient amounts of foods fortified with B12, and if you have any questions or concerns, speak to your current healthcare provider.

Photo credit: Enes Çelik / Pexels