When we’re trying to lose weight, we often turn to the obvious solutions: cutting our food intake and increasing our exercise. But we also know that nutrient deficiencies and hormone imbalances play a huge role in how efficient our metabolism is. If you’ve heard that a B12 supplement might help speed weight loss along, it’s normal to be curious. But is a B12 pill or injection really the magic key to weight loss that some supplement and weight loss companies make it out to be? Here’s what you need to know.
A quick intro: What is Vitamin B12, anyway?
Vitamin B12, which is also sometimes referred to as cobalamin, is a water-soluble vitamin that’s naturally found in animal-based foods like meat, dairy, eggs, and poultry (although it’s also added to some fortified foods). It’s part of the larger Vitamin B complex, a group of eight different water-soluble B vitamins that all help your body turn the food you eat into usable fuel by your cells.
Vitamin B12 is a particularly important B vitamin because it plays a variety of key roles in helping you synthesize DNA, fatty acids, and myelin, the insulating sheath on your nerve cells that allows for electricity conduction. Its ability to help create DNA also plays a major role in the formation of your red blood cells, which have the all-important job of delivering oxygen to the various cells in your body.
Because it’s such a critical factor for these jobs, this means that one of the most common consequences of a Vitamin B12 deficiency is megaloblastic anemia, a disease in which your body makes unusually large and immature red blood cells that can’t function efficiently. This often manifests itself as one of the tell-tale signs of a Vitamin B12 deficiency: fatigue, which unfortunately doesn’t necessarily help if you’re trying to stay active to burn calories.
But even more pertinently here, there’s been a ton of recent research surrounding the importance of Vitamin B12 for your metabolism — and how it can affect your weight management efforts.
Will Vitamin B12 supplements help me lose weight?
The field of research surrounding B12 and its potential role in weight management is relatively new, and still needs more human clinical trials to understand its exact role. However, there is definitely some evidence right now that suggests that Vitamin B12 plays a role in your metabolism, especially when it comes to lipids (aka fat).
Let’s look at what some studies have to say on the topic:
- A 2019 study that looked at 9,075 diverse American adults over the age of 20 found that individuals who had higher levels of B12 in their blood were less likely to be obese than other individuals in the study with lower Vitamin B12 levels.
- Another 2019 study found a correlation between low Vitamin B12 levels and insulin resistance, a common comorbity to obesity, in a sample of obese children aged 10-16.
- In a non-clinical study that was conducted on rats (not humans), researchers found that B vitamin supplementation helped improve metabolism in rat subjects that were fed a high-fat diet.
- Another animal study, this one on mice, saw that a severe Vitamin B12 deficiency led to increased body fat percentages and impaired lipid profiles, with researchers suggesting that it was possibly due to increased inflammation and oxidative stress.
So yes, there’s some early evidence that shows that a B12 deficiency might be associated with slowing down weight loss, or at least that low B12 levels are often found to be correlated with higher body weights and non-optimal metabolic processes. There’s also some promise that B12 supplementation for those who are deficient can improve your fat metabolism based on studies with animal subjects.
But the key word here is deficiency.
While we know that having a Vitamin B12 deficiency (or any nutrient deficiency, for that matter) can affect the various systems in your body including metabolism, there isn’t enough evidence to suggest that adding a B12 supplement will help your weight loss efforts if your body is already getting enough B12 from your current diet and supplement regimen. The evidence that we currently have from trials using human subjects only found a correlation between impaired metabolism in people who had a low Vitamin B12 status to begin with --- not people who already have normal B12 levels.
So the key takeaway here, if you’re looking to understand whether or not a Vitamin B12 injection will help weight loss, is that it simply depends on your current nutrition status.
- If your body doesn’t have enough B12 to carry out its regular metabolic functions, supplementation with injections or supplements can certainly increase your serum levels and help you meet your nutrient goals, giving your body all the nutrient tools it needs to carry out its regular metabolic functions.
- But if you are taking B12 blindly, without knowing whether or not you really need it, it isn’t likely to “speed up” your metabolism the way that it is often advertised to.
Pinpointing factors that are holding back your weight loss progress
To sum up: Vitamin B12 might aid your weight loss efforts, but evidence so far only supports this idea if you are already dealing with a Vitamin B12 deficiency. If you already have normal Vitamin B12 levels, there is no good evidence that adding more to your diet either via whole foods or supplements will do much good.
So, how do you know if a Vitamin B12 deficiency is holding back your weight loss? You take a blood test!
After all, you can only determine whether or not a dietary supplement will help by understanding your current nutrient status before making changes. So taking blood tests is often an underutilized but invaluable tool when you’re trying to decipher whether or not there’s something going on inside of your body that’s holding you back from seeing results.
The traditional way to look into this is to get a blood test from your doctor. But if you’re interested in finding out whether you’re dealing with a B12 deficiency in a more efficient and convenient way, you can get results with Base’s at-home Diet Deficiencies Test. With a simple finger prick, you can get real, quantifiable answers about your nutrient status without having to make a doctor’s appointment. It’s a great way to establish a real, effective action plan for Ferritin or Vitamin B12 deficiencies without having to pop supplements willy nilly and blindly hope for results.
Where to get Vitamin B12
So, let’s say you do discover that you’re dealing with a Vitamin B12 deficiency. How can you get more Vitamin B12 to ensure that you’re fully nourished? Your body doesn’t make any usable B12 on its own, so you’ll need to get it either from whole foods or from supplements.
Whole food sources that naturally contain good amounts of Vitamin B12 include:
- Meat
- Poultry
- Fish
- Eggs
- Milk
Because B12 is only found in significant amounts in plant-based foods, you may be at more risk of a deficiency if you’re a vegetarian or vegan. However, there are also certain fortified foods that often contain added B12 that can help you bridge the gap, including breakfast cereals, plant milks, and nutritional yeast. Read your labels at the grocery store to determine whether your choices are fortified with B12 to add more of it into your diet with foods.
You can also increase your B12 intake by taking a supplement. You can find B12 supplements on their own, or you can also get them from B-complex vitamins that contain multiple B vitamins. Again, you’ll want to keep in mind that the most efficient way to address a B12 deficiency is to talk to your doctor or take a blood test so that you can get real feedback on the correct dosage you should be looking for in a supplement.
The bottom line
Vitamin B12 certainly plays many important roles in your body on a cellular level, including influencing your energy levels and your metabolism. But as far as we know right now, popping a Vitamin B12 supplement only helps with weight management if you’re currently dealing with a B12 deficiency. It’s not a magic cure-all by any means, so understanding your weight loss roadblocks starts with taking a blood test and evaluating your current vitamin and nutrient levels before adding unnecessary and potentially unhelpful steps to your daily regimen.
