Feeling tired all the time? Struggling with memory or balance? It might be a vitamin B12 deficiency. This essential nutrient supports red blood cells, nerve health, and DNA production. Without enough B12, symptoms like fatigue, pale skin, numbness, or even depression can develop over time.

Here’s what you need to know:

• Who’s at risk? Vegans, vegetarians, older adults, and those with absorption issues (e.g., pernicious anaemia or gut conditions). Certain medications, like metformin and PPIs, can also interfere with B12 levels.
• Symptoms: Fatigue, weakness, pale or yellowish skin, tingling in hands/feet, memory issues, mood changes, and digestive problems.
• Causes: Poor diet (especially for plant-based eaters), absorption problems, or age-related changes.
• Fix it: Include B12-rich foods like meat, fish, eggs, and dairy. Vegans can use fortified foods or supplements. Severe cases might need medical treatments like injections.

Act early; untreated deficiencies can lead to irreversible nerve damage. If symptoms persist, consult a healthcare provider for testing and treatment.

Signs and symptoms of vitamin B12 deficiency

Spotting a vitamin B12 deficiency early can be tricky because the symptoms often creep in gradually and resemble other health issues. These signs can range from mild fatigue to more severe neurological problems, making it crucial to address lingering concerns with a healthcare provider.

Physical symptoms

One of the most visible effects of B12 deficiency is how it interferes with red blood cell production. Without enough healthy red blood cells, your body struggles to deliver oxygen efficiently, leading to symptoms that can resemble anaemia.

Fatigue and weakness are among the earliest and most common signs. This isn’t just feeling tired after a long day – it’s an overwhelming and persistent exhaustion that can make even simple tasks feel daunting.

Another telltale sign is changes in skin tone, such as a pale or yellowish tint, often referred to as jaundice, which may point to a lack of vitamin B12.

Shortness of breath can also occur, especially during physical activities like climbing stairs or walking short distances. This happens because oxygen delivery to your tissues is compromised.

Other physical symptoms might include headaches, heart palpitations, muscle weakness, cramps, and even tinnitus (a ringing sensation in the ears) or occasional lightheadedness. Additionally, a sore, red tongue (known as glossitis) or mouth ulcers could signal a deficiency.

These physical signs often give way to more serious effects on the brain and nervous system.

Brain and nerve symptoms

Vitamin B12 plays a critical role in maintaining nerve health, so a deficiency can lead to neurological issues that may worsen over time if untreated.

Numbness and tingling in the hands and feet are common early indicators. This sensation, often described as "pins and needles", typically starts in the extremities but can spread as the deficiency progresses.

Memory lapses and confusion can also emerge, affecting your ability to focus and make decisions.

Balance and coordination issues may develop as nerve damage advances, sometimes causing difficulty walking or a sense of instability. In severe cases, this can lead to conditions like subacute combined degeneration.

Vision disturbances can occur because the optic nerve is particularly sensitive to low B12 levels.

Mood changes are another potential symptom. Feelings of depression, irritability, or anxiety have been tied to B12 deficiency.

It’s worth noting that 20–30% of individuals with B12 deficiency experience neurological damage, emphasising the importance of identifying and addressing the issue early.

Beyond its effects on the nervous system, a lack of B12 can also disrupt digestion.

Digestive and other symptoms

B12 deficiency doesn’t just affect your energy levels and nerves, it can also take a toll on your digestive system, leading to symptoms that might not immediately seem related to a vitamin deficiency.

‍Loss of appetite is a frequent issue, which can result in unintended weight loss. Foods you once enjoyed might no longer seem appealing, or you may feel full after eating only small amounts.

Digestive problems such as diarrhoea, constipation, nausea, vomiting, bloating, and gas are also possible.

In men, erectile dysfunction has been linked to low B12 levels.

The likelihood of developing a B12 deficiency increases with age. Research shows that at least 3% of people aged 20 to 39 are affected, rising to 4% in those aged 40 to 59, and 6% or more in individuals aged 60 and older. Some studies suggest that as many as 1 in 5 people over 60 in the United States and the United Kingdom may be deficient in vitamin B12.

If you’re noticing several of these symptoms, especially if they’ve developed gradually, it’s critical to consult a healthcare professional for a proper diagnosis and treatment plan. Early intervention can prevent long-term complications.

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What causes vitamin B12 deficiency

Understanding the reasons behind vitamin B12 deficiency can help you recognise your risk factors and take steps to prevent it. The main causes generally fall into three categories: not getting enough from your diet, absorption issues tied to medical conditions, and the effects of ageing and certain medications.

Not getting enough from food

A lack of vitamin B12 in your diet is a common cause of deficiency. Since this vitamin is mostly found in animal-based foods, people following vegan or strict vegetarian diets are at higher risk. Plant-based foods naturally have little to no vitamin B12, so those on vegan diets often need to rely on supplements or fortified foods to meet their needs.

The body can store vitamin B12 for 2–5 years. This means symptoms may take time to show up, even after switching to a diet low in B12. Additionally, heavy alcohol use can play a role – studies suggest that 25% of people who misuse alcohol might experience a deficiency because it disrupts both the intake and absorption of the vitamin.

Absorption problems and medical conditions

Even if you’re eating enough B12, certain medical conditions can prevent your body from absorbing it properly. One notable example is pernicious anaemia, an autoimmune disorder that interferes with the production of intrinsic factor, a protein essential for B12 absorption.

This condition affects 151 out of every 100,000 people in the United States, with 90% of cases showing antiparietal cell antibodies.

Other gastrointestinal conditions, like coeliac disease and Crohn's disease, can damage the part of the intestine responsible for absorbing B12. Small Intestine Bacterial Overgrowth (SIBO) is another issue, as the bacteria consume B12 before your body can absorb it. Surgeries that involve removing parts of the stomach or small intestine, such as bariatric procedures or cancer treatments, can also significantly reduce absorption.

Additionally, a thinning stomach lining (atrophic gastritis) can lead to pernicious anemia by limiting intrinsic factor production. These absorption challenges highlight the importance of early diagnosis and management.

Age and medication effects

As people age, their ability to absorb and consume enough vitamin B12 naturally declines. Around 10%–15% of individuals over 65 experience this issue. Certain medications can make things worse. For example, metformin, commonly prescribed for type 2 diabetes, has been shown to increase the risk of B12 deficiency by 8% for every 100 mg dose increase.

Proton pump inhibitors (PPIs), which reduce stomach acid, also lower B12 absorption since gastric acid is needed to release the vitamin from food proteins.

This becomes particularly concerning for type 2 diabetes patients, as nearly 40% of them experience gastroesophageal reflux disease (GERD) and are often treated with PPIs or H2 receptor antagonists, further raising their risk. Combining metformin with PPIs has been linked to an even greater chance of developing a deficiency.

If you’re taking metformin, watch out for symptoms like extreme fatigue, a sore and red tongue, tingling sensations, or pale and yellowish skin, and consult your doctor if these occur. Long-term users of metformin or PPIs, especially older adults, should have their B12 levels regularly monitored.

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How to fix vitamin B12 deficiency

The great news is that vitamin B12 deficiency is treatable once identified. Depending on the severity, you can address it through dietary changes, supplements, or medical treatments. Start by incorporating B12-rich foods into your meals. If needed, consider supplements or consult a healthcare professional for tailored advice.

Foods high in vitamin B12

Animal-based foods are some of the richest sources of vitamin B12, making them a go-to for many people.

Organ meats are at the top of the list. For example, a 3.5-ounce (100-gram) serving of lamb liver contains an incredible 3,571% of the Daily Value (DV) for vitamin B12. If liver isn’t your thing, beef organ meats generally offer more B12 than pork options.

Shellfish and fish are also excellent choices. Clams, sardines, tuna, salmon, and trout can provide anywhere from several hundred to over 7,000% of the DV in just one serving.

‍Meat options include beef, which is another fantastic source. A single grilled flat iron steak (about 190 grams) delivers 467% of the DV. Opt for lean cuts and cook them by grilling or roasting to retain their B12 content.

Dairy products and eggs are reliable, moderate sources. Interestingly, your body absorbs B12 from milk and dairy products more effectively than from beef, fish, or eggs. For instance, one cup of 2% milk provides 54% of the DV, a 6-ounce container of plain, low-fat yoghurt offers 43%, and two large eggs (100 grams) supply about 46% of the DV. Egg yolks are also better absorbed than egg whites.

For vegetarians and vegans, fortified foods are essential. While meat-eaters average about 7.2 micrograms of B12 daily, vegans typically consume only 0.4 micrograms. Some fortified options include Malt-O-Meal Raisin Bran, which provides up to 62% of the DV per cup, nutritional yeast with up to 733% of the DV in two tablespoons, and fortified soy milk, offering up to 86% of the DV per cup. Always check labels to ensure these foods are enriched with vitamin B12.

Supplement options

If food alone isn’t enough, supplements can help restore your B12 levels. The recommended dietary allowance (RDA) for adults over 14 is 2.4 micrograms (mcg), with slightly higher amounts for pregnant (2.6 mcg) and breastfeeding (2.8 mcg) individuals.

Keep in mind that your body absorbs only about 10 mcg from a 500-mcg dose. Taking smaller doses throughout the day may improve absorption. Here are some common supplement types to consider:

If you follow a vegetarian or vegan diet, consulting a healthcare provider can help you find the right supplement plan. Since vitamin B12 is water-soluble, it’s generally safe even in higher doses, as no upper intake limit has been set. Interestingly, although 24% of men and 29% of women report taking B12 supplements, only 12.4% have insufficient levels, and just 3% have an actual deficiency.

When to see a doctor

While dietary changes and supplements work for many, some cases require medical attention. If you’re experiencing persistent symptoms or have a severe deficiency, it’s crucial to consult your doctor. Early treatment is key because untreated B12 deficiency can lead to irreversible neurological damage.

Your doctor will likely start with a blood test to check your B12 levels. Based on the results, treatment options might include:

• Oral medications, effective for diet-related deficiencies, are typically taken daily between meals.
• Intramuscular injections are often necessary for absorption issues. These usually start with shots every other day for two weeks, followed by maintenance doses every 2–3 months. In the UK, hydroxocobalamin is preferred over cyanocobalamin because it stays in the body longer.
• Nasal gels or sprays, which offer a convenient alternative delivery method.

Some people may need lifelong treatment, depending on the cause of their deficiency. If you’ve already been diagnosed but notice new or worsening symptoms, contact your healthcare provider right away. It’s worth noting that neurological symptoms caused by a B12 deficiency might not fully improve, even with treatment. This makes early detection and intervention especially important.

Regular monitoring is particularly crucial for older adults. Vitamin B12 deficiency affects about 1 in 10 people aged 75 or older and 1 in 20 people aged 65 to 74.

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How Vively can help you boost your energy

Addressing vitamin B12 deficiency with diet, supplements, and regular testing is important, but seeing how these changes affect your daily energy gives you a clearer health picture. Vively uses continuous glucose monitoring (CGM) to show how your body responds in real time, helping you connect your habits to your energy levels.

With Vively, you can:

• Track your glucose levels through CGM to see how meals, activity, and lifestyle changes affect your energy.
• Understand your Metabolic Health Score, which reflects how well your daily habits are supporting stable energy and overall health.
• Gain personalised insights that connect your food choices to energy dips, helping you spot patterns that might be linked to fatigue.
• Review your meal responses to learn which foods support steady energy and which may need adjusting.
• Monitor your progress in one place, making it easier to stay consistent and see long-term improvements.

Vitamin B12 is key for energy production and nervous system function. With Vively and CGM insights, you can make confident choices that support lasting energy and overall wellbeing.

Conclusion

Catching the deficiency early is critical to avoid long-term issues like irreversible nerve damage or blood-related disorders. Thankfully, addressing the problem is straightforward: include more B12-rich foods in your diet, consider supplements if necessary, and monitor your levels with tests like the Methylmalonic Acid (MMA) assay. If you follow a plant-based diet, are over 60, or take medications that interfere with absorption, supplements and regular monitoring become even more important.

Tailored monitoring plays a crucial role in maintaining healthy B12 levels and overall metabolic health. Routine lab tests not only track your progress but also ensure treatments are working. Early and consistent management often leads to better outcomes, especially for younger individuals without advanced neurological symptoms.

Staying proactive about your B12 levels can help safeguard both your metabolic and neurological health for the long term.

FAQs

How can I tell if my symptoms are caused by vitamin B12 deficiency or something else?

Vitamin B12 deficiency can show up in various ways, including fatigue, weakness, numbness or tingling in your hands and feet, and even memory problems. The tricky part? These symptoms often overlap with other health issues, making it tough to identify the root cause right away.

To figure out if a B12 deficiency is behind these symptoms, doctors typically recommend blood tests to measure your B12 levels and check the size of your red blood cells. In some cases, they might also suggest neurological tests to rule out other conditions. If you're noticing these signs, it's essential to see a healthcare provider who can provide the right diagnosis and treatment.

What are the best sources of vitamin B12 for vegans and vegetarians?

For those following a vegan diet, some of the top sources of vitamin B12 include fortified foods like plant-based milks, breakfast cereals, and soy products. Nutritional yeast and specific types of algae or seaweed may also contain B12, but it’s crucial to check labels to confirm they’re fortified with the vitamin.

Vegetarians have additional options, as they can rely on eggs and dairy products, such as milk, cheese, and yoghurt, to meet their B12 requirements. If you’re unsure about your intake, it’s a good idea to consult a healthcare provider to discuss supplementation options.

When should I see a doctor for vitamin B12 deficiency instead of relying on diet or supplements?

If you notice neurological symptoms like numbness, tingling in your hands or feet, trouble walking, memory issues, or confusion, it’s crucial to see a doctor. These signs might point to a more serious deficiency that needs medical attention.

Also, if blood tests reveal a severe deficiency or your symptoms don’t improve or even get worse despite adjusting your diet or using supplements, consulting a healthcare professional is essential. They can provide further testing and recommend treatments specifically suited to your situation.

How can I tell if my symptoms are caused by vitamin B12 deficiency or something else?

Vitamin B12 deficiency can show up in various ways, including fatigue, weakness, numbness or tingling in your hands and feet, and even memory problems. The tricky part? These symptoms often overlap with other health issues, making it tough to identify the root cause right away.

To figure out if a B12 deficiency is behind these symptoms, doctors typically recommend blood tests to measure your B12 levels and check the size of your red blood cells. In some cases, they might also suggest neurological tests to rule out other conditions. If you're noticing these signs, it's essential to see a healthcare provider who can provide the right diagnosis and treatment.

What are the best sources of vitamin B12 for vegans and vegetarians?

For those following a vegan diet, some of the top sources of vitamin B12 include fortified foods like plant-based milks, breakfast cereals, and soy products. Nutritional yeast and specific types of algae or seaweed may also contain B12, but it’s crucial to check labels to confirm they’re fortified with the vitamin.

Vegetarians have additional options, as they can rely on eggs and dairy products, such as milk, cheese, and yoghurt, to meet their B12 requirements. If you’re unsure about your intake, it’s a good idea to consult a healthcare provider to discuss supplementation options.

When should I see a doctor for vitamin B12 deficiency instead of relying on diet or supplements?

If you notice neurological symptoms like numbness or tingling in your hands or feet, trouble walking, memory issues, or confusion, it’s crucial to see a doctor. These signs might point to a more serious deficiency that needs medical attention.

Also, if blood tests reveal a severe deficiency or your symptoms don’t improve or even get worse despite adjusting your diet or using supplements, consulting a healthcare professional is essential. They can provide further testing and recommend treatments specifically suited to your situation.