Symptoms of a B12 deficiency
Signs of Vitamin B12 Deficiency: What to Watch For
Many people who need to take a vitamin B12 supplement - or any vitamin supplement - don't actually realise they might be deficient. Vitamin B12 deficiency is surprisingly common, particularly among older adults, vegetarians and vegans, and people with digestive conditions that impair nutrient absorption.
Unlike vitamin C deficiency or protein deficiency, B12 deficiency often develops gradually over years, making the symptoms easy to dismiss or attribute to other causes. So what are some of the warning signs that you have a vitamin B12 deficiency? Let's take a detailed look.
Sign 1: Pale, Yellow or Jaundiced Skin
A common visible sign among people who don't get enough vitamin B12 is noticeably pale skin, or skin with a yellow tinge (jaundice). The yellow discolouration can also affect the whites of the eyes, creating a yellowish appearance rather than the healthy clear white.
Why This Happens
This colour change results from problems with your body's production of red blood cells caused directly by the lack of B12. When B12 levels are insufficient, your body produces abnormally large, fragile red blood cells (a condition called megaloblastic anaemia) that are unable to divide properly.
These oversized, fragile red blood cells break down more easily than healthy cells. When they break down, they release bilirubin - a yellow-brown pigment produced during the breakdown of red blood cells. Excess bilirubin in your bloodstream causes the characteristic yellow tinge to skin and eyes known as jaundice.
When to See a GP
If you notice yellowing of your skin or eyes, see your GP promptly. While B12 deficiency is one cause, jaundice can also indicate liver problems or other serious conditions that require medical investigation.
Sign 2: Persistent Fatigue and Weakness
When you don't have adequate vitamin B12 in your body, it struggles to make sufficient healthy red blood cells. As a result, less oxygen is carried around your body to tissues and organs, and you naturally start to feel weaker, more tired and less able to cope with normal daily activities.
How B12 Deficiency Causes Fatigue
Vitamin B12 is essential for red blood cell maturation. Without it, your bone marrow produces immature, oversized red blood cells that cannot efficiently transport oxygen from your lungs to your tissues. This results in tissue hypoxia (oxygen deficiency), which manifests as:
- Persistent tiredness even after adequate sleep
- Physical weakness and reduced stamina
- Difficulty concentrating or "brain fog"
- Breathlessness during normal activities
- Pale complexion from reduced oxygenated blood
- Rapid heartbeat as your heart works harder to deliver oxygen
If you're beginning to feel tired for no apparent reason despite getting enough sleep and rest, it could be worth checking if you're suffering from a vitamin B12 deficiency - it's more common than you might think, particularly in women over 40 and people following plant-based diets.
Sign 3: Pins and Needles (Paraesthesia)
We've all felt the temporary pins and needles sensation after sitting in an uncomfortable position for too long, which resolves quickly once we move. Unfortunately, persistent or frequent pins and needles - particularly in hands, arms, legs or feet - can be a sign of a more serious, longer-term B12 deficiency.
The Nerve Damage Connection
A lack of B12 can actually cause progressive nerve damage (peripheral neuropathy) in more extreme or long-standing cases as a result of B12's critical role in maintaining myelin. Myelin is a fatty protective sheath that insulates and protects nerve fibres, allowing electrical signals to travel efficiently along nerves.
Unfortunately, inadequate B12 means that your body cannot produce or maintain myelin properly. As myelin degrades, nerve signals become disrupted, leading to:
- Tingling, "pins and needles" sensations (paraesthesia)
- Numbness in hands, feet, arms or legs
- Burning sensations in extremities
- Reduced sensation or ability to feel temperature or pain
- Electric shock-like sensations
- Difficulty with fine motor tasks (buttoning clothes, writing)
Persistent pins and needles can be a warning signal of B12-related nerve damage. If caught early, nerve damage may be reversible with B12 supplementation. However, long-standing deficiency can cause permanent nerve damage, which is why early recognition is crucial.
Sign 4: Poor Balance, Co-ordination and Mobility Issues
It's remarkable that a single vitamin deficiency can have such a profound impact on your body's function, but it absolutely can. As well as causing pins and needles, nervous system damage resulting from a lack of B12 can also cause significant issues with balance, co-ordination and walking (ataxia).
Why Balance Is Affected
B12 is essential for maintaining the myelin sheath around nerves in your spinal cord and brain, including the nerves responsible for proprioception (your sense of body position in space) and balance. When these nerves are damaged by B12 deficiency, you may experience:
- Unsteady gait or difficulty walking in a straight line
- Poor co-ordination and clumsiness
- Increased risk of trips, stumbles and falls
- Difficulty with tasks requiring fine motor control
- Feeling dizzy or off-balance, particularly in the dark
- Needing support or handrails when walking
People with a significant B12 deficiency can be considerably more prone to falling over, which poses serious injury risk, particularly for older adults who may suffer fractures from falls.
Typically, balance problems happen more frequently in elderly people, but they can also occur in younger people if their deficiency remains undiagnosed and untreated for an extended period.
Other Signs of B12 Deficiency
Beyond the major signs above, vitamin B12 deficiency can cause additional symptoms:
- Mouth problems: Glossitis (swollen, inflamed, smooth red tongue), mouth ulcers, burning sensation in the mouth
- Cognitive issues: Memory problems, difficulty concentrating, confusion, mood changes
- Depression and irritability: B12 is needed for neurotransmitter production affecting mood
- Vision problems: Blurred or disturbed vision from optic nerve damage (rare but serious)
- Shortness of breath and dizziness: From reduced oxygen-carrying capacity
- Heart palpitations: As your heart works harder to compensate for low oxygen levels
Who Is at Risk of B12 Deficiency?
| Risk Group | Why They're at Risk |
|---|---|
| Adults over 50 | Reduced stomach acid production impairs B12 absorption |
| Vegetarians and vegans | B12 is found naturally only in animal products |
| People with pernicious anaemia | Autoimmune condition preventing B12 absorption |
| Digestive disorders | Crohn's, coeliac disease, IBS can impair absorption |
| Post-gastric surgery | Reduced intrinsic factor production affects absorption |
| Long-term medication users | Metformin, PPIs, antacids reduce B12 absorption |
How Much B12 Do You Need?
The UK recommended daily amount (RDA) for adults is 2.4mcg (micrograms) per day. Pregnant women need 2.6mcg, and breastfeeding women need 2.8mcg. These are minimum amounts to prevent deficiency - some people may benefit from higher doses, particularly if absorption is impaired.
B12 Food Sources
- Meat (particularly beef, lamb, liver)
- Fish and shellfish (salmon, tuna, sardines, mussels)
- Dairy products (milk, cheese, yoghurt)
- Eggs
- Fortified foods (cereals, plant milks, nutritional yeast)
Note that plant foods do not naturally contain B12, which is why vegetarians and vegans are at higher risk and should consider supplementation.
B12 in Kollo Health
Kollo Premium Liquid Marine Collagen provides 1.5mcg of vitamin B12 (60% RDA) per sachet, alongside vitamins B1, B5, B6, vitamin C and 10,000mg of marine collagen peptides.
Why B12 Is Included in Kollo
While Kollo's primary focus is supporting collagen production and overall wellness, B12 is included because it works synergistically with the other nutrients:
- Energy metabolism: B vitamins work together to convert food into cellular energy
- Red blood cell production: Essential for oxygen delivery to tissues
- Protein metabolism: Supports utilisation of amino acids from collagen
- Nerve function: Maintains myelin and supports nervous system health
- Overall wellness: Complements collagen's structural benefits with metabolic support
The liquid format ensures optimal absorption of all nutrients, including B12, which can be poorly absorbed from tablets in some individuals.
When to See Your GP
If you're experiencing any of the signs above - particularly pale/yellow skin, persistent fatigue, neurological symptoms (pins and needles, balance problems) or mouth issues - see your GP for a blood test to check your B12 levels.
Early diagnosis and treatment can reverse symptoms and prevent permanent nerve damage. Treatment typically involves high-dose B12 supplements (oral or injections, depending on severity and underlying cause).
Don't wait for symptoms to worsen. B12 deficiency is easy to diagnose with a simple blood test and straightforward to treat, but untreated deficiency can lead to serious, irreversible complications.
Kollo Health was co-founded by Jenni Falconer - TV presenter, Smooth Radio breakfast host, ten-time London Marathon runner and host of the RunPod podcast. Jenni understands the importance of B vitamins for energy, performance and overall wellness, which is why Kollo includes vitamins B1, B5, B6 and B12 alongside premium marine collagen and vitamin C for comprehensive daily nutritional support.
