The NHS is urging millions of people across the UK to take vitamin D to support overall health, but experts say certain symptoms should not be ignored. In a post shared on X, an NHS spokesperson said: “From October to March we can’t make enough vitamin D from sunlight, so to keep bones and muscles healthy, it’s best to take a daily 10 microgram supplement of vitamin D. You can get vitamin D from most pharmacies and retailers.”

While health professionals agree that vitamin D supplementation is important for many people, especially during the colder months, they stress that it should be taken carefully.

Why Does Sunlight Matter For Vitamin D Production?

Sunlight plays a crucial role in how the body makes vitamin D. UVB rays trigger a reaction in the skin that converts a compound called 7-dehydrocholesterol into vitamin D3. This form of vitamin D is essential for absorbing calcium, maintaining strong bones, and supporting the immune system.

As sunlight in the UK is not strong enough between autumn and early spring, the government advises everyone to consider taking a daily supplement of 10 micrograms, or 400 IU. Relying on food alone is often not enough to meet daily needs during this period.

Expert Warns Too Much Vitamin D Can Backfire

Biomedical scientist Tobias Mapulanga, who co-founded Repose Healthcare, has warned that some people may be taking more vitamin D than their bodies can handle. He explained that as winter advice circulates, many people add tablets, sprays, or gummies without realising they are doubling up.

He said that symptoms such as constant thirst, needing the toilet more often, nausea, stomach discomfort or constipation, headaches, mental fog, and new aches or cramps can appear soon after increasing vitamin D intake. These signs are often mistaken for winter illnesses, when they may actually point to excess supplementation.

“The message is simple,” he added. “The right dose helps, but taking too much can leave you feeling worse, not better.”

High-Dose Supplements Raise Safety Concerns

Research shows that 42% of UK adults reported taking vitamin D supplements in the past year. However, an investigation by Which? found some vitamin D products on sale contained doses as high as 12.5 times the recommended safe upper limit.

NHS England also logged 42 incidents over a two-year period where high-strength vitamin D was given more often than intended. Some of these cases led to hospital treatment for hypercalcaemia, a condition caused by too much calcium in the blood, according to reports from Bristol Live.

Stop Taking Vitamin D If You Notice These Warning Signs

1. Ongoing thirst and frequent trips to the toilet

If you suddenly feel unusually thirsty or find yourself urinating more often after starting vitamin D, it may be a sign you’re overdoing it. Cut back to a single 10 microgram tablet and stop using any additional vitamin D products if this happens.

Too much vitamin D can disrupt fluid and salt balance in the body, leaving you dehydrated and running to the bathroom. Check labels carefully and remove multivitamins, sprays, gummies, and fortified foods or drinks that also contain vitamin D.

Keep water close by and sip regularly while your body settles. Stay well below the upper limit of 100 micrograms, keep just one product visible, and put the rest out of sight to avoid accidental doubling.

2. Nausea, excessive burping, or stomach discomfort

Feeling sick, bloated, or dealing with an upset stomach after taking vitamin D suggests it isn’t agreeing with you. Try taking your supplement with a full meal and switch from sprays or gummies to a plain D3 tablet if symptoms persist.

Food helps protect the stomach lining, while sprays and gummies often contain sweeteners or flavourings that can irritate digestion. Choose a simple cholecalciferol tablet with minimal ingredients and reduce the dose to 10 micrograms.

Avoid fortified shakes or energy drinks until your stomach feels normal again.

3. New muscle cramps or bone aches

If you notice more aches in your bones or frequent muscle cramps after starting vitamin D, take it as a signal to reassess. Lower your dose and focus on staying well hydrated while eating mineral-rich foods.

Excess vitamin D can interfere with mineral balance, which muscles rely on, and dehydration can make cramping worse. Drink water with meals and include yoghurt, leafy greens, beans, and bananas in your diet.

Gentle stretching and short walks can ease stiffness. Stick to one 10 microgram supplement and avoid adding anything else until symptoms improve.

4. Brain fog or headaches

Trouble concentrating or recurring headaches can be signs that your vitamin D intake is too high. Replace multivitamins or high-strength products with a single 10 microgram D3 tablet.

High doses can raise calcium levels, and extra additives found in combined supplements may affect clarity of thought. Choose a product that contains only cholecalciferol and basic fillers.

Take it with food at the same time each day for consistency and better digestion. Avoid combined vitamin A and D products and focus on one simple supplement.

To prevent accidental overuse, review everything you take that contains vitamin D. Spread out all tablets, sprays, gummies, and fortified foods, and read each label carefully. Convert IU to micrograms by dividing by 40 to make totals easier to track.

Discard any extras and stick to one daily 10 microgram source. Keep a note of symptoms such as thirst, frequent urination, stomach upset, cramps, or mental fog to see how they relate to your intake.

A pharmacist has warned that people taking certain long-term medications should stay alert to subtle symptoms such as numbness, tingling, and an unusually red or sore tongue. According to Superdrug Pharmacy Superintendent Niamh McMillan, as per Mirror, the signs are often easy to dismiss and may quietly develop over time in people with low vitamin B12 levels.

Pharmacist Warns Certain Medicines May Trigger Overlooked Vitamin B12 Symptoms

McMillan explained that vitamin B12 plays a vital role in keeping nerves and blood cells healthy. A shortage can build up slowly, which means early symptoms are often brushed aside or mistaken for everyday fatigue.

She said common warning signs include persistent tiredness or weakness, breathlessness, headaches, dizziness, pale skin, and a sore or red tongue. Some people may also notice pins and needles or numbness in their hands or feet, memory lapses, trouble focusing, or changes in mood such as feeling low or unusually irritable.

Who Is Most At Risk Of Low B12 Levels?

Vitamin B12 deficiency occurs when the body either does not get enough of the vitamin from food or struggles to absorb it properly. McMillan noted that people following vegetarian or vegan diets are at higher risk, as B12 is naturally found mainly in animal products.

Older adults are also more vulnerable, as are people with digestive conditions such as coeliac disease or Crohn’s disease. In addition, those taking certain medications may be affected, particularly long-term acid-reducing drugs such as proton pump inhibitors or diabetes medication like metformin.

Dietary Sources That Help Maintain B12 Levels

To reduce the risk of deficiency, McMillan advised including reliable dietary sources of vitamin B12 wherever possible. Foods naturally rich in the vitamin include meat, fish, eggs, milk, cheese, and yoghurt.

For people who avoid animal products, fortified foods such as some breakfast cereals and plant-based milks can help support intake. In some cases, supplements may also be useful, especially when diet alone is not enough or absorption is impaired.

When To Seek Medical Advice?

McMillan stressed that anyone experiencing symptoms or falling into a higher-risk group should speak to a healthcare professional. A simple blood test can measure B12 levels, and early treatment can help prevent lasting nerve damage or other complications.

She added that Superdrug Health Clinics offer a Vitamin B12 Injection Service at selected UK locations, following clinical assessment or confirmation of deficiency.

How Medications Can Interfere With Vitamin B12?

Several commonly prescribed medications can affect how the body absorbs or uses vitamin B12. This often happens because the drugs alter conditions in the stomach or gut, making it harder for B12 to be released from food or absorbed into the bloodstream.

Medications Linked to Vitamin B12 Deficiency

The most frequently associated medications include:

• Proton Pump Inhibitors (PPIs): such as omeprazole, esomeprazole, and lansoprazole
• H2 Blockers: including famotidine and cimetidine
• Metformin
• Oral contraceptives, although experts continue to debate whether these cause a true deficiency
• Colchicine, used to treat gout and known to damage the intestinal lining
• Anticonvulsants, including drugs like phenytoin and phenobarbital, which can affect B-vitamin metabolism
• Nitrous oxide, commonly known as laughing gas, which can rapidly inactivate existing B12 in the body
• Antibiotics, particularly long-term use of chloramphenicol or neomycin, which can disrupt gut bacteria involved in B12 processing

What To Do If You Take These Medications Long Term?

Experts advise people on these medicines not to stop treatment without medical guidance. Instead, they recommend staying alert for symptoms such as fatigue, tingling or numbness in the hands or feet, brain fog, or a sore, red tongue.

Getting tested is also key. A straightforward blood test can confirm B12 levels, and many doctors now suggest regular screening for patients who take metformin or proton pump inhibitors over extended periods.

UK researchers say fruit flies could help unlock why devastating brain and nerve conditions such as Alzheimer’s, Parkinson’s and motor neurone disease develop, despite decades of medical research. Scientists have known for years that many neurodegenerative disorders are linked to genetic mutations. What has remained unclear is how those mutations actually trigger disease inside the nervous system.

According to the Mirror, new findings published in the journal Current Biology suggest a breakthrough may lie in studying fruit flies, insects whose genes behave in strikingly similar ways to those in humans.

UK Scientists Say Fruit Flies May Hold Answers to Neurodegenerative Diseases

The study was led by Professor Andreas Prokop from the University of Manchester, who examined the role of so-called motor proteins using fruit flies as a model. These proteins are responsible for transporting materials inside nerve cells. Fruit flies are widely used in genetic research because experiments can be carried out quickly and at low cost while still offering insights relevant to human biology.

Professor Prokop explained that many human genes linked to neurodegenerative disease have close equivalents in fruit flies, performing nearly identical roles in nerve cells.

Axons and the Role of Motor Proteins

The research focused on axons, the long and fragile nerve fibres that act like cables, carrying messages between the brain and the rest of the body to control movement and behaviour. For axons to stay healthy, motor proteins must move essential materials along internal tracks called microtubules.

These motor proteins are vulnerable to genetic mutations, which can interfere with their function and ultimately cause axons to break down.

Why Different Mutations Cause Similar Damage

Professor Prokop said scientists have long struggled to explain why both disabling mutations, which reduce motor protein activity, and hyperactivating mutations, which keep them constantly switched on, can result in very similar forms of neurodegeneration.

To investigate this puzzle, his team studied fruit flies carrying different types of motor protein mutations.

What Happens Inside Damaged Nerve Fibres?

The researchers found that both disabling and hyperactivating mutations lead to the same physical damage inside axons. Healthy microtubules, which normally form straight bundles, begin to decay and curl into disorganised structures. Professor Prokop compared this change to the difference between dry spaghetti and overcooked spaghetti. This curling is a clear sign that axons are breaking down.

Transport, Damage and Repair Inside Axons

Axons rely on a complex internal system to survive over time. Materials must be transported from the nerve cell body to distant parts of the axon, a process carried out by motor proteins moving along microtubules.

Professor Prokop explained that if mutations prevent motor proteins from transporting cargo, axons begin to decay. Many inherited neurodegenerative diseases can be traced back to this failure. However, the study also showed that hyperactivating mutations cause a different but equally damaging problem.

Why Too Much Activity Can Be Harmful?

When motor proteins are constantly active and unable to pause, they generate excessive wear and tear along microtubules. Even under normal conditions, transport damages microtubules over time, much like traffic creates potholes on roads. This damage usually triggers repair and replacement mechanisms inside the cell.

The researchers found that when motor proteins are either overactive or when repair systems fail, the balance between damage and repair breaks down. The result is microtubule curling and axon decay.

The Role of Oxidative Stress

At first glance, disabling mutations might seem less harmful because fewer motor proteins mean less internal traffic and therefore less damage. However, the researchers discovered the opposite effect.

Reduced transport means vital supplies fail to reach the axonal machinery. This shortage triggers oxidative stress, a harmful condition linked to cell damage. Oxidative stress, the team showed, disrupts microtubule maintenance and leads to the same curling seen with hyperactive motor proteins.

Based on these findings, Professor Prokop and his team proposed what they call the dependency cycle of axon homeostasis. This model suggests that axon maintenance depends on motor proteins and microtubules, but those same systems rely on ongoing transport to function properly.

If mutations interfere with this balance, either by causing oxidative stress or by upsetting the repair process, the entire cycle collapses.

Professor Prokop said parallel research from his group strongly supports this model. He added that because the genetic foundations of fruit flies and humans are surprisingly alike, it is highly likely that the same mechanisms operate in people. According to Professor Prokop, there are already strong signs that these findings apply beyond fruit flies and could reshape how scientists understand and eventually treat neurodegenerative disease.

It can feel overwhelming to understand the wide range of conditions neurologists deal with. Their work spans cerebrovascular problems such as stroke and carotid artery disease, seizure disorders, and progressive illnesses like Alzheimer’s disease and frontotemporal dementia. They also treat headaches and facial pain, movement disorders including Parkinson’s, muscle conditions, sleep disorders such as narcolepsy, and many other issues.

“If there’s a nerve somewhere, a neurologist could get involved,” explains Dr. Andrew Dorsch, division chief for general neurology at Rush University System for Health and a specialist in neurologic rehabilitation. “Nerves run through the entire body. That means there are countless ways the nervous system can be affected, and figuring out the cause often requires real detective work.” He notes that many people dismiss neurological symptoms for years, blaming them on ageing or assuming they will pass. That delay can be costly.

What Are Neurological Symptoms?

Neurological symptoms are warning signs that something may be affecting the brain, spinal cord, or nerves. They can look very different from person to person. Some experience headaches, changes in vision, speech, or hearing, or sensations like numbness and tingling.

Others notice tremors, weakness, poor balance, or trouble coordinating movements. Cognitive changes such as memory lapses, confusion, seizures, sleep problems, and intense pain can also fall under this category. These symptoms happen when nerve signals are disrupted, interfering with sensation, movement, thinking, and even consciousness, according to the Cleveland Clinic.

Neurological Symptoms That Can Become Life-Threatening

According to TIME, four neurologists shared the symptoms that should never be brushed aside, along with what they could mean.

Double Vision In One Eye

Double vision affecting one eye is a symptom many people underestimate. It can stem from a range of serious conditions, including multiple sclerosis, stroke, aneurysm, myasthenia gravis, brain tumours, or infections of the brain, says Dr. Luis Cruz-Saavedra, a neurologist at Memorial Hermann Health System.

So when does it require action? “Right away,” he says. “Sudden double vision is a reason to go straight to the emergency room.” Doctors will assess vital signs, look for signs of stroke, examine the eyes and nervous system, and may recommend imaging tests such as a CT scan or brain MRI.

Weakness In One Hand Or Leg

Have you noticed one leg dragging when you walk, or found yourself limping without a clear reason? Maybe holding a cup or writing with your usual hand has become difficult. If so, it is time to see a doctor.

“I’m always struck by how many people downplay weakness on one side of the body,” Cruz-Saavedra says, noting this is far from a good thing. “Patients often come in months after it starts. Many assume it’s a pinched nerve, but it could signal a stroke, a brain tumour, multiple sclerosis, or inflammation in the brain.” During evaluation, neurologists assess muscle strength, reflexes, coordination, and walking patterns to narrow down the cause.

Transient Unresponsiveness

Some neurological conditions cause brief moments where a person seems to switch off, then quickly returns to normal without remembering what happened. These episodes are often linked to temporal lobe seizures, which affect brain areas involved in memory and emotional processing, Cruz-Saavedra explains.

Problems With Speech

Stroke remains one of the leading causes of death in the United States, yet many people fail to recognize its signs and delay seeking help. “I hear stories all the time where someone has stroke symptoms and decides to lie down and wait it out,” says Dr. Enrique Leira, director of the division of cerebrovascular diseases at the University of Iowa.

Stroke symptoms usually come on suddenly and involve a loss of function. Speech changes are a common example. A person may slur words, speak unusually slowly, struggle to find the right words, or have trouble understanding others. In such cases, immediate medical attention is essential, Leira stresses.

Sudden Headache During Physical Effort

Headaches can be tricky for neurologists because there are so many possible causes, many of them harmless. Still, certain types raise red flags. A headache that is extremely intense and appears out of nowhere, rather than building gradually, deserves attention. If it strikes during physical exertion, that concern increases.

“If it’s severe, sudden, and linked to effort, it needs to be checked right away,” Leira says, as it could point to something serious like a stroke.

Numb Feet And Fingers

When patients report numbness, it most often affects their fingers or toes. “That usually means the nerves aren’t sending signals back to the brain properly,” Dorsch explains. “The nerve may be temporarily stunned, or in some cases, permanently damaged.” This differs from tingling, which tends to suggest irritation rather than loss of signal.

The first step is a thorough evaluation to identify which nerves are involved and why. Diabetes is a common cause, but not the only one. Genetic disorders or immune conditions that attack nerves can also be responsible, Dorsch says.

A Sense Of Déjà Vu

Almost everyone experiences déjà vu now and then. But frequent episodes are a different matter. “If it’s happening regularly, it’s worth getting evaluated,” Dorsch advises. Repeated déjà vu can be an early sign of temporal lobe seizures. He recalls treating a patient who experienced these episodes weekly or every few weeks, far more often than is typical.

Difficulty Getting Out Of A Chair On A Regular Basis

With age, stiffness and slower movement are common. Still, certain difficulties stand out. If standing up from a chair becomes a recurring struggle, a medical check-up is important.

“It could be joint-related, but we also need to rule out problems with the muscles, nerves, or spinal cord,” Dorsch says. Conditions such as Parkinson’s disease or amyotrophic lateral sclerosis (ALS) may be involved. “That’s not something I’d want anyone in my family to ignore.”

Changes In Voice

Neurologists watch closely for changes in how someone speaks. One example is hypophonic speech, where the voice becomes unusually soft or breathy, which can be a sign of Parkinson’s disease, says Dr. Alexandru Olaru, a neurologist at University of Maryland St. Joseph Medical Center. Slurred speech, on the other hand, may point to a stroke.

Another concerning sign is wet dysarthria, when speech sounds gurgly, often due to saliva or mucus pooling at the back of the throat. “Muscle loss in that area makes it harder to manage saliva,” Olaru explains. Common causes include Parkinson’s disease, ALS, and multiple sclerosis.

Persistent Muscle Twitches

Occasional muscle twitching is normal. It can happen anywhere in the body and may even be visible under the skin as small ripples. “You can sometimes feel it if you place your hand over the muscle,” Olaru says. Persistent or widespread twitching, however, may warrant further evaluation.

Paranoia

Sudden shifts in behaviour or personality can signal neurological disease. Conditions such as autoimmune encephalitis, frontotemporal dementia, or other cognitive disorders may present this way. One frequent example is new-onset paranoia. A person might believe they are being targeted, betrayed, or plotted against, even when there is no logical basis, Cruz-Saavedra says.

Neurologists also take note when a typically reserved person becomes unusually talkative or disinhibited. “Some people may develop hypersexual behaviour or make inappropriate remarks,” he adds. Others may change in the opposite direction, becoming withdrawn and quiet. Dementia can also show up as new obsessive behaviours or hoarding, Cruz-Saavedra notes.