Vitamin D Deficiency in Northern Ireland: Symptoms, Testing and Supplements
Vitamin D Deficiency in Northern Ireland: Symptoms, Testing and Supplements
Vitamin D deficiency is a common concern during Northern Ireland’s darker months.
The body makes vitamin D when skin is exposed to sunlight, but the sun is not strong enough in the UK for reliable vitamin D production during autumn and winter.
Food provides some vitamin D, although it can be difficult to obtain enough from diet alone.
Low vitamin D often causes no obvious symptoms.
When deficiency is severe or lasts for a long time, it can affect bones and muscles, causing:
• Bone pain
• Muscle weakness
• Osteomalacia in adults
In children, severe deficiency can cause rickets.
Symptoms such as tiredness and general aches are common and have many possible explanations.
They cannot confirm vitamin D deficiency.
A blood test may be appropriate when a person has suggestive symptoms or a clinical reason to check, but NICE does not recommend routine testing for everybody without symptoms.
The practical advice for most people in Northern Ireland is simple:
• Adults and children over four should consider taking 10 micrograms of vitamin D each day during autumn and winter
• Some groups are advised to take this amount throughout the year
A preventive daily supplement is different from the higher doses a clinician may use to treat confirmed deficiency.
The short answer
Vitamin D helps the body regulate calcium and phosphate, which are needed for healthy bones, teeth and muscles.
Key points for people in Northern Ireland are:
• Vitamin D deficiency may cause no symptoms at all
• Severe or prolonged deficiency can cause bone pain, muscle pain or weakness and osteomalacia
• Tiredness and vague aches alone do not prove that vitamin D is low
• Routine vitamin D blood tests are not recommended for everyone
• Testing may be appropriate when symptoms, bone disease or another clinical risk gives a reason to check
• Everyone over four should consider 10 micrograms, equal to 400 IU, daily during autumn and winter
• People in specified higher risk groups should consider 10 micrograms throughout the year
• Adults should not take more than 100 micrograms, equal to 4,000 IU, a day unless a clinician has advised it
• Confirmed deficiency may require a different treatment plan and clinical follow up
Speak to a GP or pharmacist if you are unsure what applies to you, particularly if you have:
• Kidney disease
• Problems with high calcium
• A condition that affects nutrient absorption
• Medicines that may alter vitamin D
What does vitamin D do?
Vitamin D helps regulate calcium and phosphate in the body.
These minerals are central to maintaining healthy bones and teeth.
Vitamin D also supports normal muscle function.
When vitamin D remains very low, the body may not mineralise bone properly.
In adults this can lead to osteomalacia, in which bones become softer and painful.
In growing children it can cause rickets, which affects bone development.
Vitamin D is sometimes discussed online as if it were a treatment for almost every aspect of health.
That is not supported by current guidance.
Correcting a genuine deficiency is important, but taking extra vitamin D has not been shown to act as a general cure for:
• Tiredness
• Low mood
• Infections
• Weight gain
The safest approach is to follow public health supplement advice and seek clinical assessment when symptoms or risk factors suggest that more may be needed.
Why is vitamin D relevant in Northern Ireland?
The body can make vitamin D when uncovered skin is exposed to ultraviolet B light from the sun.
In the UK, most people should be able to make vitamin D from sunlight between late March or early April and the end of September.
Between October and early March, sunlight is not strong enough for the body to make enough vitamin D.
Northern Ireland is covered by the same seasonal UK guidance.
Cloudy weather, shorter days and time spent indoors can make the issue feel particularly relevant locally, but there is no need to wait for a sunny forecast before following the standard autumn and winter supplement advice.
The Public Health Agency advises people across Northern Ireland to consider a daily 10 microgram vitamin D supplement during autumn and winter.
It advises some groups to take the same amount throughout the year because they may not make enough from sunlight even in spring and summer.
This does not mean that every person in Northern Ireland is deficient.
It means that the seasonal risk is predictable enough for a simple preventive recommendation to be useful.
What are the symptoms of vitamin D deficiency?
Many people with low vitamin D have no obvious symptoms.
Others notice symptoms that are real but not specific, meaning they could have many different causes.
Possible features of significant or prolonged deficiency include:
• Bone pain, including pain in the lower back, ribs, pelvis or legs
• Muscle aches or tenderness
• Muscle weakness
• Difficulty getting up from a low chair or climbing stairs because of weakness
• Changes in walking when osteomalacia is severe
• Fractures occurring more easily than expected
• Reduced physical function, particularly in an older or frail person
Some people report tiredness or general aches when their vitamin D is low.
These symptoms can also be caused by:
• Poor sleep
• Stress
• Anaemia
• Thyroid disease
• Infection
• Low mood
• Medicines
• Other nutritional deficiencies
• Many other conditions
A symptom list cannot tell you whether vitamin D is the cause.
Persistent, worsening or unexplained symptoms deserve a broader clinical assessment rather than an assumption that a supplement will solve them.
Can vitamin D deficiency make you tired?
Tiredness can occur alongside low vitamin D, but it is not a reliable diagnostic sign.
A person may have low vitamin D without feeling tired, or feel exhausted while their vitamin D level is adequate.
If tiredness continues despite rest or affects daily life, speak to a GP.
The assessment may consider:
• Sleep
• Mental wellbeing
• Diet
• Medicines
• Anaemia
• Thyroid disease
• Other possible causes
A vitamin D test may form part of that assessment when there is a clinical reason, but it should not automatically be the only test considered.
What does osteomalacia feel like?
Osteomalacia caused by severe vitamin D deficiency may cause widespread or localised bone pain and muscle weakness.
The following areas can be affected:
• Lower back
• Shoulders
• Ribs
• Pelvis
• Legs
A person may find everyday movements more difficult or develop a waddling walk.
These symptoms can overlap with many other muscle, joint, nerve and bone conditions.
They require medical assessment.
Do not try to diagnose osteomalacia from symptoms or a home test result.
Who has a higher risk of low vitamin D?
Some people are less able to make vitamin D from sunlight or have a condition that affects how it is absorbed or processed.
Groups advised by the Public Health Agency to take 10 micrograms throughout the year include:
• Pregnant and breastfeeding women
• Breastfed babies from birth
• Babies receiving less than 500 ml of infant formula each day
• All children aged one to four
• People aged 65 and over
• People who have little sunlight exposure
• People with darker skin, including people from African, African Caribbean or South Asian backgrounds
Little sunlight exposure may apply to somebody who:
• Is housebound
• Lives in a care home
• Spends most of the day indoors
• Usually wears clothing that covers most of the skin outdoors
Other circumstances can create a clinical risk of deficiency or alter the amount of vitamin D a person needs.
These include:
• Conditions that reduce nutrient absorption, such as coeliac disease or inflammatory bowel disease
• Previous bariatric surgery
• Some liver or kidney conditions
• Some medicines, including certain antiseizure medicines and long term steroid treatment
• Disorders of calcium or parathyroid function
• A previous diagnosis of vitamin D deficiency or osteomalacia
• Osteoporosis, a fragility fracture or treatment that depends on adequate vitamin D
People living with obesity are also more likely, on average, to have lower measured vitamin D levels.
This association does not mean that body weight proves deficiency, or that a person should select a higher dose without advice.
A clinician should consider symptoms, health history and any reason that usual supplementation may not be adequate.
Should everyone have a vitamin D blood test?
No.
NICE advises health professionals not to routinely test people who have no symptoms of vitamin D deficiency.
Testing may be appropriate when:
• Symptoms suggest osteomalacia or significant deficiency
• There is unexplained persistent bone pain or muscle weakness
• A person has a bone condition that may improve with vitamin D treatment
• Vitamin D must be corrected before certain bone treatments are started
• A condition affecting absorption, the kidneys or the liver changes clinical management
• A clinician needs the result to make a specific treatment decision
A higher risk of becoming deficient does not automatically mean that a blood test is necessary.
For many people without symptoms, the recommended preventive supplement can be taken without testing.
Testing should answer a clinical question.
Repeating tests frequently without a reason can identify small seasonal changes that do not alter care and may encourage unnecessary high dose supplementation.
What happens during a vitamin D test in Northern Ireland?
Vitamin D status is usually assessed with a blood test that measures 25-hydroxyvitamin D, often shortened to 25(OH)D.
This is the main circulating form used to assess the body’s vitamin D supply.
In Northern Ireland, a GP or another clinician may arrange the test when it is clinically indicated.
The blood sample is analysed by a laboratory and the result is interpreted alongside:
• Symptoms
• Risk factors
• Medicines
• Wider health
A clinician may also consider tests such as:
• Calcium
• Phosphate
• Kidney function
• Alkaline phosphatase
These are not required for every person.
The selection depends on why deficiency is suspected and whether a treatment dose is being considered.
Some private services sell vitamin D blood tests.
A numerical result still needs suitable interpretation.
Before buying a test, consider:
• Whether the result will answer a useful question
• Who will explain it
• What will happen if it is unexpectedly low or high
A home test does not rule out other causes of pain, weakness or tiredness.
What do vitamin D blood test results mean?
Results are usually reported in nanomoles per litre, written as nmol/L.
NICE Clinical Knowledge Summaries use the following broad categories for adults:
Below 25 nmol/L
Vitamin D deficiency.
25 to 50 nmol/L
May be inadequate for some people.
Above 50 nmol/L
Sufficient for most people.
These categories are helpful, but a result should not be interpreted in isolation.
Laboratories may use their own reporting notes, and clinical decisions also depend on:
• Symptoms
• Calcium balance
• Bone health
• Absorption
• Kidney function
• Pregnancy
• Medicines
One result is not a diagnosis of every symptom a person has.
Equally, a result just above a threshold does not prove that persistent pain or weakness can be ignored.
The clinician should interpret the complete picture.
How much vitamin D should adults take?
For adults and children over four, the standard UK preventive amount is 10 micrograms each day.
This is the same as 400 international units, usually written as 400 IU.
In Northern Ireland:
• Everyone over four should consider 10 micrograms daily during autumn and winter
• People in higher risk groups should consider 10 micrograms daily throughout the year
The preventive amount is designed to reduce the risk of deficiency.
It is not the same as a treatment course for somebody with confirmed deficiency.
Supplement labels may use:
• Micrograms
• mcg
• µg
• IU
Ten micrograms equals 400 IU.
Check the amount per tablet, capsule, drop or measured dose rather than assuming that every product is the same.
If you already take a multivitamin or another supplement, check whether it contains vitamin D before adding a second product.
Fish liver oil products can contain vitamin A as well as vitamin D.
Too much vitamin A can be harmful, and supplements containing vitamin A require particular caution during pregnancy.
Vitamin D2 or vitamin D3
Supplements may contain:
• Vitamin D2, called ergocalciferol
• Vitamin D3, called colecalciferol
Vitamin D3 is widely used in UK supplements and clinical treatment.
Some vitamin D3 is derived from animal sources.
Vegan vitamin D3 made from lichen is available, and vitamin D2 is generally suitable for vegans.
Check the full product label if dietary, allergy, cultural or religious requirements matter to you.
The amount and suitability of a product matter more than marketing terms such as “maximum strength”.
A pharmacist can help you find a product close to the recommended amount.
How much vitamin D is too much?
The NHS advises adults not to take more than 100 micrograms of vitamin D a day, equal to 4,000 IU, unless advised by a doctor.
Lower limits apply to babies and children.
Taking too much vitamin D over a long period can cause excess calcium to build up in the body.
This is called hypercalcaemia.
It can:
• Weaken bones
• Damage the kidneys
• Damage the heart
Possible symptoms of too much vitamin D or high calcium can include:
• Nausea
• Vomiting
• Unusual thirst
• Passing urine more often
• Constipation
• Weakness
• Confusion
These symptoms have many possible causes, but they require prompt advice when a person has been taking a high dose or has taken much more than intended.
Contact a pharmacist, GP or GP out of hours service for advice after a dosing error or if concerning symptoms develop.
Call 999 for:
• Collapse
• Severe confusion
• A seizure
• Serious breathing difficulty
• Another life threatening emergency
Do not copy a high dose schedule found online.
Treatment courses may contain much more vitamin D than a preventive supplement and should be selected and monitored by an appropriate clinician.
What happens if a blood test confirms deficiency?
Treatment depends on:
• The result
• Symptoms
• Age
• Pregnancy
• Calcium balance
• Other health conditions
• The possible cause
A clinician may recommend a treatment course followed by a lower ongoing amount.
The treatment may be stronger than a shop bought preventive supplement.
That does not make the same dose appropriate for somebody who has not been assessed.
The clinician may need to consider:
• Whether the person has symptoms of osteomalacia
• Whether calcium is normal
• Whether the gut can absorb oral vitamin D
• Kidney, liver or parathyroid disease
• Other medicines and supplements
• Pregnancy or breastfeeding
• Whether a bone treatment is planned
• When another blood test or clinical review is needed
If a person remains deficient despite treatment, the next step is not always simply to take more.
Adherence, absorption, the original diagnosis and another medical cause may need review.
Can food provide enough vitamin D?
Vitamin D occurs naturally in a limited number of foods.
Useful sources include:
• Oily fish such as salmon, sardines, trout, herring and mackerel
• Egg yolks
• Red meat
• Liver
• Foods with vitamin D added, such as some breakfast cereals and fat spreads
• Some fortified plant drinks and dairy products
Check the label because fortification varies.
Cow’s milk in the UK is generally not fortified with vitamin D, although some other dairy and plant products are.
Mushrooms can contain vitamin D, particularly when they have been exposed to ultraviolet light, but amounts vary.
Food can contribute to intake, but the range of natural sources is narrow.
That is why public health guidance recommends considering a supplement during autumn and winter.
Liver is rich in vitamin A and should be avoided during pregnancy.
Eating more oily fish or liver is not a substitute for personalised dietary advice when pregnancy, allergy or another medical condition changes what is suitable.
Can you get vitamin D from sunlight safely?
From late March or early April to the end of September, most people in the UK should be able to make vitamin D from sunlight on their skin.
There is no single safe exposure time that works for everybody.
Vitamin D production and the risk of burning are affected by:
• Skin tone
• Age
• Clothing
• Time of day
• Cloud
• Location
• The amount of skin exposed
Spend time outdoors, but do not allow skin to redden or burn.
Cover up, seek shade and use suitable sun protection before burning becomes likely.
Sunburn increases the risk of skin cancer.
Sunbeds are not a safe way to raise vitamin D.
They emit ultraviolet radiation and increase the risk of skin cancer.
The body does not make a toxic amount of vitamin D from sunlight.
Excess vitamin D is caused by taking too much from supplements, not by normal outdoor exposure.
Does sunscreen cause vitamin D deficiency?
Sunscreen reduces ultraviolet exposure when it is applied correctly.
However, real world sun exposure varies and people do not need to risk burning to make vitamin D.
UK guidance does not recommend leaving skin unprotected for a fixed number of minutes.
Follow sun safety advice and use the recommended supplement during autumn and winter.
People with little sunlight exposure should consider supplementation throughout the year.
If you have:
• A history of skin cancer
• Photosensitivity
• Medicine that makes skin more sensitive to sunlight
follow the advice of your own clinician rather than changing protection to obtain more vitamin D.
Can vitamin D help with weight loss?
Vitamin D is not a weight loss treatment.
People living with obesity may be more likely to have a low blood level, but taking vitamin D has not been shown to produce meaningful weight loss by itself.
Correcting a confirmed deficiency may improve symptoms caused by that deficiency, such as muscle weakness.
Feeling better may make everyday activity easier, but that is different from vitamin D directly causing fat loss.
Do not replace an evidence based weight management plan with high dose supplements.
If you are using a weight management service, tell the clinician about all vitamins and supplements you take, particularly products containing several ingredients.
Can vitamin D improve mood, immunity or tiredness?
Vitamin D has important biological functions, but supplement advertising often goes beyond what evidence can support.
If a person is deficient, correcting the deficiency is appropriate.
If vitamin D is already adequate, taking a high dose has not been proven to reliably:
• Improve mood
• Prevent every infection
• Remove unexplained tiredness
Persistent low mood, frequent illness or fatigue should not be self diagnosed as vitamin D deficiency.
These symptoms may need a different assessment and support.
Who should ask for advice before taking a supplement?
The usual preventive amount is suitable for most people.
Ask a GP, pharmacist or relevant specialist before taking vitamin D if you:
• Have kidney disease or a history of kidney stones
• Have been told that your calcium is high
• Have sarcoidosis or another granulomatous condition
• Have a parathyroid disorder
• Have severe liver disease
• Have a condition that affects absorption
• Have had bariatric surgery
• Take medicines that alter vitamin D or calcium
• Are already taking a prescribed vitamin D or calcium product
• Are considering a dose above the standard preventive amount
Parents and carers should use age appropriate guidance for babies and children.
Do not give a child an adult strength product unless a clinician or pharmacist has confirmed the exact dose and formulation.
Vitamin D in pregnancy, breastfeeding and childhood
The Public Health Agency advises pregnant and breastfeeding women to take 10 micrograms throughout the year.
This supports the adult’s bone and muscle health and helps provide vitamin D for the baby.
Breastfed babies should receive 8.5 to 10 micrograms daily from birth.
Babies who have more than 500 ml of infant formula each day generally do not need an additional vitamin D supplement because formula is fortified.
Babies receiving less than this amount should have a supplement.
Children aged one to four should receive 10 micrograms daily throughout the year.
Children aged five and over should consider 10 micrograms during autumn and winter, with year round use when they are in a higher risk group.
Products for babies and children have different concentrations.
Follow the label carefully and ask a health visitor, pharmacist or GP if there is any doubt.
The Healthy Start scheme may provide vitamins to eligible families.
Seek medical advice if a child has:
• Bone pain
• Delayed growth
• Unusual muscle weakness
• Difficulty walking
• Changes in the shape of growing bones
These symptoms have different possible causes and should not be managed with an adult supplement alone.
Where can you get vitamin D support in Belfast and Northern Ireland?
People across Belfast and Northern Ireland can buy standard vitamin D supplements from:
• Community pharmacies
• Many supermarkets
A community pharmacist can explain label units, identify duplicate ingredients and advise whether a product matches the public health recommendation.
Contact your GP when:
• Symptoms suggest significant deficiency
• There is a relevant medical condition
• You need advice about testing
If a blood test is clinically indicated, a GP or another responsible service can arrange it and explain what the result means.
For babies, young children and pregnancy, a:
• Midwife
• Health visitor
• Pharmacist
• GP
can provide age specific guidance.
Eligible families can check the Healthy Start scheme for access to vitamins.
Do not assume that a more expensive supplement is more effective.
The important points are:
• The amount of vitamin D
• The suitability of the ingredients
• Whether the product is used as directed
When should you contact a GP?
Arrange a GP appointment if you have:
• Persistent or unexplained bone pain
• Muscle weakness that affects walking, stairs or getting out of a chair
• An unexpected fracture or concern about bone health
• Ongoing fatigue or aches that need a broader assessment
• A condition that can reduce vitamin absorption
• A kidney, liver, calcium or parathyroid disorder
• Symptoms despite following a treatment plan
• A child with possible features of rickets
Seek prompt advice if you:
• Have taken a very high dose
• Have accidentally repeated doses
• Develop concerning symptoms while using a strong supplement
Call 999 for a life threatening emergency such as:
• Collapse
• A seizure
• Severe confusion
• Serious breathing difficulty
Vitamin D and Keltoi Wellness
Keltoi Wellness publishes general information to help people make informed health decisions.
This article does not diagnose vitamin D deficiency and does not mean that Keltoi provides vitamin D blood testing or treatment.
Keltoi’s online questionnaire cannot determine whether vitamin D is low.
If you use a Keltoi service, give complete and accurate information about:
• Diagnosed conditions
• Current symptoms
• Medicines
• Supplements
Dr Waqar Ahmed makes clinical decisions for Keltoi weight management after considering the information available and whether care is appropriate.
Possible vitamin D deficiency, persistent pain, weakness or unexplained fatigue should be discussed with your GP or usual healthcare team.
A separate NHS or private blood result should not be used to change a treatment plan without the responsible clinician’s advice.
A practical vitamin D checklist for Northern Ireland
For most adults, the following is a sensible approach:
- Consider 10 micrograms of vitamin D each day during autumn and winter.
- Take 10 micrograms throughout the year if you are in a group advised to do so.
- Check existing multivitamins and other supplements to avoid doubling up.
- Do not exceed 100 micrograms daily unless a doctor has advised it.
- Ask a pharmacist if units or ingredients on the label are unclear.
- Do not use tiredness alone to diagnose a deficiency.
- Contact your GP if you have persistent bone pain, muscle weakness or a clinical risk that may require testing.
- Follow a clinician’s plan if a test confirms deficiency rather than copying a high dose schedule online.
The bottom line
Vitamin D deficiency often has no clear symptoms.
Severe or prolonged deficiency can affect bones and muscles, but common complaints such as fatigue and aches have many possible causes.
Routine blood testing is not recommended for everybody.
Testing is most useful when symptoms or a clinical condition make the result relevant to care.
For people in Northern Ireland, the core public health advice is to consider 10 micrograms of vitamin D daily during autumn and winter.
Higher risk groups should consider the same amount all year.
Standard supplementation, safe time outdoors and vitamin D containing foods can work together, but high dose treatment should remain clinically supervised.
Frequently asked questions
What are the first signs of vitamin D deficiency?
There may be no signs.
When symptoms occur, they can include:
• Bone pain
• Muscle aches
• Muscle weakness
• Reduced physical function
Tiredness is sometimes reported but is not specific enough to diagnose deficiency.
Should everyone in Northern Ireland take vitamin D?
Adults and children over four should consider 10 micrograms daily during autumn and winter.
Groups with a higher risk of low vitamin D are advised to take 10 micrograms throughout the year.
Do I need a vitamin D blood test before taking 10 micrograms?
Usually not.
Routine testing is not recommended for people without symptoms.
The standard preventive amount can generally be taken without a test, while a clinician may arrange testing if symptoms or a medical condition provide a reason.
Can I ask my GP for a vitamin D test in Northern Ireland?
You can discuss your symptoms and risks with your GP.
The GP will decide whether a vitamin D test or a different investigation is clinically appropriate.
A request does not automatically mean that testing is needed.
Is 10 micrograms the same as 400 IU?
Yes.
Ten micrograms of vitamin D is equal to 400 international units.
Labels may show:
• Micrograms
• mcg
• µg
• IU
Is 1,000 IU of vitamin D too much?
One thousand IU equals 25 micrograms.
It is below the adult upper limit of 4,000 IU a day, but it is more than the standard 400 IU preventive recommendation.
Ask a pharmacist or clinician what is appropriate for you, especially if you take other supplements or have relevant medical conditions.
Can I take vitamin D all year?
Yes.
Year round use at the recommended preventive amount is advised for higher risk groups and can be appropriate for others.
Check with a pharmacist or clinician if you have a condition affecting:
• Calcium
• Kidneys
• Absorption
Can too much vitamin D be harmful?
Yes.
Long term excessive intake can raise calcium in the blood, weaken bones and damage the kidneys and heart.
Adults should not take more than 100 micrograms, equal to 4,000 IU, daily unless advised by a doctor.
Which foods contain vitamin D?
Sources include:
• Oily fish
• Egg yolks
• Red meat
• Liver
• Some fortified cereals
• Some fortified spreads
• Some fortified plant drinks
Amounts vary and food alone may not provide enough during autumn and winter.
Can low vitamin D stop me losing weight?
Vitamin D deficiency is not usually a complete explanation for difficulty losing weight.
Supplements are not a weight loss treatment.
If low vitamin D causes muscle weakness, correcting it may support general wellbeing and activity, but it does not directly produce fat loss.
How long does vitamin D take to work?
That depends on:
• How low the level is
• The cause
• The treatment
• The symptom being assessed
A clinician can explain when improvement or repeat testing would be expected.
Do not increase the dose because improvement is not immediate.
Are vitamin D sprays better than tablets?
There is no universal best format.
Tablets, capsules, drops and sprays can all be suitable when they provide the correct amount and are used properly.
Choice may depend on:
• Swallowing
• Ingredients
• Age
• Clinical needs
Are expensive vitamin D supplements better?
Not necessarily.
A suitable product should:
• Provide the intended amount
• Have clear instructions
• Meet your dietary or allergy needs
Price and marketing terms do not prove that a supplement is more effective.
Can I get free vitamin D supplements in Northern Ireland?
Some pregnant people and families with young children may qualify for vitamins through the Healthy Start scheme.
A midwife, health visitor or pharmacist can explain local access and current eligibility.
Sources and further reading
• Public Health Agency: Winter wellbeing, PHA recommends a daily vitamin D supplement
• nidirect: Vitamin D
• NHS: Vitamin D
• NHS: About colecalciferol
• NICE: Vitamin D deficiency in adults
• NICE: Diagnosis of vitamin D deficiency in adults
• NICE: Vitamin D supplement use in specific population groups
• NICE: Complications of vitamin D deficiency in adults
• Healthy Start: Vitamins
Last updated: August 2026
Disclaimer: This article provides general information and does not diagnose vitamin D deficiency or replace advice from a GP, pharmacist, dietitian, health visitor or specialist. Do not use a high dose supplement to treat symptoms without appropriate clinical advice. Call 999 in a life threatening emergency.