Search the whole site for articles and discussions

View a factfile for a specific condition or supplement

Keep up to date with Nutrition Expert

The ever growing benefits of vitamin D

Published Date:

The benefits of vitamin D3 are ever growing, and emerging scientific research continues to add weight to its already long list of health benefits.

Vitamin D is the collective term for five different fat-soluble vitamins, of which the most important for human health are vitamin D3, which is found in animals, and vitamin D2 which is found in plants.


Vitamin D is made in the skin by the action of sunlight, and this is the main source of vitamin D for most people. During the summer months in Europe, about fifteen to thirty minutes of sun exposure to the arms and legs should allow you to make sufficient vitamin D3. In autumn and winter months when there is less sunlight, and we are covered up when we are outdoors, it is difficult to make enough to meet your needs. As you age, your ability to sythesise vitamin D also decreases.


As only a limited number of foods contain vitamin D3, it is difficult to obtain enough vitamin D through diet alone. Good sources include oily fish such as salmon and sardines, red meat, liver, egg yolks, and fortified foods such as fat spreads and some breakfast cereals.


Following an extensive review by the Scientific Advisory Committee on Nutrition, Public Health England therefore advises that everyone takes a daily supplement of 10 micrograms (mcg) of vitamin D to help maintain healthy bones, teeth and muscles [i]. To obtain this Government recommendation from food alone, you would need to eat the equivalent of 10 egg yolks a day.


Maintaining good intakes of vitamin D contributes towards the prevention of rickets and asthma flare ups, as well as towards the maintenance of a healthy immune system which, according to Dr. Sarah Brewer, GP and Medical Director at Healthspan, ‘is backed by extensive medical research’.


What you may not be familiar with is the continued emergence of science that underpins the benefits of vitamin D3 for optimal health.


So what is this emerging science?



Vitamin D intake is linked to a reduction in falls in people aged sixty and over



Researchers in the UK have calculated that, if everyone over the age of 60 was treated with 20mcg (800iu) of vitamin D3 daily for five years, this simple intervention would prevent over 430,000 minor falls, avoid 190,000 major falls and save 1579 lives. [ii]


A link between vitamin D3 deficiency and falls in older people may seem odd, but Dr. Sarah explains the science behind the research: -


‘Vitamin D3 binds to receptors in muscle cells to increase gene activity and protein production in ‘fast twitch’ muscle fibres. These muscle fibres help to maintain balance and co-ordination and rapidly respond to instability to help prevent a fall. This effect means supplements could help older people who are vitamin D deficient.’


Dr. Sarah adds, ‘A large analysis of data from ten studies in older adults also showed that vitamin D supplements of 5mcg to 25mcg daily reduced falls by 14% compared with inactive placebo.’[iii]


Another recent trial[iv] suggested that a combination of low frequency exercise and high dose vitamin D supplementation could help reduce the risk of falls in the elderly by more than 70%.


There is yet more evidence linking vitamin D deficiency to Alzheimer’s disease



In 2014 the medical journal of the American Academy of Neurology compiled a study, the largest of its kind, to investigate a possible link between vitamin D deficiency and the risk of developing Alzheimer’s disease and other forms of dementia. Though scientists expected to find an association between the two, they were surprised to find that not getting enough vitamin D could double the risk of developing these conditions[v].


Almost three years on and another link was found. This time, researchers from Duke University and Duke-NUS Medical School looked at the effects of vitamin D on cognitive decline, based on previous research suggesting that vitamin D protects against neuron damage and loss. They measured vitamin D levels in people aged 60 and over and assessed their mental abilities over two years. Those with low vitamin D levels at the start of the study were around twice as likely to show significant cognitive decline over time as those with higher levels[vi].


Should my vitamin D daily intake amount change in accordance with my age?


'With increasing age, your ability to synthesise your own vitamin D reduces. In one study, people aged 62 to 80 years synthesised four times less vitamin D than those aged 20 to 30 years’, says Dr. Sarah Brewer.


‘If you’re only interested in protecting the future health of your bones, then the Government recommended daily dose of 10mcg is probably fine. But, if you want to maintain optimum blood levels that boost your immunity and protect against other health issues, a higher dose is needed.

In any case, to suggest that the same 10mcg dose will suit everyone, from a tiny infant to a strapping body-builder and a frail, elderly lady is illogical.’


Dr. Sarah says, ‘If you are under the age of 50, many experts suggest that, in the absence of sun exposure, an intake of 25mcg (1000iu) vitamin D is more appropriate than 10mcg for optimum adult immune health. If you are over the age of 50, a higher intake of at least 50mcg vitamin D3 may be needed.










Sarah Brewer graduated as a doctor from Cambridge University. Having worked in hospitals and general practice, she gained a Master's degree in Nutritional Medicine from the University of Surrey. She is the author of over 60 popular health books and writes widely on all aspects of health including complementary medicine. More from this expert.

Latest Articles

You may also be interested in:


The benefits of Omega 3

Nutritionist Henrietta Norton explains the many benefits...

Dr Hilary Jones

What is Alzheimers?

Dr Hilary Jones discusses Alzheimer's disease and how...

Dr Sarah Brewer

Arthritis and your nutrition

Dr Sarah Brewer explores how your nutrition can help...


Circulation, Heart Health and Nutrition

Discover how nutrition can help keeping your heart...

No statement or article should be understood as providing treatment advice. If you have a health problem consult your GP and check compatibility of new supplements with your GP or Pharmacist if you are taking any prescription medication.

Nutrition Expert sources the latest information and advice from a range of qualified doctors, nutritionists and coaches. We always endeavour to have the most up to date information possible and publish new content weekly. However with the constant research in this field sometimes some of our older articles can become out of date. If you see anything that you believe needs to be updated please let us know via our Contact Us page