Thursday, 1 November 2018

Vitamin D

As winter is upon us in Ireland and similar countries above 33 degrees the prevalence of Vitamin D deficiency is common. The lack of sunshine, sedentary lifestyle and staying indoors have reduced our chances of exposing our skin receptors to the UV light that triggers the Vitamin D receptors to synthesise the active form.
Our dietary sources are much lower too. Unless you eat at least one of these foods (see FSAI chart below) every day you will find it hard to have sufficient levels.

Dietary source


Vitamin D (ยตg)


1 egg


Liver* (lamb)



Kidney* (Lamb)



Salmon (canned in brine)



Mackerel (grilled)



Sardines (canned in oil)



Tuna (canned in brine)



Avonmore Supermilk

200ml (glass)


Kellog's Cornflakes *



Kellogg's Special K *



Kellogg's All-Bran *



Kellogg's Rice Krispies * 



Infant formula

500 ml

5.5 – 7.5

Brennan's Vitamin D wholemeal*

2 slices


Please note: This is a reflection of Vitamin D content of the listed products at time of writing. Products are continually reformulated and are not required to be notified to the FSAI

(*Increased Vitamin D content since last reviewed/New Product).

Source:FSAI website November 2018

Having said that I would not be recommending the milk, bread or cereals mentioned above to my clients.

Why is Vitamin D so important?

  • It is the gate keeper for Calcium levels in the blood and risk of developing osteoarthritis, Rickets(yes! over 20 cases of rickets in infants and toddlers have been reported at two Dublin hospitals in the last four to five years), post menopausal bone fractures.
  • Low exposure to the sun and low mood are corrulated for alot of people.More recently research is suggesting a link between serotonin uptake and vitamin D levels.
  • Weakened immunity, auto-immunity and chronic inflammation and low vitamin D levels. Patients with Rheumatoid Arthritis, Lupus, MS and Diabetes Melitotus all show low levels of serum vitamin D. 
  • A recent study of patients with type 2 diabetes risk were supplemented with 500iu vitamin D daily and their risk reduced by 13%.
  • In cardiovascular health vitamin D reduces atheroschlerotic stickiness of the arteries to 'keep them clean' and reduce heart disease risks.
The 2 subgroups are-

Vitamin D2- sourced from plants for vegans.

Vitamin D3- sourced from lanolin

Both forms have a good research indication for effectiveness.

The main risk groups are-

  • Above 33degrees latitude
  • Darker skin tones
  • Obese individuals
  • Sedentary lifestyle
  • Some medications
  • IBD and other digestive impairments
  • Pregnant women
  • Babies
  • The elderly
Here in Galway there are so many people deficient in vitamin D the hospital only tests in certain circumstances.
So what are the recommended dosages?
Most people who fall into one or more of the main risk groups outlined are recommended to take a supplement form.
In Ireland the recommended daily amount is 5ug/200iu for infants and 10ug/400iu for adults.
In practice in clinic I see people taking up to 5000iu daily in some cases. They feel it works for them. The average dose is  generally 2000-3000iu.
Some research even suggests taking your weekly dose in one go eg. a person taking 3000iu per day will pick a day and take 21000iu on that day.
Can you overdose on vitamin D?Too much of anything is a bad thing but it is rare to see it in practice, in my own experience.

Main signs and swmptoms-
  • Elevated Blood Calcium Levels. ...
  • Nausea, Vomiting and Poor Appetite. ...
  • Stomach Pain, Constipation or Diarrhea. ...
  • Bone Loss. ...
  • Kidney Failure.
So if you are in doubt- test.
There is a simple pin prick test to see exactly what your levels are if you cannot  persuade your GP to get it done in the local lab.
Inform yourself, act on your knowledge and feel all the better for it.
Happy health,

Tara Canning Nutritionist

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