Time to take vitamin D supplements

Summer ended 100 days ago, and we now all need a vitamin D boost. Very few of us manage to get enough vitamin D from the food we eat.

Norwegian mountains

Sun setting over Norwegian mountains in the autumn. Photo: Colorbox.com.

The sun is our most important source of vitamin D during the summer. Vitamin D is formed in our skin when exposed to the sun, and excess amounts are stored in our liver. After a good summer, our body has a good stock of vitamin D, which will last for around 100 days.

Out of stock

“Without vitamin D from the food we eat, all of us will more or less be out of stock by November,” explains Associate Professor Christine Henriksen, at the Department of Nutrition.

How much do we need?

We can take supplements in the form of cod liver oil or vitamin D tablets, and the recommended dose is:

  • 10 µg (micrograms) per day for children and adults. 1 child’s spoon of cod liver oil (5 ml) provides 10 µg. For vitamin D tablets, please read the instructions that come with the supplement. 
  • 20 µg for persons older than 75.
  • Babies and the elderly in nursing homes should take supplements all year round as they do not have as much exposure to the sun.

Food containing vitamin D

Vitamin D is also present in the food we eat:

  • fatty fish
  • margarine
  • fortified milk (semi-skimmed 0.7%)
  • eggs

Christine Henriksen explains that: "The results from the most recent population survey, NORKOST 3, showed that the average intake in Norway is 6.7 µg per day, which is two thirds of the recommended intake of 10 µg per day. "

Associate Professor Christine Henriksen from the Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo. Photo: Private.

Don’t forget the kids

Babies and children have a lower intake, and intake for children in 4th grade at school is on average only one third of the recommended dose. One explanation for this may be that children eat less fatty fish and use less

margarine than adults.

Even with a diet that fulfils the national dietary advice, it is difficult to get sufficient levels of vitamin D, see table.

Average intake of vitamin D with a good, varied diet



Vitamin D per day (µg)

Fatty fish (salmon)

1 portion per week



On six slices of bread per day


Semi-skimmed milk (0.7%, fortified)

Three glasses per day



3 per week


In total



Christine Henriksen explains that it is therefore safe to recommend that persons who do not get enough vitamin D from food should take vitamin D supplements during the winter, particularly as this advice applies to almost everyone.

Sunbeds and vitamin D 

“Sunbed studios advertise sunbeds as a source of vitamin D, and this is a problem in Norway.  Sunbeds are not a suitable source of vitamin D,” explains Professor Marit B. Veierød, Oslo Centre for Biostatistics and Epidemiology, at the University of Oslo.  A group of representatives from different health authorities and Norwegian academics support this statement (the issue was discussed on research website Forskning.no and the statement can be read in full in the Norwegian expert statement regarding sunbeds and cancer (pdf in norwegian). 

Source: National council for nutrition: Vitamin D in Norway: Need for measures to ensure good vitamin D status. IS-2772. Published 11/2018.(pdf) Sunbeds are carcinogenic and not suitable as a source of vitamin D.

By Eyrun Thune
Published Nov. 29, 2019 12:28 PM - Last modified May 4, 2021 12:49 PM