Cooking reduces vitamin D content by about 30 percent – Oct 2013

Stability of vitamin D in foodstuffs during cooking

Food Chemistry, Available online 17 October 2013
Jette Jakobsen jeja at food.dtu.dk
Pia Knuthsen
Division of Food Chemistry, National Food Institute, Technical University of Denmark, Mørkhøj Bygade 19, DK-2860 Søborg, Denmark

We investigated the retention of vitamin D3 and 25-hydroxyvitamin D3 in eggs, vitamin D3 in margarine, and vitamin D3 and vitamin D2 in bread. Our set-up illustrated the cooking methods usually performed in households i.e. boiling, frying in pan and oven, and baking. All experiments were performed three times independently of one another. The retention of vitamin D compounds in eggs and margarine during heat treatment in an oven for 40 minutes at normal cooking temperature showed retention at 39-45%, while frying resulted in retention at 82-84%. Boiled eggs were found to have a similar level of retention (86-88%).

For bread baked, as recommended in the recipe, the retention of vitamin D3 in rye bread at 69% was lower than the retention in wheat bread at 85%.

A similar observation was made for vitamin D2, although the retention was slightly higher, 73% and 89%.

No difference between retention of vitamin D3 and 25-hydroxyvitamin D3 in eggs was shown. Cooking may cause detrimental loss of vitamin D, but it depends on the actual foodstuffs and the heating process. Further research is needed to optimize cooking procedures to enhance retention of vitamin D. Vitamin D retention should be taken into account in future calculations of dietary intake of vitamin D.

See also VitaminDWiki

• Food fortification especially baking in Canada - Dec 2009 file, not webpage
• Search VitaminDWiki for Baking OR Cooking 270 items as of April 2019
• Vitamin D fortification of edible oils in India starting in 2017
• Fortification with Vitamin D category listing has 135 items along with related searches
• International Conference of Vitamin D Fortification of Food (India) – Sept 2018
• Vitamin D in food not decreased as much by cooking when lemon juice added – Feb 2018