As is explained on this page: Information on Vitamin D, most people's main source of vitamin D comes from synthesis in the skin upon exposure to UV light. The newly created vitamin D then travels through the body and is hydrolyzed first in the liver, and then in the kidney. Vitamin D is involved in the regulation of calcium in the body, and therefore has major benefits with regards to bone building and retention.
Usually a 15 minute exposure to sunlight twice a week is enough to give a person an adequate supply of vitamin D. However, in the winter, when skies are cloudy, the weather is cold, and the strength of the sun is less many people do not receive adequate amounts of vitamin D.
Many people turn to vitamin D supplements, this is usually because there are not that many vitamin D rich foods. One of the best sources of vitamin D are fish and liver, therefore taking a capsule of cod liver oil daily is an ideal way of getting the nutrient for non-vegetarians.
As there are not many foods that naturally contain vitamin D it is often the case that foods are fortified with the vitamin, goods that are commonly fortified with vitamin D include milk and cereals.
Natural vitamin D rich foods include, fish and egg yolks. It is also possible to have vitamin D rich mushrooms; these are grown in the presence of UV light enabling the mushroom to synthesize the vitamin.
Here is a full Vitamin D food list.
| Food | Quantity
|
Vitamin D IU
|
| Natural Foods | ||
| Beef Liver | 100g (4oz) |
53 |
| Cod | 100g (4oz) |
140 |
| Cod Liver Oil | 1 Tablespoon |
1350 |
| Cod Liver Oil | 1 Capsule |
50 to 150 (depending on brand and size) |
| Egg Yolk | 1 (medium) |
25 |
| Grey Soul | 100g (4oz) |
75 |
| Mackerel | 100g (4oz) |
520 |
| Salmon, Atlantic (Fresh) | 100g (4oz) |
300 |
| Salmon, Sockeye (Red Salmon) (Fresh) | 100g (4oz) |
1060 |
| Salmon, Atlantic (Tinned) | 100g (4oz) |
94 |
| Salmon, Sockeye (Red Salmon) (Tinned) | 100g (4oz) |
480 |
| Sardine (tinned) | 4 sardines |
94 |
| Trout (farm) | 100g (4oz) |
520 |
| Trout (wild) | 100g (4oz) |
1050 |
| Tuna, Skipjack (fresh) | 100g (4oz) |
510 |
| Tuna, Bluefin (fresh) | 100g (4oz) |
920 |
| Tuna, albacore (tinned) | 100g (4oz) |
55 |
| Tuna, light (tinned) | 100g (4oz) |
140 |
|
Grown in UV light |
||
| Mushrooms | 100g |
535 |
|
Fortified Foods |
||
| Cheese (Usually Swiss or Edam that are fortified) | 100g (4oz) |
24 |
| Margarine | 1 desert spoon (12ml) |
48 |
| Milk | 100ml |
50 |
| Milk | 1 cup (240ml) |
120 |
| Orange Juice (varies on product) | 100ml |
40 |
| Orange Juice (varies on product) | 1 cup (240ml) |
100 |
| Soy Milk | 100ml |
50 |
| Soy Milk | 1 cup (240ml) |
120 |
| Tofu | 100g (4 ounces) |
65 |
| Yogurt | 150g (6oz) |
80 |
Nb. Farmed Salmon has only 25% the vitamin D content of wild salmon. Farmed Trout has about 50% the content of wild.
Cooking fish can have a derogatory effect upon vitamin D levels. Baking fish is the best way of maintaining vitamin D levels and typically reduces the amount of vitamin D by just 2%. Frying fish on the other hand can reduce vitamin D levels to just 50% of their fresh levels.
Ideally men and women aged from 18 to 50 should have an intake of 5 micrograms (200IU) a day to maintain bone strength; from the ages of 50 to 70 this amount is doubled to 10 micrograms (400IU); for people over the age of 70 the RDA is 15 micrograms (600IU).
Due to not eating fish and dairy products vegetarians, and especially vegans need to ensure that they get adaquate supplies of calcium and vitamin D. As the vitamin is not found naturally in vegetables it is recommended that vegans who are unable to get an adaquate supply of vitamin D via exposure to sunlight, drink soya milk, tofu or cereals that have been fortified, or eat mushrooms that have been grown to be vitamin D rich.