Vitamin D is an essential nutrient found in sunlight and animal products such as oily fish (salmon, tuna, herring, and cod liver). It is found in mushrooms and fortified foods for better bone health and the immune system.
Whenever human skin is exposed to sunlight, it produces a vital nutrient called vitamin D and could also be taken in various health vitamin D foods. However, some people have vitamin D deficiency because they do not get enough sunlight due to working indoors and eating an unhealthy western diet lacking in this vital nutrient. Vitamin D is not found in most natural foods hence the need to be selective on the foods to incorporate in your diet as a source of vitamin D. It is often found in some oily fish, fortified foods, and mushrooms. The recommended daily intake of vitamin D for individuals exposed to adequate sunlight is 20mcg of the vitamin from foods. However, for those who do not get enough sunlight, the daily intake of vitamin D from food will increase to 25 mcg per day. Vitamin D is beneficial in ensuring healthy bones, nerves, muscles, and the general immune system. It also promotes the intake of calcium, thus aiding in bone development and reduced inflammation.
Vegans and vegetarians who spend lots of time indoors may be vitamin D deficient since major sources of this nutrient are animal and fish-based products. A deficiency of this nutrient could result in rickets, impaired immune system, poor hair growth, and a high risk of cancer. On the other hand, excess vitamin D in the body could result in over-absorption of calcium, increasing the risk of diseases such as kidney stones and heart diseases.
Food Sources of Vitamin D
If you do not get enough sunlight to improve the body’s natural manufacture of this vitamin, you will need to eat certain food to supplement the required daily vitamin D.
There are several types of oily fish rich in vitamin D, and they are discussed below.
It is a popular source of vitamin D and proteins. The United States Department of Agriculture (USDA) recommends that serving 100 grams of farmed Atlantic salmon would contribute to 66% of the daily value of vitamin D. Wild salmon has a higher value of vitamin D than farmed ones. Studies show that wild salmon could provide up to 124% (988 IU per 3.5-ounce) daily value of vitamin D in every 100 grams serving. Other studies even attribute higher levels of up to 1,300 IU in every 100 grams servings. Farmed salmon can provide approximately 250 IU of vitamin D, an equivalent of 32% of the daily value.
Herring and Sardines
Herring fish can be served canned, smoked, raw, or pickled, and it is one of the best sources of vitamin D. Fresh wild Atlantic herring contributes 216 IU per 100 grams, which translates to 27% of the daily value. Pickled herring provides 112 IU for every 100 grams serving, contributing to 14% of the daily value. Canned sardines are also an immense source of vitamin D, providing 177 IU per 100 grams, which equates to 22% of the daily value.
Halibut, Mackerel, and swordfish also contain vitamin D, providing 384 IU, 360 IU, and 706 IU respectively per half a fillet.
It is an appropriate supplement for individuals who do not fancy fish and improve their vitamin D intake. For every teaspoon (4.9 ml) of cod liver, one can acquire 448 IU of vitamin D. This supplement is often used to prevent and treat vitamin D deficiency in children. However, high consumption of cod liver can be unhealthy since it contains high levels of vitamin A which could become toxic.
Canned tuna is popular because it is easy to store, cheaper, and is very sweet. It provides 268 IU of vitamin D per 100 grams serving, contributing to 34% of the DV. One downside of canned tuna is that it contains toxic methylmercury should it build up in the body.
Whole eggs can also be a wonderful source of vitamin D for those who cannot access seafood. Though some nutrients such as proteins are found in the white part of the egg, the yolk is loaded with fats, minerals, and vitamins. One egg yolk provides 37 IU of vitamin D, contributing to 5% of the daily value. Eggs from chicken that roam about in the sunlight searching for food have been found to provide three to four times higher value of vitamin D.
Apart from fortified foods, mushrooms are the only source of vitamin D from plants. It makes vitamin D when exposed to UV light. It produces vitamin D2, different from animal products rich in D3. Some types of wild mushrooms provide as high as 2,300 IU per 100grams serving, equating to almost three times the daily value of vitamin D. However, mushrooms grown in the dark may contain only very little D2 unless they are treated with UV light.
Since there are limited natural sources of vitamin D for vegetarians and those that do not love fish, fortified foods can provide the needed alternative.
Cow’s milk – In some countries, cow’s milk is infused with vitamin D, providing approximately 115-130 IU for every 237ml of milk to give you 15-22% of your daily value.
Soy milk – vegetarians and vegans who do not drink milk could resort to fortified soy milk. Soy milk can be fortified with vitamin D and other minerals found in cow’s milk, enabling it to provide 107-117 IU of vitamin D per 237 ml of soy milk, and this contributes to 13-15% of your daily value.
Orange juice – Studies show that some people are allergic to milk and are lactose intolerant. Because of these problems, some countries approve the fortification of orange juice with vitamin D and other minerals such as calcium. 237 ml of fortified orange juice provides 100 IU of vitamin D, equating to 12% of the DV.
Cereal and oatmeal – These products can also be fortified with vitamin D. A half a cup of fortified cereal provides 4-136 IU of vitamin D, resulting in 17% of the daily value.
The bottom line
The natural sunlight in the morning could help provide the needed vitamin D synthesis on the skin without the risk of harsh UV rays. However, it is becoming difficult to acquire adequate sunlight since most people spend their days working indoors and in cold weather conditions. Consuming oily fish, fortified foods, and mushrooms could supplement vitamin D nutrients in the body.