What is Vitamin D
Vitamin D is an inert, fat-soluble prohormone. Its primary function is to allow the body to absorb calcium. Calcium itself is not commonly in a usable from and without vitamin D, the calcium we consume would not be added into bones. Vitamin D helps calcium in almost every stage from the absorption of calcium out of the foods and supplements we take to the proper flowing through the bloodstream to the bones that need it. Vitamin D though is unusable by the body in its normal inert form. The liver converts the inert form into calcidiol and then the kidneys will convert it a second time into calcitriol. Calcitriol is the form that the body uses with calcium. It's for this reason that it is important to monitor levels of intake to prevent vitamin D deficiency.
Vitamin D Deficiency
The main concerns of vitamin D deficiency are brittle and weak bones. In children, vitamin D can cause the disease Rickets. This disease causes soft bones because while calcium may be in the body it is not mineralized into the bones to strengthen them. Bones may even become malformed or deformed. Luckily, Rickets is not permanent and can be reversed by an abundance of vitamin D. With the addition of vitamin D added to milk, Rickets has become a rare disease but should still be monitored.
In adults, vitamin D deficiency can lead to osteomalacia, a weakening of both muscles and bones. Noticeable symptoms include bone pain and weakness of the muscles. These are not noticeable at first so it can be difficult to detect in the beginning stages of osteomalacia. Osteoporosis is a condition in older adults where bones become fragile and brittle and is different from osteomalacia which is the more extreme case of vitamin D deficiency.
Osteoporosis occurs when he body has difficulties in the building and maintaining of the bones. It is usually slower and a more long term condition then osteomalacia but can occur with lower levels vitamin D and not just deficient levels. For this reason vitamin D is very important to take along side any calcium supplements to fight these diseases if it has not already been added.
Sources of vitamin D
Vitamin D can normally be made by the body with the proper type and amount of sunlight but current lifestyles may make it difficult to get enough to prevent vitamin D deficiency. The ultraviolet light from the sun stimulates the skin to making Vitamin D. Getting enough sun in the spring and summer can be difficult with the use of sun block lotion to prevent sunburns and other negative effects of sunlight to the skin. In the fall and winter when it gets colder most people will have an abundance of clothing which also will block the sunlight from reaching the skin. The far northern and southern reaches of the earth have another concern. The light wavelength needed to create vitamin D has to be in a range of 270-300 nm. This only occurs if the sun rises high enough. Between November and February people living north of Boston or the northern border of California will not receive enough sunlight to produce vitamin D on their own.
Receiving enough Vitamin D from foods can be difficult as it is not naturally occurring in many foods.Fish such as salmon, mackerel, and tuna have some levels as well fish liver oils.Other types of food with vitamin D are beef liver and egg yolks. Mushrooms that have been exposed to additional ultraviolet light can have some levels of vitamin D though naturally it does not occur in notable levels. This is not common and is done for the sole purpose of adding additional vitamin D to the mushrooms.
Because of its scarcity in foods, vitamin D has been added to many foods. Milk and other dairy products such as yogurt and cheese can be fortified to prevent vitamin D deficiency. Orange juice and cold breakfast cereals also can have the vitamin added.
One of the best sources of vitamin D is from a vitamin supplement or pill. Getting vitamins from food is normally the best source but because of its scarcity it may be difficult to get enough vitamin D to prevent a deficiency. With the rise of organic and natural food products, not all dairy products will be fortified with additional vitamin D. Careful review of the ingredients and label might be necessary to confirm if you are getting enough vitamin D. As natural vitamin D comes almost exclusively from animals, those on a strict vegetarian diet can have difficulties consuming enough of the vitamin. Vitamin supplements also have the added advantage that they can be mixed. This way you can be assured you get the right amount of both calcium and vitamin D at the same time.