You may be surprised to read that vitamin D is totally different from most other vitamins. Actually, it is a steroid hormone that is produced from cholesterol when the skin is exposed to the sun. For this reason, vitamin D is often known as the “sun” vitamin. However, these days sun exposure is often inadequate, so that for people there is a need to get more vitamin D through food (or supplements). This is important, because vitamin D is absolutely essential for optimal health. Unfortunately, only a handful of foods contain significant amounts of this vitamin, and having poor levels is very common. In fact, according to 2005-2006 data, 41.6% of the US population is deficient in this essential vitamin / hormone.
This article explains everything you need to know about vitamin D.
What is Vitamin D?
Vitamin D is one of the fat-soluble vitamins (A, D, E and K), which means that it dissolves in fat / oil and can be stored in the body for a long time. Actually, there are two main forms of vitamin D found in the regular diet:
- Vitamin D3 (cholecalciferol):It is found in some foods of animal origin, such as fatty fish and egg yolks.
- Vitamin D2 (ergocalciferol):It is found in some mushrooms.
Of the two forms, the first, vitamin D3 (cholecalciferol) is what interests us, because it is almost twice as effective in increasing blood levels compared to the second form of vitamin D, vitamin D2 (ergocalciferol ).
Summary: Vitamin D is a fat-soluble vitamin that can be stored in the body for long periods of time. There are two main forms, D2 and D3, of which the D3 form is much more effective.
What Does Vitamin D Do in the Body?
Vitamin D at the beginning is really very useless. You have to go through two conversion steps to be synthesized as “active”. First, it becomes calcidiol, or 25-hydroxyvitamin D (abbreviated 25 (OH) D3), in the liver. This is the way of storage of vitamin D in the body. Second, it is converted to calcitriol, or 1-alpha 25-dihydroxycholecalciferol (abbreviated 1.25- (OH) 2D3), mainly in the kidneys. This is the active form of the steroid hormone of vitamin D. Calcitriol travels through the body, entering the nuclei of cells. There it interacts with a receptor called vitamin D receptor (RVD), which is found in almost every cell in the body.
“When the active form of vitamin D binds to this receptor, it activates or deactivates the genes, causing changes in the cells”.
This is similar to the functioning of most steroid hormones. It is well known that vitamin D affects several cells related to bone health, for example, telling the intestine cells to absorb calcium and phosphorus. But scientists have discovered that it is involved in all kinds of processes, including immune function and protection against cancer. So, people who have vitamin D deficiency will have calcitriol deficiency (the form of steroid hormone).
Summary: Vitamin D is converted to calcidiol, the way vitamin D is stored, which is then converted to calcitriol, the active form of steroids. Calcitriol binds to the vitamin D receptor within cells, activating or deactivating genes to fulfill specific functions.
Sunlight is the Best Way to Get Vitamin D:
Vitamin D can be produced from cholesterol in the skin, when exposed to the sun. The ultraviolet B (UVB) rays of the sun provide the energy necessary for the reaction to occur. If you live where the sun abounds throughout the year, then you can probably get all the vitamin D you need when you go out and sunbathe a few times a week. Keep in mind that you need to expose a large part of your body. If you are only exposing your face and hands, then much less vitamin D will be produced. In addition, if it is behind glass or sunscreen is used, then less or no amount of vitamin D will be produced at all. This makes the recommendation of using sunscreen to protect against skin cancer highly questionable. Using sunscreen on the skin increases the risk of vitamin D deficiency, which can lead to other diseases. If you decide to get vitamin D from the sun, be sure to overexpose yourself as it could cause sunstroke. The sun is healthy, but burns can cause premature skin aging and increase the risk of skin cancer. If you are exposed to the sun for a long time, you should consider doing it without sunscreen for the first 10-30 minutes (depending on the sensitivity to the sun of each person), and then apply it before starting to suffer sunstroke. Vitamin D is stored in the body for a long time, weeks or months, so you only need to sunbathe occasionally to maintain adequate blood levels. That said, not everyone lives in places where there is sunlight throughout the year. In these cases, obtaining vitamin D through food or supplements is absolutely essential, especially during the winter months.
Summary: Sunlight is the best way to get vitamin D, but when using sunscreen decreases the energy needed for the production of vitamin D. Many people do not have access to sunlight for most of the year so It is essential to obtain vitamin D through food or supplements.
Very Few Foods Contain Vitamin D in Significant Amounts:
Although fatty fish such as salmon, mackerel, swordfish, trout, tuna and sardines are decent sources of vitamin D, you should eat them almost daily to get enough vitamin. The only really good dietary source of vitamin D is fish liver oils, such as cod liver oil, which contains up to twice the daily value in a single tablespoon. Keep in mind that dairy products and cereals are often fortified with vitamin D. Some rare mushrooms also contain vitamin D, and egg yolks contain small amounts.
Summary: Cod liver oil is the best source of vitamin D3. Fatty fish is also a good source, but you should eat very often to get enough vitamins.
Vitamin D Deficiency is a Serious Matter:
Vitamin D deficiency is one of the most common nutrient deficiencies. Some people are at greater risk than others. Although the average is around 41.6%, this percentage rises to 82.1% in people of color and 69.2% in Hispanics. Older people are also at a higher risk of having vitamin D deficiency. It is also very likely that people who have certain diseases have a deficiency of this vitamin. One study showed that 96% of patients with heart attacks had low levels of vitamin D. Unfortunately, vitamin D deficiency is a silent epidemic. The symptoms are usually subtle, and may take years or decades to appear. The best-known symptom of vitamin D deficiency is a bone disease called rickets, which is common in children in developing countries. However, due to public health measures, some foods with vitamin D began to be fortified, which greatly reduced the risk of rickets in Western societies. Deficiency has also been linked in osteoporosis in the elderly, which results in reduced bone density and increased risk of falls and fractures. Studies have also shown that people with low levels of vitamin D have a much higher risk of heart disease, diabetes (both type 1 and type 2), cancer, dementia and autoimmune diseases such as multiple sclerosis, among others. Vitamin D deficiency has also been linked to a significantly higher risk of death from all these causes. It is still unclear whether vitamin D deficiency really contributes to these diseases, or if people who have low levels of vitamin D are more likely to suffer from these risks.
Summary: Vitamin D deficiency is a well-known cause of a bone disease in children called rickets. However, the deficiency has also been linked to many other health problems, as well as reduced life expectancy.
Health Benefits of Getting a Lot of Vitamin D:
Vitamin D has generally received considerable attention in recent years and decades. Hundreds of studies and research on the subject have been carried out and numerous results have been obtained.
Here are Some Potential Benefits of Consuming a Lot of Vitamin D:
- Osteoporosis, falls and fractures:High doses of vitamin D can help prevent osteoporosis, falls and fractures in the elderly.
- Resistance: The use of vitamin D supplements can increase physical strength, both in the upper and lower extremities.
- Cancer: Vitamin D can help prevent cancer. One study showed that 1100 International Units (IU) per day, along with calcium, reduced the risk of cancer by 60%.
- Depression: Studies have shown that vitamin D supplements produce a slight reduction of symptoms in people with clinical depression.
- Type 1 diabetes: A study in infants found that 2000 IU of vitamin D per day reduced the risk of type 1 diabetes by 78%.
- Mortality: Some studies have shown that the use of vitamin D supplements reduced the risk of death in people during the study periods, indicating that it can help prolong the life time.
This is really just the tip of the iceberg. Low levels of vitamin D have been linked to all kinds of diseases, and the use of vitamin supplements has proven to have numerous benefits. However, it must be borne in mind that much of this is definitely not proven. According to a recent 2014 review, more tests are needed to confirm many of these benefits.
Summary: Taking vitamin D supplements has been shown to have numerous benefits related to cancer, bone health, mental health and autoimmune diseases, to name a few.
What Amount of Vitamin D is Recommended?
The only way to know if you are deficient, or if you need to take a vitamin D supplement, is by blood tests. The doctor will measure the amount of calcidiol storage or 25 (OH) D. Any number less than 12 ng / dL (nanograms per deciliter) is considered deficient, and any number above 20 ng / dL is considered adequate. The RDI (Recommended Daily Intake) for vitamin D in the United States is as follows:
- 400 IU (10 mcg): Infant babies, 0 to 12 months.
- 600 IU (15 mcg): Children and adults, 1 to 70 years old.
- 800 IU (20 mcg): Elderly and pregnant or breastfeeding.
Although the official minimum reference for vitamin D deficiency is 12 ng / dL, many health experts believe that people should aspire to higher levels of vitamin D in blood above 30 ng / dL for optimal health and prevention of diseases. In addition, many believe that the recommended intake is too low, and that people need to ingest much more vitamin D to achieve optimal levels of the vitamin in their blood. According to the Institute of Medicine, the safe upper limit is 4,000 IU, or 100 micrograms. For people who are at risk of deficiency, this can be a good amount to consider. Sometimes doctors recommend taking much more than that. Just make sure you take vitamin D3, not D2. Vitamin D3 in capsules is available in most supermarkets and health food stores.
Vitamins A, K2 and Magnesium are also Important:
It is important to keep in mind that nutrients usually do not work individually. Many of the nutrients depend on each other, and increasing the intake of one nutrient may increase the need for another. Some researchers claim that fat-soluble vitamins work together, and that it is crucial to increase the intake of vitamin A and vitamin K2 while supplementing with vitamin D3. This is especially important for vitamin K2, another fat-soluble vitamin that most people do not consume enough. Magnesium intake may also be important for the functioning of vitamin D. Magnesium is an important mineral that is often scarce in modern diets.
What Happens if You Take Too Much Vitamin D?
Actually, it is a myth that it is easy to overcome vitamin D intake. Vitamin D poisoning is very rare, and only occurs if insane doses are taken for long periods of time. For people who live in places where sunlight is not common throughout the year, it is advisable to take 4000-5000 IU per day using a vitamin D3 supplement. Many people claim to have chosen to consume vitamin D supplements to complete the recommended dose and consider it an essential alternative to promote personal health.