Everything you need to Know about Vitamin-D

Vitamin D is a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, and multiple other biological effects. In humans, the most important compounds in this group are vitamin D3 (also known as cholecalciferol) and vitamin D2 (ergocalciferol). Cholecalciferol and ergocalciferol can be ingested from the diet and from supplements. Vitamin D is not actually a vitamin. It is a steroid hormone, which is made in the body under the right conditions. However, if the body does not make enough, it can also be obtained from food sources.

As a hormone, Vitamin D does many things in the body. It was first discovered as the substance which could prevent and cure rickets. It controls the levels of calcium ions and phosphates in the blood, as well as calcium and magnesium absorption in the intestines. It helps bones grow and form. It is also good for the immune system. Nearly every tissue and cell in our body have a vitamin D receptor. Without enough activated vitamin D in the body, dietary calcium cannot be absorbed. Calcium is essential for signaling between brain cells, development of bone, and tooth formation.

SOURCES

Vitamin D is called, “the sunshine vitamin” because your skin makes it when it’s exposed to sunlight. Very few foods have Vitamin D in them naturally. Your body also makes Vitamin D when your skin is exposed to ultraviolet B (UVB) rays from the sun. However, many things affect your UVB exposure and ability to produce Vitamin D, including your age, your skin tone, how much of your skin is covered by clothing, whether you wear sunscreen, the season, where you live, and both the amount of time and what time of day you spend outside.

1. Salmon
Salmon is a popular fatty fish and a great source of vitamin D. According to the USDA Food Composition Database, one 3.5-ounce (100-gram) serving of salmon contains between 361 and 685 IU of vitamin D.

2. Herring and Sardines
Herring is a fish eaten around the world. It can be served raw, canned, smoked or pickled. This small fish is also one of the best sources of vitamin D. Fresh Atlantic herring provides 1,628 IU per 3.5-ounce (100-gram) serving, which is nearly three times the RDI. If fresh fish isn't your thing, pickled herring is also a great source of vitamin D, providing 680 IU per 3.5-ounce (100-gram) serving or 113% of the RDI.

3. Cod Liver Oil
Cod liver oil is a popular supplement. If you don't like fish, taking the cod liver oil can be key to obtaining certain nutrients unavailable in other sources. It’s an excellent source of vitamin D — at about 450 IU per teaspoon (4.9 ml), it clocks in at a massive 75% of the RDI. It's been used for many years to prevent and treat deficiency in children. Cod liver oil is also a fantastic source of vitamin A.

4. Canned Tuna
Many people enjoy canned tuna because of its flavor and easy storage methods. It’s also usually cheaper than buying fresh fish. Canned light tuna packs up to 236 IU of vitamin D in a 3.5-ounce (100-gram) serving, which is nearly half of the RDI. It’s also a good source of niacin and vitamin K.

5. Egg yolk
Eggs are a convenient way to get vitamin D. They're popular in many breakfast, lunch, dinner and dessert recipes. Since the vitamin D in an egg comes from its yolk, it's important to use the whole egg—not just the whites. One yolk will give you about 40 IUs, but don't try to get your daily vitamin D just from eggs. One egg contains about 200 milligrams of cholesterol.

6. Cheese
Cheese is one of the top 5 foods high on Vitamin D. Well, spreading an additional layer of cheese on that morning slice of toast may not be such a bad idea after all. Ricotta cheese provides the maximum amount of Vitamin D amongst others.

FACTORS CAUSING DEFICIENCY OF VITAMIN-D

Below are some of the factors that affect whether or not a person is at risk of having a deficiency:

• Living at a high latitude: This is due to there being less accessible to the sun's ultraviolet-B (UVB) rays.

• Being indoors too much: Spending little or no time outside means missing out on the sun's rays.

• Living in a highly polluted area: Pollution can absorb some of the sun's rays, so reducing scope to make vitamin D.

• Using large quantities of sunscreen: Using enough sunscreen to block UV rays might inhibit vitamin D absorption. But few people use enough sunscreen to block UV rays fully. • Having darker skin: People with darker skin need more sunlight exposure to absorb enough vitamin D.

• Ambient temperature: Warm skin is better at absorbing the sun's rays to produce vitamin D than cool or cold skin.

• Diet: Eating foods rich in vitamin D or foods that have been fortified with the vitamin, reduces the risk of vitamin D deficiency.

• Being overweight: Research suggests that being overweight correlates with lower vitamin D levels. This may be because excess body fat somehow affects vitamin D absorption.

• Age: People's ability to absorb vitamin D may decline with increasing age.

• Gut health: Disorders that affect the gut, such as Crohn's disease, can undermine the intestines' ability to absorb vitamin D.

• Kidney and liver health: People with liver or kidney disease tend to have lower vitamin D levels.

• Pregnancy or breastfeeding: The nutritional demands of an infant or fetus may lower vitamin D levels, particularly in women already at risk of vitamin D deficiency.

• Being a breastfeeding infant: Human milk is low in vitamin D. Infants who are nursing may need a vitamin D supplement, particularly if they do not go outdoors every day.

SIDE EFFECTS OF TOO MUCH VITAMIN-D

Vitamin D toxicity is extremely rare but does occur with extreme doses. It usually develops over time, since extra vitamin D can build up in the body. Nearly all vitamin D overdoses result from taking high amounts of vitamin D supplements. It is almost impossible to get too much vitamin D from sunlight or food. Vitamin D toxicity implies that vitamin D levels in the body are so high that they cause harm. It is also termed hypervitaminosis D. Vitamin D is a fat-soluble vitamin. In contrast to water-soluble vitamins, the body has no easy way of getting rid of fat-soluble vitamins. For this reason, excessive amounts may build up inside the body.

The exact mechanism behind vitamin D toxicity is complicated and isn't fully understood at this point. However, we know that the active form of vitamin D functions in a similar way as a steroid hormone. It travels inside cells, telling them to turn genes on or off. Usually, most of the body's vitamin D is in storage, bound to either vitamin D receptors or carrier proteins. Very little "free" vitamin D is available.

However, when vitamin D intake is extreme, the levels can become so high that there isn't any room left on the receptors or carrier proteins. This may lead to elevated levels of "free" vitamin D in the body, which may travel inside cells and overwhelm the signaling processes affected by vitamin D. One of the main signaling processes has to do with increasing the absorption of calcium from the digestive system. As a result, the main symptom of vitamin D toxicity is hypercalcemia - elevated levels of calcium in the blood. High calcium levels can cause various symptoms, and the calcium can also bind to other tissues and damage them. This includes the kidneys.

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About Gaurav Dhingra

Hi..I am Gaurav Dhingra..completed engineering from SRM unviersity..and doing gym since last one year..and giving personal training from last 6 months with diet and proper workouts