immune deficiency

Vitamin A

Overview

Vitamins are organic compounds that living organisms need in order to survive. These compounds are molecules that cannot be synthesized efficiently and in large enough quantities by the body and must be obtained from outside sources like food and/or nutritional supplements.

Vitamins are classified based on how they interact with the body chemically rather than on their molecular structure. This means that, a particular vitamin, like Vitamin A, is not one specific substance, but rather a group of compounds and molecules that produce the same range of effects on the human body. These compounds and molecules are called vitamers.

For example, some common vitamers of Vitamin A include retinol, retinal, alpha-carotene, beta-carotene, gamma-carotene, and beta-cryptoxanthin. All of these compounds are chemically different, but work in the same way to provide the human body with proper nutrition.

Vitamins & Nutrition

Vitamins play a crucial role in human nutrition, helping the body to regulate cell growth, regulate hormones, and help enzymes to act as catalysts in metabolism. In addition to his, certain vitamins like Vitamin A, Vitamin E, and Vitamin C can act as powerful antioxidants, which can bind to dangerous, cancer causing free radicals in the body.

Vitamins are water or fat soluble, depending on the vitamin. Soluble refers to the ability of a vitamin to dissolve in a particular substance. In the case of water soluble vitamins such as Vitamin C, the human body uses as much as it needs for metabolism. The excess water soluble vitamin is then dissolved in the body’s fluid and excreted as urine.

For fat soluble vitamins, like Vitamin A, the body uses what it needs to maintain proper nutrition, and then stores the extra vitamin in the body’s fat stores and liver. The excess of the fat soluble vitamin cannot be eliminated from the body very easily, so over time, given enough of a fat soluble vitamin, toxicity can develop. In humans, Vitamins A, D, E, and K are fat soluble, while the 8 B vitamins and Vitamin C are water soluble.

Growth and Nutritional Value

Vitamins are essential for growth and proper nutrition. They regulate many bodily functions including metabolism and hormones. Any deficiency in a particular vitamin can cause a host of medical problems including death.

History of Vitamin A

Vitamin A is one of the most important vitamins that humans need in order to survive because it is responsible for a large number of important functions in the body. Vitamin A was discovered in the early 1900s through experiments that probed the question of why cows produced healthier offspring when fed corn rather than wheat. In a series of experiments on mice, Elmer McCollum, noted that when mice were fed diets consisting only of protein, their offspring were often unhealthy and sometimes afflicted with birth defects.

When he introduced some fats into the diet, their offspring were born healthy and normal. He hypothesized that there was a certain chemical in the fat inclusive diet that was not found in the protein diet. This compound became known as Vitamin A and was recognized to be a fat soluble substance.

Until the 20th century, all vitamins had to be derived from food, but with advances in biochemistry, scientists were able to begin to synthesize all the necessary vitamins for human health. Vitamin A was synthesized in 1947 by David Adrian van Dorp and Jozef Ferdinand Arens, from the Netherlands.

Vitamers of Vitamin A

Vitamin A is not a single compound. Instead, it is a group of compounds that all have the same biologic effect on the body. These compounds are called vitamers. The vitamers of Vitamin A are retinol, retinal, alpha-carotene, beta-carotene, gamma-carotene, and beta-cryptoxanthin.

Retinol, derived from animal fat, is the body’s most usable source of Vitamin A. Several chemicals in the body have retinol as their bases including retinal, retinoic acid and retinyl esters. Retinal is a central component to human vision. Together, these molecules are referred to as retinoid compounds.

The three carotene vitamers belong to a class of organic molecules called carotenoids. Carotenoids are naturally occurring pigments found in plants and some fungi. Animals do not produce carotenoids. The names, “alpha,” “beta,” and “gamma” are used to denote structural differences on the molecular level among the organic compounds. Beta carotene is an inactive form of Vitamin A that can be readily converted into an active form by the body.

Beta-cryptoxanthin, like the carotene compounds, is a member of the carotenoid family. What differentiates it from the carotenes is that it has a slightly different structural formula in that it contains an oxygen molecule. Cryptoxanthin can be derived from both plant and animal sources including oranges, papaya, eggs, and butter.

Nutritional Benefits and Functions

Vitamin A is essential for basic bodily functions. Deficiencies in Vitamin A may cause illness or even death. Here are some of Vitamin A’s most important roles in human nutrition:

• Vision
• Immune Function
• Gene transcription
• Skin health
• Embryonic development
• Antioxidant properties
• Cell Growth

Vision

Normal vision is dependent on having a healthy retina and having enough Vitamin A. In the eye, the retina is an area of tissue on the back of the eye that is home to light sensitive cells called rods and cones. Rods are responsible for detecting light and dark, while cones allow people to perceive colors. Vitamin A plays a crucial part in vision.

In the retina, Vitamin A, in a form called cis-retinal, is combined with a protein called opsin, to form another compound called rhodopsin, which is a light sensitive compound found in rods. In cones, retinal binds with a protein to form iodopsin. When stimulated by light, Vitamin A in the form of cis-retinal transforms from being bent in shape to straight.

The straight shaped form of retinal is called trans-retinal. The molecule then detaches from the opsin protein. The opsin protein, then changes shape, signaling the brain to produce a black and white image of the objects being observed by the person. Most retinal used in this process is then released as trans-retinal and then converted back into cis-retinal where the cycle can begin again.

Immune Function

The immune system is the body’s defense against pathogens like dangerous viruses and bacteria. When a foreign invader, like a virus, enters the body, the body’s immune system detects that there is an unknown intruder and sends specialized cells to try to kill it.

Vitamin A helps to stimulate the immune system by promoting the overall health of the thymus gland. The thymus gland is a small gland in the neck that is part of the human immune system. The thymus gland produces specialized white blood cells called T-lymphocytes. These cells are the body’s “killer” cells activate during an immune response in an effort to rid the body of the pathogen.

Speeds up Immune Response

Vitamin A also helps their effectiveness and efficiency, speeding up the response time of the immune system. Also, Vitamin A has been shown to have anti-viral properties. Retinoic acid, derived from the vitamer retinol, plays an important role in the health and growth of delicate mucosal and epithelial tissues found in the respiratory and gastrointestinal systems.

Mucosal and epithelial tissues are some of the most basic defenses of the immune system. They produce mucus, which can trap bacteria and viruses, before they have a chance to invade the body any further.

Gene Transcription

Vitamin A plays an important role in gene transcription. Transcription is the process by which RNA is created from DNA, transferring genetic information to the RNA molecule. Retinol is used by cells to form retinal, which is then converted into retinoic acid. From there, retinoic acid binds with specialized receptors that can either turn on gene transcription or stop it from happening by undergoing a complex series of reactions.

Skin health

The benefits of Vitamin A have been long linked with maintaining healthy skin and complexion in humans. Deficiencies in Vitamin A can manifest themselves in people by causing dry and flaky skin. Vitamin A is important in regulating the growth and repair of skin tissue.

Although Vitamin A can be ingested for skin care, topical application remains the best treatment for skin conditions. Retinol creams have been shown to help prevent wrinkles from developing and masking the ones that already exist. Vitamin A can also help to control acne. Sebaceous glands are small glands in the skin that secrete material that is used by the body to lubricate the hair and skin.

They can harbor bacteria and get infected, which is the cause of acne outbreaks. Ongoing research has shown that retinoic acid that is applied topically can reduce the size of sebaceous glands and their secretions. The reduction of the sebaceous gland secretions is thought to be the reason why Vitamin A can combat acne.

The secretions provide nutrients for bacteria that cause acne, and without nutrition, the bacteria cannot take a foothold in the gland to produce a pimple.

Embryonic development

Vitamin A’s discovery was contingent on experiments dealing with the development of livestock offspring. It was discovered in the early 1900s by Elmer McCollum that female mice, which were deficient in Vitamin A, produced offspring that were unhealthy, had severe birth defects and/or died. Further research into this subject over the past 100 years has led to the understanding that an adequate amount of Vitamin A is a requirement for normal embryonic development.

Vitamin A is necessary for the embryo to form a healthy heart, nervous system, and skeleton. The correct balance of Vitamin A is also important in embryonic development and growth. While too little Vitamin A can cause birth defects and death of the fetus, so to can having too much of the vitamin.

Antioxidant properties

Oxidants, or free radicals, are oxygen carrying molecules in the body that can cause damage to cells, which can cause diseases like cancer. Antioxidants are molecules that can bind with free radicals, decreasing their potential to cause harm to the body on a cellular level. Some antioxidants can even help to repair damage done by free radicals. Vitamin A is a powerful antioxidant, however studies have been done that show that smokers who take Vitamin A supplements (in particular beta carotene) had an increased risk of developing lung cancer.

Cell growth

Much current research is underway to determine how Vitamin A affects cell growth. The mechanism is not fully understood, but it has been determined that retinoic acid plays a role in the production of glycoproteins. Glycoproteins are proteins that help cells adhere to one another.

Sources of Vitamin A and daily recommended values

Vitamin A in the form of retinol is found in animal products including meat, butter, eggs, and milk. The carotene vitamers of Vitamin A are plant based and can be found in large amounts in orange hued vegetables such as carrots, pumpkin, winter squashes, sweet potatoes, apricots, cantaloupe, mango, and papaya. For example, a 1 cup serving of raw carrots provides 686% of the daily value of Vitamin A required by the body. Green vegetables such as kale, spinach, broccoli, and leafy greens are also a good source of Vitamin A.

The daily recommended amounts of Vitamin A depend on age and gender. Typically, men require more than non-lactating females. For adult males, the daily recommended amount of Vitamin A is 900 micrograms per day, with a maximum of 3000 micrograms per day. For adult females, the recommended amount per day is 700 micrograms, with the maximum amount being 3000 micrograms.

Females who are breast feeding need more Vitamin A in order to provide an adequate supply of nutrition for the newborn baby. The recommended amounts for breast feeding women are 1300 micrograms with an upper limit of 3000 micrograms.

Unlike other vitamins and minerals that may be leached or destroyed by cooking and processing, Vitamin A is largely unaffected by these methods of food preparation.

Vitamin a deficiency

Vitamin A deficiency is a major nutritional problem faced by millions of people across the world. Most often, these deficiencies are seen in developing countries that have limited food supplies. Developing countries often have a lack of quality meats that are the best sources for Vitamin A. Also, meat contains the mineral iron which is important in the body’s utilization of Vitamin A.

Night blindness and a lack of tear production are major factors contributing to blindness caused by a Vitamin A deficiency. Night blindness is a condition in which a person does not have adequate photoreceptive cells that can process light entering the eye.

As seen earlier, the retinal form of retinol plays an important role in vision by binding with proteins in the retina to form molecules that help to transmit nerve impulses from the retina to the brain.

Vitamin A deficiency can also affect the eye’s ability to produce tears. Tears serve the function of washing the eye of debris and bacteria. Without tears, the eyes lose an important component in the body’s fight against infection. Each year between one quarter and one half of a million children worldwide go blind because of inadequate Vitamin A intake.

A condition called hyperkeratosis may develop in people afflicted with Vitamin A deficiency. People manifesting the symptoms of this condition develop small bumps on the skin that is the result of excess keratin proteins blocking hair follicles. Other symptoms include itching, dry skin, and eventual hair loss over the whole body.

Vitamin A deficiency can be either primary or secondary in origin. A primary deficiency is one caused by an inadequate supply of nutrients, while a secondary deficiency is caused by another underlying condition. One cause of secondary Vitamin A deficiency are medical conditions like Crohn’s disease, celiac disease, cystic fibrosis, gallbladder disease, and liver disease.

These diseases can affect the body’s ability to absorb fat, robbing the body of its best source for Vitamin A. Outside agents like chemicals and pollutants can cause the liver to not function correctly, breaking down the Vitamin A that it would normally store.

Vitamin A deficiencies can be detected by blood tests using high performance liquid chromatography. The results should be no lower than 0.7 mg/L. Blood tests to detect serum retinol binding proteins may also be used. These have the advantage of being less expensive than a liquid chromatography test, but are less accurate.

The prognosis for Vitamin A deficiency is good as long as blindness has not set in. Once a patient suffering from Vitamin A deficiency has developed blindness as a result of the condition, mortality rates increase due to other irreversible damage that occurs concurrently with blindness.

Treatment for Vitamin A deficiency includes oral and injectable supplements.

Vitamin A toxicity

Vitamin A is a fat soluble vitamin. After metabolism, excess amounts are stored in the body’s fatty tissues instead of being excreted in urine. Fat soluble vitamins that are stored in fatty tissues can linger in the body for long periods of time, thus increasing the potential for a toxic buildup of excess Vitamin A to occur. For adults, acute Vitamin A toxicity can occur if daily amounts exceed 3000 micrograms. Chronic Vitamin A toxicity can occur over a period of months when over 1200 micrograms are taken daily. Alcohol consumption can amplify the toxic effects of the vitamin.

Symptoms of acute poisoning include nausea, vomiting, headache, dizziness, vision problems, loss of muscular control, dry skin, anemia, insomnia, fatigue, and skeletal problems.

In some people, excess amounts of Vitamin A can cause osteoporosis and bone breakage. Excess Vitamin A can interfere with the uptake of Vitamins K and D which are critical to bone strength and health.

Treatment for Vitamin A toxicity includes maintaining proper hydration, providing oxygen, and cessation of Vitamin A sources and supplements.

Death from Vitamin A toxicity is rare.

Conclusion

Vitamins are essential nutrients needed by the human body to maintain normal, daily functions. Vitamin A is perhaps one of the most important vitamins because of its wide ranging implications for overall health. It has a role in every day life from birth until death by means of its effects at the cellular level on cell division and RNA transcription. It also allows humans to see the world.

Every day thousands of people around the world go blind due to a Vitamin A deficiency. Through proper nutrition, Vitamin A deficiencies are largely preventable. While foods are the primary source for Vitamin A, in the last century, humans have learned to chemically synthesize it, allowing even those people with poor nutrition to obtain enough of the vitamin to stave off blindness and other problems caused by ingesting too little of it.

References

1. Pazirandeh S, Burns DL. Overview of fat-soluble vitamins I. UpToDate. 2002.

2. Russell RM. The vitamin A spectrum: from deficiency to toxicity. American Journal of Clinical Nutrition. Apr 2000.

3. West CE. Meeting requirements for vitamin American Nutritional Review 2000 Nov;58(11):341-5 2000.

4. Groff JL, Gropper SS, Hunt SM. Advanced Nutrition and Human Metabolism. West Publishing Company, New York, 1995 1995.

Beta Carotene

Beta  Carotene or B  Carotene

Beta carotene is a vitamin A precursor that is produced by many different species of plants. It belongs to a group of chemicals known as carotenes, which are themselves part of a larger chemical group called carotenoids. beta-carotene, sometimes written as b carotene, is also known as provitamin A. Vitamin A, which can be synthesized from its provitamin, may sometimes be called retinol.

Carotenes belong to a large group of chemicals known as carotenoids. Carotenoids are all strongly colored red, yellow and orange pigments. They are fat or lipid soluble and are found in many different types of fruits and vegetables. Carotenoids are also antioxidants.

Chemical Makeup

A carotene is a type of chemical that was first discovered in the 19th Century after being isolated from carrots. There are three types of carotene that can be used by the human body to produce Vitamin A: alpha, beta and gamma carotenes. Since they are not themselves vitamins, but can be converted into a vitamin, the carotenes are considered to be precursors or provitamins.

The chemical that can be produced from the carotenes, vitamin A, is an essential nutrient that plays a role in vision and growth. A vitamin A deficiency can be seriously harmful, and may even lead to death, although it can be cured by eating a diet rich in fruits and vegetables, which contain high levels of beta-carotene.

Carotenes are produced by plants, but although they are necessary as vitamin precursors in animals, they must be obtained from food since animals cannot synthesize carotenes for themselves.

Animals can produce vitamin A, however, and it is therefore possible to get vitamin A directly from the diet rather than having to manufacture it from beta-carotene. Beta or b carotene is the most common form of carotene.

Chemistry

All carotenoids are based upon a chain of hydrocarbons. This is made up of small units of isoprene. In beta-carotene, there are eight isoprene units, which form beta cycles at either end. This means that the units on the ends of the molecule are twisted around into circles.

The exact molecular structure of beta-carotene was discovered in the early 1930s. This was the first time that the structure of any vitamin or vitamin precursor had been established.

The orange color of a carotenoid is produced by the long chain of isoprene units. This is because the hydrocarbon chain absorbs light in the blue and green ranges, but reflects back red and yellow light. Only the reflected light is seen by the observer. beta-carotenes are found in orange and yellow colored fruits and vegetables, and are responsible for the color of these foods.

There are also beta-carotenes present in many green vegetables and leaves, but the orange color of the beta-carotenes is hidden by the green color of the chlorophyll. The leaves of deciduous trees turn orange before they fall because the chlorophyll in them has been broken down, leaving only the color of the carotenes.

During the 1950s, scientists began to develop techniques for artificially synthesizing beta-carotene. This led to the production of synthetic beta-carotene supplements and food colorings.

B carotene and Vitamin A

beta-carotenes are converted by the body into vitamin A or retinol. beta-carotene is converted into retinol, which is necessary for the eyesight. Retinol is converted into retinoic acid, which is used for growth and cell division. The functions of beta-carotenes in the body are therefore the same as those of vitamin A, since beta-carotene is converted into vitamin A before being used.

Beta-carotene is usually converted into vitamin A by gradually breaking down the beta-carotene molecule from one end, but it can also be converted by splitting the molecule in two. The conversion takes place within the cells that make up the small intestine. An enzyme called beta-carotene dioxygenase carries out the process.

Once vitamin A has been produced, it needs to be stored until it is required. It is first converted into retinyl esters, and is then transported through the body in the lymphatic system and blood. The vitamin A that is produced from the breakdown of beta-carotene is mainly stored in the liver in the form of retinyl esters. Some retinyl esters are also stored in the kidneys, lungs and adipose fat tissue, but between 50 and 80 percent of stored vitamin A is found in the liver.

Function

Vitamin A is essential for vision. The body converts vitamin A or retinol, through an oxidization reaction, into retinal. This is combined with an opsin protein in order to produce a light sensitive molecule. When one of these molecules is hit by a photon of light, the retinal component changes its shape, setting off a sequence of events that will eventually lead to a signal being sent to the visual part of the brain through the optic nerve, where it will be decoded as vision. Retinal is responsible for the ability to detect light and therefore to see.

There are two different types of light sensitive cell in the eye, and they use different chemicals in which to see. Rhodopsin is present in the light receptors known as rods, whereas a different chemical called Iodopsin is used by the cone cells. Rods are most effective in dim light, while cones provide color vision. Both types of receptors depend upon the ability of retinal to react to light.

Vitamin A also performs some other functions in the body. It is used in the production of some glycoproteins, which are protein molecules to which carbohydrates have been attached. Vitamin A plays a crucial role in growth and bone development, reproduction and the maintenance of the skin and mucous membranes such as the lining of the mouth and nose.

These linings help to prevent infection by keeping out infectious agents from the digestive system, urinary tract and the respiratory system. The importance of vitamin A in the body is clear, since a deficiency of this vitamin can lead to abnormal development of the bones, reproductive disorders, a condition called xerophthalmia that caused the cornea of the eye to become dry, and even to death.

Deficiency

Most people will consume an adequate amount of beta-carotenes in their normal diet, but it is possible to suffer from a vitamin A deficiency when a poor diet does not provide enough vitamin A or the carotenes fro which it can be manufactured. A diet that contains low levels of beta-carotenes will not be harmful as long as enough vitamin A is being consumed in other food. A diet without enough vitamin A or beta-carotene will be harmful. If there is a deficiency of vitamin A, due to malnutrition or illness, it can be cured by eating beta-carotene rich foods.

The earliest symptoms of a vitamin A deficiency are visual problems in low light situations, dry hair and skin, fingernails that break easily and a lowered resistance to infection. The more serious signs of a vitamin A deficiency are anemia, abnormal bone development, and permanent damage to the eyes.

The retina may be injured badly enough to cause blindness. Even when there are no vitamin A deficiency symptoms, a person who is not getting enough vitamin A could suffer from an increased risk of developing diarrheal and respiratory infections and a decreased growth rate and bone development. Fertility can also be reduced.

Health Problems with Deficiency

A vitamin A deficiency can be very serious. It is rare in the US, where most people consume more than enough beta-carotene and vitamin A in their diet.

However, a deficiency in vitamin A is the most common cause of preventable blindness in children worldwide, and it affects people in more than half of the countries in the world. Low income families in Southeast Asia and Africa are most likely to be affected. It is the young children and pregnant women within these families who are most likely to suffer from vitamin A deficiencies.

Vitamin A is required at higher levels during pregnancy, and children have smaller stores of vitamin A in their livers than adults. An adult can have enough vitamin A in their liver to last for an entire year, but a child’s supply can only last for a few weeks at most.

During Pregnancy

During pregnancy, the highest risk of developing a vitamin A deficiency occurs during the third trimester, when both baby and mother require large amounts of vitamin A. If the mother is not receiving enough vitamin A during this period, she will suffer from night blindness, and may experience other symptoms. \

She may also have a higher risk of maternal mortality. It is not recommended for women who have a good, balanced diet to take vitamin A or beta-carotene supplements, however, since they are not necessary. Vitamin A supplements could even increase the chances of birth defects in the baby.

Deficiency in Children

Children who are not obtaining enough vitamin A are at risk of blindness and other visual impairments, and they are also more likely to catch serious diseases such as measles, or to suffer from diseases that can cause diarrhea. These illnesses can be fatal. A lack of vitamin A can also cause growth problems and defects in the development of the skeleton.

According to the World Health Organization (WHO) it is estimated that there are 250 million children of preschool age who are suffering from a vitamin A deficiency, and that between 250,000 and 500,000 of these children are made blind because of this deficiency every year. Half of the children who go blind in this way will die within the next year.

It is possible to die from a vitamin A deficiency, and according to the World Health Organization (WHO), it is possible to significantly decrease mortality rates by ensuring an adequate supply of vitamin A.

Cases in the US

In the US, cases of vitamin A deficiency are most likely to occur in patients who are elderly or who are suffering from chronic illnesses that can reduce the absorption of vitamin A and carotenes from the intestine. Patients who have inflammatory bowel disorder (IBD), pancreatic insufficiency or cystic fibrosis have an increased risk of vitamin A deficiency.

Vegans and people who suffer from alcoholism are also more likely to have a deficiency, due to decreased ingestion and absorption of vitamin A. Some cases of malnutrition do occur in the US, but these are more common overseas.

It is possible to treat a vitamin A deficiency by eating foods that contain beta-carotene or vitamin A, or by taking supplements of one of these chemicals.

If the diet contains too much beta-carotene, it can lead to the skin turning a yellowish color. It will not, however, cause an excess of vitamin A in the body. Some of the vitamin A that is produced but which is not currently needed will be stored in the liver, where it can remain for several years. Some will be stored in the fat tissue of the body. If there is a lot of beta-carotene in the diet, then it will not all be converted into vitamin A. An excess of vitamin A in the body would be harmful.

Traditional Beliefs

It is often said that carrots can help people to see in the dark. Since one of the symptoms of a vitamin A deficiency is night blindness, this belief clearly has some foundation in fact. Although eating carrots cannot enhance night vision above normal abilities it can prevent it from deteriorating by providing the precursor for vitamin A production.

Antioxidant

beta-carotene is an antioxidant. Antioxidants are chemicals that can react with free radicals, which are highly reactive, charged molecules. Free radicals are produced by the body during respiration or energy production and can cause damage that in involved in the ageing process and cancer. It may be possible for antioxidants in food to protect the body from this sort of damage, but there is no definitive scientific proof that eating foods containing high levels of antioxidants can actually help to protect the body.

Medicinal Uses

beta-carotene has been approved by the US Food and Drug Administration (FDA) as a treatment for erythropoietin protoporphyria. This is an inherited condition that is very rare. It causes problems in the metabolism of the chemical porphyrin-heme. This can lead to photosensitivity, with the skin reacting painfully to light, dysfunction of the liver, and production of gallstones. Patients are treated with an over the counter beta-carotene supplement, and may also need to take antihistamines.

Consuming beta-carotene and other carotenoids can help to prevent a vitamin A deficiency, but a diet that is rich in carotenoids is not necessary as long as there is plenty of vitamin A in the diet. There is therefore no recommended intake of carotenoids according to the Institute of Medicine’s Food and Nutrition Board.

The American Heart Association, among other health groups such as the International Agency for Research on Cancer (part of the World Health Organization) advise that people should obtain beta-carotene from a diet that is high in fruits and vegetables rather than by taking dietary supplements.

Some of the scientific research that has been conducted on beta-carotene treatment has not yet produced clear results. These treatments have not yet been proven to be successful, but neither have they been proven unsuccessful.

Potential Uses

These potential uses for beta-carotene are as treatments for cataract prevention, reducing the adverse side effects of chemotherapy, treating chronic obstructive pulmonary disease (COPD), improving cognition and memory, preventing asthma attacks that are induced by physical activity, enhancing the immune system, promoting remission in patients with oral leukoplakia, preventing and slowing the progression of osteoarthritis, treating polymorphous light eruption (PLE), reducing the risk of sunburn and UV induced erythema, and reducing complications during pregnancy. Further research may clarify the effect of beta-carotene on these conditions.

beta-carotene has also been tested as a treatment for a number of other conditions for which it was not found to be helpful.

Potential Side Effects

There was even some evidence that it could be harmful when used in patients with these conditions, particularly if beat carotene was a replacement for other more beneficial therapies. beta-carotene was not found to be effective for the prevention or treatment of Alzhemier’s disease or abdominal aortic aneurysms (AAAs), preventing the development of new moles on the skin, preventing cancer or cardiovascular disease, eradicating the bacteria that can cause stomach ulcers (Helicobacteria pylori), preventing or slowing macular degeneration, preventing stroke, or reducing injuries following surgery.

Taking supplements of beta-carotene was also found to have no effect on overall mortality rates. There is some evidence that beta-carotene may be harmful in patients who have undergone angioplasty.

Sources of Beta-Carotene

beta-carotene occurs naturally in many plants. It is found in green vegetables and fruit and vegetables that are orange or yellow. Spinach, broccoli, carrots, red peppers, nectarines, melons and mangoes are all good sources of beta-carotenes.

A diet that includes five portions of fruit and vegetables every day will provide between 6 and 8 milligrams of beta-carotene per day. A healthy body can maintain adequate levels of vitamin A with just 1800 micrograms of beta-carotene, therefore it is rare for a diet to be deficient in carotenes. There is no recommended daily allowance (RDA) for beta-carotenes, due to a lack of evidence on its importance, but the RDA for vitamin A is 0.9 milligrams per day for an adult man and 0.7 milligrams a day for an adult woman. Pregnant women and those who are breastfeeding require a higher daily intake.

Vitamin A can also be consumed directly, rather than as its precursor, beta-carotene. Egg yolks, dairy products and fish oils all contain high levels of vitamin A. Liver is also rich in this vitamin, and in fact, the liver of the polar bear contains such large amounts of vitamin A that it is poisonous to humans.

Supplements

beta-carotene is available as a dietary supplement. It can be manufactured synthetically or derived from fungi, algae or palm oil. Supplements of beta-carotene can be taken in a number of different forms, including gelatin capsules, tablets and chewable tablets.

There is some scientific evidence that consuming too much beta-carotene in the form of supplements may be harmful. A study found that there was an increased risk of developing lung cancer when people who were exposed to other risk factors for the disease, such as smoking or working in an environment where they were exposed to asbestos, took beta-carotene supplements.

There is no evidence of what the effect may be on non-smokers and people who are not already at an elevated risk of lung cancer, but it is possible that taking supplements of beta-carotene could be harmful. No similar effect has been detected when beta-carotene is eaten in food.

This means that it is important, when taking beta-carotene supplements, to avoid consuming too much beta-carotene. The UK Food Standards Agency advises against exceeding a dose of 7 milligrams of beta-carotene a day. Doctors may recommend taking a higher dose than this in some cases, but this is only when there is a serious deficiency that needs to be corrected. Anyone who is a smoker or who has been exposed to asbestos should avoid taking supplements of beta-carotene.

Absorbing Beta-Carotene

In order to absorb beta-carotene, the body must use some of the fat that has been eaten. This means that when beta-carotene is taken as a supplement, it will require some dietary fat in order to be absorbed by the body. No difference has been found in the absorption rate between individuals consuming a low fat or a high fat diet, however, since the amount of fat that is required is very low.

In order to absorb beta-carotene, the body must use some of the fat that has been eaten. This means that when beta-carotene is taken as a supplement, it will require some dietary fat in order to be absorbed by the body. No difference has been found in the absorption rate between individuals consuming a low fat or a high fat diet, however, since the amount of fat that is required is very low.

Elevated levels of vitamin A in the body can be harmful, causing problems with the bones that may lead to an increased risk of experiencing fractures in old age. Although beta-carotene is converted into vitamin A it does not pose a similar risk. The body is not efficient enough at turning beta-carotenes into vitamin A for a high intake of beta-carotenes to cause high enough levels of vitamin A to harm the body.

Food Coloring

In addition to being manufactured as a dietary supplement, beta-carotenes are produced and used as colorings in food products.

Sources:

• Mayo Clinic: Beta Carotene
• Food Standards Agency: Beta carotene
• National Cancer Institute: Beta Carotene Supplements Confirmed as Harmful to Those as Risk for Lung Cancer

D2 (Ergosterol, Ergocalciferol)

Vitamin D is present in numerous sources of food, such as cod liver oils, fish, eggs and fortified milk. The sun is also responsible for contributing a significant level of vitamin D to a daily production, and it is believed that obtaining just ten minutes of sun exposure is enough to prevent a person from developing deficiencies in vitamin D.

The term “vitamin D” does not technically refer to a single type of vitamin, but rather, it refers to several different kinds. Two forms in particular are of the most importance with regards to human: vitamin D2 (ergocalciferol) and vitamin D2 (cholecalciferol). The former kind of vitamin D is synthesized by plants, whereas the latter kind of vitamin D is synthesized by humans upon the exposure of ultraviolet-B rays directly from the sunlight onto the skin. Some foods may be fortified with both kinds of vitamin D.

The primary biological function that vitamin D has is to make sure the blood have normal levels of phosphorus and calcium in it. It is also capable of aiding with the absorption of calcium, which allows bones to remain strong and for the strong bones to form in the first place.

In recent times, it has been suggested by research that vitamin D may prove to be beneficial in protecting people from several autoimmune diseases, cancer, high blood pressure and osteoporosis.

Two Known Cases

Osteromalacia and rickets are the two classic cases of deficiency of vitamin D. When children experience a deficiency of vitamin D, they will typically develop rickets, the end result of which is a deformity in the skeletal system.

Adults who allow themselves to become deficient in vitamin D will likely develop osteomalacia, the end result of which is weakness in the muscles and the bones becoming weaker than normal.

Those who are at a high risk for developing deficiencies of vitamin D are those who are elderly, are an obese individual, are infants who are exclusively breastfed, and are regularly limited from sun exposure.

Other people at risk are those who have cystic fibrosis, or any other malabsorption syndrome or those who have an inflammatory bowel disease, including Crohn’s disease.

Synonyms

Vitamin D is known by many names, including:

• 1 alpha D3
• 19-nor-1
• 1 alpha-hydroxyvitamin D2
• 1,25-DHCC
• 1,25-dihydroxy-22-ovavitamin D3
• 1,25-dihydroxycholecalciferol
• 1,25-dihydroxyvitamin D3
• 1,25-diOHC
• 1,25 2D3
• 1-alpha-hydroxycholecalciferol
• 22-oxacalcitriol
• 25-dihydroxyvitamin D2
• 25-dihydroxyvitamin D2
• 25-HCC
• 25-hydroxycholecalciferol
• 25-hydroxyvitamin D3
• 25-OHCC
• 25-OHD3
• activated 7-dehydrocholesterol
• activated ergosterol
• alfacalcidol, calcifediol
• calcipotriene
• calcipotriol
• calcitriol
• cholecalciferol
• colecalciferol
• dichysterol
• dihydrotachysterol 2
• dihydrotachysterol
• ecocalcidiol
• ED-21
• ED-71
• ergocalciferol
• ergocalciferolum
• hexafluoro-1
• 25dihydroxyvitamin D3
• irradiated ergosterol
• MC903
• paracalcin
• paricalcitol
• viosterol
• vitamin D2 and
• vitamin D3

Evidence

Familial Hypophosphatemia

Familiar hypohosphatemia, which is the instance of the blood having low levels of phosphate, is a disorder that is both rare and inherited, which consists of the transport of phosphate being impaired in the blood, as well as the vitamin D metabolism present within the kidneys being diminished. Familial hypophosphatemia is a known kind of rickets. Familial hypophosphatemia suffers are able to take phosphate supplements, in addition to dihydrotachysterol or calcitriol in order to effectively treat some of their bone disorders. However, management should be made beneath the supervision of a physician.

Fanconi syndrome related hypophosphatemia

Fanconi syndrome, associated with renal tubular acidosis, is a defect associated with the proximal tubules within the kidney. Taking oral dosages of ergocalciferol has been found to be useful towards treating instances of hyophosphatemia that is associated with the presence of Fanconi syndrome.

Hyperparathyroidism Associated With Low Levels of Vitamin D

Some patients who have low levels of the essential vitamin D may find themselves with secondary hyperparathyroidism. As people may expect, the necessary and initial treatment for resolving this issue is to supplement a person with vitamin D. It is commonly recommended to have surgical removal of the parathyroid glands in those who have either refractory or primary hyperparathyroidism, however. There are some studies which suggest the supplementing a person with vitamin D should reduce the occurrence of hypoparathyroidism that may follow an instance of surgery in order to treat primary hyperparathyroidism, whether the parathyroid glands were partially or wholly removed.

Hypocalcemia Resulting From Hypoparathyroidism

It is rare to experience hypoparathyroidism, or having low levels of the parathyroid hormone in the blood, and it usually only occurs after removing the parathyroid glands through surgery. Taking in large doses of calcitriol, dihyrotachysterol or ergocalciferol may help with increasing concentrations of serum calcium in people who suffer from pseudohypoparathyroidism and hypoparathyroidism.

Osteomalactia, or Adult Rickets

Adults that allow their levels of vitamin D to sink far enough below to undergo severe deficiency turn out to develop osteomalacia, the loss of mineral content in the bones, the weakness of bone muscle and pain in the bones. Elderly people who do not have enough vitamin D in their diets, those who do not get an adequate amount of sun exposure, those who have an inability to absorb vitamin D, those with kidney disease and renal osteodystrophy, those who have had intestinal or gastric and those who have had a bone disease due to aluminum are all at risk of developing osteomalacia. The underlying cause of the osteomalacia ultimately determines what the best course of treatment is. For the most part, it involves taking phosphate binding agents, vitamin D, orthopedic surgical intervention and controlling the pain.

Psoriasis

There are a few different ways to treat the different forms of psoriasis skin plaques. A couple of the more mild approaches might include stress reduction, light therapy, moisturizers or even salicylic acid in order to remove the areas where scaly skin develops. In cases that are a little more severe, it may be necessary to include treatments of retinoids, such as isotretinoin (Accutane), UV-A light, corticosteroids, psoralen plus UV-A light or cyclosporine. Vitamin D3 appears to be able to control the growth of skin cells and is thus used when skin plaques are moderately severe.

Uses Based Upon Theory and Tradition

The uses as described below are based upon studies and tradition. Because some of these conditions may be very serious, it is important to first consult a doctor prior to taking any vitamin D for treatment.

• Actinic keratosis;
• Alzheimer’s disease that results in fractures of the hip;
• Ankylosing spondylitis;
• Autoimmune disorders;
• Graves disease;
• Hyperparathyroidism, particularly in renal dialysis;
• Hypocalcemia;
• Hypocalcemic tetany;
• Kidney transplant causing bone loss;
• Metabolic disorders;
• Nervous system disorders, such as hemichorea;
• Osteitis fibrosa through dialysis;
• Rheumatoid arthritis;
• Scleroderma;
• Squamous cell carcinoma;
• Systemic lupus erthematosus;
• Vaginal disorders; and
• Vitiligo.

Dosages

Adults (over 18 years old)

Most multivitamins have vitamin D included in them, and it is usually in strengths ranging from 50 IU to 1,000 IU when they are in tablets, softgels, liquids and capsules. The following levels of AI, or Adequate Intake, have been established herein by the United States Institute of Medicine.

It is recommended for all individuals, whether male, female, lactating or pregnant, to take in 5 micrograms of vitamin D on a daily basis, which also amounts of 200 IU. This only applies to those under the age of 50 years. Individuals who are between the ages of 50 years and 70 years should consider taking 10 micrograms on a daily basis, which also amounts to 400 IU. Those who are over the age of 70 years are recommended to take 15 micrograms on a daily basis, which also amounts to 600 IU per day.

There have been some authors who questioned the validity of these results, stating uncertainly with whether or not it is sufficient to meet with a person’s physiological needs, especially if they are an individual that does not regularly expose themselves to the sun adequately. The upper limit for obtaining vitamin D has been recommended to be 2,000 IU on a daily basis, based on reported toxicities with higher dosages.

Not all listed doses have previously been proven to be affective for certain conditions. However, in an oral dosage of 400 – 800 IU per day, ergocalciferol has previously been used to treat and prevent osteoporosis.

Children (under 18 years old)

It is recommended for newborns and children of all ages to take only five micrograms on a daily basis, which amounts to 200 IU per day. Children who are older than a year should not take more than the upper limit for their age, which is 50 micrograms on a daily basis, which amounts to 2,000 IU per day. Children who are below the age of one year are recommended to not exceed the maximum limit of 25 micrograms on a daily basis, which amounts to 1,000 IU per day.

It is potentially unsafe to take vitamin D in excess amounts orally, with potentially advertise affects such as high levels of calcium in the blood, or hypercalcemia.

There have been some authors who questioned the validity of these results, stating uncertainly with whether or not it is sufficient to meet with a person’s physiological needs, especially if they are an individual that does not regularly expose themselves to the sun adequately.

A review from 2008 has recommended that all infants and children, as well as all adolescents, should only take 400 IU on a daily basis based on evidence resulting from historical precedence and current, new clinical trials.

Safety

The United States Federal Drug and Food Administration is not known to strictly regulate the usage of herbs or supplements. There is no way to guarantee any strength or purity based on the usage thereof. Prior to beginning any new therapies, it is recommended to consult a physician.

Allergies

Anybody who is known to have a hypersensitivity to vitamin D or its derivatives or analogues should avoid taking it.

Side Effects and Warnings

With the recommended AI dosages, vitamin D is mostly well tolerated, though a study found that patients who took vitamin D analogues did experience a greater likelihood in experiencing daytime sleepiness.

It is possible to experience toxicity when regularly taking excess dosages of vitamin D. The end result may include excess bone loss or hypercalcemia. Those who have kidney disease, tuberculosis, sarcoidosis, hyperparathyroidism or histoplasmosis are at especially high risk. Pre-existing instances of chronic hypercalcemia should be managed by a doctor due to its potential to lead to serious or life threatening complications.

Early symptoms of this condition may include anorexia, nausea, vomiting, excess thirst, excess urination, fatigue, weakness, somnolence, dry mouth, headache, tinnitus, vertigo and ataxia. Function of the kidneys may become impaired and there may be an instance of calcium being deposited into several organs, which will also affect the kidneys. The necessary treatment for these is to stop taking calcium or vitamin D and to lower the levels of calcium under only the strictest medical supervision. It may be necessary to use corticosteroids and to acidify urine.

Pregnancy and Breastfeeding

It is recommended for pregnant women to take the same level of vitamin D as if they were not pregnant. There have been some authors who felt that pregnant women should take in more vitamin D, especially if sun deprived, but this has yet to be clearly established. Discuss higher doses of vitamin D with a physician due to the risk of vitamin D toxicity.

Maternal milk does not have much vitamin D to it, so it may be necessary to supplement an exclusively breastfed infant for the first two months of life in order to prevent vitamin D deficiency.

Walk into any pharmacy or beauty department and you will find products with retinol. It is praised for its anti-aging abilities, and the positive benefits it has to offer your skin. Here is everything you need to know to understand retinol, its benefits and its uses.

What is Retinol?

Retinol is the animal form of vitamin A. It is fat-soluble and helps keep vision sharp and bones strong. Other forms of vitamin A include retinal, retinoic acid and retinyl esters, but retinol is the most usable. All version of vitamin A together are known as retinoids.
Retinol represents the vitamin A molecule in its complete state.

More on Fat-Soluble

Fat-soluble vitamins will be absorbed into the body through the intestinal tract. They are absorbed in the same manner as fats, so any condition or medication that interferes with the absorption of fats will also interfere with the absorption of fat-soluble vitamins. These vitamins are stored in the body, most often in the liver.

Where it’s Found

Retinol can be produced synthetically. It is typically ingested through natural sources including liver, eggs, kidney, and dairy produce. Vitamin A is also found in plants with high levels of beta-carotene like dark or yellow vegetables and in carrots.

Specifically; cod liver oil, butter, margarine, eggs, cheese and milk all contain retinoids. The level is typically 0.15 mg of retinoids for every 1.75 to 7 ounces.

How it’s Measured

Retinol is measured in International Units (IU). These refer to biological activity and so each compound will have a slightly different IU measurement. One IU of retinol will be equal to roughly 0.3 microgram, or 300 nanograms.

What it Does

Retinol helps epithelial cells function properly. Glycoprotein synthesis requires certain levels of vitamin A to take place. Vitamin A is also an important ingredient that is needed by our immune systems.

Most notably, the positive effects of vitamin A are seen in vision, night vision, tooth and bone development and strength, reproduction and healthy skin.

How it Affects Skin

Retinol is most commonly known for playing an important role in successful skin care. Retinol is used to help slow the effects of aging that are shown in the skin. Retinol helps to resurface and rejuvenate the skin, leaving users with skin that is more vibrant, clear and youthful.

Retinol has an extremely small molecular structure. This tiny structure is what enables retinol to penetrate deep into skin and go to work smoothing wrinkles and improving skin. Vitamin A in this form has the ability to improve the elasticity of the skin, smooth wrinkles and lines and increase moisture. The complexion is left, smooth, glowing and the damage that is done from age and the environment is greatly minimized and even reduced.

As the body ages, skin cells can gradually take on a misshapen and altered shape. However, these same cells have receptor sites that will quickly accept retinoic acid. As the retinoic acid is absorbed, the cell begins to function normally and will resume cell generation that is normal. Retinol contains this necessary and highly beneficial retinoic acid.

Controlling Acne

Retinol has also been used to help control acne and keratosis pilaris by adding it to topical creams. Not only does vitamin A help the skin regenerate and look more youthful, it also has an exfoliating feature that can help unclog pores and clear acne.

Research also shows that retinol can stimulate the production of new collagen, another critical ingredient in maintaining youthful, healthy skin.

People with very dry skin may find that they initially see some light flaking when they first begin using products with retinol. This stage, known as the retinoid effect, is nothing more than the skin acclimating to the vitamin. It will typically pass quickly and with no ill side effects.

The use of retinol products can make you more sensitive to the sun, so be sure to use a good sunscreen.

Vitamin A Deficiency

Night Blindness is a common symptom of a vitamin A deficiency. If the deficiency persists, other symptoms can include dry eye and Bitot’s spot, where keratin debris can build up in the conjunctiva.

Other symptoms of vitamin A deficiency include a poor ability to adapt to darkness (nyctalopia), dry hair and skin, fingernails that break easily, and corneal perforation. Pruritis, or itching, can occur. Keratomalacia is a condition where the cornea can become very dry. Xerophthalmia is another form of dry eye that can occur when the body is not receiving enough vitamin A.

The immune system can be compromised by a vitamin A deficiency. Vitamin A has been used to treat children with measles that have a vitamin A deficiency. Supplementing their diet with vitamin A has been found to shorten the duration and severity of the illness. Side effects to watch for include diarrhea and pneumonia.

When vitamin A levels are too low, the body can not perform glycoprotein synthesis. This inability can lead to corneal ulcers or even liquefaction.

Retinoid Overdose

When too much vitamin A is received in retinoid form, hypervitaminosis A can occur. When levels in excess of 25,000 IU/ day are taken, overdose can occur. Toxic overdose can occur at two different levels: acute and chronic. Acute toxicity can occur within a few hours or a few days of a large overdose. Chronic toxicity takes place when the increased levels are consumed over a longer period of time.

Symptoms to watch for include nausea, blurred vision, fatigue, weight-loss and menstrual abnormalities.

Pregnant women consuming an increased level of vitamin A early in the pregnancy are also at risk for birth defects. The FDA recommends that pregnant women should not consume more than 5,000 IU of preformed vitamin A in any given day. Because vitamin A is carried in fat cells, pregnant women should take care that they are not adding too much vitamin A to their diet.

Retin-A, Renova and Alpha Hydroxy’s

Retin-A and Renova are both derived from a synthetic derivative of vitamin A, are considered pharmaceuticals and are only available with a prescription.

Alpha Hydroxy’s are used to exfoliate the skin, revealing the fresh, clear skin just under the surface. Retinols are used to actually regenerate skin growth on a much deeper level.

Cosmetic Uses for Retinol

Retinol creams – these are used to help moisturize and condition the skin. They are known to improve blemishes, acne, wrinkles and abnormal pigmentations. They are thick without being oily. They are typically used at night as part of a daily skin care routine. Look for Retinol Cream 15 by BioMedic or Time Arrest Cream by Dr. Brandt. The BioMedic cream can be found on Amazon. The cost is roughly $45 for one fluid ounce. Dr. Brandt’s website offers the Time Arrest cream. This product runs about $100 for 1.7 fluid ounces.

Retinol Lotions – these are not as thick as creams, they are a more liquid product. These are used to keep the skin moisturized. They can be used at any time of the day but will prove most beneficial when used after showering or bathing. They can make skin appear more youthful and help to reverse the damages of the sun. It can be carried with you and applied anytime your skin feels dehydrated, itchy or irritated. Afirm 3x BY Afirm can be found at Afirmskincare.com and will cost about $48 for just over one fluid ounce. Retinol Cream 60 by BioMedicare is available at the Dermstore online and will cost about $58 for one fluid ounce.

Retinol Serums – Like creams, they should only be applied once a day, preferably before bedtime. They have a greater ability to penetrate the skin, providing greater benefits to the skin. Serums are recommended for combating deep wrinkles, photo damage and any other signs of premature aging. Retinol Smoothing Serum 2x by Replenix is also available at the Dermstore online. The package size is 1.0 fluid ounce and will cost roughly $50.

Retinol Oils can be used instead of lotions or creams. Oils are a good choice for fighting the damage caused by environmental factors. Timeless Caviar Repair Cream by Pevonia Botanica. This treatment will also help increase oxygenation to your skin. 1.7 fluid ounces of this oil will cost about $171 through shoppevonia.com.

Retinol Eye Treatments – these are designed specifically for use on the sensitive area around the eyes. These treatments will effectively smooth crowsfeet, wrinkles and other fine lines. Skin Rejuvenation Eye Cream by MD Forte will run $60 for ½ fluid ounce through the Dermstore online.

Retinol Hand Treatments – your hands receive rough treatment every single day. They are constantly being washed with soap and water, as well as being exposed to the elements, cleaning detergents and environmental pollutants. The skin can become dry, brittle and even cracked. Using retinol hand treatments will bring healthy, smooth skin back to your hands, as well as strengthening your nails. Multivitamin Hand & Nail Treatment by Dermalogica can be found for as little as $24 for 2.5 fluid ounces through Amazon.

Retinol Lip Treatments – The lips are exposed to extreme air temperatures, and food temperatures, as well as other environmental dangers. The lips can gradually thin out, become drier and crack. A moisturizer that contains retinol can help plump your lips back up, making them healthier and smoother. PlumpLips Lip Plumper and Gloss by Freeze 24/7 can also be found through Amazon for as little $16.00.

Retinol Acne Treatments – Acne occurs when skin’s pores are blocked. The bacteria in the skin release a chemical to unclog the pores, and pimples result. Retinol has been proven to not only heal existing outbreaks, but also to reduce scars from past outbreaks and prevent future outbreaks. Acne Complex Kit by Murad, Exfoliating Acne Treatment Gel and Moisturing Acne Treatment Gel are all products produced by Murad to fight acne. At the Murad website you can get the entire acne treatment system for only $30.