Man is reported to have been aware since early antiquity of the substance we now know as vitamin D. Considering the fact that now we accept that the biologically active form of vitamin D, namely 1a,25(OH)2-vitamin D3, is a steroid hormone, it is somewhat ironic that vitamin D, through a historical accident, became classified as a vitamin. The chemical structures of the vitamins D were determined in the 1930s in the laboratory of Professor Adolf Otto Reinhold Windaus at the University of Gottingen in Germany. Vitamin D2 which could be produced by ultraviolet irradiation of ergosterol was chemically characterized in 1932.
A "vitamin" by definition is a substance regularly required by the body in small amounts but which the body cannot make and is, therefore, required to be supplied in the daily diet. The World Health Organization had responsibility for defining the "International Unit" of vitamin D3. Since vitamin D3 can be endogenously produced by the body and since it is retained for long periods of time by vertebrate tissue, it is difficult to determine with precision the minimum daily requirements for this seco-steroid.
In November of 2010, , the Institute of Medicine's (IOM) special committee of 15 experts from the US and Canada issued its report for the citizens of both countries defining the formal Dietary Reference Intakes (average daily doses) of vitamin D and calcium required for good health. In the United States, adequate amounts of vitamin D can readily be obtained from the diet and from casual exposure to sunlight.
For decades since the determination of the chemical structures of vitamin D3 and vitamin D2 in the 1930's it has been assumed that both vitamins had equivalent biological activity in humans. Thus the authors felt that given the greater potency and lower cost, vitamin D3 should be the preferred choice for correcting vitamin D deficiency in humans. Animal products constitute the bulk source of vitamin D that occurs naturally in unfortified foods. Subcommittee on the Tenth Edition of the RDAs, Food & Nutrition Board, Commission on Life Sciences and National Research Council.
The structures of vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol) and their provitamins are presented in Figure 1 on the right.
Vitamin D (calciferol) is named according to the revised rules of the International Union of Pure and Applied Chemists (IUPAC).
Vitamin D3 can be produced photochemically by the action of sunlight or ultraviolet light from the precursor sterol 7-dehydrocholesterol which is present in the epidermis or skin of man and most higher animals. Structural relationship of vitamin D3 (cholecalciferol) and vitamin D2(ergocalciferol) with their respective provitamins, cholesterol, and a classic steroid hormone, cortisol (see inset box). Photochemical pathway of production of vitamin D3 (cholecalciferol) from 7-dehydrocholesterol.
A detailed study of the biochemical mode of action of the fat-soluble vitamin D was not possible until the availability in the 1960s of preparations of high specific activity radioactive vitamin D. As summarized in the figure on the left, the existence of the vitamin D endocrine system is now firmly established. An additional key component in the operation of the vitamin D endocrine system is the plasma vitamin D binding protein (DBP) that carries the hydrophobic vitamin D3 and all of its metabolites through the circulatory system to their various target organs. Since 1971, research efforts have largely focused upon understanding how 1a,25(OH)2D3 generates biological responses.
Thus, vitamin D3 is, in reality, a prohormone and is not known to have any intrinsic biological activity itself. The key kidney enzymes, the 25(OH)D3-1-hydroxylase and the 25(OH)D3-24-hydroxylase, as well as the liver vitamin D3-25-hydroxylase, are all known to be cytochrome P-450 mixed-function oxidases. The most important point of regulation of the vitamin D endocrine system occurs through the stringent control of the activity of the renal 1-hydroxylase.
1a,25(OH)2D3working with its VDR is known to selectively activate ? 3% of the some 22,000 genes of the human genome. As a consequence of the significant scientific advances in the understanding of how vitamin D generates biological responses [principally via 1a,25(OH)2D3], a number of new drug forms of 1a,25(OH)2D3 have been generated by pharmaceutical companies. The objective of this presentation is to provide a brief descriptions of vitamin D's chemistry, nutritional importance, sources, production and presence in milk. A vitamin is a substance (a specific organic molecule) whose presence is crucial to the normal every day life and functions of animals.
A hormone is a chemical messenger that is produced and secreted by specific glands and cells within the body of animals. Chemistry: There are two chemical forms of vitamin D, namely vitamin D2 (sometimes referred to as ergocalciferol) and vitamin D3 (sometimes referred to a cholecalciferol). The molecular structure of vitamin D is closely allied to that of the classical steroid hormones, e.g.
Technically the molecule called vitamin D3 is not really a vitamin because it can be produced by exposure of the skin (higher animals and humans) to ultraviolet light or sunlight.
Therefore for nutritional and public health reasons, vitamin D3 continues to be classified even today in 2012 officially as a vitamin.
It has become increasingly apparent since the 1980s that 1a,25(OH)2D3 also plays an important multidisciplinary role in tissues not primarily related to mineral metabolism, e.g.
Vitamin D Deficiency: The classic deficiency state resulting from a dietary absence of vitamin D3 or lack of ultraviolet (sunlight) exposure is the bone disease called rickets in children or osteomalacia in adults. Since vitamin D3 is produced in the skin after exposure of 7-dehydrocholesterol to sunlight, the human does not have a requirement for vitamin D when sufficient sunlight is available. Since vitamin D3 can be produced by the body and since it is retained for long periods of time by animal tissues, it has been difficult to determine with precision the minimum daily requirements for this fat soluble vitamin. Animal products constitute the primary source of vitamin D that occurs naturally in unfortified foods. When the critical importance to human health of a regular dietary access to vitamin D3 was understood (in the 1930's), milk suppliers realized it would be advantageous to their customers' health to market milk which had been supplemented with vitamin D3. In 1973 in the United States some 290 trillion (290 x 10-12) International Units of vitamin D3 was manufactured and sold for over 3 million dollars. The commercial production of vitamin D3 is completely dependent on the availability of either 7-dehydrocholesterol or cholesterol.
Next the crystalline 7-dehydrocholesterol is dissolved in an organic solvent and irradiated with ultraviolet light to carry out the transformation (similar to that which occurs in human and animal skin) to produce vitamin D3. Historically, the major producers of vitamin D3 used for milk and other food supplementation were the companies F. Milk from all lactating animals, including humans, contains vitamin D3 that has been produced photochemically from 7-dehydrocholesterol present in the skin. If a "food product" is construed to include a chemically pure substance that is the same in all animal species, then those individuals with strict religious reasons for avoiding food products from a particular species have, in the instance of milk and vitamin D3, a dilemma.
Also the WEB sites for the Vitamin D Workshop and provides other general information related to vitamin D.
Relative to visible LEDs, UV LEDs are a quiet market at only $30 million, yet recent breakthroughs in radiant power and intensity have enabled the displacement of mercury-vapor lamps in applications including UV curing and counterfeit detection, reports LAURA PETERS. Curing involves the cross-polymerization of a photosensitive material, which can be an ink (printing), adhesive or coating, and is primarily performed at 395 nm, 385 nm or 365 nm, wavelengths which are part of the UV-A spectrum (315-400 nm).
In the UV-B spectrum (280-315 nm), applications for UV LEDs include curing, medical light therapy, forensic analysis and drug discovery. Beyond these applications, UV-B radiation is known to have beneficial health properties including the natural synthesis of vitamin D in humans who are exposed to sunlight.
In the lower UV-C spectral range (100-280 nm), the primary LED applications are air and water sterilization and a range of analytical tools including those that perform spectroscopic and fluorescence measurements. UV in the 250-275 nm range sterilizes water, air and surfaces by breaking-up the DNA and RNA of microorganisms and preventing their reproduction.
In production curing operations, mercury-vapor lamps are hindered by short lifetime (2000-10,000 hr), slow warm-up and cool-down times, and wide spectral power distribution.
The mercury lamp has a main peak at 365 nm but several smaller peaks in the visible and infrared regions (Fig.
Metcalf added that many people who would not have considered UV curing because of the complexity of standard curing processes a€“ the high voltage, heat of mercury bulbs and environmental issues a€“ will now consider UV-LED curing because it subverts the traditional hassles of the old process. UV LEDs bring such benefits as knowing precisely what power level is being delivered to the curing medium, as well as other advantages LEDs are known for, such as the ability to pulse-width-modulate the output, stated Eskow.
The transition to UV LEDs also opened the door to more environmentally friendly curing formulations.
For the longer-wavelength UV devices, in a similar manner to blue LED fabrication, InGaN-based epilayers are grown on sapphire substrates to produce 385, 395 and 405 nm UV LEDs for curing. In addition to producing more power, the higher-wavelength UV LEDs feature higher wall-plug efficiencies. Stacy Volk, marketing communications specialist at Phoseon Technology in Hillboro, OR, a maker of UV-LED curing systems, pointed out some of the additional advantages associated with UV-LED curing include a controlled curing intensity, scalable equipment, and the fact that the machines are smaller and compact. One of the issues the curing industry has faced has been inconsistencies in measurement practice and parameter definitions, for example, defining radiometric intensity. Companies that manufacture UV-LED chips include Crystal IS, based in Green Island, NY (Fig. UV-LED manufacturers focus on continually improving the efficiency and lifetime of their devices while reducing cost. Tim Bettles, director of marketing and sales at SETi stated that its manufacturing agreement with Seoul Optodevice is designed to help SETi drive its volumes of UV LEDs and lamps higher while driving down costs.
Devin Tang, marketing manager of SemiLEDs stated that the company has a full line of bare dice and surface-mount high power packaged LEDs in the 360-400-nm range. Epigap Optronic, based in Berlin, Germany, the main distributor for Dowaa€™s UV LEDs, stated that Dowa manufactures 265, 280, 310, 325 and 340 nm bare dice or packaged LEDs. Recently, Theodore Moustakas of Boston University has pioneered the use MBE (molecular beam epitaxy) to grow more efficient (high internal quantum efficiency) UV LED devices using AIGaN-based layers on sapphire substrates. Even though UV LED manufacturers have been working hard to improve internal quantum efficiency and optical efficiency, overall efficiency remains below 20%, meaning a great deal of heat must be dissipated from the diodea€™s junction.
While some UV LED arrays are packaged on ceramic substrates, many manufacturers, particularly of single-chip devices, use TO-can type through-hole packages with a glass top that offers high transmission of UV. The choice of whether to use hermetic sealing in the package is sometimes determined by the materials in the chip.
It is important to recognize that some of the same qualities that make UV LEDs very powerful and useful a€“ their low wavelength and high energy a€“ are also the qualities that make them dangerous. When asked to identify the key issue that might keep UV users from changing over from mercury-vapor sources to UV LEDs, many industry participants say it comes down to breaking existing industry momentum and, of course, cost. Sponsored Content is made possible by our sponsor; it does not necessarily reflect the views of our editorial staff.
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Since many insects can see light in the UV part of the spectrum, flowering plants have evolved patterns to attract pollinators that cannot be seen by human eyes.
UV, or ultraviolet, light is an invisible form of electromagnetic radiation that has a shorter wavelength than the light humans can see.
The term “ultraviolet” means “beyond violet.” In the visible part of the spectrum, wavelength decreases — and the energy of the electromagnetic waves increases — from red through orange, yellow, green, blue and violet, so UV light has a shorter wavelength, and more energy, than violet light. The Sun produces ultraviolet light of all categories; however, the shorter, higher energy wavelengths are absorbed by oxygen in the atmosphere, and, in particular, by the ozone layer. Ultraviolet light, specifically UV-B, is required to allow the skin to manufacture vitamin D.
There are other benefits associated with ultraviolet light may that seem to be independent of vitamin D production.
Many potentially harmful microorganisms are quickly killed or inactivated by exposure to UV light. The effects of UV light on viruses, bacteria, and parasites have led to its use in disinfecting drinking water supplies.
Some substances, when exposed to UV light, emit light at visible wavelengths, a phenomenon known as fluorescence.
Biologists and zoologists are quite fond of ultraviolet light as it helps them take nighttime organism surveys in the field.
Many textiles used in clothing also fluoresce, and the “black lights” often used in nightclubs and at parties exploit this fact by causing clothing to glow in the dark.
Many insects can see ultraviolet light and are attracted to it, so the light is often used in insect traps. Mapping the Milky Way and other galaxies in ultraviolet light allows astronomers to build up a picture of how galaxies evolve over time.
Analyzing minerals — fluorescence under ultraviolet light can distinguish between minerals that look the same under visible light. Microscopy — the shorter wavelength of ultraviolet light can resolve details too small to be seen with an ordinary light microscope.
Chemical markers — substances that fluoresce in UV light, such as green fluorescent protein (GFP) may be used to study biological processes. Photochemotherapy — this is used as a treatment for psoriasis and some other skin conditions.
Very fine resolution photolithography — this is used in the manufacture of semiconductor components in the electronics industry.
Checking electrical insulation — “corona discharge,” where damaged insulation on electrical equipment results in ionization of the air, can be detected by the emission of ultraviolet light. Curing of adhesives and coatings — some substances polymerize and harden on exposure to ultraviolet light. UV light is classified as light because all constituents of the elctromagnetic spectrum, which UV light is one of, are light. Can UV bulbs be an energy source used for recharging solar powered lights same as the sun, or self producing energy by using UV bulbs for the source of the energy? Vitamin D is known as “The Sunshine Vitamin” because exposing our skin to the sun is the most abundant source of vitamin D production.  One typical non-burning tanning session can produce as much vitamin D as 200 glasses of milk (20,000 IU), which is why indoor tanners have among the highest vitamin D levels, about 90% higher than the general population. Tanning is the body’s natural response to ultraviolet light, and nature’s design to protect your skin from sunburn.
Tanning beds are designed to replicate UVA and UVB produced by the sun in carefully controlled combinations. Vitamin D actually refers to a group of fat-soluble compounds that serve as precursors to the active form of Vitamin D known as calcitriol.
If you are taking a Vitamin D supplement, it’s most likely in the form of cholecalciferol (D3).
Vitamin D is then converted by the liver into a form known as 25-hydroxyvitamin D, sometimes abbreviated as 25OHD.
Finally, in the kidneys, 25-hydroxyvitamin D is converted to 1,25 dihydroxyvitamin D (calcitriol). Vitamin D production requires exposure of a large amount of your skin to ultraviolet B (UVB) light. The climate you live in will likely determine whether or not you can get enough Vitamin D through sun exposure alone. However, convincing your boss to let you take a midday Vitamin D break in your bathing suit might not be feasible for many people.
Recommendations for preventing deficiency and normative ranges vary quite a bit depending on who you ask.
Veganism: excludes all animal flesh and animal products, including milk, honey, and eggs, and may also exclude any products tested on animals, or any clothing from animals.
Fruitarianism: permits only fruit, nuts, seeds, and other plant matter that can be gathered without harming the plant. Vegetarian nutrition is the set of health-related challenges and advantages of vegetarian diets. Well-planned vegetarian and vegan diets are nutritionally adequate and are appropriate for all stages of the life cycle, including during pregnancy, lactation, infancy, childhood, and adolescence.
Evidence suggests that vegetarians have lower rates of coronary heart disease, obesity, hypertension, type 2 diabetes,[1] osteoporosis,[2] anddementia.[3] Vegetarian diets tend to be rich in carbohydrates, omega-6 fatty acids, dietary fibre, carotenoids, folic acid, vitamin C, vitamin E,potassium and magnesium. Vegetarian diets are usually rich in carbohydrates, omega-6 fatty acids, dietary fiber, carotenoids, folic acid, vitamin C, vitamin E, potassium and magnesium.
It is recommended that vegetarians and vegans eat legumes and nuts daily, along with wholegrain cereals, to ensure adequate nutrient intakes.
If you’re vegetarian or vegan, you need to make sure you get the right amount of essential dietary minerals.
Iron – vegetarian and vegan diets are generally high in iron from plant foods; however, this iron is not absorbed as well as the iron in meat. Zinc – performs essential functions in the body, including the development of immune system cells. Iodine – our bodies need iodine for the thyroid gland and other associated hormones to function normally.

Vitamin B12 is important for the production of red blood cells – it helps to maintain healthy nerves and a healthy brain. Vegans can increase their chances of avoiding vitamin D deficiency by consuming fortified soymilk and cereals. VEGETARIAN FIGHTERVegetarian Fighter was founded with the goal of heightening the profile of vegetarian fighters while educating the public about vegetarian living and nutrition. We hope to offer resources and information that will educate everyone from the most novice to seasoned vegetarians. The first scientific description of a vitamin D-deficiency, namely rickets, was provided in the 17th century by both Dr. McCollum and associates observed that by bubbling oxygen through a preparation of the "fat-soluble vitamin" they were able to distinguish between vitamin A ( which was inactivated) and vitamin D (which retained activity).
Professor Windaus had some 55 doctoral and postdoctoral chemists working on the 'vitamin D project'.
Vitamin D3 was not chemically characterized until 1936 when it was shown to result from the ultraviolet irradiation of 7-dehydrocholesterol. The induction of growth promoting and calcifying properties in a ration by exposure to light. Technically the molecular species classified as vitamin D3 is not really a vitamin because it can be produced by exposure of the skin to sunlight (see section on Chemistry). Their most recent definition, provided in 1950 states that "the International Unit of vitamin D recommended for adoption is the vitamin D activity of 0.025 micrograms (25 nanograms) of the international standard preparation of crystalline vitamin D3".
Since vitamin D3 is produced in the skin after exposure to sunlight, the human does not have a requirement for vitamin D when sufficient sunlight is available. The requirement for vitamin D is also known to be dependent on the concentration of calcium and phosphorus in the diet, the physiological stage of development, age, sex, degree of exposure to the sun, and the amount of pigmentation in the skin. Their recommendation for vitamin D is that from ages 1 to 70, people need to consume no more than 600 International Units (IU) per day. However, in some parts of the world where food is not routinely fortified and sunlight is often limited during some periods of the year, obtaining adequate amounts of vitamin D becomes major problem. This was based on biological determination in rats of their comparative antirachitic activity. Heaney and coworkers it was reported that vitamin D3 is approximately 87% more potent in raising and maintaining serum 25(OH)D levels than was vitamin D2. Salt water fish such as herring, salmon, sardines, and fish liver oils are good sources of vitamin D3. From Vitamin D to hormone D: Fundamentals of the vitamin D endocrine system essential for good health.
Vitamin D is a generic term and indicates a molecule of the general structure shown for rings A, B, C, and D with differing side chain structures. Because vitamin D is derived from a steroid, the structure retains its numbering from the parent compound cholesterol. The chief structural prerequisite of a provitamin D is that it be a sterol with a D5,7 diene double bond system in ring B (Figure 2 to the left).
Identification and characterization of noncalcemic, tissue-selective, nonsecosteroidal vitamin D receptor modulators J. Degradation chemistry of a Vitamin D analogue (ecalcidene) investigated by HPLC-MS, HPLC-NMR and chemical derivatization J. The starting point is the irradiation of a provitamin D, which contains the mandatoryD5,7-conjugated double bonds; in the skin this is 7-dehydrocholesterol. As a consequence of efforts in several laboratories a new model emerged in the late 1960’s to describe the biological mechanisms of action of vitamin D3. From 1960 – 2021approximately 25,000 scientific papers were published that used the term vitamin D either in the title or abstract. Both of the renal enzymes are localized in mitochondria of the proximal tubules of the kidney.
In this way the production of the hormone 1a,25(OH)2D3 can be modulated according to the calcium and other endocrine needs of the organism. The regulation of gene transcription by 1a,25(OH)2D3 is known to be mediated by interaction of this ligand with its personal nuclear receptor protein, termed the VDR. Over the past decade, four lines of investigation have collectively yielded striking new insights into the many newly appreciated actions of vitamin D. The table below summarizes these new drugs and the relevant pharmaceutical company, and identifies the clinical circumstance for which their use has been authorized.
This will first require a review of the biological and nutritional background on vitamin D, which is a precursor of a steroid hormone [1a,25(OH)2D3] in higher animals, including humans. After secretion of the hormone, it is transported through the bloodstream to designated target organs where the hormone by binding to its specific personal receptor delivers its "message" to that set of cells. The natural form of vitamin D for animals and man is vitamin D3; it can be produced in their bodies from cholesterol and 7-dehydrocholesterol. The skin of many animals and man has a high concentration of the sterol cholesterol which is converted by enzymes in the skin to the sterol 7-dehydrocholesterol. Thus many vitamin capsules and food sources including cows milk are supplemented with vitamin D3 to improve their nutritional value. Classically vitamin D3 has been shown to be one of the most important biological regulators of calcium metabolism through stimulating the absorption of calcium from food across the intestine and participating in the incorporation of the absorbed calcium into the skeleton (2).
Man's tendency to wear clothes, to live in cities where tall buildings block adequate sunlight from reaching the ground, to live indoors, to use synthetic sunscreens that block ultraviolet rays, and to live in geographical regions of the world that do not receive adequate sunlight, all contribute to the inability of the skin to biosynthesize sufficient amounts of vitamin D3 (5).
The requirement for vitamin D3 is also known to be dependent on the age, sex, degree of exposure to the sun, season, and the amount of pigmentation in the skin (8). The ultraviolet exposure can be as little as 3 X per week exposure of the face and hands to ambient sunlight for 20 minutes (10). Thus there developed in the 1940's, and continues to the present, a large business of industrial production of vitamin D3 used for the supplementation of foods for human consumption: milk (both homogenized and evaporated), some margarine and breads.
7-Dehydrocholesterol can be obtained via organic solvent extraction of animal skins (cow, pig or sheep) followed by an extensive purification. This vitamin D3 is then purified and crystallized further before it is formulated for use in dairy milk and animal feed supplementation. In cow's milk it has been determined that the concentration of vitamin D3 in milk provided by the cow is roughly 35-70 International Units per quart as determined via biological assay (12) and approximately 50-80 International Units as determined by modern chemical mass spectrometric procedures (13). An evaluation of the relative contributions of exposure to sunlight and of diet to the circulating concentrations of 25-hydroxyvitamin D in an elderly nursing home population in Boston. Dietary reference intakes: A risk assessment model for establishing upper intake levels for nutrients. Vitamin-D synthesis and metabolism after ultraviolet irradiation of normal and vitamin-D-deficient subjects. Ranging from 100 to 400 nm, the radiation can effectively be used to sterilize cosmetics, perform forensic analysis, cure materials (Fig. UV-B also accelerates the production of polyphenols in certain leafy vegetables such as red lettuce.
Specifically, 275 nm is believed to be the most effective wavelength for eradicating pathogens such as E-coli in water.
With the next generation of products that ink, coating and adhesive companies were developing, they used the opportunity to phase-out volatile organic compounds (VOCs) associated with the solvent-based formulations of past chemistries. Metcalf describes large flat-bed banner printers as being able to use lower-power LEDs, but higher speed digital, offset and flexographic technologies require closely-spaced banks of high-flux-density LEDs. Seoul Optodevice has a manufacturing partnership agreement with SETi, which manufactures a broad range of UV LEDs and lamps, and performs everything from wafer processing to custom lamp design. The replacement of epoxy lenses with flat or dome-shaped glass capable of UV transmission is a relatively new development, and one that has allowed an extension of lifetimes from around 5000 hours up to as high as 30,000 hours. The warning labels on UV LEDs and their products are clear but bear noting: UV-LEDs emit invisible ultraviolet radiation when in operation, which may be harmful to eyes or skin, even for brief periods. Lim thinks that a rounding out of the wavelength portfolio would go a long way toward adoption.
It carries more energy than visible light and can sometimes break bonds between atoms and molecules, altering the chemistry of materials exposed to it. Wavelengths are measured in nanometers (nm), or billionths of a meter, and ultraviolet wavelengths range between 10nm and 400nm. As a result, the ultraviolet that reaches the surface consists mostly of UV-A, with a little U-VB. It converts a chemical found in the skin to a precursor of the vitamin, which then forms the vitamin itself.
Airborne virus infections, such as influenza, are generally spread via droplets expelled by coughs and sneezes.
The more energetic UV-B is responsible for sunburn, can cause premature aging of skin and can alter DNA in a way that can lead to skin cancers, such as melanoma. It has the advantages of requiring little maintenance, not affecting the taste of treated water, and leaving no potentially harmful chemicals behind.
Common fluorescent lamps, for example, are powered by UV light produced by ionizing low-pressure mercury vapor. Sensitive documents, such as currency, driver's licenses, credit cards, and passports, have invisible symbols on them that light up only in the presence of UV light. Certain birds, reptiles, and invertebrates, such as insects, fluoresce under UV, and quickly flashing a light over a small area can allow observers to count the approximate number of organisms of a given type.
These lights primarily produce light in the UV portion of the spectrum, but they also produce a slight violet glow. These may be used by entomologists to study the insect population in a specific habitat or to trap and kill nuisance insects in restaurants food stores. Visible light is simply the segment on the electromagnetic spectrum that represents light with a wavelength perceptible to the human eye. Visible light is simply the segment on the spectrum that classifies the light that the human eye can perceive. Tanned skin is several times more resistant to sunburn, and a tanning bed is a controlled way to get that protection.  That’s why millions of tanners visit professional tanning salons before taking sun-filled vacations. The result allows trained operators to control clients’ exposure and provide them with a great tan in moderation, while minimizing the risk of sunburn. Deficiency has been linked with a variety of health problems such as cardiovascular disease, cognitive impairment, asthma in children, and even cancer. Exposure to sunlight causes the skin to produce a form of vitamin D known as 7-dehydrocholesterol. If you go to your doctor, or order a blood panel from an independent lab, this is usually the form that is being tested. Interestingly enough, vitamin D isn’t really a true vitamin in the strict sense of the word. It’s essential for bone health, but also plays a role in reducing risk of chronic diseases such as diabetes, heart disease, cancers, multiple sclerosis, rheumatoid arthritis, and infectious diseases. Generally speaking, paler skin types tend to produce more Vitamin D and darker skin types tend to produce less.
Or you might avoid sun exposure due to concerns about skin cancer and skin aging from UVA exposure.
Athletes in colder climates will likely need to supplement with more as they probably don’t get as much sun exposure as athletes that live in warmer climates.
A vegetarian diet can provide adequate protein, iron, zinc, vitamin B12, and calcium intake, though these nutrients can be relatively low in poorly planned vegetarian diets, particularly when not enough calories are consumed. Good food sources of iron include green leafy vegetables, peas and wholegrains, enriched cereals and legumes.
Good food sources of zinc include nuts, tofu, miso, legumes, wheat germ and wholegrain foods.
Good food sources of calcium include dairy products, fortified cereals and fruits juices, fortified soymilk, tahini and some brands of tofu. Vegans are at risk of developing vitamin B12 deficiency because it is not found in plant products. If a breastfeeding mother is following a vegan diet, the lack of vitamin B12 in her milk can interfere with normal brain development of her baby.
There are fortified vegan foods such as some soy beverages and some vegetarian sausages and burgers.
As the sun is also a major source of vitamin D, dietary intake is only important when exposure to UV light from the sun is inadequate – for example, in people who are housebound or whose clothing covers almost all of their skin. Through interviews, stories, recipes, clinical data and sharing knowledge we hope to prove that making the switch to being vegetarian is not something to be intimidated by, but embraced. Every vegetarian gets asked, “Where do you get your protein?” and as elite athletes, fighters are asked this question possibly more than any one else. In 1921 he wrote, "The action of fats in rickets is due to a vitamin or accessory food factor which they contain, probably identical with the fat-soluble vitamin." Furthermore, he established that cod liver oil was an excellent antirachitic agent.
In 1923 Goldblatt and Soames clearly identified that when a precursor of vitamin D in the skin (7-dehydrocholesterol) was irradiated with sunlight or ultraviolet light, a substance equivalent to the fat-soluble vitamin was produced. Professor Windaus received a Nobel Prize in Chemistry in 1928 for his work on sterols and their relationship to vitamins. Virtually simultaneously, the elusive antirachitic component of cod liver oil was shown to be identical to the newly characterized vitamin D3. A study of rats on a normal diet irradiated daily by the mercury vapor quartz lamp or kept in darkness.
However, for nutritional and public health reasons, vitamin D3 continues to be classified officially as a vitamin (see section on History of Vitamin D). The 13th and 14th Vitamin D Workshops reported in white papers that two thirds of the world population has a vitamin D deficiency. However in 1997, the IOM vitamin D reference intake publication for vitamin D, serum 25-hydroxyvitamin D [25(OH)D], rather than antirachitic activity, was defined as the functional indicator of vitamin D status.
In addition, vitamin D3 produced a 2- to 3-fold greater storage of vitamin D than does equimolar D2.
Small quantities of vitamin D3 are also derived from eggs, veal, beef, butter, and vegetable oils while plants, fruits, and nuts are extremely poor sources of vitamin D. The A, B, C, and D ring structure is derived from the cyclopentanoperhydrophenanthrene ring structure for steroids. Asymmetric centers are designated by using the R,S notation; the configuration of the double bonds are notated E for "entgegen" or trans, and Z for "zuzammen" or cis. The conjugated double bond system in this specific location of the molecule allows the absorption of light quanta at certain wavelengths in the UV range; this can readily be provided in most geographical locations by natural sunlight (or UV-B). It is to be emphasized that vitamin D3 is the naturally occurring form of the vitamin; it is produced from 7-dehydrocholesterol, which is present in the skin, by the action of sunlight (see Figure 2). After absorption of a quantum of light from sunlight (UV-B), the activated molecule can return to the ground state and generate at least six distinct products. This model is based on the concept that, in terms of its structure and mode of action, vitamin D is similar to the classic steroid hormones, e.g. The chief regulatory factors are 1a,25(OH)2D3 itself, parathyroid hormone (PTH), and the serum concentrations of calcium and phosphate.
Target organs and cells for 1a,25(OH)2D3 by definition contain nuclear receptors for 1a,25(OH)2D3 (VDRnuc). Accordingly, the daily requirements for each vitamin must be met through regular dietary intake of appropriate quantities of the vitamin(s). An alternative vitamin D2 is commercially prepared from ergosterol that is present in yeast. All steroid hormones and vitamin D3 are chemically related to the well known sterol cholesterol. Exposure of skin (including human skin) to sunlight for regular intervals results in the photochemical conversion of 7-dehydrocholesterol into vitamin D3. In the 1940's this milk supplementation process reduced the incidence rate of juvenile rickets by 85% in the United States.
These important biological effects are only achieved as a consequence of the metabolism of vitamin D into a family of daughter metabolites, including 1a,25(OH)2-vitamin D3 [1a,25(OH)2D3]. The classical skeletal disorder of rickets includes deformity of the bones, especially in the knees, wrists, and ankles, as well as associated changes in the rib joint functions, which have been termed by some as the rachitic rosary (1). These recommendations are all summarized in a 2010 publication from the Food and Nutrition Board of the Institute of Medicine (9).
However, in some parts of the world where food is not routinely fortified and sunlight is often limited during some periods of the year, obtaining adequate amounts of vitamin D becomes more of a problem. Small quantities of vitamin D3 are also found in eggs, veal, beef, butter, and vegetable oils while plants, fruits, and nuts are extremely poor sources of vitamin D.

Since the 1960's vitamin D3 has been used also for the supplementation of farm animal and poultry food.
Cholesterol typically is extracted from the lanolin of sheep wool and after thorough purification and crystallization can be converted via a laborious chemical synthesis into 7-dehydrocholesterol. The exact details of the chemical conversion of cholesterol to 7-dehydrocholesterol and the method of large-scale ultraviolet light conversion into vitamin D3 and subsequent purification are closely held topics for which there have been many patents issued (3). However these are rather low levels of vitamin D3 from the perspective of providing the 600 IU per day as recommended by the Food and Nutrition Board of the Institute of Medicine in 2010.. Seasonal changes in plasma 25-hydroxyvitamin D concentrations of young American black and white women.
Identification of vitamin D3 and 7-dehydrocholesterol in cow's milk by gas chromatography-mass spectrometry and their quantitation by high-performance liquid chromatography. UV-LED flashlights in this range are used to detect fraudulent identification and currency, and offer the benefit of use in well-lit environments, which is difficult using a mercury-vapor lamp.
He added that the UV output of a mercury vapor lamp drops off rapidly over its operational life because some of its electrode material vaporizes, depositing a film on the inside of the quartz tube which the UV cannot penetrate.
A downside to these extraneous peaks is the generation of heat during printing and other curing operations. At 385 nm, this efficiency improves, but only to ~15%, making the higher-wavelength chip the better choice. Depending on the equipment and curing application, the media can be 1 to 100 mm from the emitter window, for which AMS has produced special optics.
Even though the radiation is not visible, collimating optics are utilized to deliver the radiation with a uniform power level across the target media. The association also seeks to help speed development of applications especially suited to UV LEDs, educate researchers, integrators and end users regarding the benefits of UV LEDs, and provide a forum for industry communication and collaboration. The company provides UV emitters in hermetically-sealed metal-glass packages (TO-18, TO-39 and TO-3), with standard products and custom solutions spanning the wavelength range from 240 to 355 nm. We are now gearing SETia€™s capacity for high-volume manufacturing to cater to new demands coming from mainstream consumer markets,a€? said Bettles.
Crystal IS manufactures 260 nm UV LEDs and is the only company to produce LEDs on AlN substrates. Nonetheless, AlN substrates are only available in small sizes and remain much more expensive than sapphire wafers, thereby limiting this market. This is only possible with an LED package capable of handling extreme power densities for the life of the product. UV accelerates degradation of the epoxy material in a non-linear manner, directly impacting lifetime. The new copper- and glass-based package from Schott offers the advantages of high thermal conductivity and hermeticity. UV light can also cause some substances to emit visible light, a phenomenon known as fluorescence.
This vitamin is essential to human health, and a lack of it has been implicated in immune system disorders, cardiovascular disease, high blood pressure and various cancers.
Virus particles in these droplets do not survive long if exposed to sunlight, and as a result, these diseases may not spread so easily in sunny conditions. The main disadvantage is that, unlike some chemical methods — such as chlorination — it will not protect against contamination after treatment.
This light is absorbed by a special fluorescent coating, which in turn produces visible light. This is very helpful because many of these animals are mainly nocturnal and rarely if ever seen during the day. Special posters or other works of art can also be created with the express purpose of fluorescing a certain way under a black light.
They also produce a higher proportion of their ultraviolet light at the extreme end of the spectrum. Where as the strength and amount of UV light emitted by the sun varies from day to day, increasing the risk of sunburn.
It is then converted into a form known as cholecalciferol, more commonly known as Vitamin D3.
Vitamin D2, or ergocalciferol, is found in plant foods like mushrooms and nuts, and is also used to fortify processed foods. A fair skinned person might only need 10 minutes of exposure around noon while someone that is darker could need up to 2 hours of exposure. If you are fortunate enough to live in a sunny climate like San Diego, adequate sun is available almost all year round.
In either case, supplementation is certainly worth considering if your Vitamin D levels are low. Of course, you should get tested first to see if you are deficient and then consult with a qualified professional to determine how much Vitamin D you need to take. Combining these foods with foods high in vitamin C and food acids, such as fruit and vegetables, will help your body absorb the iron.
Leafy dark green vegetables (especially Asian greens), legumes, almonds and Brazil nuts also contain calcium.
If vegans don’t obtain their B12 requirement from these foods, they are advised to take B12 supplements. They contain a compound with a similar structure to B12 but it doesn’t work like B12 in the body.
There is very little vitamin D in most people’s diets unless they eat fatty fish, eggs, liver or foods fortified with vitamin D (such as margarine). One of the main goals of Vegetarian Fighter is to showcase that it is possible to compete at the top echelon of combat sports while being vegetarian. The major breakthrough in understanding the causative factors of rickets was the development in the period 1910 - 1930 of nutrition as an experimental science and the appreciation of the existence of vitamins. These results clearly established that the antirachitic substance vitamin D was chemically a steroid, more specifically a seco-steroid.
With the discovery of the metabolism of vitamin D3 to other active seco-steroids, particularly 1?,25(OH)2D3, it was recommended that 1.0 unit of 1?,25(OH)2D3 be set equivalent in molar terms to that of the parent vitamin D3. In the United States, artificial fortification of foods such as milk (both fresh and evaporated), margarine and butter, cereals, and chocolate mixes help in meeting the RDA recommendations. Vitamin D2 (which is equivalently potent to vitamin D3 in humans and many mammals, but not birds) is produced commercially by the irradiation of the plant sterol ergosterol with ultraviolet light. The four steroids that do not have a broken 9, 10-carbon bond (provitamin D, lumisterol, pyrocalciferol, and isopyrocalciferol) represent the four diastereomers with either an a- or b-orientation of the methyl group on carbon-10 and the hydrogen on carbon-9.
Mitochondrial mixed-function oxidases are composed of three proteins that are integral components of the mitochondrial membrane; they are renal ferredoxin reductase, renal ferredoxin, and cytochrome P-450. The most important determinant of the 1-hydroxylase activity is the vitamin D status of the animal. Also, 1a,25(OH)2D3 generates biological effects involving rapid signal transduction pathways utilizing a putative membrane receptor. There are many scientific publications; a list of recent summary articles are available at the end of this presentation. There are two general chemical categories of vitamins based on their solubility: water soluble vitamins (the B vitamins and others) and fat soluble vitamins (A, D, E and K). Cholesterol in animals and man is a precursor substance for all steroid hormones and as well vitamin D3.
1a,25(OH)2D3, is considered to be a steroid hormone because the general mechanism by which it produces the biological responses attributed to vitamin D is similar to those of steroid hormones (3;4). A regular access to vitamin D3 throughout life is important to facilitate the normal absorption into the body of dietary calcium which, in turn, is essential for normal bone health and may diminish or prevent the onset in the elderly of the bone disease osteoporosis.
As a result, the incidence of rickets in these countries is higher than in the United States. In the United States, fortification of foods such as milk (both fresh and evaporated), margarine and butter, cereals, and chocolate mixes help in meeting the adequate intake (RDA) recommendations (11). It should be appreciated that once chemically pure, crystalline 7-dehydrocholesterol has been obtained, it is impossible to use any chemical or biological tests or procedures to determine the original source (sheep lanolin, pig skin, cow skin, etc.) of the cholesterol or 7-dehydrocholesterol. Accordingly, as discussed above, the business practice of supplementing cows milk with chemically synthesized vitamin D3 was initiated. It is simply not possible to distinguish the origins of the two vitamin D3 preparations by any biological or chemical procedure, because they are the same molecular structure.
Today, as is the case with LEDs in the visible spectrum, UV LEDs are only beginning to replace the established UV sources in a likewise diverse array of markets.
As a result, the user cannot easily predict the amount of UV generated at a later time; often this is a critical process parameter.
All the major providers of curing formulations (photoinitiators and resins), have recently brought higher-wavelength inks and coatings to market to fill this need. Digital inkjet curing was the first segment to adopt UV LEDs due to the required close distance to the media for the print heads to optimally perform. Figure 6 shows examples of UV-LED arrays in lamps designed to deliver radiation in the 300-320 nm range for phototherapy applications such as the treatment of skin conditions such as psoriasis or eczema. SETi recently announced the purchase of a new facility, where it plans to manufacture over 100 million UV LEDs per year. A thermally matched stress-free package and glass lens help eliminate common packaging failure modes associated with UV LEDs,a€? said Thomas. This form of light — which is present in sunlight — can be beneficial to health, as it stimulates the production of vitamin D and can kill harmful microorganisms, but excessive exposure can cause sunburn and increase the risk of skin cancer. There is evidence that people with outdoor occupations are less susceptible to the disease. UV light stimulates the production of the pigment melanin, and because of this, people may intentionally expose themselves to strong sunlight to obtain a tanned skin. Areas where new stars are forming therefore glow more brightly in UV, enabling astronomers to identify and map these areas. Vitamin D production is one of the benefits that has been associated with human exposure to ultraviolet-B (UVB) emitted in sunlight and by an estimated 90 percent of commercial indoor tanning equipment. The biggest difference between the sun and tanning beds is that the sun also produces UVC which is the most harmful ray, where as tanning beds will filter out UVC rays, so that a tanner is only getting UVB AND UVA rays. This active form is similar to steroid hormones such as estrogen, testosterone, and cortisol.
Vitamin D is also involved in the regulation, either directly or indirectly, of hundreds of different genes in your body. Vitamin B12 absorption becomes less efficient as we age, so supplements may also be needed by older vegetarians. They may contain some B12 on their surface, from soil (bacteria) or fertiliser contamination. They excised a small portion of skin, irradiated it with ultraviolet light, and then fed it to groups of rachitic rats.
An experimental demonstration of the existence of a vitamin which promotes calcium deposition. Thus, 1.0 unit of 1?,25(OH)2D3 has been operationally defined to be equivalent to 65 pmoles. Seco-steroids are those in which one of the rings has been broken; in vitamin D, the 9,10 carbon-carbon bond of ring B is broken, and it is indicated by the inclusion of "9,10-seco" in the official nomenclature. The two secosteroid products, vitamin D3, previtamin D3, and tachysterol3 have differing positions of the three conjugated double bonds. In addition, the VDR is known to localize with the plasma membrane of the target cell where it initiates rapid responses (e.g. The precise biological roles of 24,25(OH)2D3 are not yet defined although it is believed to function in bone and cartilage.
Under these circumstances vitamin D3 is not a vitamin because it has been produced by the body (with the assistance of sunlight). Because only fluid milk is fortified with vitamin D, other dairy products (cheese, yogurt, etc.) only provide the vitamin that was produced by the animal itself. At the present time almost all milk sold commercially in the United States has 400 IU of chemically synthesized vitamin D3 added per quart. Further, there is no legal requirement for the manufacturer of the vitamin D3 formulated for human food supplementation to specify the animal sources of the precursor molecules that were employed in the synthesis of the D vitamin. Interestingly, we have evidence that when those plants are exposed to UV-B LEDs a short time before harvest, their polyphenol content is boosted without compromising plant mass,a€? explained Cary Eskow, global director of advanced LEDs and illumination for Avnet Electronics Marketing in Phoenix, AZ, which distributes UV LEDs. SETi has demonstrated disinfection of drinking water in an in-line flow-through system using less than 40 mW of UV power. He gave examples that include plastic gift cards or credit cards, which use sheet-fed lithographic printing. This was a natural fit for UV-LED lamps as the curing intensity is highest at the emitter window.
He described LED Engina€™s patented multi-layer ceramic substrate with extremely low thermal resistance that quickly conducts heat from the die junction (Fig.
Another alternative is to combine a glass lens with silicone encapsulant to accommodate even higher flux density and higher efficiency yet shorter lifetime (15,000-20,000 hr). Lack of sunlight is the main cause of vitamin D deficiency, and sunscreen prevents its formation. Children who spend a lot of time on outdoor activities also appear to be at less risk of developing skin cancers later in life. The effects associated with this form of light may be aggravated by the popularity of tanning studios and sunbeds, which use artificially produced ultraviolet light to cause tanning.
However, most people aren’t sure how much vitamin D they should take or if they need to take it in the first place.
A true vitamin can’t be produced in sufficient quantities by your body and must be acquired through diet.
The skin that had been irradiated provided an absolute protection against rickets, whereas the unirradiated skin provided no protection whatsoever; clearly, these animals were able to produce by uv irradiation adequate quantities of "the fat-soluble vitamin", suggesting that it was not an essential dietary trace constituent.
In addition to geographical and seasonal factors, ultraviolet light from the sun may also be blocked by air pollution. Thus, it is important to appreciate that vitamin D3 can be endogenously produced and that as long as the animal (or human) has access on a regular basis to sunlight there is no dietary requirement for this vitamin. In the skin, the principal product is previtamin D3, which then undergoes a 1,7-sigmatropic hydrogen transfer from C-19 to C-9, yielding the final vitamin D3: Vitamin D3 can be drawn as either a 6-s-trans representation or as 6-s-cis representation depending upon the state of rotation about the 6,7-single bond. Any vendor of milk for human consumption containing added vitamin D3 is required by the US Food and Drug Administration (FDA) to include a notice on the milk carton label.
He continued a€?This is a novel method for increasing the appeal of some foods without using chemicals. Other possible beneficial effects include reduced incidence of cardiovascular disease, improvement of some skin conditions, and mood enhancement.
Vitamin D can be produced by your body but many people don’t get enough sun exposure to produce adequate amounts. In parallel studies, Steenbock and Black at the Biochemistry Department of the University of Wisconsin found that rat food which was irradiated with ultra violet light also acquired the property of being antirachitic. The tendency to wear clothes, to live in cities where tall buildings block adequate sunlight from reaching the ground, to live indoors, to use synthetic sunscreens that block ultraviolet rays, and to live in geographical regions of the world that do not receive adequate sunlight, all contribute to the inability of the skin to biosynthesize sufficient amounts of vitamin D3. The resulting vitamin D3, which is formed in the skin, is removed by binding to the plasma transport protein, the vitamin D-binding protein (DBP), present in the capillary bed of the dermis.
A number of excellent articles have appeared describing the current understanding of how the VDR regulates both gene transcription and rapid responses. Under these conditions, vitamin D becomes a true vitamin which dictates that it must be supplied in the diet on a regular basis.
However, because of the rapid rise of the science of nutrition -- and the discovery of the families of water-soluble and fat-soluble vitamins -- it rapidly became firmly established that the antirachitic factor was to be classified as a vitamin. Under these conditions vitamin D becomes a true vitamin in that it must be supplied in the diet on a regular basis. However it is not required by law to indicate either the manufacturer of the added vitamin D3 or the sources of the cholesterol and 7-dehydrocholesterol used for its production.

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Comments Uv light and vitamin d

  1. Hulya
    And just waiting to burn me when I handled it carelessly, without realising.
  2. Prodigy
    Region of the spectrum, wavelengths are (from opening to almost closing time), but it was.
    First, Bondic dries by using must use eye and skin.