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It is involved in bile production which is key in estrogen metabolism and detoxification. Niacin lowers LDL cholesterol. It is also a memory enhancer. It has an indirect effect on serotonin levels , because the body uses tryptophan the amino acid that is the precursor to serotonin production , to produce niacin. It has an effect on the adrenal hormones.

Niacin also promotes the release of growth hormone. You have a history of gallstones, gallbladder problems and low stomach acid, hence GERD or acid reflux. Your LDL cholesterol is high even though your diet is good. You struggle with depression, poor memory and you look older than your age. Pantothenic acid provides foundational support for both Phase I and Phase II detoxification, and more specifically, the elimination of inflammatory substances. It plays an important role in the production of adrenal hormones and is vital for coping with extreme stress.

All the steroid hormones, such as estrogen and progesterone, will be produced only with ample B5 in the system. Pantothenic acid is also involved in the production of neurotransmitters. Pantothenic acid is a stamina enhancer and prevents certain types of anemia. Deficiency might cause fatigue, headaches, nausea and tingling in the hands. You had gone through long periods of stress and feel depleted. You struggle with depression and addictions. Vitamin B6 is truly fascinating: It is involved in more bodily functions than any other single nutrient; effecting both mental and physical outlook.

Sufficient levels of B6 keep the liver functioning optimally by promoting the proper flow of fat and bile to and from the liver. Also of note is that Pyridoxine has one of the most dramatic mood-elevating effects of all the B vitamins. It activates many enzymes and aids B12 absorption. It can help to correct brain metabolism dysfunctions that cause depression.

It heightens serotonin production.

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It binds to estrogen, progesterone, and testosterone , helping to detoxify excess amounts of these steroid hormones, helping to reduce the risk of hormone-related cancers. You suffer from water retention, low stomach acid hence GERD or acid reflux , your homocysteine levels are high sign of inflammation. You lack energy, have anemia, convulsions, headaches and nausea. In spite of taking B12, you are still low. Food high in oxalates causes you kidney stones, vulvodynia, and pain. B12 is the most chemically complex of all the vitamins and it is a blanket name for a group of essential compounds called cobalamins.

B12 comes in various forms and not all of them are effective. Methylcobalamin is the most effective but expensive to produce and cyanocobalamin is least effective, not well absorbed and cheapest to produce it is unfortunately, found in many supplements. It is an important factor for the activation of the liver detox pathway that detoxes the heavy metals and histamines.

The B complex vitamins function as enzyme cofactors coenzymes or the precursors for them. Vitamin D has a hormone-like function as a regulator of mineral metabolism for bones and other organs. Vitamins C and E function as antioxidants. Before , the only source of vitamins was from food. If intake of vitamins was lacking, the result was vitamin deficiency and consequent deficiency diseases.

Then, commercially produced tablets of yeast-extract vitamin B complex and semi-synthetic vitamin C became available. This was followed in the s by the mass production and marketing of vitamin supplements , including multivitamins , to prevent vitamin deficiencies in the general population. Governments mandated addition of vitamins to staple foods such as flour or milk, referred to as food fortification , to prevent deficiencies.

The term vitamin is derived from the word vitamine , coined in by biochemist Casimir Funk , who isolated a complex of micronutrients essential to life, all of which he presumed to be amines. When this presumption was later determined not to be true, the "e" was dropped from the name. For the most part, vitamins are obtained from the diet, but some are acquired by other means: Humans can produce some vitamins from precursors they consume: Vitamins are classified as either water -soluble or fat-soluble.

In humans there are 13 vitamins: Water-soluble vitamins dissolve easily in water and, in general, are readily excreted from the body, to the degree that urinary output is a strong predictor of vitamin consumption. Vitamins A and D can accumulate in the body, which can result in dangerous hypervitaminosis. Fat-soluble vitamin deficiency due to malabsorption is of particular significance in cystic fibrosis.

Each vitamin is typically used in multiple reactions, and therefore most have multiple functions. Vitamins are essential for the normal growth and development of a multicellular organism. Using the genetic blueprint inherited from its parents, a fetus begins to develop from the nutrients it absorbs.

It requires certain vitamins and minerals to be present at certain times. If there is serious deficiency in one or more of these nutrients, a child may develop a deficiency disease. Even minor deficiencies may cause permanent damage. Once growth and development are completed, vitamins remain essential nutrients for the healthy maintenance of the cells, tissues, and organs that make up a multicellular organism; they also enable a multicellular life form to efficiently use chemical energy provided by food it eats, and to help process the proteins, carbohydrates, and fats required for cellular respiration.

The USDA has conducted extensive studies on the percentage losses of various nutrients from different food types and cooking methods. The effect of cutting vegetables can be seen from exposure to air and light. Water-soluble vitamins such as B and C dissolve into the water when a vegetable is boiled, and are then lost when the water is discarded. The body's stores for different vitamins vary widely; vitamins A, D, and B 12 are stored in significant amounts, mainly in the liver , [15] and an adult's diet may be deficient in vitamins A and D for many months and B 12 in some cases for years, before developing a deficiency condition.

However, vitamin B 3 niacin and niacinamide is not stored in significant amounts, so stores may last only a couple of weeks. Deficiencies of vitamins are classified as either primary or secondary. A primary deficiency occurs when an organism does not get enough of the vitamin in its food. A secondary deficiency may be due to an underlying disorder that prevents or limits the absorption or use of the vitamin, due to a "lifestyle factor", such as smoking, excessive alcohol consumption, or the use of medications that interfere with the absorption or use of the vitamin.

In contrast, restrictive diets have the potential to cause prolonged vitamin deficits, which may result in often painful and potentially deadly diseases. Well-known human vitamin deficiencies involve thiamine beriberi , niacin pellagra , [29] vitamin C scurvy , and vitamin D rickets. Some vitamins have documented acute or chronic toxicity at larger intakes. The European Union and the governments of several countries have established Tolerable upper intake levels ULs for those vitamins which have documented toxicity see table.

In setting human nutrient guidelines, government organizations do not necessarily agree on amounts needed to avoid deficiency or maximum amounts to avoid the risk of toxicity. Governments are slow to revise information of this nature. RDA US Recommended Dietary Allowances; higher for adults than for children, and may be even higher for women who are pregnant or lactating.

In those who are otherwise healthy, there is little evidence that supplements have any benefits with respect to cancer or heart disease. The European Union and other countries of Europe have regulations that define limits of vitamin and mineral dosages for their safe use as dietary supplements. Most vitamins that are sold as dietary supplements are not supposed to exceed a maximum daily dosage referred to as the tolerable upper intake level UL. Vitamin products above these regulatory limits are not considered supplements and should be registered as prescription or non-prescription over-the-counter drugs due to their potential side effects.

Dietary supplements often contain vitamins, but may also include other ingredients, such as minerals, herbs, and botanicals. Scientific evidence supports the benefits of dietary supplements for persons with certain health conditions. Most countries place dietary supplements in a special category under the general umbrella of foods , not drugs. As a result, the manufacturer, and not the government, has the responsibility of ensuring that its dietary supplement products are safe before they are marketed.

Regulation of supplements varies widely by country. Even though product registration is not required, these regulations mandate production and quality control standards including testing for identity, purity and adulterations for dietary supplements. Likewise, monographs of the European Pharmacopoeia Ph. At the time, most but not all of the letters from F through to J were already designated, so the use of the letter K was considered quite reasonable.

There are other missing B vitamins which were reclassified or determined not to be vitamins. For example, B 9 is folic acid and five of the folates are in the range B 11 through B 16 , forms of other vitamins already discovered, not required as a nutrient by the entire population like B 10 , PABA for internal use [50] , biologically inactive, toxic, or with unclassifiable effects in humans, or not generally recognised as vitamins by science, [51] such as the highest-numbered, which some naturopath practitioners call B 21 and B There are also nine lettered B complex vitamins e.

There are other D vitamins now recognised as other substances, [50] which some sources of the same type number up to D 7. The controversial cancer treatment laetrile was at one point lettered as vitamin B There appears to be no consensus on any vitamins Q, R, T, V, W, X, Y or Z, nor are there substances officially designated as Vitamins N or I, although the latter may have been another form of one of the other vitamins or a known and named nutrient of another type.

Once discovered, vitamins were actively promoted in articles and advertisements in McCall's , Good Housekeeping , and other media outlets.

Vitamins as hormones. - PubMed - NCBI

They promoted foods such as yeast cakes, a source of B vitamins, on the basis of scientifically-determined nutritional value, rather than taste or appearance. Yoder is credited with first using the term vitamania , in , to describe the appeal of relying on nutritional supplements rather than on obtaining vitamins from a varied diet of foods. The continuing preoccupation with a healthy lifestyle has led to an obsessive consumption of additives the beneficial effects of which are questionable.

Anti-vitamins are chemical compounds that inhibit the absorption or actions of vitamins. For example, avidin is a protein in raw egg whites that inhibits the absorption of biotin ; it is deactivated by cooking. The value of eating certain foods to maintain health was recognized long before vitamins were identified.

The ancient Egyptians knew that feeding liver to a person may help with night blindness , an illness now known to be caused by a vitamin A deficiency. Note that 25OHD levels obtained from nursing home subjects did not demonstrate the seasonal variation indicating their housebound and low vitamin D status. Some interesting observations on the effects of the variation of vitamin D metabolism through ageing have come from animal studies. Kidney CYP27B1 activity is highest in the newborn and declines exponentially throughout the remainder of life both in rodents and humans. In rats followed from 3 weeks of age until 2 years during which they were fed a constant level of vitamin D, the mRNA level of kidney CYP27B1 was negatively related to their serum 25OHD level in the early weeks of life between 3 and 15 weeks.

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If these data are reproduced in humans then factors that up-regulate the expression of kidney CYP24 expression may be important in reducing vitamin D status in the elderly. As with most clinical laboratory testing, when plasma 25OHD tests were introduced into routine clinical laboratories in the late s and early s reference intervals were obtained from testing levels in a reference population. However in other cities at different latitudes the reference interval was often different. Around the world the reference interval, particularly the lower limit, was inversely related to the latitude of the city in which the reference population was living.

Therefore testing of vitamin D status in a reference population is inappropriate for identifying the minimum or toxic levels of plasma 25OHD levels. It is necessary to identify objective measures from which we can derive clinical decision limits for vitamin D requirement. Currently the only known in vivo requirement for vitamin D metabolites is to maintain calcium homeostasis. Thus the first task in this field is to define the vitamin D requirement, in terms of plasma levels of 25OHD, necessary to maintain calcium homeostasis and optimal skeletal health.

A number of studies have been published reporting plasma 25OHD levels to reduce plasma parathyroid hormone PTH levels and biochemical bone turnover markers. Currently only surrogate markers of calcium homeostasis and bone metabolism have been used and ultimately clinical decision limits for skeletal health will require definition based on bone strength or fracture data. Of course if vitamin D status is confirmed to affect human health through other systems such as cell growth and proliferation, and therefore impact on cancer risk for example, then other assessments of clinical decision limits for vitamin D status will have to be defined.

Provisional critical levels for 25OHD for the determination of vitamin D status are presented in Table 5. Clinical requirements for measuring plasma 25OHD levels include assessing vitamin D status and monitoring vitamin D supplementation. A number of radioimmunoassays are used in routine laboratories as well as an automated system that utilises competitive-protein binding technology.

Thus clinical laboratories and assay kit manufacturers must work together to improve the precision of this assay. Furthermore these data indicate a significant bias between the various methods being used in clinical laboratories, a bias that is more important at lower 25OHD levels.

Currently assay performance does not achieve such a criterion.

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An international 25OHD assay standardisation will be necessary before clinical laboratories can provide such a service. Monitoring vitamin D supplementation provides further difficulties for the clinical laboratory. In many countries including Australia the major supplement available is ergocalciferol or vitamin D 2 which is derived from plants. Mammals produce cholecalciferol or vitamin D 3.

While it is currently considered that there are no known differences with regard to biological activity between the two forms of vitamin D, it is clear that our routine assays do not measure them identically. As discussed above the medical profession currently takes a very conservative approach to prescribing dosages of vitamin D. This is partly a result of the adverse experiences with vitamin D toxicity in earlier times and partly because of the paucity of quantitative data regarding the plasma 25OHD levels achieved with various doses in humans.

Recent studies on healthy men in Omaha, USA latitude 41 degrees north indicate This is in close agreement with another value published. Knowledge of the physiology and pathology of vitamin D is currently increasing at a rapid rate. The realisation that vitamin D can act in a paracrine and autocrine manner in addition to its well-described endocrine action opens up considerable opportunities for the development of new understanding of the requirement for an adequate vitamin D status for optimal health.

It is encouraging that the relatively simple and cheap practice of maintaining an adequate vitamin D status has the potential to provide health benefits in a number of areas, which afflict an increasing proportion of the population, as well as consume an increasing proportion of the healthcare budget to provide treatment. The reduction of the risk of hip fracture in the elderly is one such area. A high priority of research must be to identify the critical 25OHD values required to maintain a healthy skeleton in the elderly.

As well research must determine whether a low vitamin D status influences the development of cancer, whether it increases the absolute risk of cancer or whether it modulates the growth or invasiveness of cancers. Clinical laboratory professionals have a responsibility to improve the precision and accuracy of current 25OHD assays in clinical use. This work will require the collaboration between the profession and instrument and reagent manufacturers. The International Federation of Clinical Chemistry and Laboratory Medicine is in an optimal position to coordinate such a project.

The contents of articles or advertisements in The Clinical Biochemist — Reviews are not to be construed as official statements, evaluations or endorsements by the AACB, its official bodies or its agents. Statements of opinion in AACB publications are those of the contributors. No literary matter in The Clinical Biochemist — Reviews is to be reproduced, stored in a retrieval system or transmitted in any form by electronic or mechanical means, photocopying or recording, without permission.

Requests to do so should be addressed to the Editor. ISSN — National Center for Biotechnology Information , U. Journal List Clin Biochem Rev v.

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Professor Howard Morris e-mail: This article has been cited by other articles in PMC. Introduction Rickets is a bone disease in children, producing weak bones that are easily bent because of a defect in bone mineralisation. Vitamin D Toxicity During the period between the s and s considerable experience was gained with vitamin D toxicity when overdoses of vitamin D were often provided to patients being treated for hypocalcaemic disorders such as hypoparathyroidism.

Open in a separate window. Table 1 Concepts of Vitamin D status from the s. Vitamin D Depletion and Hip Fracture More recently considerable information about the effect of low levels of vitamin D on bone health has come from studies of the hip fracture syndrome. Data derived from reference Table 3 Current concepts of Vitamin D status. Bio-activation and Metabolism of Vitamin D, the Endocrine System Vitamin D is obtained from sunlight exposure of the skin where the UVA and UVB light converts 7-dehydrocholesterol to vitamin D, which is then subject to sequential hydroxylation reactions for bio-activation 16 Figure 2.

What are the Biological Activities of Vitamin D? Vitamin D and Cancer An area of particular interest for novel vitamin D activities is the regulation of cell growth and differentiation. Determinants of Serum 25OHD levels Sunlight exposure is clearly the major determinant of the vitamin D status of the individual and for populations. How much 25OHD do we need? Table 5 Current suggested decision limits for Vitamin D status.

How good are we at measuring 25OHD? Conclusions Knowledge of the physiology and pathology of vitamin D is currently increasing at a rapid rate. Notes The contents of articles or advertisements in The Clinical Biochemist — Reviews are not to be construed as official statements, evaluations or endorsements by the AACB, its official bodies or its agents.

Osteomalacia and related disorders. An experimental investigation of rickets. Identification of 1,dihydroxychole-calciferol, a new kidney hormone controlling calcium metabolism. Current understanding of the molecular actions of vitamin D. Mason RS, Posen S. The relevance of hydroxycalciferol measurements in the treatment of hypoparathyroidism. Vitamin D supplementation, hydroxyvitamin D concentrations, and safety.


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Am J Clin Nutr. Efficacy and safety of vitamin D3 intake exceeding the lowest observed adverse effect level. Osteomalacia and femoral fractures. Seasonal variation of histological osteomalacia in femoral-neck fractures. Plasma hydroxyvitamin D concentrations in patients with fractures of the femoral neck. Absence of metabolic bone disease in the proximal femur in patients with fracture of the femoral neck.

J Bone Joint Surg Br. Vitamin D and femoral neck fractures in elderly South Australian women. Calcium, vitamin D, milk consumption, and hip fracture: Vitamin D3 and calcium prevent hip fractures in elderly women. N Eng J Med. Effect of calcium and cholecalciferol treatment for three years on hip fractures in elderly women.