Hi there, welcome to my 'personal library'. I am just another ordinary guy who love to share and care! This is some sort of my very own one-stop reference centre. It's kinda 'out of the box' thinking, not to the average Malaysians.. to dig of such infos up to this depth. Whatever health challenge happened to the other side of the globe is possible to happen to me as well. U R most welcome to visit my library.. I Care, U Care, We Care!! Love U all..
Monday, August 24, 2009
Potassium Benefits
Thursday, August 20, 2009
Synthetic Vitamins Danger
The majority of commercial vitamin supplements are made up of synthetic vitamins.
Synthetic vitamins do not perform the same functions in your body as vitamins found naturally in whole food.
Many synthetic vitamins deplete your body of other nutrients and tax your kidneys before being excreted through your urine. If you want a comprehensive understanding of what vitamins are and what they do in your body, it would be best to take a full course in biochemistry. Do you remember all of those molecular formulas and chemical reactions that you studied in your high school chemistry class? Biochemistry is really just an extension of chemistry, with an emphasis on the thousands of chemical reactions that occur in your body on a moment-to-moment basis. Anyone who studies biochemistry learns that vitamins do not exist as single components that act on their own. Vitamins are made up of several different components –
- enzymes,
- co-enzymes,
- and co-factors–
that must work together to produce their intended biologic effects. Vitamins that are found naturally in whole foods come with all of their necessary components. The majority of vitamins that are sold in pharmacies, grocery stores, and vitamin shops are synthetic vitamins, which are only isolated portions of the vitamins that occur naturally in food.
A good example is vitamin C. If you take a look at a variety of vitamin C supplements, you will find that the majority of them contain only ascorbic acid or a compound called ascorbate, which is a less acidic form of acorbic acid.
Ascorbic acid is NOT vitamin C.
It represents the outer ring that serves as a protective shell for the entire vitamin C complex, much like an orange peel that serves as a protective shell for an orange.
Real vitamin C found in whole foods like fruits and vegetables contain the following components:
- Rutin
- Bioflavonoids (vitamin P)
- Factor K
- Factor J
- Factor P
- Tyrosinase
- Ascorbinogen
- Ascorbic Acid
When you take only ascorbic acid found in your synthetic vitamin C tablet or powder, your body must gather all of the other components of the full vitamin C complex from your body’s tissues in order to make use of it. In the event that your body does not have adequate reserves of the other components, ascorbic acid itself does not provide any of the health benefits that the full vitamin C complex does. After circulating through your system, the unused ascorbic acid is eliminated through your urine.
Just like vitamin C, almost all other vitamins that we know of offer their full health benefits when they are in the presence of a number of
enzymes, co-enzymes, co-factors, and even minerals.
For example:
- Vitamin D may have as many as twelve different active components,
- while vitamin P has at least five different components.
- The mineral copper is needed for full vitamin C activity,
- while vitamin E works closely with the mineral selenium to provide its health promoting, anti-oxidative effect.
Clearly, it is best to get your vitamins from whole foods because whole foods provide complete vitamins rather than fractions of them. In many cases, whole foods also provide the minerals that are necessary for optimal vitamin activity. For example, sunflower seeds are an excellent whole food source of vitamin E and the mineral selenium, both of which need each other to offer their full health benefits. How do you know if the vitamins on your kitchen counter are from whole foods or if they are synthetic?
If the list of ingredients includes an actual vitamin like “Vitamin C” rather than an actual food that contains natural vitamin C like “acerola cherry powder”, you can bet that it is a synthetic vitamin.
If you choose to use nutritional supplements, it is in your best interest to use only those products that list actual foods as their ingredients rather than synthetic and isolated vitamins. While some synthetic and isolated vitamins have been shown to provide minimal health benefits, on the whole, most of them cause more harm than good and you are far better off spending your money on whole foods. It is important to note that the principles in this article are just as relevant and applicable to minerals and mineral supplements.
Thursday, July 30, 2009
VIRUS H1N1 adakah satu wabak @ ciptaan?
Segalanya ada kemungkinan. Terlalu awal untuk membuat kesimpulan. Namun, dari siri bukti-bukti sejarah, reaksi Obama dan pengkajian saintis serta bukti-bukti yang didapati dari kes sebelumnya, segalanya mungkin! Ketika selsema babi mengganas di US pada tahun 1976, manusia yang paling mendapat keuntungan diatas merebaknya wabak ini ialah Presiden Donald Rumsfeld, yang mana pada masa itu dia adalah CEO kepada syarikat Gilead Sciences Pharmaceutical. Syarikat yang bertanggungjawab untuk memproduksi vaksin kepada selsema babi ini. Syarikat ini berjaya mengaut keuntungan ber-million dollar dan saham syarikat ini pada masa itu melambung tinggi. Cerita ini bermula bila seorang tentera mati akibat daripada apa yang disyaki oleh pakar sebagai selsema babi pada tahun 1918. Sebagai alasan daripada insiden ini, Rumsfeld selaku Setiausaha Pertahanan berjaya melancarkan 1 kempen mempengaruhi rakyatnya bahawa pemerintahan US yang baru akan memastikan bahawa setiap lelaki, wanita dan kanak-kanak di Ameika akan diberikan vaksin. Pada masa itu, Kemenangan berpihak pada Gerard Ford dan dia berjaya menjadi presiden. Lantas, vaksin dicipta dan diedarkan diseluruh US sepantas kilat! Namun, program distribusi vaksin itu berhenti sebulan selepas tamatnya pilihanraya.
Dari segi keuntungan harga saham,Reuters telah menjalankan kajian dan mendapati bahawa sejak tersebarnya selsema babi, syer saham bagi syarikat Biocryst Pharmaceuticals melonjak sehingga 26% dan Novavax melonjak sehingga 75%, hasil daripada spekulasi yang menyatakan kemungkinan 2 syarikat gergasi ini akan menjadi pengeluar kepada vaksin selsema babi ini. Walaubagaimanapun, syarikat Baxter International Inc. mengesahkan bahawa mereka sedang bekerjasama dengan WHO untuk mengeluarkan vaksin bagi menghalang merebaknya virus ini. Syarikat ini telah berjaya untuk membina teknologi yang akan memungkinkan penciptaan vaksin virus ini dalam masa yang singkat. Jurucakap Baxter - Christopher Bona telahpun meminta sampel virus daripada WHO untuk menjalankan ujikasi makmal bagi mencipta vaksin yang berpotensi. 1 perkara yang cukup 'menarik' perhatian saintis dan pengkaji adalah, SEBULAN sebelum tercetusnya epidemik tersebut, Baxter telahpun menjalankan ujikajinya terhadap sampel virus tersebut!
Menurut Mike Adams, aktivis dan penulis NaturalNews.com, mitos tentang virus dicipta oleh pihak tertentu, menyebarkan virus tersebut dengan sengaja untuk mengakibatkan kucar kacir dan dalam masa yang sama mengaut keuntungan berlipat ganda adalah sebenarnya fakta yang telah berlaku dan sedang berlaku! Sepertimana yang telah dilaporkan oleh LifeGen.de -Deerfield, Illinois-Syarikat Baxter International Inc telah dibongkar kejahatannya apabila salah seorang pegawainya ditangkap sedang membuat penghantaran virus hidup selsema burung yang dicampur dengan perkakas vaksin kepada pembekal perubatan di 18 buah negara. "Kesilapan" ini dibongkar oleh National Microbiology Laboratory, Canada. Persoalannya, bagaimana perkara ini boleh berlaku? Jika dilihat dari sudut pandang yang berbeza, Baxter dilihat sebagai satu organisasi bio-terroris yng dengan sengaja menghantar virus ke seluruh dunia. Masakan mempertahankan tanahair dari cengkaman penjajah barat dan mempertahankan akidah dengan mengangkat senjata ketika diperangi dianggap pengganas, dan Baxter, yang semestinya didalangi oleh beberapa pemimpin dunia kapitalis terlepas walaupun ada buktinya?
Harus difahami bahawa Baxter International mempunyai satu kodifikasi keselamatan yang dinamakan BL3 iaitu (Biosafety Level 3). Dibawah BL3, Mereka yang terlibat secara langsung dalam menguruskan pathogen dan agen merbahaya, telah melelaui latihan yang spesifik dan dikawalselia oleh saintis yang berpengalaman. Semua ujikaji dijalankan dalam bekas keselamatan biologi ataupun sebarang alat fizikal, dan mereka yang terlibat diwajibkan memakai pemakaian yang bersesuaian dengan tahap keselamatan pengendalian pathogen dan agen merbahaya. Malah, makmal-makmal tersebut dilengkapi dengan ciri-ciri keselamatan yang tinggi. Jadi, dibawah kawalan BL3, ianya suatu perkara yang MUSTAHIL untuk virus selsema burung, mencemari pengeluaran bahan vaksin yang dipasarkan ke pembekal seluruh dunia.
Maka disini terjadi 2 kebarangkalian :
1. Baxter tidak mengikut kodifikasi BL3 yang menyebabkan virus tersebar diluar kawalan mereka
2. Ada pekerja mereka yang berkomplot untuk memusnahkan dunia dengan menyebarkan virus ini ke pembekal ke seluruh dunia.
Namun, kita harus faham bahawa penyebaran sesuatu virus, akan menyebabkan peningkatan dalam permintaan vaksin. 1 fakta yang tidak boleh disangkal bahawa memang ada corporations yang sanggup untuk membahayakan nyawa jutaan manusia atas kesempatan mengaut keuntungan. Dan 'sayangnya' corporations ini datangnya dari Amerika Syarikat, negara dambaan penguasa negara kaum muslimin.
Bagaimana pula dengan virus selsema babi ini? Menurut Mike Adams, suatu keanehan yang perlu diperhatikan apabila virus H1N1 ini bersifat hybrid atau percampuran. Daripada sumber yang beliau dapati, virus selsema babi ini terdiri daripada bahagian kodifikasi virus human influenza, selsema burung daripada America Utara, selsema babi daripada Eroah dan selsema babi daripada Asia! Bagaimana virus yang dibawa oleh burung dari Amerika Utara ini mampu berjangkit kepada babi di Eropah, kemudian bermutasi dan menjangkiti kembali burung tersebut, lalu ianya terbang dan menjangkiti pula babi di Asia dan kemudian virus itu bermutasi lagi menjadi virus yang mampu menjangkiti manusia, daripada babi di Asia lalu menjangkiti manusia di Mexico!! Sekali pandang, proses ini adalah suatu yang mampu berlaku secara alami. Namun, dek kerana butanya mata kerana wang, ianya suatu yang tidak mustahil, untuk ada campurtangan manusia dalam 'menjayakan' kewujudan H1N1 ini.
Ditambah pula dengan kenyataan daripada pegawai tinggi Amerika Syarikat seperti Fort Detrick, U.S. Army Medical Command dan Chad Jones, jurucakap Fort Meade yang mengsyaki akan keilangan sampel-sampel virus H1N1 daripada U.S. Army Medical Research Institute of Infectious Diseases.Kehilangan sampel, penghantaran virus hidup dengan sengaja, peningkatan pembelian saham syarikat yang bertanggungjawab memproduksi vaksin dan mungkin pernyataan bersahaja Obama Presiden US yang terbaru bahawa statistik dan penyebaran wabak selsema babi ini tidak memerlukan perintah darurat namun perlu diberi perhatian yang terperinci, merupakan antara poin-poin penting dalam mengkaji semula keberadaan virus-virus yang melanda dunia masa kini.
Akibat daripada keruntuhan ekonomi Amerika Syarikat, mungkinkah ini merupakan 'jalan keluar' bagi Amerika dan sekutunya dalam mendapatkan kembali pengaruhnya dimata dunia, dan dalam masa yang sama, mengaut sumber kewangan dari seluruh pelusuk dunia, akibat merebaknya virus yang merbahaya ini? Dalih yang pelbagai telahpun digunakan. Bush, pernah menggelar dirinya sebagai Bapa Peperangan. Telah berjaya dibuktikan bahawa 9/11 merupakan suatu pembohongan besar terhadap dunia sebagai alasan menduduki Iraq dan merampas hak-hak kaum muslimin. Tidak mustahil, akibat kebencian dunia terhadap Bush, maka pelobi-pelobi yahudi yang menguasai White House menggunakan Obama sebagai Bapa Virus dalam meneruskan hegemoni mereka terhadap dunia dan Islam. Terbukti bahawa sepanjang sejarah siri peperangan Amerika Syarikat terhadap musuh-musuh mereka, senjata biologi dan kimia seperti agent orange, tidak terkecuali daripada digunakan untuk memusnahkan musuh, yang membawa kepada kesan jangkasama panjang dan penderitaan yang tidak berkesudahan.
KesimpulanAdakah ini yang dikatakan sebagai an act of God? Ataupun terbit dari tangan-tangan kotor penguasa kapitalis, yang disokong penuh tanpa soal oleh penguasa negara kaum muslimin? Pada hari ini, kita semua akan diperdaya oleh para kapitalis bangsat yang akan memaksa ke atas manusia penggunaan vaksin ciptaan mereka, mengaut keuntungan dan natijahnya, kita menjadi mereka yang 'bersyukur' kepada para kapitalis dan sekutunya..Dari itu memanglah benar “setiap penyakit pasti ada ubatnya kecuali mati”.Kita sebagai orang ISLAM tidak terlepas dari berdoa kepada Yang Maha ESA,minta dijauhkan wabak,dan bala bencana ini.Sekiranya berlaku juga,kita diminta menilai & muhasabah adakah kita memang patut ditimpa penyakit ini diatas kezaliman,kemaksiatan yang telah kita lakukan @ ianya adalah ujian terhadap hambanya yang bersabar &beriman moga ditingkatkan lagi martabat imannya ke tahap yang lebih tinggi dengan diuji dengan pelbagai bentuk ujian.La Hau La Wala Quwwata illa BILLAH
Friday, July 17, 2009
Health Hazard Assessment of Morpholine in Wax Coatings of Apples
Why are wax coatings used on some fruits and vegetables? Are they safe? Many fruits and vegetables make their own natural waxy coating to help retain moisture because most produce is 80 to 95 percent water. After harvest, but before the produce is paJul 15, 08 Morpholine is a solvent and emulsifier used in the preparation of wax coatings for fruits and vegetables. In the presence of excess nitrite, formed mainly from naturally-occurring nitrate in the diet, morpholine can be chemically modified (nitrosated) to form N-nitrosomorpholine (NMOR), a genotoxic carcinogen in rodents.
While morpholine alone does not appear to pose a health concern, the main issue is whether sufficient NMOR can be produced by humans upon ingestion, to pose a health risk. Morpholine itself is neither a carcinogen nor a teratogen and does not cause chronic toxicity in rats and mice. Based on a no observed adverse effect level (NOAEL) in a chronic oral toxicity study and several safety factors, an acceptable daily intake (ADI) of 0.48 mg/kg bw/day was estimated. When not considering the potential for nitrosation, the respective morpholine exposure for children and adults is about 8% and 5% of the ADI, and not a cause for concern. In studies conducted in experimental animals it has been determined that the formation of NMOR is dependent on the administration of sufficiently large doses of morpholine and nitrite.
Under these specific conditions, rats fed morpholine and nitrite develop hepatocellular carcinoma (cancer of the liver), presumably due to the formation of NMOR. Although it is often assumed that there is some probability of harm at any level of exposure to a genotoxic carcinogen, actual exposure may be so low that the health risk is essentially negligible. Extrapolation of rat tumour data was used to estimate a safe dose in humans (4.3 ng/kg bw/day). Regarding the presence of NMOR on apples coated with wax containing morpholine: No NMOR was determined to be present on these apples, and no NMOR was formed when morpholine and nitrite were combined in experiments conducted in the presence of apple flesh.
The possibility that morpholine might be nitrosated by humans to form NMOR during digestion was investigated. Since there is no direct human data on the nitrosation rate of morpholine to NMOR, this was estimated indirectly. The inhibitory effects of antioxidants present in apple were also considered. From the estimated morpholine exposure, the possible endogenously formed NMOR was estimated to be 2.2 and 3.6 ng/kg bw/day for adults and children, respectively. This possible exposure to NMOR derived from morpholine on waxed apples is less than the above estimated safe dose of 4.3 ng/kg bw/day. Uncertainties in this estimate of NMOR formation include the physiological differences between humans and rats, and actual levels of nitrite consumed.
It is unlikely that these uncertainties would increase the estimated NMOR formation. Waxes are applied in order to: help retain moisture in fruits and vegetables during shipping and marketing; help inhibit mold growth; protect fruits and vegetables from bruising; prevent other physical damage and disease; enhance appearance. By protecting against moisture loss and contamination, wax coatings help fresh fruits and vegetables maintain wholesomeness and freshness. Waxing does not improve the quality of any inferior fruit or vegetables; rather, waxing — along with proper handling — contributes to maintaining a healthful product.
Waxes by themselves do not control decay; rather, they may be combined with some chemicals to prevent the growth of mold. The Food and Drug Administration and the Environmental Protection Agency strictly regulate the safety and use of these substances. Waxes are also used on candies, pastries and gum and come from natural sources. Wax sources generally are plants, food-grade petroleum products or insects (similar to honey from bees). Some waxes can be made from dairy or animal sources, but we are not aware of any such coatings being used on fruits and vegetables in this country.
This is particularly important for people following Kosher or vegetarian diets and who don’t want any animal-based wax on their produce. Any commodities that do have this type of coating must be labeled "Coated with animal-based wax." Waxes are used only in tiny amounts. In fact, each piece of waxed fruit only has a drop or two of wax. Waxes may be mixed with water or other wetting agents to ensure they are applied thinly and evenly. The government regulates wax coatings to ensure their safety. Coatings used on fruits and vegetables must meet the food additive regulations of the U.S. Food and Drug Administration.
Extensive research by governmental and scientific authorities has shown that approved waxes are safe to eat. Waxes are indigestible, which means they go through the body without breaking down or being absorbed. Produce shippers and supermarkets are required by federal law to label produce items that have been waxed so you will know whether the fruits and vegetables you buy are coated. Consumers will see signs in produce departments that say "Coated with food-grade vegetable-, petroleum-, beeswax-, and/or shellac-based wax or resin, to maintain freshness." None of these coatings are animal-based, and they all come from natural sources. Any consumers who have questions about wax coatings should talk to their grocers. Waxes may turn white on the surface of fruits or vegetables if they have been subjected to excessive heat and/or moisture.
This whitening is safe and is similar to that of a candy bar that has been in the freezer. Consumers do have choices. Waxes generally cannot be removed by regular washing. If consumers prefer not to consume waxes — even though the waxes are safe — they can buy unwaxed commodities or can peel the fruit or vegetable, thereby removing any coating. Commodities that may have coatings applied include apples, avocados, bell peppers, cantaloupes, cucumbers, eggplants, grapefruits, lemons, limes, melons, oranges, parsnips, passion fruit, peaches, pineapples, pumpkins, rutabagas, squash, sweet potatoes, tomatoes, turnips and yucca. However, they are not always waxed.
Wednesday, July 15, 2009
How enzymes work
Enzymes are chemicals found in living things that act to speed up specific chemical reactions. Enzymes are catalysts for biochemical (living) reactions. If there is any chemical reaction in any living thing there is an enzyme that works to bring it about.
A simple definition of life would be: the transfer of energy through the breakdown of nutrients. In other words, all living things get their energy for life by breaking down the chemicals in other living things. Sounds simple enough but in point of fact, the activity of getting nutrients and energy from food is maybe the most complex group of chemical reactions in the universe. This is because chemical reactions that occur inside living organisms can't happen without a catalyst that would make these reactions happen and control them.
Catalysts are chemicals that while helping a reaction come about, are not themselves changed. Catalysts, in reactions other than biochemical, generally are common inorganic substances which have uses outside of being catalyst for a reaction. For example, platinum is used as a catalyst the reaction that breaks down nitrogen oxides in car exhaust, yet platinum has many other uses. Most biological catalysts, or enzymes, on the other hand are very specific. They exist and are created with only one purpose, to act as a catalyst for one specific reaction biochemical reaction.
Enzymes are proteins which are used as catalysts for a specific reaction. The exact nature of how enzymes work is not known. If is only recently that scientist have had any clue as to the mechanism of enzyme catalyzation. Made up of a complex of amino-acids, enzymes are part of every chemical reaction in living things. Examples of enzyme aided reactions include all digestion, growth and building of cells, any breakdown of substances such as vitamins, and nutrients, all reactions involving transformation of energy. Reactions are also controlled by enzymes. The rate and location or site of a reaction is also controlled by enzyme action. A good example of the involvement of enzyme action is in the building of living material within the cell.
Lack of specific enzymes is the cause of many disorders. Disorders such as albinism, diabetes, and cystic fibrosis are traceable to either a lack of a specific enzyme or an imbalance of one.
Another benefit of enzymes in biochemical reactions is that they control the release of energy in living reactions. The breakdown of chemical bonds releases energy. If you were to measure the amount of energy from a candy bar, you would see that it might have 200 calories or more. While the body needs energy to function, the immediate release of chemical energy from the breakdown of food and nutrients would be disastrous. The small candy bar mentioned here would have release enough energy to raise the body temperature of a 200 pound man 3 1/2 degrees Fahrenheit! It is the work of enzymes that allow for the controlled release of the energy in living chemical reactions.
Plants turn the energy of sunlight directly into food by using sunlight energy for chemical bonds in the form of sugar. Enzymes are responsible here, too, they control the absorption of radiant energy. Think about it, have you ever sat under a tree during a hot summer afternoon and wondered what keeps the leaves so cool? The sunshine will be hot enough to melt tar on the streets, but plant leaves remain barely warm to the touch. Where does all the energy go? It is slowly being tied up in the chemical bonds of sugar. The process is photosynthesis and it is the basis of all life on earth, but without enzymes controls this process would be impossible.
Enzymes are at work wherever there is life. Yeast use enzymes to leaven bread and ferment sugar into alcohol. Bacteria use enzymes to break down cellulose fiber in the stomachs of cows and the stomachs of termites. Plants, animals, bacteria, or fungi, if they are alive, use enzymes to control all living chemical reactions. Reproduction, growth, metabolism, synthesis, are all enzyme regulated reactions in living things. Enzymes are the chemicals that make life work.
What Is Hormone
I Introduction
Hormone, chemical that transfers information and instructions between cells in animals and plants. Often described as the body’s chemical messengers, hormones regulate growth and development, control the function of various tissues, support reproductive functions, and regulate metabolism (the process used to break down food to create energy). Unlike information sent by the nervous system, which is transmitted via electronic impulses that travel quickly and have an almost immediate and short-term effect, hormones act more slowly, and their effects typically are maintained over a longer period of time.
Hormones were first identified in 1902 by British physiologists William Bayliss and Ernest Starling. These researchers showed that a substance taken from the lining of the intestine could be injected into a dog to stimulate the pancreas to secrete fluid. They called the substance secretin and coined the term hormone from the Greek word hormo, which means “to set in motion.” Today more than 100 hormones have been identified.
Hormones are made by specialized glands or tissues that manufacture and secrete these chemicals as the body needs them. The majority of hormones are produced by the glands of the endocrine system, such as the pituitary, thyroid, adrenal glands, and the ovaries or testes. These endocrine glands produce and secrete hormones directly into the bloodstream. However, not all hormones are produced by endocrine glands. The mucous membranes of the small intestine secrete hormones that stimulate secretion of digestive juices from the pancreas. Other hormones are produced in the placenta, an organ formed during pregnancy, to regulate some aspects of fetal development.
Hormones are classified into two basic types based on their chemical makeup. The majority of hormones are peptides, or amino acid derivatives that include the hormones produced by the anterior pituitary, thyroid, parathyroid, placenta, and pancreas. Peptide hormones are typically produced as larger proteins. When they are called into action, these peptides are broken down into biologically active hormones and secreted into the blood to be circulated throughout the body. The second type of hormones is steroid hormones, which include those hormones secreted by the adrenal glands and ovaries or testes. Steroid hormones are synthesized from cholesterol (a fatty substance produced by the body) and modified by a series of chemical reactions to form a hormone ready for immediate action.
II How Hormones Work
Most hormones are released directly into the bloodstream, where they circulate throughout the body in very low concentrations. Some hormones travel intact in the bloodstream. Others require a carrier substance, such as a protein molecule, to keep them dissolved in the blood. These carriers also serve as a hormone reservoir, keeping hormone concentrations constant and protecting the bound hormone from chemical breakdown over time.
Hormones travel in the bloodstream until they reach their target tissue, where they activate a series of chemical changes. To achieve its intended result, a hormone must be recognized by a specialized protein in the cells of the target tissue called a receptor. Typically, hormones that are water-soluble use a receptor located on the cell membrane surface of the target tissues. A series of special molecules within the cell, known as second messengers, transport the hormone’s information into the cell. Fat-soluble hormones, such as steroid hormones, pass through the cell membrane and bind to receptors found in the cytoplasm. When a receptor and a hormone bind together, both the receptor and hormone molecules undergo structural changes that activate mechanisms within the cell. These mechanisms produce the special effects induced by the hormone.
Receptors on the cell membrane surface are in constant turnover. New receptors are produced by the cell and inserted into the cell wall, and receptors that have reacted with hormones are broken down or recycled. The cell can respond, if necessary, to irregular hormone concentrations in the blood by decreasing or increasing the number of receptors on its surface. If the concentration of a hormone in the blood increases, the number of receptors in the cell wall may go down to maintain the same level of hormonal interaction in the cell. This is known as downregulation. If concentrations of hormones in the blood decrease, upregulation increases the number of receptors in the cell wall.
Some hormones are delivered directly to the target tissues instead of circulating throughout the entire bloodstream. For example, hormones from the hypothalamus, a portion of the brain that controls the endocrine system, are delivered directly to the adjacent pituitary gland, where their concentrations are several hundred times higher than in the circulatory system.
III Hormonal Effects
Hormonal effects are complex, but their functions can be divided into three broad categories. Some hormones change the permeability of the cell membrane. Other hormones can alter enzyme activity, and some hormones stimulate the release of other hormones.
Recent studies have shown that the more lasting effects of hormones ultimately result in the activation of specific genes. For example, when a steroid hormone enters a cell, it binds to a receptor in the cell’s cytoplasm. The receptor becomes activated and enters the cell’s nucleus, where it binds to specific sites in the deoxyribonucleic acid (DNA), the long molecules that contain individual genes. This activates some genes and inactivates others, altering the cell’s activity. Hormones have also been shown to regulate ribonucleic acids (RNA) in protein synthesis.
A single hormone may affect one tissue in a different way than it affects another tissue, because tissue cells are programmed to respond differently to the same hormone. A single hormone may also have different effects on the same tissue at different times in life. To add to this complexity, some hormone-induced effects require the action of more than one hormone. This complex control system provides safety controls so that if one hormone is deficient, others will compensate.
IV Types of Hormones
Hormones exist in mammals, including humans, as well as in invertebrates and plants. The hormones of humans, mammals, and other vertebrates are nearly identical in chemical structure and function in the body. They are generally characterized by their effect on specific tissues.
A. Human Hormones
Human hormones significantly affect the activity of every cell in the body. They influence mental acuity, physical agility, and body build and stature. Growth hormone is a hormone produced by the pituitary gland. It regulates growth by stimulating the formation of bone and the uptake of amino acids, molecules vital to building muscle and other tissue.
Sex hormones regulate the development of sexual organs, sexual behavior, reproduction, and pregnancy. For example, gonadotropins, also secreted by the pituitary gland, are sex hormones that stimulate egg and sperm production. The gonadotropin that stimulates production of sperm in men and formation of ovary follicles in women is called a follicle-stimulating hormone. When a follicle-stimulating hormone binds to an ovary cell, it stimulates the enzymes needed for the synthesis of estradiol, a female sex hormone. Another gonadotropin called luteinizing hormone regulates the production of eggs in women and the production of the male sex hormone testosterone. Produced in the male gonads, or testes, testosterone regulates changes to the male body during puberty, influences sexual behavior, and plays a role in growth. The female sex hormones, called estrogens, regulate female sexual development and behavior as well as some aspects of pregnancy. Progesterone, a female hormone secreted in the ovaries, regulates menstruation and stimulates lactation in humans and other mammals.
Other hormones regulate metabolism. For example, thyroxine, a hormone secreted by the thyroid gland, regulates rates of body metabolism. Glucagon and insulin, secreted in the pancreas, control levels of glucose in the blood and the availability of energy for the muscles. A number of hormones, including insulin, glucagon, cortisol, growth hormone, epinephrine, and norepinephrine, maintain glucose levels in the blood. While insulin lowers the blood glucose, all the other hormones raise it. In addition, several other hormones participate indirectly in the regulation. A protein called somatostatin blocks the release of insulin, glucagon, and growth hormone, while another hormone, gastric inhibitory polypeptide, enhances insulin release in response to glucose absorption. This complex system permits blood glucose concentration to remain within a very narrow range, despite external conditions that may vary to extremes.
Hormones also regulate blood pressure and other involuntary body functions. Epinephrine, also called adrenaline, is a hormone secreted in the adrenal gland. During periods of stress, epinephrine prepares the body for physical exertion by increasing the heart rate, raising the blood pressure, and releasing sugar stored in the liver for quick energy.
Initially, hormones used in medicine were collected from extracts of glands taken from humans or animals. For example, pituitary growth hormone was collected from the pituitary glands of dead human bodies, or cadavers, and insulin was extracted from cattle and hogs. As technology advanced, insulin molecules collected from animals were altered to produce the human form of insulin.
With improvements in biochemical technology, many hormones are now made in laboratories from basic chemical compounds. This eliminates the risk of transferring contaminating agents sometimes found in the human and animal sources. Advances in genetic engineering even enable scientists to introduce a gene of a specific protein hormone into a living cell, such as a bacterium, which causes the cell to secrete excess amounts of a desired hormone. This technique, known as recombinant DNA technology, has vastly improved the availability of hormones.
Recombinant DNA has been especially useful in producing growth hormone, once only available in limited supply from the pituitary glands of human cadavers. Treatments using the hormone were far from ideal because the cadaver hormone was often in short supply. Moreover, some of the pituitary glands used to make growth hormone were contaminated with particles called prions, which could cause diseases such as Creutzfeldt-Jakob disease, a fatal brain disorder. The advent of recombinant technology made growth hormone widely available for safe and effective therapy.
B. Invertebrate Hormones
In invertebrates, hormones regulate metamorphosis (the process in which many insects, crustaceans, and mollusks transform from eggs, to larva, to pupa, and finally to mature adults). A hormone called ecdysone triggers the insect molting process, in which these animals periodically shed their outer covering, or exoskeletons, and grow new ones. The molting process is delayed by juvenile hormone, which inhibits secretion of ecdysone. As an insect larva grows, secretion of juvenile hormone declines steadily until its concentrations are too low to prevent the secretion of ecdysone. When this happens, ecdysone concentrations increase until they are high enough to trigger the metamorphic molt.
In insects that migrate long distances, such as the locust, a hormone called octopamine increases the efficiency of glucose utilization by the muscles, while adipokinetic hormone increases the burning of fat as an energy source. In these insects, octopamine levels build up in the first five minutes of flight and then level off as adipokinetic hormone takes over, triggering the metabolism of fat reserves during long distance flights.
Hormones also trigger color changes in invertebrates. Squids, octopuses, and other mollusks, for example, have hormonally controlled pigment cells that enable the animals to change color to blend in with their surroundings.
C. Plant Hormones
Hormones in plants are called phytohormones. They regulate most of the life cycle events in plants, such as germination, cell division and extension, flowering, fruit ripening, seed and bud dormancy, and death (see Plant: Growth and Differentiation). Plant biologists believe that hormones exert their effects via specific receptor sites in target cells, similar to the mechanism found in animals. Five plant hormones have long been identified: auxin, cytokinin, gibberellin, abscisic acid, and ethylene. Recent discoveries of other plant hormones include brassinosteroids, salicylates, and jasmonates.
Auxins are primarily responsible for protein synthesis and promote the growth of the plant's length. The most common auxin, indoleacetic acid (IAA), is usually formed near the growing top shoots and flows downward, causing newly formed leaves to grow longer. Auxins stimulate growth toward light and root growth.
Gibberellins, which form in the seeds, young leaves, and roots, are also responsible for protein synthesis, especially in the main stem of the plant. Unlike auxins, gibberellins move upward from the roots. Cytokinins form in the roots and move up to the leaves and fruit to maintain growth, cell differentiation, and cell division. Among the growth inhibitors is abscisic acid, which promotes abscission, or leaf fall; dormancy in buds; and the formation of bulbs or tubers, possibly by preventing the synthesis of protein. Ethylene, another inhibitor, also causes abscission, perhaps by its destructive effect on auxins, and it also stimulates the ripening of fruit.
Brassinosteroids act with auxins to encourage leaf elongation and inhibit root growth. Brassinosteroids also protect plants from some insects because they work against some of the hormones that regulate insect molting. Salicylates stimulate flowering and cause disease resistance in some plants. Jasmonates regulate growth, germination, and flower bud formation. They also stimulate the formation of proteins that protect the plant against environmental stresses, such as temperature changes or droughts.
V Commercial Use of Hormones
Hormones are used for a variety of commercial purposes. In the livestock industry, for example, growth hormones increase the amount of lean (non-fatty) meat in both cattle and hogs to produce bigger, less fatty animals. The cattle hormone bovine somatotropin (BST) increases milk production in dairy cows. Hormones are also used in animal husbandry to increase the success rates of artificial insemination and speed maturation of eggs.
The United States Food and Drug Administration (FDA) approved the use of BST in November 1993. However, the safety and ethics of BST use are disputed by several consumer groups, which object to the production of milk using artificial stimulation. They claim that after a regular course of injections, cows show symptoms of production stress. Reanalysis of industry data by several scientists pointed to increased incidence of mastitis and other health problems in BST-treated cows. Concerns about the side effects of BST prompted authorities in Canada and the European Union to prohibit its use.
In plants, auxins are used as herbicides, to induce fruit development without pollination, and to induce root formation in cuttings. Cytokinins are used to maintain the greenness of plant parts, such as cut flowers. Gibberellins are used to increase fruit size, increase cluster size in grapes, delay ripening of citrus fruits, speed up flowering of strawberries, and stimulate starch break down in barley used in beer making.
In addition, ethylene is used to control fruit ripening, which allows hard fruit to be transported without much bruising. The fruit is allowed to ripen after it is delivered to market. Genetic engineering also has produced fruits unable to form ethylene naturally. These fruits will ripen only if exposed to ethylene, allowing for extended shipping and storage of produce.
Wednesday, July 1, 2009
What is a Calorie ... and Why Should I Care?
The official definition of a calorie is "...the amount of heat needed to raise the temperature of a liter of water 1 degree (DHHS)." But if that's a little too scientific for you, think of it this way...
A calorie isn't actually a tangible thing, it's a unit of measurement.
No matter the form of your calories ... if you "overload your tank" you will find yourself gaining weight.
Understanding caloric needs is an integral part of weight loss. Research over the years has proven -- whether diets focus on fat or carbs -- that calories still count. Why? Regardless of what diet you're following, if you take in more calories than you need ... you gain weight.
The daily recommended caloric intake for the average American maintaining their weight is 2,000 calories, give or take a few: Men can eat a little more, women, less. Your specific, individual calorie needs depend on several factors such as your activity level and metabolism.
Where are Calories?
- fat,
- carbohydrates,
- protein and
- alcohol (i.e., sugar).
Fat contains twice the calories of carbohydrates or protein.
There is a bit of controversy about whether or not a calorie's value can vary among particular foods or when people follow a certain diet.
But until medical science can prove there are different types of calories that bring different results, it's safe to assume that there aren't any variations.
How do Calories Get Stored as Fat?
When you are in excess of that, your body doesn't have any choice but to do something with those extra calories. It puts them in storage in the form of fat.
In other words, calories turn into fat when they're sitting around doing nothing. When you have taken in 3,500 calories above your caloric needs ... you gain a pound.
Learn to Count Calories and You'll Lose WeightIt follows that if it takes 3,500 extra calories to gain a pound, all it takes is to cut 3,500 calories to lose one. This is best achieved by
Reducing your caloric intake by and/or burning a total of 500 calories a day will lead to an average of one pound lost each week, a healthy and sustainable rate at which to lose weight. The most important thing to remember is to not cut calories too drastically. Not only can it "backfire" and actually prevent weight loss, doing so puts your health at risk.