Vitamin D Benefits...
Everything from Bone Health to Cancer?
Vitamin D, together with the mineral calcium, are well known nutrients participating in the structural support of your body - the skeleton! In fact, milk of course, is fortified with vitamin D to aid in calcium absorption for strong bones.
But today, vitamin D benefits are touted in a staggering array of conditions ranging from psoriasis to cancer! Is this just popular media hype or is there any science to back up these claims? Turns out, strong evidence supports well-known bone health benefits of vitamin D, while science for newer claims like cancer is more circumstantial or suggestive in nature. Lets take a quick look at the facts we can substantiate from current scientific data...
Potential Vitamin D Benefits
For Your life
Vitamin D Receptors Exist in Virtually Every Cell of Your Body, Indicating Vitamin D Benefits Apply to A Vast Array of Biological Functions
Vitamin D Supports Calcium and Phosphorus Deposition for Building Strong Bones, Helping Prevent Metabolic Bone Diseases like Rickets and Osteoporosis
Vitamin D Receptors Discovered in Cancer Cells Suggests Vitamin D plays an Important Anti-Proliferative Role, Essentially Putting the Brakes on Dangerous, Uncontrolled Cell Growth or "Proliferation" Common of Various Cancers. In Fact...
Experimental Applications of Vitamin D Successfully Inhibit Cell Proliferation and Induce Differentiation in a Number of Cancerous and Non-Cancerous Cell Types.
Risk Factors for Several Cancers like Prostate, Colon and Breast Cancer are Associated with Vitamin D Deficiency Conditions
Chemical Analogues of Vitamin D are Commonly Used to Control Severe Psoriasis, Another Condition Characterized By Dangerous, Uncontrolled Cell Growth (Proliferation)
Vitamin D Receptors are Expressed in Cells of the Immune System, Implying Vitamin D Benefits Play Important Roles Protecting Your Body From Disease Causing Pathogens Like Bacteria and Viruses
Lets take a whirlwind look at the role of vitamin D in your body to understand the proper context of these facts...
Your Vitamin D Benefits
Begin With Sunshine!
Everyone knows too much sun is bad for us, right? After all, premature aging of the skin and melanoma of the skin (cancer) is caused by excessive exposure to the sun. In fact, health professionals warn us regularly to avoid the sun like the plague!
But while too much sun may cause skin cancer, new science is telling us that a small, daily "medicinal dose" of sun actually may help prevent a long litany of serious maladies like breast, lung, colon and prostate cancer. How can this be?
As it turns out, the remarkable activity of vitamin D may be responsible. Lets take a closer look at this vitamin to see how sunshine and its activity in the human body may be responsible for a large array of vitamin D benefits...
Sunshine and Formation of Vitamin D
"Vitamin D, or the sunshine vitamin, is actually a steroid hormone formed within your body by the photolytic action of sunlight within the skin."
Specifically, the 290 - 315 nm wavelength of the UVB band of the sun converts a derivative of cholesterol to an important form of vitamin D called "cholecalciferol". Solar radiation less than 290 nm are unable to participate in the synthesis of cholcalciferol, as it is prevented from reaching the earth by the ozone layer. Cholecalciferol is a precursor to active forms of vitamin D, "calcidiol" and "calcitriol" which are eventually manufactured in your liver and kidney.
Do You Receive Enough Sunshine
to Generate Optimal Levels of D?
If you are healthy and receive moderate levels of sunshine daily, you may synthesize adequate levels of vitamin D within your skin to meet your bodies vitamin D requirements.
However, as many of us spend more time indoors behind a computer screen, than farming in the noonday sun like our predecessors, vitamin D deficiency and associated pathologies may be relatively modern maladies.
So if you shun the sun, live in a sun-challenged climate (like northerly latitudes, especially in winter), use sunscreen, are older, or have a high level of skin pigmentation (blocks sunlight), then you may have a raging vitamin D deficiency. For most of us, therefore, vitamin D really is a vitamin that must be supplied by diet.
Lets begin with the most well known benefit of vitamin D...
Vitamin D Benefits
Help Build Strong Bones
Fact #1 "Vitamin D Improves Intestinal Absorption of Calcium and Phosphorus, Required for Building Strong Bones, Helping Prevent Metabolic Bone Diseases like Rickets and Osteoporosis"
The benefits of vitamin D, in conjunction with the minerals calcium and phosphorus, are well-established nutrients required for optimal bone health. Bone is living, dynamic tissue, constantly re-modeled or sculpted in response to the activity of vitamin D, calcium and phosphorus. If these vital nutrients are missing or in short supply, metabolic bone diseases like osteoporosis, osteomalacea or rickets may eventually result.
Vitamin D Benefits...
Not for Bone Only
Fact #2 "Vitamin D Receptors Exist in Virtually Every Cell of Your Body, Indicating Vitamin D Benefits Apply to A Vast Array of Biological Functions"
But bone health is only one aspect of the numerous benefits of vitamin D. Vitamin D receptors are actually found in most tissues throughout your body... intestine, kidney, bone, skin, muscle, immune cells, virtually every tissue examined reveals the presence of vitamin D receptors!
When vitamin D attaches to these receptors within the cell, the vitamin D/receptor complex translocates into the nucleus of the cell and interacts with your DNA to induce or inhibit the synthesis of new proteins. In this way, vitamin D acts as a classical hormone, triggering various physiological responses only in specific tissues within your body containing vitamin D receptors
What are some of these physiological responses? Let's take a look..
The most classical benefits of vitamin D are, of course, orchestrating the deposition of calcium and phosphate within bone for growth and maintenance.
But do you know vitamin D also resorbs or removes calcium from bone? Bone is living tissue and is continuously remodeled by cells called "osteoblasts" which lay down bone (mineralization) and "osteoclasts" which remove or resorb bone (demineralization). What is the point of this activity?
The Central Role of
Vitamin D in Your Body
The central role of vitamin D in your body is not only regulating calcium deposition for building strong bones but more fundamentally...
Fact #3 "Vitamin D Helps Maintain the Physiological Concentration of Calcium and Phosphate in Your Blood Within Very Precise Limits."
Why?
Because the transport of calcium and phosphorus within your blood to various tissues is critical to many cellular processes vital to life. For example...
Roles of Calcium
1) Propagation of nerve Impulses
2) Release of Neurotransmitters
3) Contraction of Smooth, Skeletal and Cardiac Muscle
4) Blood Clotting
5) Cell Proliferation
6) Intracellular Signal Transduction
Roles of Phosphorus
1) Phosphorus is an Element of "Hydroxyapatite" Which Contributes to Hardness of Your Skeleton
2) "Phospholipids" Are a Major Component of All Cell Membranes
3) Phosphorus Contributes to the Structure of the Nucleic Acids, DNA and RNA
4) The Conversion of Food into Energy Is Dependent Upon Phosphorus
5) Many "Signaling" Molecules Depend on Phosphorus to Trigger a Hormonal Response
6) Phosphorus Helps Balance the pH of Your Body Fluids
Vitamin D Benefits Helps Maintain
These Essential Life Processes
Regulation of your heartbeat, nerve transmission, muscle contraction, etc. are essential to life. Your body will never allow suboptimal dietary intake of calcium to threaten these essential functions. This is why maintaining your blood calcium and phosphorus concentrations within very precise limits is so important... your blood provides the calcium and phosphorus required for these vital life processes.
In fact, if your blood calcium concentration drops too low, your body will actually "cannibalize" or steal calcium from your bones to maintain constant blood calcium levels for these essential life processes.
This is where vitamin D enters the picture...
Specifically, a drop in your blood calcium concentration activates an adaptive response designed to normalize blood calcium levels. A hormone called "parathyroid hormone" converts vitamin D to its most active form called "calcitriol".
Calcitriol maintains the all important blood calcium concentration via interaction with the vitamin D receptors in bone, kidney and intestine, a "triple-end organ response" Here is how...
Physiological Control of Blood
Calcium and Phosphorus Levels
By Vitamin D
1) Intestine: Vitamin D Increases Intestinal Absorption of Dietary Calcium
2) Bone: Vitamin D Increases Osteoclastic Resorption of calcium From Bone
3) Kidney: Vitamin D Reduces Urinary Calcium Losses by Increasing Renal Conservation of Calcium
These activities regulated by vitamin D help boost blood calcium levels, increasing the calcium and phosphorus within your blood to their precisely defined physiological limits.
But, if intestinal absorption of calcium cannot be increased because your not ingesting enough calcium in your diet, additional calcium is cannibalized from your bones. In other words, your bones are the calcium reserve calcitriol acts upon when dietary intake of calcium is insufficient to increase intestinal absorption.
Short-term resorption of calcium from bones by osteoclasts (demineralization) is normal and your calcium debt is paid back when dietary intake of calcium increases.
However, chronically low intake of dietary calcium lowers blood calcium concentration, ramps up PTH secretion, resulting in a sustained extraction or demineralization of calcium from bones. In adolescents, this may prevent bones from reaching their full genetic potential, setting the stage for other metabolic bone diseases later in life such as osteoporosis, etc.
But bone health is not the only benefit of vitamin D...
Newly Discovered Vitamin D Benefits
Vitamin D receptors are present in other tissues like skin, immune cells and even malignant tumor cells. This suggests the scope of vitamin D benefits goes beyond control of calcium balance or "homeostasis". For example, diseases as diverse as psoriasis and cancer may be benefited by vitamin D.
Specifically, these pathologies are characterized by explosive cell division or growth (proliferation). Cell proliferation is a good thing and must naturally occur during normal growth of your body and wound healing. Eventually, the process of proliferation slows down as cells mature or "differentiate" into new cell types.
But in diseases like psoriasis and cancer, cells continue their explosive cell growth unabated. This eventually causes serious problems...
Can Vitamin D Benefits Protect You
From Diseases Like Cancer and Psoriasis?
The presence of vitamin D receptors in skin and cancer cells suggests vitamin D may play an important "anti-proliferative" effect, essentially putting the brakes on this dangerous cell growth. In fact, calcitriol or chemical analogues of vitamin D are commonly used as topical creams to control severe psoriases.
Cancers of the breast, lung, skin, colon and bone also reveal the presence of vitamin D receptors. These receptors respond to the addition of vitamin D or calcitriol in laboratory tests...
Fact #4 Experimental applications of calcitriol successfully inhibit proliferation and induce differentiation in a number of cancerous and non-cancerous cell types.
Vitamin D Deficiency
What is Your Risk of Disease?
Today, life-threatening cancers take a terrible toll on our health and wellbeing, to say nothing of the personal grief and suffering they cause. Is it possible simply upping your levels of vitamin D by sun or supplements increases your vitamin D benefits and decreases your risk of cancer? Consider this fact...
Fact #5) Risk of Prostate, Colon and Breast Cancer are Associated with Vitamin D Deficiency Factors
For example, increased age, decreased sun exposure (decreased capacity to synthesize vitamin D) and increased melanin content of skin (blocks sunlight) are all factors reducing endogenous synthesis of vitamin D within your skin and increase risk of prostate cancer. In fact, the geographical mortality rate of prostate cancer parallels very closely the availability of sunlight...
In areas where sunlight is limited, especially in winter, such as the U.S. or areas of northwest Europe, the mortality rate from prostate cancer is relatively higher, compared to area where sunlight is more abundant, such as south Africa, Central and South America.
Vitamin D Benefits...
Sunlight and Colorectal Cancer
The prevalence of colorectal cancer also "mirrors" the geographical distribution of rickets, the vitamin D deficiency disease in infants and children that is highest in areas where sunlight is limited. (northerly latitudes in the winter). This provides circumstantial evidence that decreased sunlight and inhibited endogenous synthesis of vitamin D may be associated with increased risk of colorectal cancer.
Vitamin D Benefits...
Sunlight and Breast Cancer
Likewise, the geographical distribution of breast cancer mirrors the geographical incidence of colorectal cancer, again, providing indirect evidence these cancers correlate with lack of sunlight and diminished endogenous synthesis of vitamin D.
Immunity
Vitamin D and Protection
from Bacteria and Viruses
Vitamin D receptors (VDR) are also expressed in cells of the immune system, implying vitamin D benefits play a role protecting your body from disease causing pathogens such as bacteria and viruses...
Vitamin D Activates
Your Immune System
for Destruction of Bacteria
For example, vitamin D is essential for the activation of specialized immune cells called "macrophages" Macrophages destroy foreign particles like bacteria by engulfing them (phagocytosis) and releasing lethal reactive oxidants such as hydrogen peroxide that kill the bacteria in a process called the "respiratory burst"
In fact, macrophages from vitamin D deficient mice have defective anti-tumor activity and impaired respiratory burst ( low production of bacterial-killing hydrogen peroxide ). When vitamin D status is restored, normal immune response returns.
Migratory Ability of
Immune System Cells
Enhanced by Vitamin D
"Chemotaxis", the localized migration of immune cells to the specific site of injury or foreign invasion by pathogens is also enhanced by vitamin D.
For example, pretreatment of normal human monocytes with vitamin D increases their responsiveness to a variety of chemoattractants. Even diseases like acquired immune deficiency syndrome (AIDS) are characterized by impaired chemotaxis. When vitamin D is administered to these patients, the migratory or "chemotactic" capacity of immune cells improves.
How Much D Do You Need
for Maximum Vitamin D Benefits?
Exposure to sunlight is your most important source for maximum vitamin D benefits. In fact, full body exposure to sunlight easily generates about 250 micrograms vitamin D per day (250 ug/day) which is equivalent to 10000 IU (International Units). This cutaneously synthesized vitamin D can be stored within fat reserves of your body and released as needed during the sunlight deprived days of winter.
In sharp contrast, the current recommended dietary allowance (RDA) for vitamin D is about 10 ug or 200 IU. This is enough to prevent severe vitamin D deficiency diseases such as rickets or osteomalcea, but falls well short of optimal levels established in clinical trials necessary to prevent osteoporosis and secondary hyperparathyroidism. Generally, a vitamin D dosage of at least 600 IU in conjunction with 1200 mg supplemental calcium, increases bone mass and reduces hip and bone fractures in the elderly. Other benefits of higher vitamin D supplementation, such as prevention of osteoarthritis, have been implicated from the results of numerous "epidemiological" studies.
To insure you are meeting your optimal vitamin D requirement, the Linus Pauling Institute (Oregon State University) recommends 400 IU supplemental vitamin D per day, in addition to 10-15 minutes sun exposure on the face, arms and legs, 3 times a week. Elderly folks do not metabolize or use vitamin D as efficiently as younger people and the Linus Pauling Institute recommends a total of 800 IU supplemental vitamin D/day, in addition to the aforementioned exposure to sunlight.