Vitamin Trader - Healthy Discounts on Quality Vitamins

 By Mark Timon, M.S. Clinical Nutrition, founder and formulator Vibrant Health supplements.

The last decade has seen a tremendous upsurge in vitamin D research. The primary goal has been to determine just what the optimal daily intake should be. Along the way, a great deal of new knowledge about this standard vitamin has come to light. As a result, vitamin D has burst from the chorus ranks of nutrition to center stage front as a major star of the health show.

Vitamin D Vitamin D is the fat-soluble vitamin (the others are A, K, and E) that in the 1920s was shown to be essential for maintaining normal calcium metabolism, and a healthy skeleton. More recent research in the last fifteen years has identified a new role for vitamin D in disease resistance.

Vitamin D doesn’t do anything... at first Vitamin D3 is converted to calcidiol, the telltale form of vitamin D found in circulation. Increased exposure to sunlight or increased dietary intake of vitamin D3 increases serum levels of calcidiol. This means that the amount of calcidiol in blood serum is a useful indicator of a person’s vitamin D nutritional status. Most of the physiological benefits of vitamin D in the body are related to the activity of calcitriol. It is so powerful that it is often referred to as “hormonal D. and some of its effects are explained below.

Calcium Balance It is vital for normal functioning of the nervous system, as well as for bone growth, and maintenance of bone density to maintain a steady level of serum calcium flowing through the blood If calcium levels drop too low, parathyroid glands respond by secreting parathyroid hormone. Parathyroid hormone and calcitriol then direct the kidneys to reabsorb calcium trying to escape with the urine and to mobilize calcium from bone.

A Skeletal Connection We see that if dietary calcium intake or dietary vitamin D intake is inadequate, then insufficient supplies of calcium will be absorbed, and enter circulation. As a consequence, parathyroid hormone will be secreted, resulting in the breakdown of bone tissue. This happens more dramatically at night, while you sleep. This natural daily event can be subdued in the interest of maintaining a strong skeleton if supplemental calcium and vitamin D are taken at night, just before going to bed. Remember, vitamin D3 alone can increase the intestinal absorption of dietary calcium. The process is enhanced if there is a nice quantity of calcium in the digestive tract at the same time. With these two nutrients abundantly supplied at night, serum calcium can remain at appropriate levels.

And don’t forget Boron In every mammalian species tested, from mice to humans, adding the trace mineral boron to the diet has reduced or eliminated negative calcium balance. Negative calcium balance exists when more calcium is lost in the urine than is absorbed and put into circulation by the gastrointestinal tract. In such a state, the body loses more calcium than it takes in. We now know that boron plays a strong role in regulating levels of hormonal D, calcitriol. Supplemental boron as calcium fructo-borate proved to be highly effective at restoring optimal calcitriol levels and maintaining vitamin D homeostasis, the constant state of the internal equilibrium.

Cell Differentiation While cellular proliferation is essential for growth and wound healing, uncontrolled proliferation of cells with certain mutations may lead to diseases like cancer. The active, hormonal form of vitamin D, calcitriol, inhibits proliferation and stimulates the differentiation of cells. How much vitamin D3 can help when malignancy is discovered? Opinions vary, but recommended dosages can reach up to 25,000 i.u. per day. Daily intakes associated with chemoprevention appear to range between 2,000 i.u. and 4,000 i.u.

Immunity The Vitamin D metabolite, calcitriol, is a potent immune system modulator. Accumulating research is beginning to confirm that calcitriol has a variety of effects on immune system function. Indications are that it may enhance immunity and inhibit the development of autoimmunity, possibly protecting against autoimmune disorders such as Lupus and Rheumatoid arthritis.

Insulin Secretion Results of animal studies suggest that calcitriol plays a role in insulin secretion under conditions that demand increased insulin. Limited data in humans suggest that insufficient vitamin D levels may have an adverse effect on insulin regulation, leading to unbalanced secretion and glucose tolerance in type 2 diabetes.

Blood Pressure Regulation Early research with mice implies that vitamin D may be one important factor in regulating blood pressure. It may be that, as in mice, adequate vitamin D can reduce amounts of angiotensin II, a tiny protein (peptide) that can increase blood pressure by inducing the constriction of small arteries and by increasing sodium and water retention. Thus vitamin D may be important for decreasing the risk of high blood pressure.

Muscle Weakness and Pain: Vitamin D deficiency causes muscle weakness and pain in children and adults. In a cross sectional study of 150 consecutive patients referred to a clinic in Minnesota for the evaluation of persistent, nonspecific musculoskeletal pain, 93% had serum calcidiol levels indicative of vitamin D deficiency. A randomized controlled trial in 124 nursing home residents (average age, 89 years) found that those taking 800 i.u./day of supplemental vitamin D had a 72% lower fall rate than those taking a placebo.

What if I get an F as my vitamin D intake grade? Although it has long been known that severe vitamin D deficiency has serious consequences for bone health, recent research suggests that less obvious, “subclinical” states of vitamin D deficiency are common and increase the risk of osteoporosis, cancer, immune disorder, infectivity, blood sugar disorders and cardiac problems. Persistent under-nutrition of vitamin D may be related to – that is, may be one of the underlying factors contributing to – the prevalence of diabetes, osteoporosis, cardiovascular disease, and other seemingly intractable health problems present in our modern society.

What can set the stage for Vitamin D Deficiency? Exclusively breast-fed infants: Infants who are exclusively breast-fed and do not receive vitamin D supplementation are at high risk of vitamin D deficiency.

Dark skin: People with dark-colored skin synthesize less vitamin D on exposure to sunlight than those with light-colored skin

Aging: The elderly have reduced capacity to synthesize vitamin D in skin when exposed to UVB radiation, and the elderly are more likely to stay indoors or use sunscreen.

Covering all exposed skin or using sunscreen whenever outside: The application of sunscreen with an SPF factor of only 8 reduces production of vitamin D3 by 95% !

Fat malabsorption syndromes: Irritable bowel syndrome, celiac disease, other food allergies, cystic fibrosis, and cholestatic liver disease impair the absorption of dietary vitamin D (and other fat soluble vitamins A, E & K).

Inflammatory bowel disease: People with inflammatory bowel disease such as diverticulitis and Crohn’s disease are at increased risk of vitamin D deficiency, especially those who have had small bowel resections.

Obesity: Obesity increases the risk of vitamin D deficiency because vitamin D synthesized in the skin or ingested is deposited first in body fat, awaiting later mobilization. It is entrapped longer and, therefore, made less bioavailable in those with large stores of body fat.

Sources of Vitamin D

Sunlight: Solar ultraviolet-B radiation (UVB) stimulates the production of vitamin D3 in the epidermis of the skin. Sunlight exposure can provide most people with their entire vitamin D requirement. Children and young adults who spend a short time outside two or three times a week will generally synthesize all the vitamin D they need to prevent deficiency. One study reported that serum vitamin D concentrations following exposure to one dose of simulated sunlight, sufficient to cause a slight pinkness of the skin, was equivalent to ingesting approximately 20,000 i.u. of vitamin D.

In latitudes around 40 degrees north or 40 degrees south (Boston is 42 degrees north), there is insufficient UVB radiation available for vitamin D synthesis from November to early March. Ten degrees farther north or south (e.g. Edmonton, Canada) the “vitamin D winter” extends from mid-October to mid-March. According to Dr. Michael Holick, as little as 5-10 minutes of sun exposure on arms and legs or face and arms three times weekly between 11:00 am and 2:00 pm during the spring, summer, and fall at 42 degrees latitude should provide a light-skinned individual with adequate vitamin D and allow for storage of any excess for use during the winter with minimal risk of skin damage.

Food sources: Natural Vitamin D is found in very few foods. Fatty fish (mackerel, salmon, sardines), fish liver oils, and eggs from hens that have been fed vitamin D are respectable dietary sources. In the U.S., milk and infant formula are fortified with vitamin D so that they contain 400 i.u. (10 mcg) per quart. Some cereals and breads are also fortified with vitamin D. Orange juice has also now joined their ranks. Still, in spite of fortification, intakes of vitamin D are highly variable in the population due to individual dietary habits.

The Adequate Intake: 5,000 i.u. to 10,000 i.u. taken as a supplement can generate circulating calcidiol levels comparable to those found in persons who spend many hours outside in the sun each day. Clearly then, an adequate intake of vitamin D for adults would lie somewhere between 1,000 i.u. and 10,000 i.u. per day from both dietary and supplemental sources.

What’s safe? Vitamin D toxicity (hypervitaminosis D) induces abnormally high serum calcium levels (hypercalcemia), which could result in bone loss, kidney stones, and calcification of organs like the heart and kidneys if untreated over a long period of time. Hypercalcemia has indeed been observed, but only following use of daily doses greater than 50,000 i.u. No cases of hypercalcemia or hypercalciuria have been reported among subjects taking 10,000 i.u. vitamin D3 per day in their human trials.

Infants - minimum daily intake of 400 i.u. of vitamin D3, as recommended by the American Academy of Pediatrics in 2008.

Children, and adolescents - minimum daily intake of 2,000 i.u. of vitamin D3,

Healthy adults - 2,000 i.u. of supplemental vitamin D3 daily. Most multivitamins contain 400 i.u. of vitamin D3, and single ingredient vitamin D3 supplements are available in potencies ranging from 400 i.u. to 5,000 i.u. Sun exposure, diet, skin color, and obesity have variable, and substantial, impact on body vitamin D levels.

Senior citizens - daily supplementation with 2,000 i.u. of vitamin D3 or more. Supplementation is especially important for older adults because aging is associated with a reduced capacity to synthesize vitamin D3 in the skin upon exposure to sun.

WARNINGS: Certain medical conditions can increase the risk of hypercalcemia in response to vitamin D, including primary hyperparathyroidism, sarcoidosis, tuberculosis, and lymphoma. People with these conditions may develop hypercalcemia in response to any increase in vitamin D nutrition and should thus consult a qualified health care provider regarding any increase in vitamin D intake . The following medications increase the metabolism of vitamin D and may decrease serum calcidiol levels: phenytoin (Dilantin), fosphenytoin (Cerebyx), phenobarbital (Luminal), carbamazepine (Tegretol), and rifampin (Rimactane). The following medications should not be taken at the same time as vitamin D because they can decrease the intestinal absorption of vitamin D: cholestyramine (Questran), colestipol (Colestid), orlistat (Xenical), mineral oil, and the fat substitute Olestra. The oral antifungal medication, ketoconazole, inhibits the 25(OH) D3-1-hydroxylase enzyme (the enzyme required to convert calcidiol to calcitriol), and has been found to reduce serum levels of calcitriol in healthy men. The induction of hypercalcemia by toxic levels of vitamin D may precipitate cardiac arrhythmia in patients on digitalis (Digoxin).