Saturday, November 24, 2007

Vitamin D Supplementation


  • For Adults, the 5 mcg (200 IU) Vitamin D recommended dietary allowance may prevent Osteomalacia in the adsence of sunlight, but more is needed to help prevent osteoporosis & secondary hyperparathyroidism.

  • Other benefits of Vitamin D supplemetation are inplicated epidemiologically: prevention of some cancers, osteoarthritis progression, multiple sclerosis and hypertension.

  • Total Body sun exposure easily provides the equivalent of 200 mcg (10 000 IU) Vitamin D per day. In contrast, we modern humans usually cover all except about 5 % of our skin surface & it is rare for us to spend time in unshielded sunlight.

  • To ensure that serum 25 (OH) D concentrations exceed 100 nmol/L. a total Vitamin D supply of 100 mcg (4000IU) per day is required.

  • before 1997, the recommended dietary allowance of Vitamin D for infant & children was 10 mcg (400 IU). In essence, the scientific basic for this dose was that it approximated what was in a teaspoon (5mL) of cod-liver oil & had long been considered safe & effective in preventing Rickets.

  • The objective way to assess Vitamin D nutritional status is through the circulating 25 (OH) D concentration.

  • Concentration less than 20 - 25 nmol/L indicate severe Vitamin D deficiency; which will lead to rickets & histologically evident osteomalacia.


  • Concentrations between 25 & 40 nmol/L reflect marginal Vitamin D deficiency.

  • All 25(OH) D values are presented as nmol/L. ( 1 nmol/L = 1 ng/mL X 2.5 )

  • Vitamin D has a half life > 1 or 2 months.

  • Amounts of Vitamin D are given in mcg, each being equivalence to 40 IU or 2.6 nmol Vitamin D3.

  • However, Vitamin D2 is less effective at raising serum 25(OH) D concentrations than is Vitamin D3.

  • Sunshine alone can bring 25 (OH) D concentration to 210 nmol/L in normal people & Vitamin D intake of 30 mcg (1200 IU) per day contribute only a negligible fraction of this.

  • At least 4 studies support the concept that one full-body exposure to sunlight can be equivalent to an oral Vitamin D intake of 250 mcg (10 000 IU). They calculated a production of Vitamin D in the skin equivalent to 0.045 nmol.d-1.cm-2 expose skin. This equivalent to 10.9 mcg (435 IU) Vitamin D per day for 5 % of skin surface.

  • Upper levels of Vitamin D intake were set at 50 mcg per day (2000 IU per day) for all ages. Some individuals would require higher levels than these to achieve serum 25-hydroxyvitamin D concentrations for optimal Calcuim absorption.

  • The normal range of serum 25-hydroxyvitamin D concentration is broad at 25-137.5 nmol/L.

  • Calcuium absorption efficiency increase with serum 25-hydroxyvitamin D concentration until levels of 80-90 nmol/L were achieved.

  • Vitamin D deficient individuals may require Vitamin D intakes that exceed the current upper levels to achieve serum 25-hydroxyvitamin D concentration of >= 80 nmol/L.

  • Recommended that serum 25(OH) D should exceed 75 nmol/L in person with osteoarthritis of the knee.

  • From what is known now, there is no practical difference whether Vitamin D is required from ultraviolet exposed skin or through the diet.

Risk Assessment for Vitamin D



  • Cholecalciferol (Vitamin D3) is produced naturally in human skin exposed to untraviolet-B light. It occurs in some animal products and is added to various dietary supplements (such as multivitamins) and fortified foods (such as milk).

  • One IU of Vitamin D is defined as the activity produced by 0.025 mcg Cholecalciferol in bioassays with rats. Vitamin D3 is generally considered to be the primary form of dietary Vitamin D, although ergocalciferol (Vitamin D2), a secondary form, is derived from the yeast & plant sterol precursor, ergosterol.

  • Both Calciferols appears to be absorbed with equal efficiency, but Vitamin D2 may be less potent & may have a different toxicological profile.

Adverse Effect Reports



  • Excessive Vitamin D intake is associated with additional significant clinical adverse effects, including pain, conjunctivitis, anorexia, fever, chills, thirst, vomitting & weight loss.

  • Hypercalcemia due to Vitamin D intoxication per se is always accompanied by serum 25(OH) D concentration > 220 nmol/L.

  • Numerous reports of accidental or unimformed consumption of vey high doses of vitamin D:

  • Over 4 days period (15 000 mcg/day) develop resistant hypercalcemia & hypertension.

  • 42 000 mcg/day for several months resulting hypercalcemia included pain, conjunctivitis, anorexia, fever, chills, thirst, vomitting & weight loss.

  • Patient with severe osteoporosis had a Vitamin D intake of 1250 mcg/day and get hypercalcemia.

  • Patient with nephritic syndrame, hypertension, and renal insufficiency being treated with hydrocholorothizide develop hypercalcemia while taking 1250 mcg Vitamin D2 per week.

  • Patient with history of hypertension treated with hydrocholorothizide & Alpha-methyldopa develop hypercalcemia while been treated with prednisone & taking 1250 mcg Vitamin D per day.

Monday, October 15, 2007

Bioavailability & Effectiveness of Dietary Supplements.

Are All Supplements Created Equal?
Currently, there are no FDA regulations that establish minimum standards of practise for the manufacturing of dietary supplements. Another legitimate concern for the consumer is the question of safety in the manufacturing process. Purity is paramount.Consumer assurance that a particular product has surpassed the highest standards for quality, purity and guaranteed potency can only be met through compliance with U.S. and Canadian Good Manufacturing Practices (GMPs) for pharmaceuticals. These criteria used as a quality benchmark to ensure the highest level of quality control and purity, right from the raw material to the finished product. It is far better to purchase a professional designed broad-spectrum nutritional supplement in which the questions of completeness, potency, balance and synergy have been factored into the formulation.

For example: What can the consumer or health care provider do to obtain a quality product containing pure chondroitin sulfate or glucosamine?

A recent review by The Arthritis Foundation provides the following suggestions :
  • consumers should consult with their physician or healthcare provider concerning these two supplements;
  • healthcare professional should become knowledgeable about glucosamine and chondroitin sulfate products;
  • consumers should not purchase through the mail or Internet unless they know the vendor;
  • consumers should buy from companies that use USP material.

Some findings verify the scientific community's skepticism towards nutraceuticals based on lack of quality control by some manufactures. these substances are not pharmaceuticals; there is no requirement for pharmaceutical GMPs to guarantee high quality, batch-to-batch consistency. The use of validated analytical methods for the raw materials and finished products is the only mechanism to verify purity. It is not surprising to know that Arthritis Foundation has recently recommended that "when a supplement has been studied with good results, find out which brand was used in the study, and buy that".

Despite terms like 'quality tested" appearing on labels, consumers and healthcare providers have no basis to compare one product against another or to judge the quality of the products they purchasing or recommending.

Product Quality Checklist

  • Is the product delivered in a single dose? (potency of once-daily always better than multiple doses)
  • Are the potency levels of the ingredients high enough to provide optimal daily nutritional intake without compromising safety?
  • Are the ingredients provided in their most bioavailable form? (Organic carrier can absorb better by human body)
  • Is the safety profile of each ingredient thoroughly researched and evaluated?
  • Does the company meet U.S. and Canadian GMPs?
  • Is the product formulated to meet pharmaceutical standards for full disintegration and dissolution?
  • Is the product potency guaranteed for a specified shelf life?
  • Is the product independently tested and guaranteed for potency and safety?
  • Is the product manufactured in-house? or contracted out to the lowest bidder?
  • Is the product free of ingredients that may have cumulative toxicities ?

In reality, it is just not feasible for the consumer to consider all these points about a product simply by scanning the label. many nutritional manufacturers don't make such detailed information easily available. Furthermore, consumer should shy away from the products that are backed only by testimonials and not scientific research.

Nutraceuticals for Osteoarthritis (OA)

Diagnosis of OA is based on clinical and radiological findings. The first manifestations are pain, stiffness, swelling, crepitus, and restriction of joint movement. Pharmacologic treatment begins with acetaminophen, adding a low-dose NSAIDs (Nonsteriodal anti-inflammatory drug), salicylate, selective COX-2 inhibitor, or topical capsaicin cream if needed.

Drawbacks to the patient of long term use of NSAIDs have inspired researchers to investigate agents that have minimal or no side effect. Studies have been conducted on the nutraceuticals such as chondroitin sulfate and glucosamine to demonstrate their efficacy in the symptomatic treatment of OA.

Glucosamine
The amino-monosaccharide glucosamine is precursor of the disaccharide unit of glucosamineglycan (GAG) and is reported to stimulate the production of proteoglycans, the ground substance of articular cartilage. Glucosamine also stimulates synovial production of hyaluronic acid (HA), which is responsible for the lubricating and shock-absorbing properties of synovial fluid.Improvement in the symptoms of OA associated (including knee OA) with the use of glucosamine has been observed in several clinical trials.

Chondroitin Sulfate
Chondroitin sulfate is an important component of cartilage. Two types, chondroitin-4-sulfate and chondroitin-6-sulfate, vary in molecular weight and thus differ in their bioavailability and purity. Studies suggested that a reduction of the proteoglycan content of cartilage, the same process associated with OA, can be inhibited by chondroitin sulfate. and also inhibitory effects of chondroitin sulfate on many degradative enzymes.

Radiolabelled chondroitin sulfate given orally to humans was 70% absorbed. Its affinity for synovial fluid and articular cartilage has also been demonstrated.

COMBINED THERAPY
Over the years the combined use of these nutraceuticals has become extremely popular. It is important to note that experimental studies have documented a synergistics effect when glucosamine and chondroitin sulfate are administered together.Studies reported that the body responds best when glucosamine and chondroitin sulfate are consumed simultaneously.

Monday, September 24, 2007

Nutrient and Vegetarian

Challenges for vegetarians

Protein – Vegetarians can get protein from grains, pulse, legume, seeds
and nuts.

Fat – Plant foods like fruits and nuts can be good source of essential
fatty acids. Olives, soy, peanuts, walnuts, avocadoes and sunflower
seeds provide unsaturated fats. Strict vegetarians may lack of
docosahexanoic acid (DHA).

Calcium – Eating broccoli, spinach and tofu can help in calcium
requirement.

Vitamins – the only concerns is Vitamins B-12 deficiency because
vitamin B-12 does not naturally occur in plant food in a
biological active form (usable by the human body).

Iron – Not many plant contain iron. Although vitamin C does help in the
absorption of iron.

Zinc – food like grains, pulses, wheat germ, seeds, soy foods provide zinc
but strict vegetarians are recommended to take fortified food to
meet the requirement.

Why go Vegetarian ?

Why go vegetarian?

Foods of plant origin are naturally low in saturated fats and contain no cholestrol. Plant foods also have more fiber than any animal food. Fiber curbs overeating, helps keep blood-sugar levels onstant, reduces cholestrol, promotes regularity of bowel movement and lessens the risk of cancer. High-fiber food also satisfies the need to chew.

Some studies also show that vegetarians have lower rates of cancer, likely from an abundance of antioxidant and phytonutrients like flavonoids and carotenoids in plant foods. Vegetarians are also less vulnerable to intestinal disorders like constipation and diverticulosis.

Types of Vegetarians

Types of Vegetarians
- Vegans are strict vegetarians
- Lacto-vegetarians eat dairy product like milk, cheese and
butter, but no eggs.
- Lacto-ovo vegetarians include dairy product and eggs.
- Pesco-vegetarians eat dairy, eggs and fish.
- Semi-vegetarians eat almost every food exclude or limit
consumption of red meat.
- Fruitarian eat only raw or dried fruits, seeds and nuts.
- Macrobiotic-diet followers are extreme vegetarians who
progressively eliminate more and more food varieties until they
feed only on brown rice, water and herba tea.

Sunday, September 23, 2007

Vitamin B-12 in vegetarians

When you stop eating vitaminB-12 (cobalamins), you will passes through four stages of negative cobalamin balance:
  • Stage I-Serum depletion (low vitamin B-12 on transcobalamin II)
  • Stage II-Cell depletion (low red cell vitamin B-12 concentrations)
  • Stage III-Biochemical deficiency (slowed DNA synthesis)
  • Stage IV-Clinical deficiency (anemia)

There are six ways you can get vitamin B-12 deficiency:

-Three inadequacies

  • inadequate ingestion
  • inadequate absorption
  • inadequate utilization (defect in enzymes or other protein)

-Three excesses

  • increased requirement (pregnacy)
  • increased excreased (alcoholism)
  • increased destruction (very high doses of vitamin C)

Dietary deficiency of vitamin B-12 results from strict vegan (all plant food) diet because there is no vitamin B-12 synthesized by any plant. Vegetarins who are not vegans (lactoovovegetarians and lactovegetarians) ingest adequate amounts of vitamin B-12 in animal (egg,milk and other) products.

If daily vitamin B-12 absorption continues to be less than daily vitamin B-12 loss, negative balance will progress to stage II, depletion of stores. Eventually, however, continuing slight negative balance will deplete vitamin B-12 stores, after which stage III negative balance occurs (biochemical deficiency).

Active vitamin B-12 can be destroyed by very high doses of vitamin C. Vitamin C acts as an antioxidant primarily at physiologic doses. At pharmacologic doses, in the presence of iron, it is one of the most potent oxidants known and drives iron-catalyzed free radical generation which can damage vitamin B-12.

Negative vitamin B-12 balance also common in a large group of eldery people.