Friday, August 21, 2009

Vitamin D: how much we know about it?

1. Vitamin D in the News

D Vital for the Heart

2. Role of vitamin D
• Promotes the proper synthesis and functioning of important proteins essential for proper calcium utilization
• Supports the maintenance of bones
• Supports immune health
• Helps maintain cardiovascular health
• Helps maintain normal blood pressure

3. Sources of vitamin D
• Fat-soluble vitamin can obtain from:
• Food (Salmon: 360 IUs; Mackerel: 345 IUs; Tuna: 200 IUs; Sardines: 250 IUs; Fortified Milk: 98 IUs)
• Supplementation
• Sunlight
• Supplementation
• Sunlight

4. Vitamin D Deficiency
• More than1 billion people worldwide do not consume adequate amounts of vitamin
• More than 50% of postmenopausal women taking medication for osteoporosis have suboptimal levels of vitamin D
• Without adequate vitamin D, only 10-15% of dietary calcium is absorbed
• Vitamin D deficiency: a worldwide problem with health consequences ( Am J Clin Nutr. 2008 Apr;87(4):1080S-6S)
• Vitamin D deficiency is now recognized as a pandemic.
• Very few foods naturally contain vitamin D, and foods that are fortified with vitamin D are often inadequate to satisfy either a child's or an adult's vitamin D requirement
• Vitamin D deficiency causes rickets in children and will precipitate and exacerbate osteopenia, osteoporosis, and fractures in adults
• Vitamin D deficiency has been associated with increased risk of common cancers, autoimmune diseases, hypertension, and infectious diseases

5. Research findings
• Vitamin D supplementation and total mortality (Arch Intern Med. 2007 Sep 10;167(16):1730-7)
• A meta-analysis of randomized controlled trials including 57,311 participants.
• Intake of ordinary doses (300 to 2000 IU) of vitamin D supplements seems to be associated with decreases in total mortality rates.
• Vitamin D and calcium supplementation reduces cancer risk ( Am J Clin Nutr. 2007 Jun;85(6):1586-91)
• A 4-year, population-based, double-blind, randomized placebo-controlled trial.
• 1179 healthy postmenopausal women aged >55 years.

6. Current Researches
• Vitamin D may reduce prostate cancer metastasis by several mechanisms including blocking Stat3 (Am J Patholo. 2008 Nov;173(5):1589-90)
• Double-dose vitamin D lowers cancer risk in women over 55 (J Fam Pract. 2007 Nov;56(11):907-10 )

7. Use of vitamin D in clinical practice (Altern Med Rev. 2008 Mar;13(1):6-20)
• Natural vitamin D levels, those found in humans living in a sun-rich environment, are between 40-70 ng per ml.
• Treatment of vitamin D deficiency in otherwise healthy patients with 2,000-7,000 IU vitamin D per day should be sufficient to maintain year-round 25(OH)D levels between 40-70 ng per mL.
• In those with serious illnesses associated with vitamin D deficiency, such as cancer, heart disease, multiple sclerosis, diabetes, autism, and a host of other illnesses, doses should be sufficient to maintain year-round 25(OH)D levels between 55 -70 ng per mL.

8. Why Vitamin K2?
• Promotes normal calcium absorption
• Promotes healthy arteries
• Active form of vitamin K with highest bioavailability
• Women with low bone density have been found to be deficient in vitamin K
• Addresses the “calcium paradox”
• Vitamin K1 vs. K2
• Both are naturally occurring forms of vitamin K. Different chemical structures resulting in different pharmacokinetic properties
• K1 is absorbed primarily in the liver where at high doses it may interfere with anticoagulant medications
• K2 is transported primarily to the bones and blood vessels
• Only 10% of dietary vitamin K is in K2 form

9. Why take vitamins D and K as supplements?
• Most people are vitamin D deficient or insufficient
• Diet
• Sun exposure
• Very little vitamin K is stored in the body
• These vitamins work together

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