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Recurrent Injuries? Drop in Exercise Performance? Check for Vitamin D Deficiency

If you are a regular exerciser, having low levels of vitamin D is associated with a drop in exercise performance, increased risk for muscle injuries, failure to recover from intense workouts, loss of coordination, decreased muscle strength and bone fractures.

VITAMIN D PILLS CURE VITAMIN D DEFICIENCY-CAUSED MUSCLE WEAKNESS: Giving 5000 IU of vitamin D a day for eight weeks to athletes with low blood levels of vitamin D increased blood levels of hydroxy vitamin D from an average of 29 (deficient) to 103 nmol/L. This helped them to run faster and jump higher than those receiving placebo pills. (J Sports Sci, October, 2012; Am J Sports Med, February, 2013;41(2):461-464) Sixty-two percent of the competitive athletes tested in England had deficient Vitamin D levels (less than 50 nmol/L{ = 20 ng/ml}).

VITAMIN D DEFICIENCY WEAKENS MUSCLES: Dr. John Cannell of the Vitamin D Council quoted 14 studies that show that athletic performance improves in the summer months when sunshine is abundant (Vitamin D Council Newsletter, March 2007). Vitamin D deficiency is associated directly with muscle weakness (Scandinavian Journal of Medicine & Science in Sports, October 2009) and athletic injuries (Current Opinion in Clinical Nutrition & Metabolic Care, November 2009; Molecular Aspects of Medicine, December 2008).

Lack of vitamin D is associated with muscle weakness in older people (Molecular Aspects of Medicine, June 2005). With aging, you lose muscle fibers. For example, the vastus medialis muscle in the front of the upper leg has 800,000 fibers in a 20 year old, but only 250,000 in a 60 year old. Vitamin D slows this loss of muscle fibers, preserves muscle strength and helps to prevent falls, while lack of vitamin D increases loss of fibers, muscle weakness and falls (Pediatric Clinics of North America, June 2010).

HOW VITAMIN D DEFICIENCY WEAKENS MUSCLES: Vitamin D acts directly on specific receptors in muscles to make them stronger and prevent injury (Scandinavian Journal of Medicine & Science in Sports, April 2010). As people age, they become increasingly susceptible to muscle weakness and falls linked to lack of vitamin D.

Muscles are made of thousands of individual fibers that are classified into two types: slow twitch fibers that govern endurance, and fast twitch fibers that govern primarily strength and speed. Vitamin D specifically maintains the function of the fast twitch strength fibers.

Lack of vitamin D is also associated with loss of muscle size and strength, falls & muscle pain (J Bone Miner Res 2003;18:343-351; J Am Geriatr Soc 1979;51:1219-1226) and with decreased strength and coordination (American Journal of Epidemiology, Nov, 2012; Society for Endocrinology annual conference in Harrogate, UK. Mar. 18, 2013; Journal of Clinical Endocrinology & Metabolism, Feb 2009).

• Check your blood level of hydroxy vitamin D. That is the only available dependable test. If it is below 75 nmol/L (30 ng/ml), you are deficient.
• Try taking vitamin D at a dose of at least 2000 IU/day for a month.
• If that does not bring your D level to normal, check with your doctor about taking higher doses. You can be poisoned by overdoses of vitamin D (see next article).
• A certain percentage of people will have their vitamin D levels go above a normal 75 nmol/L and still suffer from muscle weakness, fatigue, pain and injuries. These people may benefit from exposure to sunlight. Since skin cancer is caused by cumulative exposure to sunlight over a lifetime, you should avoid exposing your face, top of ears, scalp, arms and hands. For most people, the legs and torso have had the least exposure. Be careful to avoid sunburn. Start at low exposures of just a few minutes a day and work up gradually. Fifteen to twenty minutes is all you need for vitamin D production. See my other recent reports on vitamin D:

Sunshine More Effective than Vitamin D Pills
Vitamin D Deficiency Is a Genetic Disease


You Can Get Too Much Vitamin D from Pills

Researchers in Israel reviewed almost 1.3 million health records over 4.5 years and showed that both high and low blood levels of hydroxy vitamin D increase risk for heart attacks (The Journal of Clinical Endocrinology & Metabolism, published online March 26, 2013).

Normal blood levels of hydroxy vitamin D are from 25 nmol/L to 90 nmol/L (10 ng/mL to 36 ng/mL). Those who had blood levels below normal had almost twice (1.88) the heart attack rate as those in the normal range. The lower the hydoxy vitamin D level, the greater their chances of suffering a heart attack.

Those who had blood levels above the normal range also were at increased risk (1.13 times normal values) for heart attacks.

HOW MUCH VITAMIN D IS TOO MUCH? A major function of vitamin D is to increase absorption of calcium from the intestinal tract. Taking excess vitamin D pills can raise blood calcium levels. This can cause
• irregular heartbeats including atrial fibrilation,
• increased deposition of calcium to form in arteries plaques that cause heart attacks, and
• kidney stones.

HOW MUCH VITAMIN D IN PILLS IS SAFE? The people most likely to suffer harmful side effect from high doses of vitamin D pills are those whose blood calcium levels rise above normal (J Bone Miner Res. 2011; 26:35-41). It is impossible for sunlight or unfortified food to drive blood levels of hydroxy vitamin D above normal (100 nmol/L). You can only get toxic levels of vitamin D from pills. The upper safe limit for Vitamin D is 4,000-10,000 IU/day and for Calcium(food & pills) it is 2,000 - 3,000 mg/day (J Bone Miner Res. 2011; 26:35-41).

I think that you should not take in more than 2000 IU of vitamin D per day. Also, I think that you should not take calcium pills.


Most Diabetics Cause Their Disease

The U.S. Centers for Disease Control and Prevention reports that only 11 percent of the 80 million people who have metabolic syndrome know they are headed for diabetes, a disease that can destroy every cell in their bodies and will markedly shorten their life spans (Morbidity and Mortality Weekly Report, March 22, 2013). The American Diabetes Association reports that almost nine percent of all Americans (26 million) already suffer from diabetes.

HOW TO TELL YOU ARE BECOMING A DIABETIC: If you have any three of the signs and symptoms listed below, you have Metabolic Syndrome. You are highly likely to have high blood sugar levels and are already suffering damage to your brain, kidneys, heart, arteries and every other tissue in your body if you:
• store fat primarily in your belly
• have small and narrow hips
• are overweight
• have blood triglycerides >150
• have blood Healthful HDL cholesterol 100 (HbA1c> 5.7)
• have high fasting insulin (>15 uUnits/ml, 90 pmol/L)
• have high blood pressure (Systolic >120 at night)
• have a family history of diabetes

MOST DIABETICS DON'T KNOW THAT THEY ARE DIABETIC: Type II Diabetes is a preventable disease and this incredible unawareness that a sloppy lifestyle causes diabetes occurs in people of all incomes and education levels, regardless of access to health care or health insurance.

1) Avoid overweight. Full fat cells cause high blood sugar levels by blocking insulin receptors to prevent cells from responding to insulin.
2) Eat large amounts of fruits and vegetables. They prevent blood sugar levels from rising too high by delaying absorption of other foods, and reduce inflammation.
3) Do not take sugared drinks in any form, including fruit juices, except during prolonged intense exercise. Sugared drinks cause the highest rises in blood sugar which, in turn, can cause sugar to stick to cell membranes to destroy these cells.
4) Restrict foods with added sugar.
5) Restrict fried foods.
6) Do not eat red meat. The saturated fats in red meat block insulin receptors. Red meat causes inflammation.
7) Try to exercise at least 30 minutes every day. Resting muscles draw no sugar from the bloodstream. Contracting muscles can draw sugar from the bloodstream without even needing insulin.
8) Grow muscle. Larger muscles draw more sugar from the bloodstream.
9) Keep blood levels of hydroxy-vitamin D > 75 nmol/L. Lack of vitamin D blocks insulin receptors to prevent cells from responding to insulin.


This week's medical history:
The Despicable Dr. Julius Reiter

For a complete list of my medical history biographies go to Histories and Mysteries


Recipe of the Week:

Portobello Mushroom Casserole

You'll find lots of recipes and helpful tips in The Good Food Book - it's FREE

March 31st, 2013
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About the Author: Gabe Mirkin, MD

Sports medicine doctor, fitness guru and long-time radio host Gabe Mirkin, M.D., brings you news and tips for your healthful lifestyle. A practicing physician for more than 50 years and a radio talk show host for 25 years, Dr. Mirkin is a graduate of Harvard University and Baylor University College of Medicine. He is board-certified in four specialties: Sports Medicine, Allergy and Immunology, Pediatrics and Pediatric Immunology. The Dr. Mirkin Show, his call-in show on fitness and health, was syndicated in more than 120 cities. Read More
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