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Coconut Water Is Not a Special Sports Drink

The headline reads: "Coconut Water Is an Excellent Sports Drink" (Science Daily, August 20, 2012; presented at the 244th National Meeting & Exposition of the American Chemical Society (ACS) in Philadelphia). The author states: "Coconut water is a natural drink that has everything your average sports drink has and more. It has five times more potassium than Gatorade or Powerade. Whenever you get cramps in your muscles, potassium will help you to get rid of the cramps. It's a healthy drink that replenishes the nutrients that your body has lost during a moderate workout."

This flies in the face of everything I have learned about potassium:

• POTASSIUM DEFICIENCY IS NOT A PROBLEM IN HEALTHY EXERCISERS. In 1967, Dave Costill of Ball State University tried to create potassium deficiency in runners. He couldn't do it because potassium is found in all foods except refined sugar, and his athletes would not stay on a diet that consisted only of hard candy. The kidneys and sweat glands conserve potassium so well that you don't lose much. If an athlete develops potassium deficiency, it is usually caused by drugs, such as diuretics or corticosteroids, or by diarrhea or repeated vomiting. Some athletes try to control their weight by making themselves vomit. This is called bulemia, and the person usually denies vomiting. Their physicians can prove that they are vomiting by ordering blood and urine tests. If blood levels of potassium are low and urine levels are high, vomiting is the likely cause.

• POTASSIUM DEFICIENCY IS NOT A USUAL CAUSE OF CRAMPS OR TIREDNESS IN EXERCISERS. Tiredness and cramps in athletes can have many causes, but lack of potassium in the diet is not one of them. Athletes who are tired and suffer frequent muscle cramps need an evaluation for other causes of chronic tiredness. If none can be found, the athlete may be overtraining and should talk to the coach or a personal trainer about changing workouts.

• THE ONLY MINERAL THAT EXERCISERS NEED TO REPLACE IS SODIUM, COMMON TABLE SALT. The definitive studies on minerals and exercise were done during World War II. Dr. James Gamble of Harvard Medical School paid medical students to lie on rafts in his swimming pool, taking various amounts of fluids and salt and having blood drawn to measure salt and mineral levels. He showed that you have to take a lot of salt when you exercise for several hours, particularly in hot weather. For many years after that, students at Harvard Medical School heard Dr. Gamble give his lectures on minerals and exercise, and today, most serious students still read the Gamble lectures published in 1958 by The Harvard University Press. Now, more than sixty years later, nobody has improved on his research.

After Gamble published his studies, people who worked or exercised in hot weather were given salt tablets. Then doctors became concerned because they thought that a person could have his blood pressure raised by taking in too much salt, so they recommended restricting salt, causing many people to suffer heat stroke and dehydration during hot weather exercise. A low-salt diet does not lower high blood pressure for most people. A high-salt diet causes high blood pressure usually only in people with high blood insulin levels. Eating salty foods and drinks when you exercise for more than two hours is unlikely to raise blood pressure. We don't recommend salt tablets because they can cause nausea and vomiting, but you can use table salt or any salty food.

If you don't take salt and fluids during extended exercise in hot weather, you will tire earlier and increase your risk for heat stroke, dehydration and cramps. We eat heavily- salted potato chips or peanuts and drink fluids at least every 15 minutes when we ride in hot weather. Potassium deficiency doesn't occur in healthy athletes. The only mineral that athletes need to take when they exercise is salt.

If you like the taste of coconut water, it is a perfectly satisfactory fluid to take during exercise, but don't believe claims that it has any special benefits as a sports drink. If you use it during intense exercise, you will need other sources of sugar and salt.


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Coconut Oil Does Not Make You Smarter

Don't believe the advertisements claiming that high- priced coconut oil will make you smarter. This claim comes from a study that showed coconut oil can improve brain function in diabetics who pass out from low blood sugar caused by taking too much insulin (Diabetes, May 2009; 58(5):1237-1244). However, it does not make people with normal blood sugar levels smarter.

No data exists to show that coconut oil prevents or treats Alzheimer's disease. One doctor proposed a theory that Alzheimer's is like diabetes of the brain. A normal brain gets almost all its energy from sugar in the bloodstream. She claims that people with Alzheimer's disease have brains that cannot use sugar effectively to supply energy for their brains. Coconut oils contain medium chain triglycerides that can produce ketones that will supply the brain with energy and keep it from being damaged. No data exists to prove this theory. I can find no studies that show that coconut oils prevent or cure Alzheimer's disease.

HOW YOUR BRAIN GETS ENERGY: Your brain gets almost all of its energy from the sugar in your bloodstream. It does not store sources of energy in its cells. So when your blood sugar level drops, expect to pass out. This happens to diabetics when they take too much insulin, and to bicycle racers who do not take in sugar when they race for hours ("bonking").

KETONES: Blood sugar supplies almost all the energy for your brain. However, your brain can also get energy from ketones, formed when your liver converts fat to energy. Your body uses carbohydrates, fats and proteins for energy. If you were placed on a diet that is low in carbohydrates, your body would be forced to burn fat for energy. Blood sugar levels would then drop and you would pass out from low blood sugar. However, your body has a way to protect your brain from low blood sugar levels. When your body uses fats to produce energy, it forms ketones that can accumulate in your bloodstream and travel to supply energy for your brain.

MEDIUM CHAIN TRIGLYCERIDES: Most fats require bile from your gall bladder to be absorbed from your intestines into your bloodstream. Coconut oils are loaded with a type of fat called medium chain triglycerides which can be absorbed more rapidly than other fats because they do not need bile to be absorbed. They travel faster to the liver where they are converted into ketones, enter the bloodstream and travel to the brain as an energy source.

COCONUT OIL TO CONTROL SEIZURES: One study showed that children with uncontrollable seizures may benefit from coconut oil. They are put on a diet that severely restricts carbohydrates, particularly all sugars. This forces their livers to burn fat primarily for energy. The ketones, produced by turning fat into energy, travel into the brain and replace glucose as its energy source. This reduces the seizures (Pediatrics, March 2007;119(3):535-43).

NORMAL PEOPLE DON'T NEED COCONUT OIL: Taking coconut oils, which are rich in medium chain triglycerides, could help to protect your brain from starving to death when you have low blood sugar levels. However, no good data show that normal people improve brain function when they take coconut oil. It's an acceptable choice for cooking, but has no special health benefits. More on tropical oils


This week's medical history:
Who Killed George Washington?

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


Recipe of the Week:

Pink Beans and Brown Rice

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


August 26th, 2012
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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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