August 1998

Magnesium supplementation lowers blood pressure

Aug 21 

Magnesium supplements may stimulate small but significant reductions in blood pressure, according to a report in the August issue of Hypertension.

Dr. Yuhei Kawano and others, at the National Cardiovascular Center in Osaka, Japan, conducted a prospective, crossover study of the office and ambulatory blood pressures of 60 patients, aged 33-74 years, with treated or untreated essential hypertension. All subjects received 20 mmol/day of magnesium or placebo for 8-week periods. 

"Office, home, average 24-hour, and daytime [systolic blood pressure] as well as [diastolic blood pressure] were significantly lower in the [magnesium] period than in the control period," the authors discovered, with an "...average reduction in 24-hour [blood pressure of] 2.5/1.4 mm Hg..." during magnesium therapy. They note that this antihypertensive effect was greater in those subjects with higher blood pressures at baseline. 

These findings suggest to the Japanese investigators that hypertensive patients may benefit from increases in dietary magnesium. "However, the therapeutic value of high [magnesium] intake may be limited because its antihypertensive effect appears to be small." 

Hypertension 1998;32:260-265.


Exercises Can Help Prevent Golf Injuries
August 11, 1998

The bad news for golfers is that more than 115,000 of them were treated for golf-related injuries last year in the US at a cost of $1.7 billion, including medical, legal, liability, pain, suffering, and work loss expenses, according to the US Consumer Product Safety Commission. 

The good news is that many of these injuries can be prevented with a few warm-up exercises, according to the American Academy of Orthopaedic Surgeons in Rosemont, Illinois. 

"Many golfers are at potential risk of suffering serious injuries to the elbow, spine, knee, hip or wrist," said Dr. W. Andrew Hodge, an orthopaedic surgeon at the Orthopaedic Research Laboratory in West Palm Beach, Florida, in a statement issued by the Academy. 

Leading the list of injuries is golfer's elbow, an inflammation of the tendons on the inside of the elbow, he said. It is usually caused when golfers have an improper swing and place unnecessary force on the elbow and forearm area. 

To avoid golfer's elbow, the Academy recommends three simple exercises to build up forearm muscles: squeezing a tennis ball for 5 minutes at a time, wrist curls using a lightweight dumbbell, and reverse wrist curls, also using the lightweight dumbbell. 

Low back pain, another common complaint among golfers, can be caused by a poor swing. "The rotational stresses of the golf swing can place considerable pressure on the spine and muscles," said Hodge. "Poor flexibility and muscle strength can cause minor strains in the back that can easily become severe injuries." 

To avoid this type of injury, the Academy suggests two exercises. In the first, called "rowing," firmly tie the ends of rubber tubing and place it around an object at shoulder height, such as a door hinge. Standing with arms straight out, grasp the tubing with palms away from your body and slowly pull it toward your chest. Release slowly. Perform three sets of 10 repetitions, at least three times a week.

In the second exercise, called "pull-downs," with the rubber tubing still around the door hinge, kneel and hold the tubing, palms facing away from you, over your head. Pull down slowly toward your chest, bending your elbows as you lower your arms. Raise the tubing slowly over your head. Perform three sets of 10 repetitions at least three times a week. 

"One of the best ways for golfers to stretch their muscles and avoid injury could be considered old-fashioned," said Hodge. "Before your round of golf, engage in some simple stretching exercises, and then... hit a few golf balls on the driving range. It not only will help your game, but will make you healthier in the long run."


The Truth About Sports Enhancers
August 12, 1998

By Edward G. McFarland, M.D.

Creatine is the latest headline-grabbing substance said to help boost athletic performance. But how do it and other products really fare?  

In a world where the difference between champion and loser is measured in hundredths of a second, athletes are willing to do just about anything to gain a competitive edge. When ability has been fully developed and training has maxed out, the next step for many athletes is to take sports-performance enhancers or ergogenic aids -- substances believed to make you bigger, faster and stronger by enhancing the body's energy use. 

The use of dietary aids to enhance athletic prowess is as old as competition itself: Centuries ago, men ate ground lion's teeth to give them strength and deer liver to increase their speed. Today, a wide range of substances from coffee to herbal supplements are used by professional athletes and weekend warriors alike for that "edge." The latest to gain attention is creatine, a compound produced naturally in the body. Reports in the popular press suggest that taking creatine supplements may result in higher energy levels. 

Studies do show that high-dose creatine supplements (approximately 20 g/day) can increase the amount of creatine in muscles. But performance data are mixed, with nearly as many studies showing positive results as negative ones. If creatine does work as an ergogenic aid, its benefits will most likely be seen in high-intensity short-burst athletes and in vegetarians. Still, despite often favorable "reviews" in the popular press, its long-term effects are unknown. And since creatine is excreted by the kidneys, there are concerns about possible long-term effects on that organ. 

A run-down of other popular so-called "sports enhancers":  

  • Protein:

Since muscles are composed of protein, some athletes believe that eating more protein will translate into more muscle. While athletes may require slightly more protein than non-athletes to build muscles (but not enhance performance), this extra amount is usually fulfilled by a balanced, varied diet. In fact, the typical American diet usually provides more than the recommended 15 percent of calories from protein -- more than enough to aid muscle integrity. 

Advice: Unless you're a strict vegetarian, you don't need to increase protein consumption to boost athletic performance. 

  • Amino acids:

Over-the-counter amino acids have become a popular ergogenic supplement sold in health food stores because they are theorized to build muscle, accelerate the rate of recovery during training and generally improve both psychological and physiological responses during endurance training. Yet research studies have not demonstrated benefits to most athletes.

Advice: Amino acids are ineffective and their long-term health effects are unknown. 

  • Coenzyme Q10:

Coenzyme Q10 (also known as CoQ10) is a type of lipid found in the energy producing mitochondria of cells. Some benefit of CoQ10 supplementation has been seen in patients with heart disease, including improvement in exercise capacity, but ergogenic improvements are generally not seen in healthy subjects. 

Advice: Don't waste your money.

  • Caffeine:

Affordable and readily available in coffee or tea, caffeine seems to be among the few ergogenic aids that have been shown to work in a number of scientific studies. The caffeine equivalent of two cups of coffee ingested before exercise increases endurance in both well-trained and weekend athletes. The theory is that caffeine stimulates the breakdown of fats for energy, which slows the depletion of glycogen, the main energy stores of the body. 

Caffeine doesn't seem to improve performance during conditions of high heat, and it can have harmful side effects if you have heart disease. 

Advice: If you're already a coffee-drinker, have two cups about 2 hours before activity. 

  • Chromium picolinate:

This trace mineral has generated a lot of interest -- and publicity -- for its alleged ability to build muscle, burn fat and increase energy. Research has not supported these claims. 

Advice: Chromium picolinate does nothing to improve athletic performance or burn fat. 

  • Ginseng:

Ginseng is an herbal plant that has been used as a medicinal for thousands of years in China and Korea, and more recently has been "discovered" in the U.S. and touted as a possible ergogenic. It's available in supermarkets and health food stores as supplemental pills, powders, and in teas. 

Advice: Research has found that ginseng does not improve oxygen use, aerobic performance, exercise recovery rate or mood.

  • Anabolic steroids:

Anabolic steroids are substances that are similar to the naturally-occurring hormone testosterone, which helps regulate growth and sexual development in men. Steroids are popular among weight lifters and track and field athletes because of their ability to increase muscle size and strength. 

Advice: The price far outweighs the benefits. Serious and sometimes irreversible side effects include liver damage, liver cancer and heart disease. In addition, the improvements made with steroids usually disappear when their use is discontinued. 

  • Growth hormone:

Growth hormone is taken by athletes who believe that it will build muscle and strength the way anabolic steroids do, but without the dangerous side effects. They are wrong. Although very little research has been done on its effects on athletes, it seems that growth hormone does not result in the kind of muscle growth seen with steroid use, and it does not improve athletic performance, strength or endurance. Further, the side effects can be severe. 

Advice: Downright dangerous! Large quantities taken during the development stage can impair normal growth and hormonal balance. It is a banned substance for most athletic competitions. 

Edward G. McFarland, M.D., a former Academic All-American
college football player, is an Associate Professor of Orthopaedic
Surgery and Director of the Sections of Sports Medicine and
Shoulder Surgery. He is Orthopaedic Consultant to the Baltimore
Orioles and other athletic teams.


Exercise cuts disease risk in middle age
August 17, 1998

Men and women who switch from a sedentary to a more active lifestyle as they approach middle age reduce their risk of certain chronic diseases, according to a report. 

Increasing physical activity lowers total cholesterol, increases HDL (''good'') cholesterol and improves other metabolic factors that can lead to chronic diseases of old age, such as heart disease and diabetes. Conversely, reducing activity level with age -- which seems to be a common trend -- can have the opposite effect, according to the report in the Archives of Internal Medicine. 

``These observations strengthen the importance of leisure time activity in the prevention of certain chronic diseases,'' reported Dr. Inger Thune and colleagues from the University of Tromso in Norway. 

The finding is from a study of 5,220 men and 5,869 women who had an average age of about 34 (range 20 to 49) when first surveyed in 1979 and 1980. When surveyed 7 years later, 31% of men and 22% of women described decreased physical activity levels, while 18% of men and 17% of women had increased their exercise levels. 

Overall, the group showed an increase in body mass index (a measure of weight versus height), triglycerides and total cholesterol, and a decrease in HDL cholesterol. However, those who exercised at the first survey and who continued to do so throughout the 7-year period, did not have as great a change. 

Men who sustained very hard exercise -- regular hard training for competition several times a week -- had cholesterol and triglyceride levels 9% to 27% lower than their sedentary peers. Such a change could lower the risk of dying of heart disease by up to 25%, according to the report. 

And women who reported hard (vigorous exercise for 4 hours per week) or very hard exercise also had a better metabolic profile compared with sedentary women, as did those who switched from a sedentary to an active lifestyle. 

``The differences observed are sufficiently large to have a beneficial effect in the prevention of certain chronic diseases,'' the authors conclude.  

SOURCE: Archives of Internal Medicine 1998;158:1633-1640.


Vasectomy Not Linked To Prostate Cancer
August 7, 1998

Vasectomy does not increase a man's risk of prostate cancer, according to an analysis of recent studies investigating a possible link between the two.  

Some recent studies have suggested that the procedure may increase risk of prostate cancer, but these studies appear to have been biased, or flawed in their design, according to the authors of the analysis published in the August issue of the journal Fertility and Sterility. 

"We conclude that the empirical evidence available on the association between vasectomy and prostate cancer is of low quality because of numerous sources of bias that favor the overestimation of the effect of vasectomy," write the authors, a team of researchers led by Dr. Enrique Bernal-Delgado of the University of Zaragoza in Valencia, Spain. 

Bernal-Delgado and colleagues reviewed 14 recent studies examining the relationship between vasectomy and prostate cancer. Though 6 of the studies linked the procedure to an increased prostate cancer risk, these studies were flawed, the researchers write. Among other things, the studies failed to take into account other factors - aside from vasectomy - that could influence prostate cancer risk. 

"Individuals who have undergone vasectomy are not at high risk for the development of prostate cancer," the researchers write.  In an accompanying editorial, Dr. Herbert B. Peterson and Dr. Stuart S. Howards of the Centers for Disease Control and Prevention in Atlanta and the University of Virginia Health Sciences Center in Charlottesville, Virginia, write that "there is little biologic plausibility for an effect of vasectomy on risk of prostate cancer, with the arguments for a beneficial effect as strong as those for a harmful effect." 

Vasectomy is a safer and more effective contraceptive alternative than surgical sterilization for women, Peterson and Howards write. 

One of the most widely used contraceptive methods, vasectomy involves surgically severing and closing off the ducts that carry sperm from the testicles to the seminal vesicles. After a vasectomy, a man can still ejaculate, but his semen no longer contains sperm. 

SOURCE: Fertility and Sterility 1998;70:191-200, 201-203.


American diets may lack Vitamin C
August 17, 1998

Arizona State University researchers found ``surprisingly high rates'' of vitamin C deficiency in a group of American middle class patients attending a healthcare facility for routine health exams. 

Blood tests showed that 30% of 494 study participants were vitamin C depleted, and 6.3% suffered from the more severe condition, vitamin C deficiency, according to a report published in the Journal of the American College of Nutrition.  

``If a physician examined these (vitamin C deficient) people,'' lead author Dr. Carol Johnston, told Reuters Health, ''it is very likely they would have found some of the early indications of scurvy.'' Scurvy, a disease caused by vitamin C deficiency, is thought to be rare in modern societies with year-round access to fresh fruits and vegetables. The early symptoms of scurvy include tiredness, weakness, irritability, weight loss, and vague muscle aches. 

Although the researchers did not obtain dietary data on the study subjects, those who were vitamin C deficient and vitamin C depleted were probably not eating enough fruits and vegetables that are high in vitamin C, said Johnston. Fresh produce with high levels of the vitamin include oranges, grapefruits, broccoli, cauliflower, and cabbage. 

``If you are just eating apples, bananas, green beans and lettuce, that's not going to do it,'' said Johnston. ``They are the most commonly consumed and they literally have no vitamin C. Potatoes have a little bit. I think french fries are probably keeping people over the edge of having a problem.'' 

In their report, the researchers also note that the ``poor vitamin C status of some of our subjects may be related in part to smoking.'' Previous studies have shown that smokers need over 200 milligrams of the vitamin daily to maintain blood levels comparable to those of nonsmokers consuming the recommended daily allowance of the vitamin. 

``Efforts should be made to further establish the prevalence of poor vitamin C status in the US population and to delineate the clinical significance of below normal plasma vitamin C concentrations,'' conclude the research team. 

SOURCE: Journal of the American College of Nutrition 1998;17:366-370.


Change In "Morning-After" Pill Advised 
August 7, 1998

For women who need a "morning-after pill" to prevent pregnancy following unprotected intercourse, doctors most often recommend a combination of two hormones - an estrogen (ethinylestradiol) and a progesterone derivative (levonorgestrel) - commonly found in oral contraceptives. 

Now, researchers have concluded that taking levonorgestrel alone is more effective and has fewer side effects than taking both hormones, according to a report in the August 8th issue of The Lancet, a British medical journal. 

Dr. Helena von Hertzen, of the World Health Organization in Geneva, Switzerland, and a task force in 14 countries found that the pregnancy rate was 3.2% among women who took both ethinylestradiol and levonorgestrel and 1.1% among women who took levonorgestrel alone. 

"The proportion of pregnancies prevented (compared with the expected number without treatment) was 85% with the levonorgestrel regimen and 57% with the (dual hormone) regimen," the team reports. 

The research team reports data for 1,955 women, average age 27 years, who requested emergency contraception within 72 hours after one act of unprotected intercourse. Most women, 80%, received contraception within 48 hours. 

"The earlier either emergency contraceptive treatment was given, the greater its efficacy," the investigators report. 

Approximately half of the women took one levonorgestrel tablet plus an inactive tablet. The others took two active tablets, each of which contained both ethinylestradiol and levonorgestrel. Both groups took the same dose again 12 hours later.    Levonorgestrel taken alone produced fewer side effects than ethinylestradiol plus levonorgestrel. "Nausea, vomiting, dizziness, and fatigue were all significantly less common among women who received levonorgestrel," the study authors write. 

The World Health Organization task force concludes that using levonorgestrel alone "should improve the acceptability of hormonal emergency contraception, and family-planning programs providing emergency contraception should consider making this change." 

In an editorial, Dr. John Guillebaud, of University College London, UK, comments that women who receive emergency contraception need information about the importance of a long-term method of contraception, as well as help in finding a physician to provide contraception. 

Guillebaud considers it "legitimate to encourage women to keep a reserve pack (of emergency contraceptives) at home." He cites a recent Scottish study that showed that "doing so increased the use of emergency contraception without lessening the practice of other contraceptive methods."

SOURCE: The Lancet 1998;352:416, 428-433.


Don't Blame Weight Gain On DNA
August 20, 1998

As geneticists race to map the code of the human race, many people wonder how much of their natural makeup is attributed to DNA -- including obesity. CBS News Health Correspondent Dr. Emily Senay explains in her monthlong series, The Great American Weight Loss that genetics do not mean biological destiny. 

The Excuse of the Day: My whole family is overweight.

For the majority of Americans, this is not a valid excuse. Only 30 percent of the American public really has a strong genetic inheritance, says Dr. Pamela Peeke, an obesity specialist. The remaining 70 percent is related to lifestyle and environment.  

For those 30 percent, studies show that a genetic predisposition can affect metabolism and appetite. 

Even if you do have a genetic predisposition to obesity, you can avoid gaining weight by taking simple preventative measures.   "Genetics may load the gun but environment pulls the trigger,"Peeke says. "Although you may have a predisposition, you can do plenty about it and prevent what may happen -- in this case, obesity." 

There are good health reasons to safeguard against excessive weight gain. Obesity can lead to heart disease, cancer, diabetes, stroke, high blood pressure, and many other health problems.  

Those who are genetically predisposed to obesity may have to work a little harder to lose weight, Peeke says, but the effort is worth the goal of maintaining health and fitness. 

Peeke says the extra work is comparable to someone who has to work harder at learning certain subjects in school. For some, algebra is easy, while for others, to understand the same material, they must study harder. As with everything else in life, we must acknowledge our shortcomings and work harder to meet our goals. 

"It's being pro-active, positive and progressive about something many people want to write off," Peeke says.  

Peeke says that people need to first understand that, despite their family medical history, they can do something about it.  

"It's empowering to know that you can alter your environment and your life enough to be able to prevent something like obesity which can lead to a foreshortened life," Peeke says. 

The Great American Weight Loss Tip of the Day is: Don't blame your genes! 

Parents play a key role in how their children manage their weight. Peeke encourages parents to be mentors for themselves and their children by being attentive to how they are eating and to how they are getting their exercise. 

Peeke suggests that parents be careful not to turn eating and exercise into a "health project," but to make it fun. 

Instead, take control of your life and your health by making fitness a priority. 




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