While there's little doubt that creatine supplements can aid short-duration, high-intensity exertions, there's been considerable debate about whether extra intakes of the amino acid might help endurance athletes during efforts which last for more than a few minutes.

Muscle cells use creatine primarily to form creatine phosphate, a high-octane chemical which provides the energy needed for short, fast efforts, but those who are sceptical about creatine's ability to enhance endurance performance point out that the supply of creatine inside muscles is fairly limited. In fact, an exertion as brief as a 400-metre run can drastically deplete leg muscles of their creatine phosphate. Since most of a muscle cell's creatine phosphate can be wiped out after just 60 seconds of exercise, how could creatine aid performance in longer efforts like a 5K race or a 20-minute cycle competition?
The pro-creatine people counter that creatine phosphate is not depleted as rapidly during less intense exertions and that extra creatine phosphate might be helpful for fast starts during medium-distance races, for 'kicks' at the ends of races, and for uphill surges during exercise on hilly terrain. They also note that since creatine phosphate 'carries' energy to locations inside muscle cells where it is critically needed to sustain muscle contractions, surplus creatine might lead to improved fatigue resistance during endurance exercise.

However, these contentions have been pretty much theoretical until now. Brand-new research with creatine supplements and endurance runners has been carried out, and the news is not good for creatine advocates. In the current investigation, which was completed at the famed Karolinska Institute in Stockholm, Sweden, nine well-trained runners ingested five grams of creatine monohydrate four times per day (20 grams per day) for six days, while nine other experienced runners consumed a glucose placebo. After the six-day period, the runners completed a six-kilometre race over undulating terrain and (on a second day) a high-speed treadmill run to exhaustion at a velocity slightly faster than their best one-mile race speed.

Strangely enough, although neither creatine- nor placebo-group members were able to improve their performances during the treadmill efforts, runners actually fared slightly worse during the 6K forest trial after creatine supplementation (they required about 25 more seconds to complete the course). Following creatine ingestion, they also produced considerably more blood lactate during the sizzling treadmill effort.

Why did creatine ingestion lead to slightly inferior 6K performances - and higher blood-lactate levels at one-mile race pace? Previous research has indicated that creatine supplementation may produce a slight muscle-building effect, or - more specifically - an expansion in the size of type 11 ('fast twitch') muscle fibres. Although the Karolinska researchers didn't measure muscle-cell diameters, they did find that the creatine supplementers boosted body weight by about 1 per cent, while the placebo-takers maintained a constant weight. It's possible that this increased weight could have been due to greater muscle bulk and could have led to slower performances during the 6K. (Especially intriguing is the fact that average 6K time and body weight each expanded by about 1 per cent.) The higher lactate during treadmill running could have been due to the increased girth of the lactate-producing type 11 fibres - or to the need to do more anaerobic work to push the runners' heavier bodies through the rugged test.

Regardless of what actually happened to the creatine consumers, the results weren't encouraging for creatine supporters. The Swedish scientists involved in the study concluded that the performance-enhancing effects of creatine supplementation are probably restricted to short duration, high-intensity exercise. 'Creatine Supplementation Per Se Does Not Enhance Endurance Exercise Performance, Acta Physiologica Scandinavica, vol. 149, pp. 521-523, 1993.

Vitamin E supplements linked with lower risk of heart disease in men and women
Can the intake of increased amounts of vitamin E lower your risk of coronary artery disease - the number-one health problem in both Great Britain and the United States? Some scientists have thought so, since vitamin E blocks a chemical reaction which might shove increased amounts of low-density lipoprotein (LDL) into the walls of your heart's arteries. LDL can block the free flow of oxygenated blood to your hard-working heart muscle and may have a number of damaging effects on artery walls.

Now, there's evidence that vitamin E supplements can indeed lower the chances of cardiovascular problems. In a unique study carried out by researchers at Harvard University, 39,910 health professionals (dentists, veterinarians, pharmacists, optometrists, podiatrists, and osteopathic doctors) aged 40 to 75 were studied between 1986 and 1990. At the beginning of the study, the men were free of heart disease, high blood-cholesterol levels, and diabetes. Detailed questionnaires revealed the nutrient compositions of their diets.

During the four-year follow-up, 667 men (almost 2 per cent) developed coronary artery problems, but the disease was most common among men who did not take vitamin E supplements. For example, individuals who supplemented their normal diets with at least 100 IU of vitamin E per day had about a 37-per cent lower risk of developing heart disease, compared to men who took no supplements.

Some scientists have suggested that vitamin C and carotene (a yellowish-orange compound in fruits and vegetables which your body readily converts to vitamin A) might also lower cardiovascular risk, but a high intake of vitamin C had no protective effect whatsoever in the Harvard study. High carotene consumption didn't help individuals who had never smoked, but taking in more than about 14,000 IU per day lowered the risk of heart problems by 70 per cent among current smokers, and the risk reduction was about 40 per cent for former smokers.

Although the Harvard study doesn't prove that there's a cause-and-effect relationship between higher vitamin E intake and a reduced risk of heart maladies, the link between E and better heart health is intriguing, especially since a second study carried out by Harvard researchers detected lower rates of coronary disease among women who were taking vitamin E supplements. In this second research project, 87,245 female nurses aged 34 to 59 were studied between 1980 and 1988. The women were initially free of both heart disease and cancer.

During the eight-year research period, 552 women (less than 1 per cent) developed heart disease, but again the cardiac difficulties took place at a much higher rate in women who didn't supplement with E. Women who ingested at least 200 IU of vitamin E per day for at least two years enjoyed a 40-per cent lower risk of heart disease, compared to non-supplementers. This was about the same benefit attained by the E-taking men. The bottom line is that taking in 200-400 IU of supplemental vitamin E per day appears to present few health hazards and may keep blood flowing freely through your coronary arteries. 'Vitamin E Consumption and the Risk of Coronary
Heart Disease in Men,' The New England Journal of Medicine, vol. 328, pp. 1450-1456, 1993 and
'Vitamin E Consumption and the Risk of Coronary Disease in Women,' The New England Journal of Medicine, vol. 328, pp. 1444-1449, 1993

creatine monohydrate effects