By: Owen Anderson
Wouldn't it be great if there were something you could drink or eat just before a marathon - something which would be almost guaranteed to knock five to 10 minutes off your performance time?
Well, according to some scientists, that 'something' does exist. It's found in egg yolks and organ meats. It's also present in spinach and cauliflower. Nuts and wheat germ contain good quantities of it. And a new commercial product called 'Boston Sports Supplement' has a rich lode of the stuff. It's called choline, and it may help you run the final miles of your marathon at a faster-than-usual pace.
What exactly is choline? It's a vitamin-like compound (in fact, some nutritionists have contended that it is a vitamin) which is an essential part of the human diet. Without it, no cell in the human body could function normally.
And without an adequate supply of it, runners can not possibly reach their potential in the marathon, according to some exercise scientists. That contention is based on the fact that choline is used by nerve cells to manufacture a closely related chemical called acetylcholine.
Acetylcholine
Acetylcholine allows nerve cells to communicate with each other; if there were no acetylcholine in your brain, you wouldn't remember who you were, let alone find your way to the starting lines of your races. However, the key point to remember about acetylcholine is that no leg-muscle cell in your body could take part in the act of running unless it was 'told' to do so by acetylcholine.
You see, your leg muscles don't have a mind of their own. They would lie around in your legs like useless straps of leather unless they were commanded to contract and push you toward the finish line by their 'big brothers,' the nerve cells. And how do nerves tell muscles what to do? They 'push' small quantities of acetylcholine across small spaces called neuromuscular junctions. When enough acetylcholine attaches itself to the outer surface of a muscle cell, the muscle cell becomes 'excited enough' to contract.
When you run, hundreds of nerve cells issue their acetylcholine commands to an even larger number of leg-muscle cells, forcing them to work hard to keep you going. If you ran out of acetylcholine, your muscles would cease functioning, and you would stop dead in your tracks, even if your muscle cells were still rich in carbohydrate, enzymes, and the other essentials necessary for contraction. The acetylcholine message is absolutely essential.
Choline In The Marathon
So what? Well, under ordinary circumstances there's a fair amount of choline roiling around in your blood at all times. As needed, your nerve cells grab some of this choline, use it to make acetylcholine, and keep their muscular friends happy and active.
Of course, there's not an infinite supply of choline in your body, which means that you've got to eat the stuff on a regular basis. True, some nutritionists have contended that if you don't eat much choline and your body's levels of the stuff drop too low, an amino acid called methionine can 'pinch-hit' for choline, but we now know that this can only happen if you're eating abundant quantities of methionine. Since that can be hard to do, it's safest to just eat adequate amounts of choline. Around a half-gram to gram of choline daily is about right.
Full Marathons Only
Now, when you run a race like the 5K or 10K, not much of a dent is made in your blood-choline levels, and even when you compete in something long like the half-marathon, choline concentrations stay okay.
It appears that your choline levels plummet precipitously only when you run a marathon (or exercise continuously for approximately two hours or more).
However, it's important to note that when choline concentrations do drop, they really drop: careful studies carried out with Boston-Marathon participants in 1985 and 1986 revealed that their blood-choline levels bottomed out at up to 50 percent below normal levels by the end of the race.
Why Does This Happen?
Physiologists reckon that acetylcholine is actually broken down inside the neuromuscular junctions during prolonged exercise. Nerve cells then 'reach out and touch' the choline floating by in the blood, using it to make new acetylcholine so that they can keep the sinews simmering. As a result, your blood- choline levels start a downward slide.
New York Marathon
Click To Enlarge.
Naturally, if your choline levels fall too far, acetylcholine production can come to a relative standstill, and your nerve cells will simply refuse to stimulate your muscles. Some exercise scientists believe that this is behind at least a portion of the devastating fatigue which strikes near the end of a marathon.
As mentioned, toward the end of the marathon, there simply may not be enough choline left to keep acetylcholine in decent supply. Therefore, some scientists reason that choline supplements - if taken at the right time and in the right amount - might help the nervous system continue to stimulate muscle cells and keep you striding toward the marathon finish line at your desired rate, even after 20 or more miles of very hard work.
Evidence For Choline Supplements
But can choline supplements really be beneficial? We know for sure that choline levels do plunge near the end of a marathon, and we also know that choline supplements can prevent this devastating downswing. In one study, the simple act of taking in two grams of choline before exercise began totally prevented the fall in choline normally associated with prolonged activity.
However, the simple maintenance of choline levels does not automatically mean that performance will be enhanced. To check on the performance part of the equation, researchers recently asked 10 trained runners (eight males and two females) to run 20 miles as fast as possible after taking 2.8 grams of choline citrate one hour before the run and the same amount (adding up to 5.6 total grams of choline) at the half-way (10-mile) point of their efforts.
On a second occasion, the athletes ran the same distance without taking choline. Seven of the 10 subjects ran better times after taking choline, and average time for the 20-miler was five minutes faster when choline was utilized (2:33 versus 2:38).
The researchers were also able to show that plasma choline levels decreased significantly after the placebo (non-choline- supplemented) run but actually increased by 74 percent at the end of the 20-mile exertion when choline was taken before and half-way through the run.
Choline Dunking
College Basketball Study
In a separate study carried out with college basketball team members at Harvard, Holy Cross, and Northeastern University, players were given a fruit-juice drink containing 2.43 grams of choline bitartrate or just plain fruit juice (the placebo) 15 to 30 minutes before practice and again at the midway point through practice (adding up to 4.86 total grams of choline per day in the treatment group) for a period of one week.
As part of a crossover design, players who had ingested choline for one week 'crossed over' and drank only placebo for a week, while placebo sippers tried out the choline bitartrate.
Results
While the choline had no effect on vertical leaping ability, free-throw shooting accuracy, or post-scrimmage fatigue levels, the choline supplements were associated with several positives:
- Choline takers were less fatigued before practices.
- Choline takers reported that they felt more vigour as practices began.
- They also felt more vigorous at the ends of practices.
On the negative side, two Holy Cross shooters complained of diarrhea while on choline (that's a common side effect), and another was forced to warn his teammates of flatulence (another common occurrence). All in all, though, daily intakes of choline seemed to increase vigor and suppress fatigue in these college athletes.
Choline In The Pool
Northeastern University Study
Swimmers have also been part of the choline picture. In a very recent study, 16 members (nine males and seven females) of the Northeastern University swim team swallowed either a placebo or 2.83 grams of choline citrate 30 minutes before practice and again half-way through practice (5.66 grams total per day) for a period of five days Again, the study used a crossover design so that all athletes had a chance to perform with and without choline supplementation.
On the third day of each five-day period, the swimmers took part in a 'T-30 Assessment,' which involved freestyle swimming at an all-out intensity for approximately 30 minutes. In this test, each swimmer began by swimming 300 yards as fast as possible, followed by a 10-second rest.
After this brief respite, the swimmer again covered 300 yards at top speed, with only a 10-second rest at the end. This alternating pattern of 300 yards at full velocity and 10 seconds of rest was continued for a total of 30 minutes.
After 30 minutes, the total yardage covered by the swimmer was computed, and average pace per 100 yards was calculated. Just to make things a little more difficult, the assessment was completed after a regular 4000-meter practice had already taken place.
Results
Again, choline supplements appeared to be effective. Without choline supplementation, blood-choline levels skidded downward by about 22 to 32 percent after workouts; with choline, they went up by 27 to 33 percent. Choline also enhanced pre-workout vigor and reduced post-workout fatigue. Finally, 11 of the 16 swimmers improved their performances on the T-30 assessments after taking choline, compared to the placebo, an effect which was statistically significant.
The Evidence Against Choline
Nobody really disputes the basic choline story: choline is used to make acetylcholine. Acetylcholine is needed for normal muscle functioning. Choline (and therefore acetylcholine?) levels do drop after prolonged exercise. Therefore, there is a reasonable justification for choline supplementation. And, as we've shown, runners, swimmers, and basketball players have benefited from choline consumption.
However, a few studies have failed to link choline with any gains in performance. In one investigation, 20 well-trained cyclists (average training volume > 100 miles per week, VO2max between 58 and 81) tried either pedaling as long as possible at a supra-maximal intensity (150% VO2max) or at a moderate level of exertion (70% VO2max, or about 80% of max heart rate), with and without choline.
