Choline: Supplements Of This Essential Compound Help Many Types Of Athletes!
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 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.
A neuromuscular junction is the junction of the axon terminal of a motoneuron with the motor end plate, the highly-excitable region of muscle fiber plasma membrane responsible for initiation of action potentials across the muscle's surface.
Every skeletal muscle fiber -- no matter how long it may be -- has only one such neuromuscular junction.
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.
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 hard work.
Evidence For Choline Supplements
But can choline supplements really be beneficial? We know for sure that choline levels 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.
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 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 5-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.
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 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, VO2 max between 58 and 81) tried either pedaling as long as possible at a supra-maximal intensity (150% VO2 max) or at a moderate level of exertion (70% VO2 max, or about 80% of max heart rate), with and without choline.
In both cases (during near-maximal and moderate-intensity exercise), the use of choline supplements caused a big upswing in blood-choline levels. However, there was no difference in performance between choline and placebo groups, either during short- or long-duration exercise.
In interpreting this study, though, bear in mind that plasma choline levels did not actually drop significantly during exercise in the placebo groups, indicating that choline downturns were not a limiting factor during the exertions - and that choline supplements shouldn't be expected to have much of an effect.
Surprisingly, only three of the cyclists were able to exercise longer than 100 minutes (most exercised for 'only' 70 to 80 minutes) during the moderate-intensity test. It's important to remember that a single dose of choline - or even a couple of shots of the stuff, taken an hour or two apart, as in some of the studies mentioned above - probably won't do you much good unless you've been working away for two hours or more. In this cycling study, the athletes simply may have not exercised long enough to derive a choline benefit.
In a second study which was carried out in Dave Costill's famous laboratory at Ball State University, athletes cycled for 105 minutes at 70% VO2 max (a popular lab intensity) and then rode 'full-out' for the following 15 minutes, with and without pre-ride choline supplementation.
Choline supplements did raise blood-choline levels in this investigation, but they failed to improve performance at all. It's possible that the choline dosage utilized - 1.1 to 1.8 grams - was not large enough to make a performance difference, or that the cyclists simply didn't work long enough to gain any benefits from choline.
What To Do?
Should you consider using choline supplements? Well, choline is perfectly safe to take, the only potential problems being an occasional bout of diarrhea or the appearance of some foul flatulence. And choline levels might be routinely low in endurance athletes who exercise for prolonged periods on a regular basis (recall that choline levels fall in response to long workouts), although choline deficiencies haven't been documented by scientific research.
You could certainly forgo supplementation and try to obtain plentiful amounts of choline in your regular diet: liver, cauliflower, soybeans, spinach, lettuce, nuts, and wheat germ are decent natural sources of the stuff and eggs contain rich veins of choline.
However, ingesting several pounds of raw liver the night before a marathon is certainly not a strategy which will take the running world by storm. And many runners have cut back on their consumption of choline-rich eggs in hopes of harmonizing their blood-cholesterol levels. The bottom line is that even a choline-rich natural diet probably wouldn't prevent the plunges in blood-choline levels which happen after 20 miles or so of marathon running.
What about lecithin? Lots of athletes take the stuff, at least in part because they believe it's a good source of choline. And many are buoyed by the news of 'research findings' linking lecithin with improved strength and power.
The bad news is that the research was carried out more than 50 years ago - with fairly poor experimental designs. And lecithin is not such a great source of choline after all: The truth is that the choline in lecithin is found only in a chemical called phosphatidylcholine, and phosphatidylcholine makes up just 25 to 35 percent of lecithin. In turn, only about 12 percent of phosphatidylcholine is actually choline. 12 percent of 35 percent adds up to a paltry 4-percent choline content for lecithin.
Before we actually give you our choline verdict, it's a good time to mention that the compound plays other roles in the body besides just boosting acetylcholine concentrations. Choline is also an extremely important structural element of cells, especially cell membranes, and is absolutely essential for the process of breaking down fat for energy (without choline, your liver would quickly clog itself completely with fat).
Researchers also recognize that choline 'carries signals' from the exterior of cells into the nucleus, helping to control cell activity. And there's evidence that choline can enhance creatine synthesis inside one's body (regular readers of PP are well aware of creatine's ergogenic role). In addition to its contribution to acetylcholine production, this creatine-boosting mechanism might be one additional way in which choline allays fatigue during marathon-type efforts.
So, should you take some choline before you run your marathon? We asked Steven H. Zeisel, Ph.D., probably the world's leading expert on the compound and also the Chairperson of the Department of Nutrition at the University of North Carolina. 'It's probably effective at helping your marathon performances - but not your ability to run shorter races,' he said. That's more or less the answer we expected: After all, the 'story' underlying choline's ergogenic potential is sound, and there's enough evidence to suggest that the stuff might really work.
Don't Rely On Lecithin ///
But don't rely on lecithin to get your choline boost. As mentioned, there's not a lot of choline in lecithin, and it takes about three hours for the choline in lecithin to actually raise blood-choline levels, provided you eat enough lecithin. You'd be better off trying the quicker-acting and safe 'salts' of choline - either choline chloride or choline bitartrate, both of which can spike blood choline within 30 minutes after ingestion.
The right amount is probably about 2.5 grams or so, swallowed about an hour before your marathon begins (practice this in training before you do it prior to the big one). However, as Zeisel points out, even with this dosage your blood choline may begin to fall three hours after you've taken it (e.g., two hours into your marathon), so it makes sense to take another 2.5- gram dose at the 10- to 13-mile point of your race.
Long-Haul Benefits Only ///
If you do decide to give choline a try, remember that it won't help you shoot baskets, play an hour-long game of squash, run a 10K, or cycle, swim or ski for around 100 minutes or less.
Choline is a nutritional supplement for a long-haul effort like the marathon: After all, research shows that choline levels usually don't really begin to fall until you've been running 16 to 20 miles or more.
As a rule of thumb, you can figure that choline probably won't help you much unless you're going to exercise continuously for almost two hours or more. Don't forget, too, that to get a benefit from the compound, you probably need to take 2.5 grams of choline before and at the half-way point of your marathon or long-duration exertion.
- Follow This Discussion by: