Tag Archives: choline

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HOW TO: Important factors in marathon swim feeding

Evan did a great 4-part series on open water marathon feeding and nutrition. I’ve covered the possible use of Choline supplementation and I’ve a long-standing request in with a friend for a guest post on the subject of further supplementation.

Given some questions that have arisen though, it seems we haven’t covered enough of the subject. It struck me that we hadn’t covered mechanics and some of the complicating factors.

Let’s start with a reminder:

The most important thing is: Feeding is different for everyone.

Feeding is not diet or general nutrition, but the process of taking in nutrition/food for energy during a long swim. It’s a long and complex subject which entertains and causes endless discussion amongst marathon swimmers.

The next most thing, the marathon swimming motto: Practice everything.

  • First, when do you have to feed?

You can generally assume that you have enough glycogen in your body to last from two to three hours. (Contingent on not having depleted it in training or recent exercise).

So for a swim or race under two hours, you probably don’t need to feed.

Swims where feeding is necessary dictate practice and experience.

FINA marathoners will probably feed small amount every 10 minutes from a plastic cup. This technique was pioneered by Peggy Dean and the US team in the 80’s. The rest of us tend to feed at intervals from 15 minutes to 45 minutes. (I feed at thirty minutes). But this MUST be tested, everyone’s requirements are different.

Also, you may not need or want to start on intervals right from the start of a marathon swim. it’s quite common that swimmers will feed hourly for the first two OR three hours and then switch to their shorter interval. Once again, I cannot tell you what those times will be for you. The four to eight-hour swims that we do in Sandycove give us the advantage to test these factors. It is another reason faking a qualifying swim makes someone a fool to a more experienced swimmer.

  • Second – what do you feed on?

For most swimmers, the primary fuel is maltodextrin, pure carbs,, as Evan has covered in detail. (Not however glucose). The product name isn’t important though Maxim is by far the most popular for distance swimmers as it has no taste and can be added to any food or drink. It’s a 100% maltodextrin. High5 or similar are carbs with a protein mix in a 4:1 ration, scientifically shown to be more effective in metabolization but has proven to be a problem for many swimmers (e.g. me) in distance sea swimming for a few reasons: (salt intake, prone position, soya protein metabolization).

Again, there are many exceptions. Some swimmers like gel pack (like GU) others won’t touch them, as they can be useless because they require a separate liquid intake, and the salt intake during a swim can make them useless or cause exceptional bloating or vomiting. Some English Channel Pilots only believe in/use Maxim.  Many swimmers have no problem with a 4:1 protein/carb mix, (I am not one, like a lot of swimmers, I found after about four to five hours with it I am no longer able to digest). Some swimmers forego these methods and swim on solid food (Penny Palfrey used dilute porridge).

  • How do you feed?

For myself for swims, I attach a D-clip to the bottle itself (whether by tape, string or lid attachment), and then the line attached to the clip, rather than tying a line to a bottle directly, as having multiple changeable bottles allows more flexibility.

Alan Clack’s feed pole

Feed (dolly) poles (typically a wooden brush handle … ) have a hook or holder on the end, which hand a cup or bottle to the swimmer. The one on the left is one used by Alan Clack on a 10k Lac d’Archambeau swim last year.  Poles are good in flat water but they are less flexible in bad weather as they require a fixed distance to the swimmer. If using a pole the swimmer must not grab the pole itself. I’ve also seen (and used) a telescopic fishing pole but the line is too light and too easily tangled.

Or simply a bottle dropped on a rope. The problem with this is knots and retracting the line (this was a mistake I hadn’t considered in the Channel).  A solution I’ve seen and really liked is a simple traditional-type kite reel (usually made of plastic).

My subsequent solution … A retractable dog-leash, my choice for future swims. So much easier for the crew.

Retractable Dog leash


  • Feed containers

Many experienced swimmers will often only use a container or bottle with particular features. I’ve written before about the God Bottle. This is not necessarily a minor concern as using a wrong bottle type for a swimmer can lead to salt water or air ingestion, both significant is you are swimming for more than 6 or 8 hours. Gábor used a narrow neck squeezy sports bottle, as that was what he used in training and practised with. (I must have a wide neck bottle… However some swimmers just don’t care or don’t have an issue).

Mike Oram, famous English Channel pilot, prefers plastic milk cartons, which have a wide neck and a handle to attack the line, and are easily replaced. Liam Maher added the point that it might be good idea to collect your milk lids for a week before hand, so the crew have more lids than bottles, that way the swimmer isn’t focused on trying to replace the lid.

Stephen Redmond feeding in Catalina

Stephen Redmond  uses a twin bottle approach to swimming: A standard squeezy bottle and a shaker bottle, taped together but in opposite directions for easier access!


  • Is it a cold water swim?

You must consider the water temperature: Should the food be warm or cold? Most Channel swims are cold or cool water so warm feeds are essential. But that can require  a lot of warm water. Your pilot may have a galley where water can be heated, but in rough weather this isn’t easy. One solution to this, just in case, is to bring a thermos (or many) of hot water. Pre-mix the feed to double concentration (half volume) and top up with hot water. The crew MUST be careful not to burn the swimmer, which can happen easily as the swimmer’s mouth will cool down during a swim. Bringing a thermos also frees up the crew to look after you.

  • Will you need/use electrolytes?

In a sea swim, the best swimmers will still ingest salt from the air. So the actual salt requirement is low. One misconception I run with swimmers into all the time, is the bodies need for potassium. How many times have you seen/heard someone have a cramp while pool swimming and someone tells them to eat a banana beforehand “for the potassium”? But usually that’s just simple dehydration. Bananas also provide magnesium, another essential salt, used for ATP synthesis, but we do not need huge amounts of either and deficiencies are rare, and in fact too much potassium in a 24 hours period will slow digestion and cause vomiting. That said, scheduling in an electrolyte is not uncommon for long swims, and allows the body a respite from the carbs.

  • Do you have a feed plan?
An hourly feed plan give a swimmer confidence their requirements are being met. Just as importantly, if the primary crew person goes down with sea-sickness, a feed plan that can be handed onto the next person means continuity in feeding. Feed plans can include extras. For example mine includes an asthma inhaler drop on four hourly breaks, just in case. The plan can also be used to schedule in special treats or prophylactic pain-killers.
  • How long do you expect the swim to last?

Do you have enough supplies if your swim runs over expected time? If you are Lisa or Stephen and are out in the water for 24 to 36 hours, do you have enough water and carb to keep going, all other things being equal? Are there enough supplies … for the crew? Better to take 40 litres and throw out 20, than take 10 litres and need 12. (I know this is not environmentally sound, but there is no way around it).

Finally, do not assume that knowledge of feeding in other endurance events will transfer to sea-swimming. It most likely will not, for example the gel packs beloved of tri-athletes, the extra salt intake and the prone position, are all complicating factors in sea-swimming.

Remember, practice everything. Which means consider and think about everything.

Use of choline supplementation in marathon swims (or ultra-endurance events)

I don’t like dietary supplements. B Complex, multivitamins etc. The little reading I’ve done so far on the subject indicates little or no benefit is gained from commercial multivitamins for endurance athletes But I don’t rule it out…

Since my EC, (too late that is), I’ve had a few interesting conversations with an online friend and endurance athlete (hey Herman!), who has a background in nutrition, who has convinced me to look at some specifics. When I’ve talked to others in this line, they don’t have any experience with real endurance events, much more in strength events, track or field or team events. But given his own endurance exploits Herman has given this more thought than those advising other athletes. Also, having done a Solo, I am interested in how we can do it better and the scientific improvements we can bring to our almost non-studied pursuit. Evan Morrison has started a series on this subject also, which prompted this post, as so much Evan writes so often does.

So, what can we do better?

Amongst the things that Herman suggested we increase was Choline. I’ll address the others separately, (why write one post when I can write two?).

So what is Choline, and why increase it?

To the Research-mobile Batman!

(There’s three links there, for the hypertext inadequate).

Mihai Niculescu

Choline is a dietary and nutritional Requirement, like vitamins. It’s often grouped together with B-complex vitamins. It’s required for a variety of purposes including supporting cell structure and integrity, muscular control and neuro-transmission (signalling between neurons). So just thinking from a heavy training point of view, and the precision that swimming normally requires combined with heavy training loads, these seem quite apposite.

The body has a good supply of choline, and retains it well into endurance events but can drop precipitously. Studies at the Boston Marathon in the 80’s show runners could drop 50% over the curse of a marathon. So what about a 5 to 40 hour swimming event?

WE DON’T KNOW! On an initial search I can’t find (unsurprisingly) any studies on choline in ultra-endurance events.

Oh, and apparently, low choline can lead to an unpleasant (fishy) body odour, which no amount of washing will remove. I’m not sure how you segregate this from open water (sea) swimmers who just smell of fish anyway! :-) Which is no worse than the six months of pool training when you smell of chlorine.

Like ALL essential nutrients we can get everything we need from our diet. But the primary forms of choline and changes to a modern diet both mean we could be operating on low choline levels.

The Adequate Intake (AI) of choline is 425 mg (milligrams) per day for adult women; higher for pregnant and breastfeeding women. The AI for adult men is 550 mg/day.

There’s a study that shows AI, Adequate Intake, may not actually be adequate.

Here’s a table straight from Wikipedia:

Animal and plant foods Choline (mg) Calories
5 ounces (142 g) raw beef liver 473 192
Large hardboiled egg 113 78
Half a pound (227 g) cod fish 190 238
Half a pound of chicken 149 270
Quart of milk, 1% fat 173 410
A tablespoon (8 g) soy lecithin 250  approx. 60
A pound (454 grams) of cauliflower 177 104
A pound of spinach 113 154
A cup of wheat germ 202 432
Two cups (0.47 liters) firm tofu 142 353
Two cups of cooked kidney beans 108 450
A cup of uncooked quinoa 119 626
A cup of uncooked amaranth 135 716
A grapefruit 19 103
3 cups (710 cc) cooked brown rice 54 649
A cup (146 g) of peanuts 77 828
A cup (143 g) of almonds 74 822

So you can see why it would be easy to not get enough. I like liver, but I don’t eat beef liver, (which is horrible and better fed to dogs) and half a kilo of liver a day of any kind would lead to vitaminosis, which is pretty dangerous, and why I limit liver intake when training hard to once a week.

Maybe you really do eat a kilo and a half of cauliflower a day, more power to you if so, but I pity the people living with your colon.

Or just a daily, and probably quite odd mix of these items. Maybe a cauliflower, milk, quinoa, spinach and fish smoothie? Yum.

But modern diet has had us reduce red meat and eggs for other reasons, concerns over cholesterol, etc. Milk is a good source (human milk is very high in choline, for infant development) and probably the easiest to take, something I drink plenty of to support training. I’m wasn’t sure what the hell a quart of milk was, apparently it’s almost a litre. America, please see above cartoon. Again.

Choline is beneficially linked to foetal development, cardiovascular system, and anxiety reduction (not depression), increased IQ in infants, possibly lowered cholesterol (contradicting studies), and mental acuity and memory in mice, and diets with no choline can lead to liver or muscle damage in 80% of cases. On the negative side, there’s a study that it can lead to colonic polyps in women. Or increased risk of diarrhoea or flatulence. One study shows that endurance athletes can be deficient in choline, which is the real point.

Lacking this intake of, it seems choline is possibly a good recommendation for diet supplement in endurance athletes. It is assumed to come in diet from Lecithin, which is how strength athletes (always keen to shove pills into themselves) often supplement. It’s European E-number E322, derived from soy or egg yolk and it’s used as an emulsifier (stabiliser) in processed food, such as some margarine, baking or processed chocolate bars (not high cocoa percentage chocolate bars). But (older) studies show lecithin isn’t effective in choline supplementation, that maybe only 4% of lecithin is actually converted to choline.

Yes … but. The but is ask what we can do. Without studies of deficiencies, supplementation and effects for ultra events, we simply don’t know.

Extracting from one article:

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 utilised (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 per cent at the end of the 20-mile exertion when choline was taken before and half-way through the run.

Cavet: Those are only two small-scale studies, in different conditions (because we always have to remember a few things: Cold & Salt water ingestion as environmental factors for us).

There are two counter studies also. A study of moderate distance cyclists (150 kilometres per week) training at less than VO2 Max displayed NO improvement from choline supplementation. But there is a suggestion in an analysis of one study that choline supplementation is only effective OVER two hours of exercise. Whereas in the other, blood choline was raised, but performance wasn’t.

There IS a small study on pool swimmers, who were using results from an Interval T-30  (thirty minute time test for distance) as the measurement. 11 out of 16 showed an improvement.

Okay, so we’re not left with a lot of conclusive evidence. But there does seem to be a leaning toward choline as being beneficial for ultra-endurance events.

WE NEED MORE STUDIES.

In the meantime, it’s not a regular supplement, I don’t significant use in boosting it daily, but that would depend, as above, on your diet. Eat more eggs, you need less choline supplementation. If it is of any use to us, it’s directly prior to and during the events themselves. I see if I can influence any of next year’s Aspirants to try it out. In the meantime I don’t like keeping these thoughts to myself, our community is based on friendship and sharing knowledge. So here it is for your consideration. And any useful information anyone could add would be great.

Lastly, the actual supplementation. Well it’s not something you find in pill form on the supermarket or pharmacy shelf. Apparently some electrolytes has choline as an addition. The best uptake form is either of the choline salts, choline chloride or choline bitartrate, which are absorbed really quickly into the blood, within 30 minutes. If taking it, you take about 2.0 to 2.5 grams before the event, and after 2 hours, (about 0.2 gr per kg of body weight). For a multi-hour ultra event, I would GUESS, that taking it subsequently every two to three hours would be best. If it is of any benefit.

References from:

Wikipedia, PubMeD, Cochrane, American Journal of Clinical Nutrition, Peak Performance Sporting Excellence, new England journal of medicine, Google Scholar