Jim is a tile setter and Mark a bricklayer.  If they are working together on a job, they have their special jobs to do.  But if Mark has a lot to do, Jim can help him run a few courses of brick.  If Jim is slammed, Mark can help set tile.

Our bodies are the same way.

For example, choline is needed to make acetylcholine which is a neurotransmitter.  The nerve impulse says contract the muscle, acetylcholine is released and attaches to a receptor on the muscle fiber, then the muscle contracts.  This is one of its unique jobs, like Jim the tile setter.

Secondly, choline forms part of the cell membrane helping to keep its shape.

Thirdly, just as Mark helps Jim, choline and its derivative, betaine, are used, like the B vitamins discussed in "Homocysteine, B Vitamins and Heart Disease" to turn homocysteine back into methionine.  It is so important to get rid of homocysteine that the body has developed several ways to do it.   What happens is, choline metabolizes into betaine which donates a methyl group to turn homocysteine back into methionine.

Choline Deficiency

If you don’t get enough choline, your liver becomes fatty and your muscle breaks down.  The body cannibalizes the choline in the cell membranes to convert homocysteine back to methionine.  This leads to muscle damage.

Less choline results in less acetylcholine which is necessary for muscle contractions.  So the muscles are weak unable to work well.

In 2005 researchers found that the MTHFD1 1958A allele makes it hard for the body to produce its own choline.   In particular, young women are 15 times more likely to get fatty liver or have muscle break down on a low choline diet. Half of Caucasians and 18% of African Americans have this variation of the gene.  So it is especially important to have a diet with a lot of choline and betaine in it.

Exercise and Choline

If you work out for more than 2 hours at >70% VO2 max you will deplete blood choline levels.  So hard intense exercise can deplete choline in the blood.

For more on the effects of exercise on choline level see the review by Jason Penry and Melinda M. Manore.  Jason Penry is a student of Professor Melinda M Manore at Oregon State University in Corvallis, OR.

Sources of Choline and Betaine

Most people get enough choline in their diet.  Red meat, liver, poultry, fish, beer, OJ all contain choline.  Also you get betaine from spinach, pasta, white bread and cold cereals.

Choline supplements

o Choline bitartrate hits the bloodstream 45 minutes after taking it. The effect lasting 4 hours. Increasing the choline level in the blood by 86%.

o Though lecithin has only approx 35% choline, it increases choline level by 265% and lasts 12 hours