Are You Getting Enough Choline?
In a recent study published in the American Journal of Clinical Nutrition, researchers have found that the current Adequate Intake (AI)* for choline may not be sufficient to prevent fatty liver and muscle damage.
*An AI is a suggested intake in place of a Recommended Daily Allowance (RDA) in cases where there is insufficient scientific information to make a definitive intake recommendation.
Specifically, the scientists gave the study participants 550 mg choline per day (the AI for men) for every 70 kg in body weight for 10 days, followed by a diet of < 50 mg choline (plus 400 mcg of folic acid in some participants).
When given the choline deprived diet, 77% of the men and 80% of the post-menopausal women developed fatty liver or muscle damage, whereas only 44% of pre-menopausal women developed such signs. Estrogen increases the body’s production of phosphatidylcholine (see below) and may account for this observed difference.
Notably, nearly 1/4 of the men in the study developed signs of fatty liver and muscle damage while consuming the current AI level of choline.
Choline - What is It and Why Should You Care?
Choline is a molecule created in the body through the methylation of serine, an amino acid, and has several important functions.
Choline acts as methyl donor, meaning it donates methyl groups to enable chemical reactions to occur throughout the body, such as helping to reduce high homocysteine levels, a potential heart disease risk factor. Here’s a picture of the methylation process and how choline fits in:
(Image: LPI-OSU)
Choline is widely found in the body in the form of phosphatidylcholine (PC), a phospholipid. A phospholipid is similar to a triglyceride (fat), but one of the three fatty acids is replaced by a phosphate molecule, to which a molecule such as choline is attached. These phospholipids concentrate in cell membranes, where they help to maintain the structural integrity of the membranes and regulate cell signaling.
Choline also is a precursor for acetylcholine, an important neurotransmitter involved in helping the brain to maintain focus, attention, and memory function. It’s unclear whether supplementing with choline can directly increase acetylcholine levels in the brain. Supplementing with lecithin (see below) does increase blood levels of choline, including in the brain. However, the limiting factor in acetylcholine production may be a reduction in the activity of the enzyme (choline acetyltransferase) that converts choline into acetylcholine. Acetylcholine is also used elsewhere in the body (e.g., the gut).
And lastly, as shown in the study above, choline is important for proper liver function. The reason is that PC is required to help form molecules in the liver (VLDLs - very-low density lipoproteins) that act as delivery trucks to carry necessary fats and cholesterol to cells around the body. Without adequate PC, enough VLDL molecules aren’t formed, fat and cholesterol builds up in the liver, fatty liver develops, and liver function is impaired. Liver cancer risk may also increase.
Deficiency Common?
In the past, it was thought that choline generated internally might be sufficient to meet the body’s needs, but now the understanding is that significant amounts of choline are also required from the diet to meet the body’s needs.
Here’s a list of foods highest in choline:
-
Beef liver (3 oz.) - 355 mg
-
Wheat germ (1 CUP) - 172 mg
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Egg (1 large) - 126 mg
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Beef (3 oz.) - 66 mg
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Broccoli (1 cup) - 62 mg
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Salmon (3 oz.) - 56 mg
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Peanut butter (2 T.) - 20 mg
(Source: LPI - OSU)
You can see that unless you’re eating a lot of beef liver or cups of wheat germ, you’re unlikely to be getting the 550 mg (men) / 425 mg (women) suggested daily intake of choline. Vegans not eating dairy or eggs are especially likely to be deficient in choline. But even omnivores may not be getting adequate amounts, especially if they avoid eating egg yolks (which is the part of the egg that contains choline).
How to Ensure Adequate Intake
Your best bet for ensuring adequate intake of choline is to supplement with lecithin, which is high in phosphatidylcholine (PC), which, in turn, is about 13% choline by weight. Lecithin is commonly derived from soy fats (not protein, so it contains no potentially estrogenic isoflavones).
Lecithin is most commonly sold in gelcaps and granules. I prefer the granules (preferably made from non-GMO soybeans). They’re less expensive per gram of PC than the gelcaps, and you don’t have to take lots of pills. The granules have a neutral, slightly nutty flavor and can be stirred into shakes or sprinkled on food.
Each lecithin product, whether gelcaps or granules, varies in PC content, so you need to check labels. There are lecithin gelcaps out there that are concentrated for PC content. If you don’t like lecithin granules, these concentrated gelcaps can be a convenient, if slightly more expensive, option.
Ensuring adequate intake of phospholipids containing choline is an important part of a program to help maintain a healthy heart, brain, and liver.
(Image - egg yolk: CancerActive)
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May 11th, 2007 at 10:46 am
What do you know about Choline antagonists? Studies like these often seem to base their AIs on assumed standard american diets. This makes good sense, of course, but it then skews the results for, say, healthy vegans whose bodies may have lower requirements.
That said, I am going to take a closer look at my own food intake to see where I stand. I’ve certainly been surprised before.
May 11th, 2007 at 4:02 pm
Maile, thanks for your comment.
I’m not that familiar with choline antagonists. Some drugs, like methotrexate, inhibit methylation by interrupting folate metabolism, which may lead to the development of fatty liver. This damage may be reversed to some degree by choline supplementation, but that may intefere with the intended drug effect.
I agree that AI levels are set based on the average amount of a nutrient that a group of healthy people consumes. That may or may not well reflect any one individual’s needs. Not sure if vegans would have lower requirements. I would think their choline requirements would be generally the same as omnivores, on average.