Choline & lethal PCa (with a note on Lecithin)

This is a follow-on from my Eggs post.

Erin Richman speculated that the increased risk of lethal PCa associated with eggs, was due to choline. While eggs are rich in choline, choline is present in many foods at significant levels. One can't avoid choline & nor should one try, but it seems prudent to avoid over-indulging, & supplementation seems unwise at this point.

It's true that eggs are a good source of choline, but there is a limit to the number of eggs I want to eat in a day, & plenty of opportunity to load up on choline from other sources.

Richman followed up on her eggs-meats studies with one on "Choline intake and risk of lethal prostate cancer" [1] (2012):

"Of the 47,896 men in our study population, choline intake was associated with an increased risk of lethal prostate cancer."

"Men in the highest quintile of choline intake had a 70% increased risk of lethal prostate cancer"

From the Linus Pauling Institute [2]:

"Eggs, liver, and peanuts, are especially rich in choline (27). Major contributors to choline in the American diet are meat, poultry, fish, dairy foods, pasta, rice, and egg-based dishes (77). Spinach, beets, wheat, and shellfish are also good sources of the choline metabolite, betaine (78). Betaine cannot be converted back to choline but can spare some choline requirements for homocysteine remethylation (1). Phosphatidylcholine, which contains about 13% choline by weight, is the main form of choline in dietary products (79). Lecithin extracts, which comprise a mixture of phosphatidylcholine and other phospholipids, are often added during food processing. Lecithins in processed food have been estimated to increase the daily consumption of phosphatidylcholine by about 1.5 mg/kg of body weight for adults (27)."

"Food Serving Total Choline (mg)

Beef liver, pan fried3 ounces*356

Wheat germ, toasted1 cup202

Egg1 large147

Beef, trim cut, cooked3 ounces97

Scallop, cooked, steamed3 ounces94

Salmon, pink, canned3 ounces75

Chicken, breast, cooked, roasted3 ounces73

Atlantic cod, cooked3 ounces71

Shrimp, canned3 ounces69

Brussel sprouts, cooked, boiled1 cup63

Broccoli, cooked, boiled1 cup, chopped63

Milk, skim8 fluid ounces38

Peanut butter, smooth2 tablespoons20

Milk chocolate1.5-ounce bar20

Peanuts1 ounce15"

See the paper [1], Table 2, for the foods considered by Richman, (as well as the chemical forms of choline involved).

In the main part of the study, mortality risk rose with intake quintile:

1 = 1.00 (reference)

2 = 1.24

3 = 1.38

4 = 1.55

5 = 1.70

"In the case-only survival analysis, we observed 271 lethal cases ..." "Postdiagnostic choline intake was not statistically significantly associated with the risk of lethal prostate cancer ..." There was a similar risk for quintile 5 versus quintile 1: +69%, but the the overall picture seems less clear:

1 = 1.00 (reference)

2 = 1.64 (!)

3 = 1.30

4 = 1.40

5 = 1.69

From the Discussion section:

"In this novel prospective analysis, we observed a positive association between intake of choline and risk of lethal prostate cancer. We attempted to account for the association between choline intake and risk of lethal prostate cancer by adjusting for nutrients found in animal products that may also affect risk of prostate cancer, such as cholesterol, fatty acids, protein, zinc, phosphorus, and vitamin D. Furthermore, we examined the association between choline intake and the risk of lethal prostate cancer adjusting for the top food contributors to choline (eg, whole eggs, beef or lamb as a main dish, skim milk, and chicken or turkey without skin), because several of these foods have been positively associated with the risk of prostate cancer in our study population (4, 20). The positive relation between choline intake and risk of lethal prostate cancer remained in all of these models. Yet, we cannot exclude the possibility that unmeasured factors in animal foods or persons who consume animal foods accounted for the association we observed between choline intake and risk of lethal prostate cancer."

"Biologic mechanisms linking higher choline intake to an increased risk of lethal prostate cancer are unknown. Additionally, it is not known whether dietary choline is correlated with, or affects, choline concentrations in the prostate. However, choline metabolism is clearly altered in prostate cancer, with greater concentrations of choline-containing compounds in malignant than in normal cells (6). Because of the selective and high uptake of circulating choline by prostate cancer cells, radiolabeled choline is used to identify prostate cancer recurrence and metastases (22, 23), and patients with high-grade prostate cancers have higher concentrations of choline-containing compounds than do those with low-grade prostate cancers (24)."

"Choline is an essential nutrient; therefore, it must be consumed in the diet for optimal health. Low concentrations of choline are associated with the development of fatty liver and liver damage (34, 35). In addition, animal data suggest that choline intake may be beneficial to cognitive function and memory (36–39), and cytidinediphosphocholine—the intermediate produced in the conversion of choline to phosphatidylcholine—has been associated with improved memory in elderly persons in short-term randomized controlled trials (40). Thus, future studies need to examine whether the benefits of choline intake outweigh the potential risks among men."

A note on lecithin supplements.

Supplemental lecithin contains phosphatidylcholine. Given the study, it doesn't seem prudent to take a lecithin supplement.

In addition, soy lecithin is an ingredient in a large number of commercially prepared foods. Check the labels of salad dressings, ice creams - & even bread. Plus many more.

-Patrick

[1] ajcn.nutrition.org/content/...

[2] lpi.oregonstate.edu/mic/oth...

5 Replies

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  • If we eliminate all the foods with choline what is there left we can eat? Can we be healthy without choline or is it necessary to maintain good health?

  • "In 1998, choline was classified as an essential nutrient by the Food and Nutrition Board of the Institute of Medicine (USA).[10]"

    en.wikipedia.org/wiki/Choline

    Outright deficiency is bad news & not an option, in my view.

    The AI (adequate intake) for adult men is given as 550 mg, which I understand to be based on the more precise 7 mg/kg.

    Omnivores probably have no problems getting close to 7 mg/kg, but would have to overindulge in choline-rich foods to get a lot higher.

    A 2005 study [1] looked at choline intake in 16 men fed an ad libitum diet:

    "Twelve of 16 men ... met or exceeded their estimated choline requirement"

    Note that men who have much higher energy requirements (e.g. runners) could be at risk & should, perhaps, chose choline-poor foods for their excess calories.

    Vegans would be expected to have lower intakes, & there is some dispute as to the accuracy of the AI number in that quarter. If a vegan were to avoid soy products, it's hard to see how 550 mg could easily be acheived. Quinoa, at 42 mg / cup would be useful. Sprinkling wheat germ on everything, maybe.

    But for men with PCa who have converted to veganism, the presumed reduction in choline intake might translate to reduced PCa mortality risk.

    For omnivores, I'd say to stay away from wheatgerm, limit liver to 'very occassional' & pass on the 3-egg omelets. & no lecithin supplements. But I don't view a single egg (147 mg) as a significant threat. Choline is an essential nutrient.

    -Patrick

    [1] jn.nutrition.org/content/13...

  • Wow, this would turn my diet upside down. I have been a vegetarian since 1992. I fond a pure vegan diet very hard so a added fish, shell fish and a few eggs to the diet. I eat organic when possible and avoid anything with GMOs, and other additives. I use Almond milk and Earth Balance butter substitute. I eat a lot of salmon and white fish and love peanut butter (all natural).

    When I was diagnosed the doctor gave me 5 to 10 years to live. I have always attributed my survival way past the 10 year mark to my diet.

    Oh well, I guess I will continue with my diet anyway.

  • Hi Magnus,

    You might find it interesting to estimate your average daily choline intake. Perhaps track your meals for the coming week. Your intake is probably neither high nor low.

    A few years back I came across an analysis of cancer deaths by diet type. Pescetarians (fish, but no meat) invariably did better than omnivores & vegans for each type of cancer. Strangely, the meat eaters beat out the others for brain cancer (but no other type).

    Salmon is problematic these days. I could write pages on it - the farms can mimic the flesh of any type of salmon. The fish farmers aren't exactly innocent, but the label that gets put on the fish can make a lot of money for the distributor. Even the best fishmongers get scammed.

    When the NY Times wrote about the fact that farmed salmon can have very little omega-3 - often the rationale for eating salmon, the demand for wild salmon took off. Sometime later, a school project, of all things, revealed that most "wild salmon" sold in NYC lacked the expected DNA.

    The corn/soy pellets in salmon feed results in flesh that has no color. Astaxanthin is added to the diet to get the pink color. The farms were already used to customizing the fish for the end-user. High-end restaurants wanted a fattier fish with a subtle shade of pink. The standard for supermarkets called for a little more color & less fat.

    But suddenly, with demand for wild salmon climbing, distributors were asking for a lot more color & a lot less fat. Without the head, how many people can identify the species?

    The only wild salmon you can rely on is canned Alaskan, IMO. Comes in those odd-shaped cans. (That's to do with the cost of shipping empty cans to Alaska. The salmon cans can be stacked to seriously reduce shipping volume.)

    Here in Asheville, I buy fish from a guy who makes a weekly trip to the coast, to buy from fishermen. He used to bring back a selection of whole fish, which I preferred, since you could examine the gills & eyes for freshness. & the head & bones make a nice stock for a sauce. But customers wanted filets, so no more heads. I trust him if he specifies the type of snapper, say, that he has brought back that week.

    But investigators have reported that there is widespread label upgrading in the fish that gets to stores & restaurants.

    Best, -Patrick

  • Dear pjoshea13,

    That is interesting about the Pescetarians beating out others for less cancer. I buy most of my fish from Vital Choice over the Internet. It is promoted by Dr Andrew Weil. The salmon I buy from them is a lot redder and denser the salmon I see in the stores. Vital Choice is expensive but I think it is worth it not be getting who knows what from the store. Besides, the FDA approved that new larger GMO salmon for sale to public.

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