August 14, 2006
Faster Brain Decline With More Fat And Copper In Diets

A high copper diet may accelerate brain aging but only if a diet also includes lots of saturated and trans fats.

Martha Clare Morris, Sc.D., associated professor at the Institute for Healthy Aging at Rush University Medical Center, and her colleagues assessed the connection between dietary fat and dietary copper intake in 3,718 Chicago residents age 65 years and older. Participants underwent cognitive testing at the beginning of the study, after three years and after six years. An average of one year after the study began, they filled out a questionnaire about their diets. The dietary recommended allowance of copper for adults is .9 milligrams per day. Organ meats, such as liver, and shellfish are the foods with the highest copper levels, followed by nuts, seeds, legumes, whole grains, potatoes, chocolate and some fruits. Copper pipes may also add trace amounts of the metal to drinking water.

Cognitive abilities declined in all participants as they aged. Overall, copper intake was not associated with the rate of this decline. However, among the 604 individuals (16.2 percent of the study group) who consumed the most saturated and trans fats, cognitive function deteriorated more rapidly with the more copper they had in their diets. “The increase in rate for the high-fat consumers whose total copper intake was in the top 20 percent (greater than or equal to 1.6 milligrams per day) was equivalent to 19 more years of age,” the authors write.

This sounds like a stronger argument for reducing saturated and trans fats than for reducing copper in the diet. We already have plenty of reasons to avoid saturated and trans fats. Here's another one.

Share |      Randall Parker, 2006 August 14 11:11 PM  Aging Diet Brain Studies

Polarman said at August 15, 2006 3:40 AM:

Chocolate has copper!!?? Please tell me it's not dark chocolate.

Richard said at August 15, 2006 4:17 AM:

"nuts, seeds, legumes, whole grains, potatoes, chocolate and some fruits."

That's it. Only ice cream for me from now on. If it's a choice between copper and fat, I know where I stand.

Randall Parker said at August 15, 2006 7:26 PM:


Life is full of ugly truths.

A study by Joo and Betts in the USA found that dark chocolate contributed high levels of copper, 22.1% of estimated safe and adequate daily intake, and milk chocolate 11.3% of estimated safe and adequate daily intake. It was shown that chocolate is a major source of dietary copper in the North American diet, making the highest contribution to mean daily copper intake. Research by the CMA found 5mg of copper per 100g of cocoa powder.

The darker the higher the copper content.

Here's a post arguing that chocolate has too much lead and copper.

I wonder if any chocolate vendor has a process that removes the copper.

Randall Parker said at August 15, 2006 9:11 PM:


Maybe there's still hope. Another page shows little copper in one dark chocolate bar. But maybe an incomplete analysis was done on it.

This dark chocolate does have copper in it though, about 4 times the RDA. That sounds bad. But this dark Hershey's chocolate has little copper in it.

I came across mention of copper being used in some fungicide used on cocoa plants. So maybe copper concentrations vary for that reason.

Randall Parker said at August 15, 2006 9:31 PM:

We can cut back on copper in a few ways:

Copper absorption may be decreased by excess dietary iron or zinc. Conversely, too much copper may cause an iron deficiency. Vitamin C supplementation results in decreased copper status. In rats, large doses of vitamin C can lead to copper deficiency. Other dietary components have an influence upon copper status, but not necessarily absorption. Feeding rats either sucrose or fructose, as opposed to glucose or cornstarch, decreases copper status and exacerbates the signs of copper deficiency.
Lou Pagnucco said at August 16, 2006 7:09 AM:

According to an article on, curcumin and resveratrol are two natural substances that chelate copper. The article also mentions that the richest source of copper in the U.S. diet is beef.

I am not sure that taking excess zinc is a good way to reduce copper levels. If I recall correctly, an experiment in which Alzheimers patients were given zinc supplements resulted in a much faster mental decline. Apparently zinc can also increase amyloid deposits - see "Rapid induction of Alzheimer A beta amyloid formation by zinc" at URL:

Randall Parker said at August 16, 2006 5:06 PM:


I suspect the people who are getting most of their copper from beef are not getting all that much copper in total. 704 calories worth of beef top sirloin contains only .214 mg of copper. Also, 254 calories of ground beef contains .14 mg of copper.

You could get all your calories from beef and still not reach the US National Academy of Sciences (NAS) Recommended Daily Allowance (RDA) for copper.

Copper. The new RDA for copper -- a nutrient necessary for proper development of connective tissue, nerve coverings, and skin pigment -- is 900 micrograms a day for both men and women. To protect against possible liver damage, the UL was set at 10 milligrams per day. Copper is widely distributed in foods such as organ meats, seafood, nuts, and seeds; some foods that are consumed in substantial amounts, such as milk, tea, chicken, and potatoes, also contain the nutrient, but at lower levels.
Lou Pagnucco said at August 17, 2006 8:48 AM:


Thanks for the information.

Also consider, though, that vegetarians consume more copper than meat eaters and yet absorb less copper. See-
"Apparent copper absorption from a vegetarian diet" at:

The summary reads:
"Vegetarian diets often contain more copper than do nonvegetarian diets, but observations of decreased plasma copper associated with vegetarian diets suggest that these diets have lower copper bioavailability than do nonvegetarian diets."

BTW, in the paper "Curcumin Inhibits Formation of Amyloid beta-Oligomers and Fibrils, Binds Plaques, and Reduces Amyloid in Vivo" (at:, the authors indicate that high dietary doses of curcumin may result in brain and serum levels sufficient to chelate iron and copper, possibly accounting for its beneficial effects in Alzheimers. However, they do not consider the possibility that lower dose curcumin could bind iron or copper in the digestive tract. (I cannot find any information on whether consuming curcumin with food decreases copper bioavailablity.)

Possibly also relevant -
"Curcumin interaction with copper and iron suggests one possible mechanism of action in Alzheimer's disease animal models" at:,3,17;journal,16,45;linkingpublicationresults,1:105656,1

Randall Parker said at August 17, 2006 5:08 PM:


Yes, I agree differences in bioavailability are important. This reminds me of the recent post I did where I included info about how lutein from eggs is far better absorbed than from plants. Same general idea.

Though I have to wonder whether there are plant types with high copper which do have high bioavailability. Maybe studies on copper bioavailability have been done for different nuts and seeds?

Still, avoiding red meat is a good idea for other reasons anyway and I do not eat much red meat.

Curcumin: But occasional consumption of curcumin reduces Alzheimer's risk. Could occasional consumption of curcumin cause a big excretion of copper?

Lou Pagnucco said at August 17, 2006 10:10 PM:


Perusing the literature convinces me that mineral absorption depends on food preparation, presence of fiber and anti-nutrients (like phytate), stomach acidity, ... This is a very messy situation.

That occasional consumption of curcumin is protective against Alzheimers is really puzzling. None of curcumin's speculative therapeutic effects seem to apply in that case. My only improbable guess is that the curcumin might penetrate and stain intestinal walls and inhibit copper absorption for several days. That could cause systemic copper depletion, but that is certainly a longshot. In this case, people who consume tumeric should have low copper stores.

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