Low carb diets and copper
I’ve been working on a long post that is an analysis of the recent JAMA article showing that women who eat low-carb, high-protein diets may be protected against heart disease. Problem is, that to show what I need to show, I need to insert a few charts, which I haven’t been able to do because it’s more difficult to insert images into WordPress than it was to do so in Movable Type. I’ve gotten help so the post along with all charts should be up shortly.
In the meantime an interesting article in yesterday’s New York Times Magazine caught my eye because of its relevance to low-carb dieting.
The article titled The Healing Problem was about how a young physician tracked down the cause of a serious immune problem in a patient who had undergone a gastric bypass procedure and a subsequent hernia operation. Here are the pertinant facts.
The patient was a 47 year old man who had undergone gastric bypass surgery four years earlier and had then lost about 100 pounds. Two years after the gastric bypass the patient had developed a hernia, a fairly common occurrence after abdominal surgery. He underwent another operation to repair his hernia after which he developed a serious infection.
He needed weeks of intravenous antibiotics, and he was still living with the consequences: the incision that the doctors made to repair the hernia never healed. It remained an open wound, and no one could figure out why. That wasn’t the only mystery: six months ago, routine blood work showed that he had developed anemia (too few red blood cells) and neutropenia (too few infection-fighting white blood cells). He had a slew of tests, but no one could explain this newest complication either.
His blood work showed that he had fewer than 2,000 white cells per microliter of blood — less than half the number he should have had, even without an infection. The neutrophils — the type of white blood cells that serve as the front line of the immune system, our body’s version of the Marine Corps — were below 500 cells per microliter, an inadequate force to fight off even the most insignificant infection.
This patient’s doctor racked her brain and her medical books to come up with some reason for his immune problem. She rightly figured that people don’t just develop a disorder like this for no reason: something had to be causing it. As it turned out, there was a cause, and it came from an unlikely source: the patient’s own physicians.
The patient’s wife brought all his nutritional supplements to the hospital so he could continue taking them. His surgeons had started him on a regimen of vitamins and minerals to help the healing process after his surgery, and the patient had continued to take these supplements since, even during his subsequent hospitalizations for his recurrent infections.
In going over the patient’s list of supplements his doctor noted that along with his multivitamin that patient was taking extra vitamin A and zinc. In fact, he had been taking 10 times the recommended amount of vitamin A and 15 times the recommended amount of zinc. His doctor read up on these supplements and learned that excess zinc could cause all the problems that her patient was suffering, not because of the excess zinc itself, but because of the copper deficiency the excess zinc causes.
Zinc and copper are absorbed through the same ionic channel, and when there is an overabundance of zinc it gets absorbed instead of the copper. Think of a turnstile leading into a stadium. If there are an equal number of people with green shirts and yellow shirts outside the stadium pushing toward the turnstile, both will get in at about the same rate. If suddenly a bus dumps of a crowd of people with green shirts who then outnumber the yellow shirts by a factor of 20 to 1, there will be way fewer yellow-shirted people who make it through the turnstile.
It’s much the same way in the body. Certain elements in their ionic form get absorbed through the same channel. As long as these elements present to the channel in a specific ratio, they get through in that same ratio. If, however, there is an overabundance of one, it occupies the channel, preventing the other from getting through and can create an deficiency of the other despite an adequate intake.
Intake is only one half of the equation; absorption is the other half. It doesn’t matter how much comes in through the mouth if it doesn’t get absorbed through the GI tract.
This patient’s doctor did the right thing:
She directed the patient to stop taking all his vitamins and sent off blood for a copper-level test. Even before the results came back, the effect was visible. Within days, his white-cell count was in the normal range. He was sent home with a prescription for copper and told to take it for the next six months. When the copper test finally came back, it confirmed the deficiency. Over the next couple of months, the anemia resolved too, and the wound finally healed.
Why is all this of interest to low-carb dieters?
Because copper is an extremely important trace element that is essential to good health and is often lacking in ‘modern’ low-carb diets. And low-carb diets are typically pretty high in zinc, which exacerbates the problem of low copper.
Copper is an essential component in enzymes involved with heart function, bone formation, energy metabolism, nerve transmission, elastin synthesis, skin pigmentation, normal hair growth, and red blood cell formation. Copper is lacking in most foods that are staples of the ‘modern’ low-carb diet, especially meat. According to the USDA Nutritional Database it would take over two pounds of t-bone steak just to get the daily requirement of copper–and that would come with a whopping amount of zinc (about 40 times the amount of copper), which would compete with the copper for absorption. The other components of a ‘modern’ low-carb diet–the green leafies, the colorful fruits and vegetables–contain minuscule amounts of copper as well.
Even the average American diet doesn’t go overboard on copper. A study published a few years ago in the Journal of Nutrition presented data from a detailed and thorough study of copper intake of 80 subjects over a year. The results showed that only about 20% of the subjects consumed even the RDA of copper over the long term.
I made the case above that the ‘modern’ low-carb diet was low on copper. What do I mean by that?
Simply this. We modern humans typically eat the muscle meats of animals. We eat steak and ham and chicken and lamb chops and pork chops. Our early ancestors ate the whole carcass except for the bones (which were split for marrow) and the hair. Everything else was consumed. Just to give you an idea, here is an excerpt from the Protein Power LifePlan of how native Australians ate a wallaby after it had been flung on the fire for several minutes (warning: not for the squeamish):
The first cut was made horizontally on the ventral [belly] surface at the level of the anus, and the next on the dorsal [back] surface along both sides to sever the leg muscles. Another cut was then made from the anus to the neck. The viscera were pulled out; and the kidneys, liver, heart and lings, and the omental and mesenteric fat [the fat surrounding the intestines] were separated from the rest, and cooked on the hot stones and coals for 5 minutes. The cooked lungs were used to soak up the blood inside the carcass and then eaten. The offal was regarded as a delicacy by everybody and a certain amount of squabbling always followed its distribution.
All the organ meats, especially liver, are rich sources of copper. Other foods our ancient ancestors would have eaten–seeds, nuts, and shellfish–are also rich sources. If you eat a lot of these as part of your ‘modern’ low-carb diet, you probably get plenty of copper. If you stick mainly with the muscle meats and low-carb fruits and veggies, you’ll be getting a lot of zinc, but may be walking the low-copper tightrope.
Copper is exceedingly important in bone formation. A number of studies have shown that low copper intake leads to osteoporosis. A number of papers have been published detailing how the mild metabolic acidosis caused by long-term meat consumption can dissolve bone and lead to osteoporosis. I’m not so sure it’s not the copper deficiency created by the intake of a high-meat (high zinc) diet.
One of the other problems I see, especially with bad weather and cold and flu season coming on is that zinc has gained a reputation as an immune-enhancing element. In fact, zinc has almost reached glamor trace-element status. The drug store and health food store shelves are awash in all kinds of zinc-containing supplements that are recommended to be taken at the first sign of a cold. There are zinc pills, zinc lozenges, zinc sprays, and even zinc gums.
Take a bunch of this zinc while you’re on a low-carb diet and you could be risking a copper deficiency.
My recommendation is that you eat liver every now and then (if you like it) and add some nuts and seeds to your low-carb diet if you don’t include them already. Short of that, I would recommend that you take a supplement containing some copper. If you want to take zinc to ward off a cold (it really does work), let the zinc absorb, then take a copper supplement a couple of hours later.
You can also compensate for the excess zinc consumption by taking a few Tums after your meal. Somehow calcium interferes with the zinc absorption and even offsets the damage done to bones by a copper deficiency. Some researchers believe that the idea that calcium prevents osteoporosis arose from the fact that “calcium supplementation lessens the adverse effect of too much meat.”
Another way to prevent the zinc/copper problem, at least as far as supplements are concerned, is to take supplements in which the zinc and copper are chelated. Chelation is the process in which the zinc and copper ions (and other ions as well) are attached to a much larger molecule that isn’t absorbed through the ion channel. If one or both are chelated, they don’t compete for absorption, and you get pretty much full absorption of both.
How can you tell if the zinc and/pr copper are chelated? Instead of saying ‘zinc’ on the label it will say ‘zinc aspartate’ or ‘zinc (amino acid chelate)’ or something like that. Same with copper.
One bright spot is that dark chocolate and cocoa are rich sources of copper, so if you can make your chocolate-coated nuts and/or your hot chocolate low-carb, you’re in business.
If all this is just too confusing, throw a wallaby on the fire, roast and consume as described above and you shouldn’t have anything to worry about.