Who Should Avoid Coffee?

Oct 19 Coffee copy.jpeg

Do coffee drinkers live longer than non-coffee drinkers? Is it "wake up and smell the coffee" or don't wake up at all? I discuss these questions in my video, Coffee and Mortality.

The largest study ever conducted on diet and health put that question to the test, examining the association between coffee drinking and subsequent mortality among hundreds of thousands of older men and women in the United States. Coffee drinkers won, though the effect was modest, a 10-15% lower risk of death for those drinking six or more cups a day. This was due specifically to lower risk of dying from heart disease, respiratory disease, stroke, injuries and accidents, diabetes, and infections.

However, another study that amount of coffee was found to increase the death rate of younger people under age 55. It may be appropriate, then, to recommend that you avoid drinking more than four cups a day. But if you review all the studies, the bottom line is that coffee consumption is associated with no change or a small reduction in mortality starting around one or two cups a day, for both men and women. The risk of dying was 3% lower for each cup of coffee consumed daily, which provides reassurance for the concern that coffee drinking might adversely affect health, or at least longevity.

A recent population study found no link between coffee consumption and symptoms of GERD, reflux diseases such as heartburn and regurgitation. If you actually stick a tube down people's throats and measure pH, though, coffee induces significant acid reflux, whereas tea does not. Is this just because tea has less caffeine? No. If you reduce the caffeine content of the coffee down to that of tea, coffee still causes significantly more acid reflux. Decaf causes even less, so GERD patients might want to choose decaffeinated coffee or, even better, opt for tea.

Coffee intake is also associated with urinary incontinence, so a decrease in caffeine intake should be discussed with patients who have the condition. About two cups of coffee a day worth of caffeine may worsen urinary leakage.

A 2014 meta-analysis suggested that daily coffee consumption was associated with a slightly increased risk of bone fractures in women, but a decreased risk of fractures in men. However, no significant association was found between coffee consumption and the risk of hip fracture specifically. Tea consumption may actually protect against hip fracture, though it appears to have no apparent relationship with fracture risk in general.

Certain populations, in particular, may want to stay away from caffeine, including those with glaucoma or a family history of glaucoma, individuals with epilepsy, and, not surprisingly, people who have trouble sleeping. Even a single cup at night can cause a significant deterioration in sleep quality.

We used to think caffeine might increase the risk of an irregular heart rhythm called atrial fibrillation, but that was based on anecdotal case reports like one of a young woman who suffered atrial fibrillation after "chocolate intake abuse." These cases invariably involved the acute ingestion of very large quantities of caffeine. As a result, the notion that caffeine ingestion may trigger abnormal heart rhythms had become "common knowledge," and this assumption led to changes in medical practice.

We now have evidence that caffeine does not increase the risk of atrial fibrillation. Low-dose caffeine--defined as less than about five cups of coffee a day--may even have a protective effect. Tea consumption also appears to lower cardiovascular disease risk, especially when it comes to stroke. But given the proliferation of energy drinks that contain massive quantities of caffeine, one might temper any message that suggests that caffeine is beneficial. Indeed, 12 highly caffeinated energy drinks within a few hours could be lethal.


To learn more about various health aspects of coffee, see my videos Coffee and Cancer, What About the Caffeine?, Preventing Liver Cancer with Coffee?, and Coffee and Artery Function.

What else can we consume to live longer? Check out Nuts May Help Prevent Death, Increased Lifespan from Beans, Fruits and Longevity: How Many Minutes per Mouthful?, and Finger on the Pulse of Longevity.

And, for more on controlling acid reflux, see Diet and GERD Acid Reflux Heartburn and Diet and Hiatal Hernia.

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Original Link

Who Should Avoid Coffee?

Oct 19 Coffee copy.jpeg

Do coffee drinkers live longer than non-coffee drinkers? Is it "wake up and smell the coffee" or don't wake up at all? I discuss these questions in my video, Coffee and Mortality.

The largest study ever conducted on diet and health put that question to the test, examining the association between coffee drinking and subsequent mortality among hundreds of thousands of older men and women in the United States. Coffee drinkers won, though the effect was modest, a 10-15% lower risk of death for those drinking six or more cups a day. This was due specifically to lower risk of dying from heart disease, respiratory disease, stroke, injuries and accidents, diabetes, and infections.

However, another study that amount of coffee was found to increase the death rate of younger people under age 55. It may be appropriate, then, to recommend that you avoid drinking more than four cups a day. But if you review all the studies, the bottom line is that coffee consumption is associated with no change or a small reduction in mortality starting around one or two cups a day, for both men and women. The risk of dying was 3% lower for each cup of coffee consumed daily, which provides reassurance for the concern that coffee drinking might adversely affect health, or at least longevity.

A recent population study found no link between coffee consumption and symptoms of GERD, reflux diseases such as heartburn and regurgitation. If you actually stick a tube down people's throats and measure pH, though, coffee induces significant acid reflux, whereas tea does not. Is this just because tea has less caffeine? No. If you reduce the caffeine content of the coffee down to that of tea, coffee still causes significantly more acid reflux. Decaf causes even less, so GERD patients might want to choose decaffeinated coffee or, even better, opt for tea.

Coffee intake is also associated with urinary incontinence, so a decrease in caffeine intake should be discussed with patients who have the condition. About two cups of coffee a day worth of caffeine may worsen urinary leakage.

A 2014 meta-analysis suggested that daily coffee consumption was associated with a slightly increased risk of bone fractures in women, but a decreased risk of fractures in men. However, no significant association was found between coffee consumption and the risk of hip fracture specifically. Tea consumption may actually protect against hip fracture, though it appears to have no apparent relationship with fracture risk in general.

Certain populations, in particular, may want to stay away from caffeine, including those with glaucoma or a family history of glaucoma, individuals with epilepsy, and, not surprisingly, people who have trouble sleeping. Even a single cup at night can cause a significant deterioration in sleep quality.

We used to think caffeine might increase the risk of an irregular heart rhythm called atrial fibrillation, but that was based on anecdotal case reports like one of a young woman who suffered atrial fibrillation after "chocolate intake abuse." These cases invariably involved the acute ingestion of very large quantities of caffeine. As a result, the notion that caffeine ingestion may trigger abnormal heart rhythms had become "common knowledge," and this assumption led to changes in medical practice.

We now have evidence that caffeine does not increase the risk of atrial fibrillation. Low-dose caffeine--defined as less than about five cups of coffee a day--may even have a protective effect. Tea consumption also appears to lower cardiovascular disease risk, especially when it comes to stroke. But given the proliferation of energy drinks that contain massive quantities of caffeine, one might temper any message that suggests that caffeine is beneficial. Indeed, 12 highly caffeinated energy drinks within a few hours could be lethal.


To learn more about various health aspects of coffee, see my videos Coffee and Cancer, What About the Caffeine?, Preventing Liver Cancer with Coffee?, and Coffee and Artery Function.

What else can we consume to live longer? Check out Nuts May Help Prevent Death, Increased Lifespan from Beans, Fruits and Longevity: How Many Minutes per Mouthful?, and Finger on the Pulse of Longevity.

And, for more on controlling acid reflux, see Diet and GERD Acid Reflux Heartburn and Diet and Hiatal Hernia.

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Original Link

How Seafood Can Impact Brain Development

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In my video Fish Intake Associated With Brain Shrinkage, I discussed evidence suggesting that mercury exposure through fish intake during pregnancy may decrease the size of the newborn's brain. However, just because fish-eating mothers may give birth to children with smaller brains doesn't necessarily mean their children will grow up with neurological defects. In the video, Mercury vs. Omega-3s for Brain Development, you can see real-time functional MRI scans of teens whose moms ate a lot of seafood when pregnant. Because these kinds of scans can measure brain activity, as opposed to just brain size, we can more accurately determine if exposure to mercury and PCBs affected these kids. You can see an MRI of what a normal brain looks like when you flash a light in someone's eyes, but the MRI is significantly different for the mercury and PCB exposed brains, suggesting toxicant related damage to the visual centers in brain. (For more on the effect of mercury on teens, see Nerves of Mercury). Fish consumption may also increase the risk of our children being born with epilepsy.

So does maternal fish consumption have an effect on how smart our kids turn out? The DHA in fish--a long chain omega 3 fatty acid--is good for brain development, but mercury is bad for brain development. So a group of researchers looked at 33 different fish species to see what the net effect of these compounds would have on children's IQ. For most fish species, they found that "the adverse effect of mercury on the IQ scores of children exceeded the beneficial effects of DHA." In fact, so much brainpower may be lost from fish consumption that the United States may actually lose $5 billion in economic productivity every year.

For example, if pregnant women ate tuna every day, the DHA would add a few IQ points. But the mercury in that very same tuna would cause so much brain damage that the overall effect of eating tuna while pregnant would be negative, wiping out an average of eight IQ points. The only two fish that were more brain-damaging than tuna were pike and swordfish.

At the other end of the spectrum, the brain boosting effect of DHA may trump the brain damaging effects of mercury in salmon by a little less than one IQ point. Unfortunately, IQ only takes into consideration the cognitive damage caused by mercury, not the adverse effects on motor function and attention and behavior deficits. We think that attention span may be particularly vulnerable to developmental mercury exposure, probably due to damage to the frontal lobes of the brain.

And the IQ study didn't take into account the relatively high levels of PCBs in salmon and the accompanying concerns about cancer risk. Sustainability concerns are another wrinkle, as farm-raised salmon are considered a "fish to avoid." While king mackerel is considered a best choice for sustainability, the mercury levels are so high as to warrant avoiding consumption--exceeding both the FDA and EPA action levels for mercury contamination. But why risk any loss in intelligence at all when pregnant women can get all the DHA they want from microalgae supplements without any of the contaminants? We can then get the brain boost without the brain damage.

More on PCBs in:

-Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, and From Table to Able.

Images thanks to Dion van Huyssteen / Flickr

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Chronic Headaches and Pork Parasites

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Neurocysticercosis is the sciencey name for an infection of the human central nervous system by pork tapeworm larvae. The invasion of baby pork tapeworms in the brain "has become an increasingly important emerging infection in the United States," and is the #1 cause of epilepsy in the world. It is the most common parasitic disease of the human brain and used to be found throughout only the developing world (with the exception of Muslim countries, since less pork is consumed there). That all changed about 30 years ago, and now it's increasingly found throughout North America.

Besides seizures, the pork parasites may actually trigger brain tumors or cause an aneurism or psychiatric manifestation like depression. It can also result in dementia, but with deworming drugs this is often reversible. Only rarely do surgeons have to surgically remove the larvae.

I've talked about pork tapeworms before (see my videos Pork Tapeworms on the Brain, Avoiding Epilepsy Through Diet, and Not So Delusional Parasitosis). What's new is that we now know that they may present as chronic headaches--either migraines or so-called "tension-headaches"--even when the worms in our head are dead. What researchers think is happening is that as our body tries to chip away at the worms' calcified bodies, bits of them may be released into the rest of our brain causing inflammation that could be contributing to headaches.

This condition is rare even in endemic areas, but we can avoid getting infested with an adult tapeworm in the first place by cooking pork thoroughly. It's found in some parts of pig carcasses more than others (see the meat chart here), and the worms can be frozen to death no matter how infested the muscles are by storing pork (cut up into small pieces) for a month at subzero temperatures. Then to ensure the larvae are dead the meat is recommended to be cooked for more than two hours. That's one well-done pork chop!

The New England Journal of Medicine recently featured a case of some guy who must have had thousands of pork tapeworm larvae wriggling through his muscles. In my video, Chronic Headaches and Pork Tapeworms, you can see an x-ray, showing the thousands of little white streaks in this man's body. Each white streak is a baby tapeworm. That's why you can get infected by pork, it gets in the muscles. So cannibals might want to cook for two hours too.

Not all parasites are associated with meat, though. An anxious but healthy 32-year-old male physician presented to the family medicine clinic with a sample of suspected parasites from his stools, which had been retrieved from the toilet that same day. They looked to be about an inch long. He had previously traveled to India, had Chinese food the night before--who knows what he had. Maybe it was hookworms? The sample was sent to the microbiology laboratory for analysis. Later that day, the microbiology physician called to report positive identification of Vigna radiata (previously known as Phaseolus aureus) in the stool sample. Or in common parlance, a bean sprout. They were bean sprouts!

"The patient was called and gently but firmly informed of the diagnosis. Given the nature of the identified specimen, the information was presented in a non-judgmental, respectful manner so as not to offend the sensibilities or sensitivities of the patient."

Their parting advice to fellow physicians in cases of this nature was as follows: "as comical as the findings might seem--try not to laugh!"

Other parasites in meat include toxoplasma (Brain Parasites in Meat), sarcosystis (USDA Parasite Game), and Anisakis (Allergenic Fish Worms). There can even be critters in some dairy products (Cheese Mites and Maggots). Eating Outside Our Kingdom describes a brain malady caused not by meat parasites, but by meat proteins themselves.

One of the nice things about eating plant-based is that plant parasites, like aphids, don't affect people. When is the last time you heard of someone coming down with a bad case of Dutch elm disease?

If you haven't yet, you can subscribe to my videos for free by clicking here.

-Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, and From Table to Able.

Image Credit: ML Cohen / Flickr

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How Animal Proteins May Trigger Autoimmune Disease

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Although slaughterhouse workers with the most poultry exposure appear to suffer the greatest excess mortality (see Poultry Exposure Tied to Liver and Pancreatic Cancer), increased risk of death from cancer is also found in other slaughterplant workers. This research goes back decades and shows higher cancer rates in butchers, slaughterhouse workers, meat cutters, and those working in meat processing plants.

The increased risk for meat industry workers in developing and dying from cancer "may be due to animal-to-human viruses or antigenic stimulation through chronic exposure to animal protein." Cancer-causing virus exposure could also help explain why those who eat meat have higher cancer rates. There's even a retrovirus associated with cancerous fish tumors, which has been speculated as the cause for increased cancer rates in American seafood workers.

Growing up on a livestock farm is associated with higher rates of blood-borne cancer, lymphomas and leukemia. Worst, though, is growing up on a poultry farm, which is consistent with chicken consumption being most closely tied to these cancers. Eating a quarter of a chicken breast daily is associated with a doubling or tripling of risk for these cancers (see EPIC Findings on Lymphoma). Growing up on a farm raising only plant crops, however, is not associated with blood-borne cancers.

What about growing up with dogs and cats? See Pets & Human Lymphoma and Are Cats or Dogs More Protective for Children's Health? You still probably shouldn't eat them, though (see Foodborne Rabies).

Researchers are finally able to start connecting the dots. High levels of antibodies to avian leucosis/sarcoma viruses and reticuloendotheliosis viruses in poultry workers provide evidence of infectious exposure to these cancer-causing poultry viruses. The highest levels were found not in the eviscerators, or gut-pullers, or those that hang the live birds, but among the line workers that just cut up the final product.

In an attempt to narrow down which diseases were associated with which meat, researchers tried separating out those in pig slaughtering and pork processing. "One of the primary sources of concern in using pig organs and tissues as transplants in humans is the fear of introducing zoonotic infections" from animals. We're concerned about what's called PERV transmission, the pig-to-human transmission of porcine endogenous retroviruses, raising theoretical concerns about cancer, immunological, and neurological disorders. However, we don't need to get a pig transplant to be exposed. PERVs are also found in blood, so people exposed to pig blood may be exposed to the virus.

The main finding unique to the pork study (profiled in my video Eating Outside Our Kingdom), which was not found in beef and sheep processing, was the significant excess of deaths "from senile conditions such as Alzheimer's disease." It reminds me of all those poor pork brain extraction workers. You think your job is bad? How would you like to work at the "head-table"? Well, that doesn't sound so bad until you learn it's where, through the "unbridled use of compressed air in the pursuit of maximum yield of soft tissue," they remove the brains of severed swine heads.

In one study, researchers noted that as the line speeds increased, "the workers reported being unable to place the skulls completely on the brain removal device before triggering the compressed air, causing greater splatter of brain material." The aerosolized "mist of brain" is suspected to be the cause of dozens of cases of inflammatory neurological disease in workers who started with symptoms as mild as pain, tingling, and difficulty walking, and ended up so bad that doctors had to put them in a coma for six weeks because of unrelenting seizures.

At first researchers thought it was a brain parasite, but now it's known to be an auto-immune attack triggered by the exposure to aerosolized brain. A similar mechanism has been blamed for meat proteins triggering inflammatory arthritis in people eating meat. By eating fellow animals, we are exposed not only to fellow animal diseases, but to animal tissues that our body may mistake as our own. This may be one advantage to eating a more plant-based diet. By eating outside of the animal kingdom--dipping into the plant or mushroom kingdoms for supper--not only do we not have to worry about getting something like Dutch elm disease, but we can be reassured by the fact that never has an "auto-immune polyradiculoneuropathy" been blamed on a head... of lettuce.

For more on foodborne illnesses one can contract from fellow animals, see, for example:

Probably the strangest example of this whole concept is the Neu5Gc story. A 7-part video series worth checking out:

  1. Cancer as an Autoimmune Disease
  2. Clonal Selection Theory of Immunity
  3. Clonal Deletion Theory of Immunity
  4. The Inflammatory Meat Molecule Neu5Gc
  5. How Tumors Use Meat to Grow: Xeno-Autoantibodies
  6. Nonhuman Molecules Lining Our Arteries
  7. Meat May Exceed Daily Allowance of Irony

-Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death and More Than an Apple a Day.

Image Credit: vgm8383 / Flickr

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