So how does curcumin affect this process? It appears to have the ability to reprogram the self-destruct mechanism back into cancer cells. All cells contain so-called death receptors that trigger the self-destruction sequence, but cancer cells can disable their own death receptors. Curcumin, however, appears able to reactivate them.17 Curcumin can also kill cancer cells directly by activating “execution enzymes” called caspases inside cancer cells that destroy them from within by chopping up their proteins.18 Unlike most chemotherapy drugs, against which cancer cells can develop resistance over time, curcumin affects several mechanisms of cell death simultaneously, making it potentially harder for cancer cells to avoid destruction.19
Curcumin has been found to be effective against a variety of other cancer cells in vitro, including those of the breast, brain, blood, colon, kidney, liver, lungs, and skin. For reasons not fully understood, curcumin seems to leave noncancerous cells alone.20 Unfortunately, turmeric has yet to be tested in clinical trials for the prevention or treatment of lung cancer, but with no downsides at culinary doses, I’d suggest trying to find ways to incorporate the spice into your diet. I offer a number of suggestions in part 2.
Dietary Secondhand Smoke
Though the majority of lung cancer is attributed to smoking, approximately a quarter of all cases occur in people who’ve never smoked.21 Although some of these cases are due to secondhand smoke, another contributing cause may be another potentially carcinogenic plume: fumes from frying.
When fat is heated to frying temperatures, whether it be animal fat, such as lard, or plant fat, such as vegetable oil, toxic volatile chemicals with mutagenic properties (those able to cause genetic mutations) are released into the air.22 This happens even before the “smoke point” temperature is reached.23 If you do fry at home, good ventilation in the kitchen may reduce lung cancer risk.24
Cancer risk may also depend on what’s being fried. A study of women in China found that smokers who stir-fried meat every day had nearly three times the odds of lung cancer compared to smokers who stir-fried foods other than meat on a daily basis.25 This is thought to be because of a group of carcinogens called heterocyclic amines that are formed when muscle tissue is subjected to high temperatures. (We’ll talk more about these in chapter 11.)
The effects of meat fumes can be hard to separate from the effects of eating the meat itself, but a recent study on pregnant women and barbecuing attempted to tease them out. When meat is grilled, polycyclic aromatic hydrocarbons (PAHs) are also produced, one of the probable carcinogens in cigarette smoke. The researchers discovered that not only was the ingestion of grilled meat in the third trimester associated with smaller birth weights, mothers merely exposed to the fumes tended to give birth to babies with a birth weight deficit. Exposure to the fumes was also associated with a smaller head size, an indicator of brain volume.26 Air pollution studies suggest prenatal exposure to polycyclic aromatic hydrocarbons may then translate into adverse effects on children’s future cognitive development (as manifested by a significantly lower IQ).27
Even just living next to a restaurant may pose a health hazard. Scientists estimated the lifetime cancer risk among those residing near the exhaust out-lets at Chinese restaurants, American restaurants, and barbecue joints. While exposure to fumes from all three types of restaurant resulted in exposure to unsafe levels of PAHs, the Chinese restaurant proved to be the worst. This is thought to be due to the amount of fish being cooked,28 as the fumes from pan-fried fish have been found to contain high levels of PAHs capable of damaging the DNA of human lung cells.29 Given the excess cancer risk, the researchers concluded that it wouldn’t be safe to live near the exhaust of a Chinese restaurant for more than a day or two a month.30
What about that enticing aroma of sizzling bacon? The fumes produced by frying bacon contain a class of carcinogens called nitrosamines.31 Although all meat may release potentially carcinogenic fumes, processed meat like bacon may be the worst: A UC-Davis study found that bacon fumes cause about four times more DNA mutations than the fumes from beef burgers fried at similar temperatures.32
What about tempeh bacon? Tempeh is a fermented soyabean product used to make a variety of meat substitutes. Researchers compared the DNA-mutating effects of the fumes from frying bacon and beef to tempeh. The bacon and burger fumes were mutagenic, but the tempeh fumes were not. Nevertheless, it’s still not a good idea to eat fried foods. Though no DNA changes were detected after exposure to tempeh smoke, the fried tempeh itself did cause some DNA mutations (though 45 times fewer than the beef and 346 times fewer than the bacon). The researchers proposed that these findings might account for the higher incidence of respiratory diseases and lung cancer among cooks and lower incidence overall among vegetarians.33
If you do need to be around frying bacon or eggs, it would be safer to limit your exposure by using a barbecue. Studies show that the number of particles deposited into the lungs increases by a factor of ten when frying indoors versus outdoors.34
Chronic Obstructive Pulmonary Disease
Chronic obstructive pulmonary disease (COPD), such as emphysema and chronic bronchitis, is a condition that makes it difficult to breathe and gets worse and worse over time. In addition to shortness of breath, COPD can cause severe coughing, excess mucus production, wheezing, and chest tightness. The disease affects more than twenty-four million Americans.35
Smoking is far and away the leading cause of COPD, but other factors can contribute, such as prolonged exposure to air pollution. Unfortunately, there is no cure for COPD, but there is some good news: A healthy diet may help to prevent COPD and help keep it from getting worse.
Data going back fifty years show that a high intake of fruits and vegetables is positively associated with good lung function.36 Just one extra serving of fruit each day may translate into a 24 percent lower risk of dying from COPD.37 On the other hand, a twin pair of studies from Columbia and Harvard Universities found that consumption of cured meat—like bacon, ham, hot dogs, sausage, and salami—may increase the risk of COPD.38,39 It’s thought to be due to the nitrite preservatives in meat, which may mimic the lung-damaging properties of the nitrite by-products of cigarette smoke.40
What if you already have the disease? Can the same foods that appear to help prevent COPD be used to treat it? We didn’t know until a landmark study was published in 2010. More than a hundred COPD patients were randomized into two groups—half were instructed to boost their fruit and vegetable consumption, while the others remained on their normal diet. Over the next three years, the standard-diet subjects became progressively worse, as expected. In contrast, the disease progression was halted in the group consuming more fruits and veggies. Not only did their lung function not get worse, it actually improved a little. The researchers suggested this could be due to a combination of the antioxidant and anti-inflammatory effects of the fruits and vegetables, along with a potential reduction in the consumption of meat, which is thought to act as a pro-oxidant.41
Regardless of the mechanism, a diet with more whole plant foods may help both prevent and arrest the progression of this leading killer.
Asthma
Asthma is an inflammatory disease characterized by recurring attacks of narrowed, swollen airways, causing shortness of breath, wheezing, and coughing. Asthma can start at any age, but it usually emerges during childhood. One of the most common chronic diseases in kids, asthma’s prevalence has been increasing year after year.42 In the United States, twenty-five million people suffer from asthma, and seven million of them are children.43
A groundbreaking study recently demonstrated that the rates of asthma vary dramatically around the world. The International Study of Asthma and Allergies in Childhood followed more than a million children in nearly one hundred countries, making it the most comprehensive survey ever undertaken of this disease. The study found a twentyfold to sixtyfold difference in the prevalence of asthma, allergies, and eczema.44 Why does the prevalence of rhinoconjunctivitis (itchy eyes an
d runny nose) range from 1 percent of children in parts of India, for instance, to as much as 45 percent elsewhere?45 While such factors as air pollution and smoking rates may play a role, the most significant associations were not with what was going into their lungs but what was going into their stomachs.46
Adolescents living in areas where more starchy foods, grains, vegetables, and nuts were consumed were significantly less likely to exhibit chronic symptoms of wheezing, allergic rhinoconjunctivitis, and allergic eczema.47 Boys and girls eating two or more servings of vegetables a day appear to have only half the odds of suffering from allergic asthma.48 In general, the prevalence of asthma and respiratory symptoms reportedly appears to be lower among populations eating more foods of plant origin.49
Foods of animal origin have been associated with increased asthma risk. A study of more than one hundred thousand adults in India found that those who consumed meat daily, or even occasionally, were significantly more likely to suffer from asthma than those who excluded meat and eggs from their diets altogether.50 Eggs (along with fizzy drinks) have also been associated with asthma attacks in children, along with respiratory symptoms, such as wheezing, shortness of breath, and exercise-induced coughing.51 Removing eggs and dairy from the diet has been shown to improve asthmatic children’s lung function in as few as eight weeks.52
The mechanism by which diet affects airway inflammation may lie with the thin coating of fluid that forms the interface between your respiratory-tract lining and the outside air. Using the antioxidants obtained from the fruits and vegetables you eat, this fluid acts as your first line of defense against the free radicals that contribute to asthmatic airway hypersensitivity, contraction, and mucus production.53 Oxidation by-products can be measured in exhaled breath and are significantly lowered by shifting toward a more plant-based diet.54
So if asthmatics eat fewer fruits and vegetables, does their lung function decline? Researchers out of Australia tried removing fruits and vegetables from asthma patients’ diets to see what would happen. Within two weeks, asthma symptoms grew significantly worse. Interestingly, the low-fruit, low-vegetable diet used in the study—a restriction to no more than one serving of fruit and two servings of vegetables per day—is typical of Western diets. In other words, the diet they used experimentally to impair people’s lung function and worsen their asthma was effectively the standard American diet.55
What about improving asthma by adding fruits and vegetables? Researchers repeated the experiment, but this time increased fruit and vegetable consumption to seven servings a day. This simple act of adding a few more fruits and vegetables to their daily diet ended up successfully cutting the study subjects’ exacerbation rate in half.56 That’s the power of eating healthfully.
If it’s the antioxidants, why not just take an antioxidant supplement? After all, popping a pill is easier than eating an apple. The reason is simple: Supplements don’t appear to work. Studies have repeatedly shown that antioxidant supplements have no beneficial effects on respiratory or allergic diseases, underscoring the importance of eating whole foods rather than trying to take isolated components or extracts in pill form.57 For example, the Harvard Nurses’ Health Study found that women who obtained high levels of vitamin E from a nut-rich diet appeared to have nearly half the risk of asthma of those who didn’t, but those who took vitamin E supplements saw no benefit at all.58
Who do you think did better? A group of asthma patients who ate seven servings a day of fruits and vegetables, or a group who ate three servings plus fifteen “serving equivalents” in pill form? Sure enough, the pills didn’t seem to help at all. Improvements in lung function and asthma control were evident only after subjects increased their actual fruit and vegetable intake, strongly suggesting that consuming whole foods is paramount.59
If adding a few daily servings of fruits and vegetables can have such a significant effect, what if asthma sufferers were put on a diet composed entirely of plant foods? Researchers in Sweden decided to test out a strictly plant-based diet on a group of severe asthmatics who weren’t getting better despite the best medical therapies—thirty-five patients with long-established, physician-verified asthma, twenty of whom had been admitted to hospitals for acute attacks during the previous two years. One patient had received emergency intravenous infusions a total of twenty-three times, another reported he’d been hospitalized more than a hundred times, and one subject had even suffered a cardiac arrest after an attack and had to be revived and placed on a ventilator.60 These were some pretty serious cases.
Of the twenty-four patients who stuck with the plant-based diet, 70 percent improved after four months, and 90 percent improved within one year. And these were all people who had experienced no improvement in their conditions at all in the year prior to switching to a plant-based diet.61
Within just one year of eating healthier, all but two patients were able to drop their dose of asthma medication or get off their steroids and other drugs altogether. Objective measures like lung function and physical working capacity improved; meanwhile, subjectively, some patients said their improvement was so considerable that they felt like “they had a new life.”62
There was no control group, so the placebo effect may have accounted for some of the improvement, but the nice thing about a healthier diet is that there are only good side effects. In addition to improvements in their asthma control, the study subjects lost an average of eighteen pounds, and their cholesterol and blood pressures got better. From a risk-benefit standpoint, then, it’s definitely worth giving a plant-based diet a try.
The most lethal lung diseases vary widely in presentation and prognosis. As noted, smoking is far and away the leading cause of lung cancer and COPD, but diseases like asthma typically develop during childhood and can be associated with a range of contributing factors, such as low birth weight and frequent respiratory infections. While quitting smoking remains the most effective way to ward off the worst kinds of lung disease, we can also help the body bolster its defenses by eating a diet rich in protective plant foods. The same kind of diet that appears to help severe asthmatics may also help prevent all three diseases from occurring in the first place.
If you’re one of the millions of Americans who already suffer from lung disease, quitting smoking and changing your diet can still make a difference. It’s never too late to start living and eating healthier. The restorative powers of the human body are remarkable, but your body needs your help. By including foods that contain cancer-fighting compounds and loading up on antioxidant-rich fruits and veggies, you may be able to strengthen your respiratory defenses and breathe easier.
In my clinical practice, whenever I’ve felt under too much time pressure to address a patient’s smoking or bad dietary habits, I stop and think back to the hideous death of that man in Boston. No one deserves to die like that. I’d like to think no one has to.
CHAPTER 3
How Not to Die from Brain Diseases
My mum’s father died of a stroke, and her mother died of Alzheimer’s disease.
As a kid, I loved going to see my grandma in Long Island. We lived out west, so I got to fly on a plane—sometimes all by myself! She was the perfect—and perfectly doting—grandmother. She’d want to take me to toy stores, but, geeky me, I just wanted to go to the library. When we’d get back to the house, my arms filled with borrowed books, she’d let me sit way back on her big couch—shoes off, of course—and read and draw pictures. Then she’d bring me blueberry muffins she made with a big mechanical mixer that took up half the kitchen counter.
Later in life, my grandma started to lose her mind. By then, I was in medical school, but my newfound knowledge was useless. She had turned. My previously sweet and stately grandmother? Now she threw things at people. She cursed. Her caretaker showed me the teeth marks on her arm where my once kind, loving grandma had bitten her.
That’s the horror of brain disease. Unlike a problem with your foot or your back or even another vital organ, brain
disease can attack your self.
The two most serious brain diseases are stroke, which kills nearly 130,000 Americans each year,1 and Alzheimer’s disease, which kills nearly 85,000.2 Most strokes can be thought of as “brain attacks”—like heart attacks, but the rupturing plaques in your arteries cut off blood flow to parts of the brain rather than to parts of the heart. Alzheimer’s is more like a mind attack.
Alzheimer’s disease is one of the most physically and emotionally burdensome diseases, for both sufferers and caregivers. Unlike stroke, which can kill instantly and without any warning, Alzheimer’s involves a slower, more subtle decline over months or years. Instead of cholesterol-filled plaques in your arteries, plaques made of a substance called amyloid develop in the brain tissue itself, associated with the loss of memory and, eventually, loss of life.
While the pathology of stroke and Alzheimer’s are different, one key factor unites them: Mounting evidence suggests that a healthy diet may help prevent them both.
Stroke
In about 90 percent of strokes,3 blood flow to part of the brain gets cut off, depriving it of oxygen and killing off the part fed by the clogged artery. That’s called an ischemic stroke (from the Latin ischaemia, meaning “stopping blood”). A small minority of strokes are hemorrhagic strokes, which are caused by bleeding into the brain when a blood vessel bursts. The damage wrought by a stroke depends on which area of the brain was deprived of oxygen (or where bleeding occurred) and for how long the deprivation lasted. People who experience a brief stroke might only need to contend with arm or leg weakness, while those who suffer a major stroke can develop paralysis, lose the ability to speak, or, as is too often the case, die.
How Not to Die Page 6