How Not to Die

  Your brain is 75 percent water.20 When you become dehydrated, your brain actually shrinks.21 How might this affect brain function?

  Based on urine samples obtained from groups of nine- to eleven-year-old kids in Los Angeles and Manhattan, nearly two-thirds of children may arrive at school in a state of mild dehydration,22 which may in turn negatively affect scholastic performance. If you take a group of schoolkids and randomly assign them to drink either 250 ml or no water before taking a test, guess which group does significantly better? The group given the water. These results, the researchers concluded, suggest that “even children in a state of mild dehydration, not induced by intentional water deprivation or by heat stress and living in a cold climate, can benefit from drinking more water and improve their cognitive performance.”23

  Your hydration status may also affect your mood. Restriction of fluid intake has been shown to increase sleepiness and fatigue, lower levels of vigor and alertness, and increase feelings of confusion. But as soon as study subjects are allowed to drink again, the deleterious effects on alertness, happiness, and clarity of thought are almost immediately reversed.24 Water absorption begins very rapidly, within five minutes from mouth to bloodstream, peaking around minute twenty.25 Interestingly enough, cold water gets sucked in about 20 percent faster than body-temperature water.26

  How can you tell if you’re dehydrated? Just ask your body. If you chug some water and pee most of it out soon after, this would be your body’s way of saying it was all topped off. But if you drink a bunch of water and your body keeps most of it, then your tank was running low. Researchers used this concept to develop a formal dehydration assessment tool: Empty your bladder, chug 750 ml of water, and then see how much you pee an hour later. They determined that if you drink 750 ml and urinate less than 250 ml within that hour, there’s a good chance you were dehydrated.27

  But you know, water can be so boring. So try adding fresh fruit or veggies as they do in fancy spas and upscale hotels. I like adding frozen strawberries in place of ice cubes. Sometimes I add a few drops of a potent juice concentrate, like tart cherry or pomegranate. Cucumber slices, ginger shavings, a cinnamon stick, lavender, and a mint leaf or two are also common refreshing additions. My latest favorite flavor fusions involve mixing tangerine slices and fresh basil or frozen blackberries and fresh sage.

  Bubbles! One of my colleagues at work has a SodaStream on his desk, and he makes his own sparkling water for about 16 pence per 250 ml. In addition to making water more interesting, carbonation may also help relieve gastrointestinal symptoms. A randomized trial of the effects of sparkling versus still water found that drinking carbonated water may improve symptoms of constipation and dyspepsia, including bloating and nausea.28

  What if you took water and added beans or greens—that is, coffee beans or tea leaves? Wouldn’t you get all the water you need plus a bonus of additional nutrients? A cup of black coffee, tea, or herbal tea only has two calories, potentially offering nutrition at little caloric cost. Think of healthy beverages as the opposite of junk food: Junk food offers calories with scarce nutrition, whereas healthy beverages offer nutrition with scarce calories. But just how healthy are coffee and tea?

  Coffee

  I have already discussed the benefits of coffee for the liver (chapter 8), mind (chapter 12), and brain (chapter 14). What about overall longevity? Do people who drink coffee live longer lives than people who don’t?

  The National Institutes of Health–AARP Diet and Health Study, the largest-ever prospective study conducted on diet and health, put that question to the test. Yes, drinking lots of coffee is associated with a longer life, but the effect is relatively modest. People who drank six or more cups per day had a 10–15 percent lower mortality rate due to fewer deaths from heart disease, respiratory disease, stroke, injuries and accidents, diabetes, and infections.29 However, when a study looked at people under the age of fifty-five, the opposite effect was found: Drinking more than six cups of coffee daily was found to increase the risk of death. “Hence,” the researchers concluded, “it may be appropriate to recommend that younger people, in particular, avoid heavy coffee consumption (less than 28 cups per week or less than 4 cups in a typical day).”30

  The bottom line, based on all the best studies to date, is that coffee consumption may indeed be associated with a small reduction in mortality,31 on the order of a 3 percent lower risk of premature death for each cup of coffee consumed daily.32 Don’t worry, it’s not “wake up and smell the coffee or don’t wake up at all”—the findings are less prescriptive than they are reassuring for those concerned about their coffee addiction.

  Coffee is not for everyone. For example, be careful if you have gastro-oesophageal reflux disease (GERD). While a population study found no link between coffee consumption and subjective symptoms of GERD, such as heartburn and regurgitation,33 scientists who actually stuck tubes down people’s throats to measure their pH found that coffee does seem to induce significant acid reflux, whereas tea does not. Caffeine does not appear to be the culprit, since caffeinated water doesn’t cause a problem. However, the coffee decaffeination process seems to reduce the level of whichever compounds are responsible, since decaf coffee appeared to cause less reflux. The researchers advised that people who suffer from GERD should consider switching to decaf or—even better—drink tea instead.34

  Daily coffee consumption is also associated with a slightly increased risk of bone fractures among women, but, interestingly, a decreased fracture risk among men.35 However, no association was found between coffee and hip fracture risk. Conversely, tea may reduce hip fracture risk36 but appears to have no significant effect on fracture risk in general.37 This is an important distinction, because hip fractures are associated with a shortened life span more than other types of bone fractures.38

  People with glaucoma,39 or perhaps even with merely a family history of glaucoma,40 may also want to stay away from caffeinated coffee. Coffee intake is associated with urinary incontinence in both women41 and men.42 And there are case reports of individuals with epilepsy having fewer seizures after laying off coffee, so avoiding it is certainly worth a try for people with seizure disorders.43 Finally, it almost goes without saying that people who have trouble sleeping might not want to drink too much coffee. Just a single cup at night can cause a significant deterioration in sleep quality.44

  The mystery as to why some studies showed that coffee consumption increased cholesterol and others did not was solved when it was discovered that the cholesterol-raising compound thought to be responsible was fat soluble. The culprit compound, cafestol, is found in the oils of coffee beans that become trapped in the paper filter, so drip coffee doesn’t raise cholesterol as much as french press, boiled, or Turkish (“mud”-style) coffee. Neither the degree of roasting nor decaffeination appears to make a difference, though Robusta beans have less cafestol than Arabica beans. If you don’t have optimal cholesterol levels, you should consider sticking to filtered coffee or using instant coffee, which also lacks these compounds.45 If these tweaks don’t help, consider eliminating coffee completely, as even paper-filtered coffee may raise cholesterol levels a small amount.46

  We used to think caffeine might increase the risk of an irregular heart rhythm called atrial fibrillation, but this was based on anecdotal case reports involving the acute ingestion of very large quantities of caffeine47 (including a case blamed in part on a woman’s “chocolate intake abuse”).48 As a result, the erroneous notion that caffeine ingestion may trigger abnormal heart rhythms became “common knowledge,” an assumption that led to changes in medical practice. More recently, however, actual studies were performed that revealed caffeine intake does not appear to increase the risk of atrial fibrillation after all.49 Moreover, “low-dose” caffeine, which was defined as drinking fewer than about six cups of coffee a day, may even have a protective effect on heart rhythm.50

  Moderate caffeine consumption in healthy, nonpregnant adults is not only safe but has been foun
d to increase energy and alertness and enhance physical, motor, and cognitive performance.51 Despite these benefits, one medical journal editorialized that doctors should “temper any message that suggests that caffeine is beneficial . . . given the proliferation of energy drinks that contain massive quantities of caffeine . . .”52 Indeed, drinking a dozen highly caffeinated energy drinks within a few hours could cause a lethal caffeine overdose.53 That said, drinking a few cups of coffee a day may actually extend your life a bit54 and even has the potential to slightly lower your overall cancer risk.55

  I cannot recommend drinking coffee, though. Why? Because every cup of coffee is a lost opportunity to drink a potentially even healthier beverage—a cup of green tea.

  Tea

  Black, green, and white teas are all made from the leaves of the same evergreen shrub. Herbal tea, on the other hand, involves pouring hot water over any plant in the world other than the tea plant.

  What’s so special about the tea bush? Phytonutrients exclusive to the tea plant appear so powerful that they can reverse disease even when merely applied to the skin. For example, the topical application of green tea in ointment form on genital warts results in an astounding 100 percent clearance in more than half the patients tested.56 It’s no wonder that this wonder treatment is now officially incorporated into the Centers for Disease Control STD Treatment Guidelines.57 There was even a remarkable case report of a woman whose skin cancers were apparently stopped with topical green tea application.58 If green tea can do that on the outside of your body, what might it be able to do internally?

  I already discussed the role green tea may play in breast cancer prevention in chapter 11. Drinking tea may protect against gynecological malignancies, such as ovarian cancer59 and endometrial cancer,60 as well as lower your cholesterol,61 blood pressure,62 blood sugar,63 and body fat.64 It may protect the brain from both cognitive decline65 and stroke.66 Tea consumption is also associated with decreased risk of diabetes,67 tooth loss,68 and up to half the risk of dying from pneumonia.69 Those who suffer from seasonal allergies may also benefit from drinking tea. Randomized trials have shown that drinking about three cups of Japanese Benifuuki green tea per day starting six70 to ten71 weeks before pollen season significantly reduces allergy symptoms. That’s nothing to sneeze at!

  Riding the Waves

  The invention of the electroencephalogram (EEG) to measure brain-wave activity has been described as “one of the most surprising, remarkable, and momentous developments in the history of clinical neurology.”72 Scientists discovered that humans have four main mental states—two while sleeping and two while awake. Delta waves, in which your brain is electrically pulsing slowly at about one wave per second, are typically only seen in deep sleep. Then there’s theta-wave sleep. At about five cycles per second, this mental state occurs when you’re dreaming. The two waking states are alpha and beta. The alpha state is relaxed, aware, and attentive, such as when you close your eyes and meditate. Beta, meanwhile, is the stimulated, hustle-and-bustle state in which most of us live our lives.

  Alpha, however, is where you want to be—fully alert and focused, yet calm. How do you get there? If you relax in a pleasant, peaceful place, after about ninety minutes, you can start to generate some significant alpha activity (though such practicing meditators as Buddhist monks can achieve this state much earlier and maintain it even with their eyes open). To acquire this talent, you could meditate every day for a few years—or you could just drink some tea. Within minutes of tea consumption, anyone may be able to attain that same relaxed but alert brain-wave pattern.73 That dramatic alteration in brain activity may explain why tea is the world’s single most popular beverage after water.

  Both white and green teas are less processed than black tea and are probably preferable.74 White tea is made from young leaves and is named after the silvery-white hairs on the immature buds; green tea is made from more mature leaves. Which tea is healthier? The answer seems to depend on whether or not you add lemon. If you drink your tea without lemon, green tea appears preferable to white tea. But if you add lemon, white tea jumps ahead.75 The reason is that while there are more phytonutrients in white tea, they may only be released at a certain pH level.76

  In terms of cancer prevention potential, both green and white teas have been shown to protect against DNA damage in vitro against PhIP, the cooked-meat carcinogen I described in chapter 11. White tea won out, though, blocking upward of 100 percent of DNA damage compared to green tea, which at the same concentration only blocked about half. The “potent antimutagenic activity of white tea in comparison with green tea” was achieved at a brewing time of one minute. For most of the teas tested, steeping longer than a minute had no additional effect. In terms of antioxidant activity, though, it may be better not to brew at all.77

  Cold-steeping is a popular way to prepare tea in Taiwan, especially during the summer months. Cold-steeped tea is not like conventional iced tea, in which you brew your tea hot and then cool it down. Rather, cold-steeping involves tossing the tea in cold water and letting it sit at room temperature or in the fridge for at least two hours. This method has been found to reduce the caffeine content and is said to reduce bitterness and improve the aroma.78 But what does cold-steeping do to the nutrient content? You would think that cold water wouldn’t draw out as many antioxidants. After all, nutrient extraction is presumably the whole point of brewing tea with hot water, right? A group of scientists took it upon themselves to compare the antioxidant activity of hot- versus cold-steeped tea. Essentially, they mixed LDL (“bad”) cholesterol with free radicals and timed how long it took the cholesterol to oxidize in the presence of both hot- and cold-steeped tea.

  In a surprise upset, cold-steeped white tea was significantly better at slowing down oxidation.79 (No significant effect of brewing temperature on the antioxidant activity of green tea was found.) The researchers surmised that traditional tea water is so hot that it manages to destroy some of the more sensitive antioxidants in white tea. I no longer brew my tea; I just let it sit overnight in the fridge. Cold-steeping saves prep time and energy, and may even be healthier.

  You don’t have to care how much nutrition is extracted from tea leaves, though, if you simply eat them. Matcha is powdered green tea, produced by milling whole tea leaves into a fine powder that can be added straight to water. Why waste nutrition by dumping a tea bag when you’re done, when you can drink the leaves instead? Think of it this way: Drinking steeped tea is akin to boiling a pot of collard greens and then throwing away the veggies and just drinking the cooking water. Sure, some of the nutrition leached into the water, but wouldn’t it be better to eat the leaves themselves? That’s why I now just throw whole tea leaves straight into my smoothies (see here). This is also a great way to incorporate tea in your diet if drinking tea on an empty stomach causes discomfort. If you develop a taste for matcha (I find it a bit grassy), you can carry around little packets of it wherever you go and just put some in your water bottle and shake. For essentially zero calories, you can drink dark-green leafies all day.

  If green tea is so good, why not just take green-tea extract pills? Because of dozens of reported cases of liver toxicity linked to their use80—yet another demonstration that it’s better to eat the whole food than some glorified “active ingredient” concentrate. There is one tea beverage I’d stay away from, though. Based on a few cases of serious, life-threatening outcomes linked to kombucha tea, a type of fermented tea, the consumption of kombucha “should be discouraged,” according to one case report of a person who ended up in a coma after drinking the stuff.81

  Are there any caveats to regular tea consumption? The fluoride content of tea appears to be the limiting factor. The tea plant naturally concentrates fluoride from the soil, which is one of the reasons tea consumption may help fight cavities,82 but too much fluoride can be toxic. A recent case reported in the New England Journal of Medicine described a woman who started experiencing bone pain after seventeen years of habitually co
nsuming a pitcher of tea made from 100 to 150 tea bags daily.83 That’s too much.

  To prevent skeletal fluorosis, adults should probably not drink more than about twenty tea bags’ worth of black tea a day for twenty years straight, or thirty bags of green daily, or eighty bags of white tea a day.84 To prevent dental fluorosis, a harmless but unsightly mottled tooth discoloration, children should probably refrain from drinking more than about three bags of black tea a day (or around four bags of green or twelve of white)85 while their teeth are still developing, up until around age nine.86

  The Best Sweetener

  In chapter 12, I shared research suggesting that adding sugar may negate some of the benefits of beverages, while adding artificial sweeteners like aspartame or saccharine may even make things worse. Are there any health-promoting sweeteners? The only two concentrated, green-light sweeteners may be blackstrap molasses and date sugar. Other natural caloric sweeteners, such as honey, less processed cane sugars, and maple, agave, and brown rice syrups don’t appear to have much to offer nutritionally.87 Date sugar is a whole food—just dried dates ground up into a powder—as are date and prune pastes, which can be homemade or purchased. These are all good options for baking, but for sweetening drinks, the taste of molasses may be too strong, and the whole-food sweeteners don’t fully dissolve.

  How about stevia? During the 1990s, research out of Japan found that steviosides, the “active” ingredient in stevia, appeared harmless. But in the guts of rats, intestinal bacteria transformed steviosides into a toxic substance called steviol, which can cause a big spike in mutagenic DNA damage in vitro.88 Unfortunately, it turns out that humans have the same bacterial activity in their guts.89 It’s the dose that makes the poison, though. The World Health Organization considers up to 1.8 mg of stevia compounds per pound of body weight to be a safe amount. Given the American sweet tooth, though, if we sweetened everything with stevia, you could exceed that safety limit. But just drinking up to two stevia-sweetened beverages a day should be considered harmless.90