How about putting saffron head-to-head against one of the most popular Alzheimer’s drugs on the market: donepezil (commonly marketed under the brand name Aricept)? A twenty-two-week double-blind study (meaning that neither the researchers nor the subjects knew who was on the drug and who was on the spice until the study’s conclusion) found that saffron appears just as effective at treating Alzheimer’s symptoms as the leading drug.131 Unfortunately, working just as well as medication isn’t saying much,132 but at least a person doesn’t have to risk the drug’s side effects, most typically nausea, vomiting, and diarrhea.133
While there is no proven way to halt the progression of Alzheimer’s, if you do know anyone suffering from the disease, regularly cooking him or her saffron-spiced paella may help.
Gerontotoxins
Each of us contains tens of billions of miles of DNA—enough for one hundred thousand round trips to the moon if you uncoiled each strand and placed them end to end.134 How do our bodies keep it from all getting tangled up? Enzymes known as sirtuins keep our DNA wrapped up nice and neat around spool-like proteins.
Although they were only discovered recently, sirtuins represent one of the most promising areas of medicine, as they appear to be involved in promoting healthy aging and longevity.135 Autopsy studies show the loss of sirtuin activity is closely associated with the hallmarks of Alzheimer’s disease—namely, the accumulation of plaques and tangles in the brain.136 Suppression of this key host defense is considered a central feature of Alzheimer’s.137 The pharmaceutical industry is trying to come up with drugs to increase sirtuin activity, but why not just prevent its suppression in the first place? You may be able to do this by reducing your dietary exposure to advanced glycation end products, or AGEs.138
AGE is an appropriate acronym, as they are considered “gerontotoxins,”139 meaning aging toxins (from the Greek geros, meaning “old age,” as in “geriatric”). AGEs are thought to accelerate the aging process by cross-linking proteins together, causing tissue stiffness, oxidative stress, and inflammation. This process may play a role in cataract formation and macular degeneration in the eye, as well as damage to the bones, heart, kidneys, and liver.140 They may also impact the brain, appearing to accelerate the slow shrinkage of your brain as you age141 and suppressing your sirtuin defenses.142
Older adults with high levels of AGEs in their blood143 or urine144 appear to suffer an accelerated loss of cognitive function over time. Elevated levels of AGEs are also found in the brains of Alzheimer’s victims.145 Where are these AGEs coming from? Some are produced and detoxified naturally in your body,146 but other than cigarette smoke,147 major sources are “meat and meat-derived products” exposed to dry-heat cooking methods.148 AGEs are formed primarily when fat- and protein-rich foods are exposed to high temperatures.149
More than five hundred foods have been tested for AGE content, everything from Big Macs and Hot Pockets to coffee and Jell-O. In general, meat, cheese, and highly processed foods had the highest AGE content, and grains, beans, breads, vegetables, fruits, and milk had the least.150
The top-twenty most AGE-contaminated products per serving tested were various brands of:
1. BBQ chicken
2. Bacon
3. Grilled hot dog
4. Roasted chicken thigh
5. Roasted chicken leg
6. Pan-fried steak
7. Oven-fried chicken breast
8. Deep-fried chicken breast
9. Stir-fried steak strips
10. McDonald’s Chicken Selects breast strips
11. Pan-fried turkey burger
12. BBQ chicken
13. Oven-fried fish
14. McDonald’s Chicken McNuggets
15. Grilled chicken
16. Pan-fried turkey burger
17. Baked chicken
18. Pan-fried turkey burger
19. Boiled hot dog
20. Grilled steak151
You get the idea.
Yes, cooking methods matter. A baked apple has three times more AGEs than a raw apple, and a grilled hot dog has more than a boiled hot dog. But the source is what matters most: a baked apple has 45 units of AGEs compared to a raw apple’s 13 units, while a grilled hot dog has 10,143 units compared to a boiled hot dog’s 6,736. The researchers recommend cooking meat using moist-heat cooking methods, such as steaming or stewing, but even boiled fish has more than 10 times more AGEs than a sweet potato roasted for an hour. Meat averages about 20 times more AGEs than highly processed foods like breakfast cereals and about 150 times more than fresh fruits and vegetables. Poultry was the worst, containing about 20 percent more AGEs than beef. The researchers concluded that even a modest reduction in meat intake could realistically cut daily AGE intake in half.152
Because sirtuin suppression is both preventable and reversible by AGE reduction, avoiding high-AGE foods is seen as potentially offering a new strategy to combat the Alzheimer’s epidemic.153
Halting Cognitive Decline with Exercise?
There is exciting news for people on the verge of losing their mental faculties. In a 2010 study published in the Archives of Neurology, researchers took a group of people with mild cognitive impairment—those who are starting to forget things, for example, or regularly repeating themselves—and had them engage in aerobic exercise for forty-five to sixty minutes a day, four days a week, for six months. The control group was instructed to simply stretch for the same time periods.154
Memory tests were performed before and after the study. Researchers found that in the control (stretching) group, cognitive function continued to decline. But the exercising group not only didn’t get worse, they got better. The exercisers got more test answers correct after six months, indicating their memory had improved.155
Subsequent studies using MRI scans found that aerobic exercise can actually reverse age-related shrinkage in the memory centers of the brain.156 No such effect was found in the stretching and toning control groups or a nonaerobic strength-training group.157 Aerobic exercise can help improve cerebral blood flow, improve memory performance, and help preserve brain tissue.
Let’s face it: A life without memories is not much of a life. Whether those memories are lost all at once from a massive stroke, chipped away by ministrokes that leave little holes in the brain, or destroyed from within by degenerative diseases like Alzheimer’s, eating and living healthier can help eliminate some of the worst risk factors for the most serious brain diseases.
But the key is starting early. High cholesterol and high blood pressure may begin hurting your brain as early as your twenties. By your sixties and seventies, when the damage can become apparent, it may already be too late.
Like so many other organs, the brain possesses a miraculous ability to heal itself, to forge new synaptic connections around old ones, to learn and relearn. That is, however, if you don’t keep damaging it three times a day. A wholesome diet and exercise may offer your best hope for remaining sharp and healthy into your twilight years.
Thankfully, I can conclude this chapter on a happier note than how it began. Despite our family history, both my mum and my brother, Gene, now eat a healthy, plant-based diet, and my mum shows no signs of succumbing to the same fate of brain disease that claimed the lives of her parents. Although Gene and I know that one day we’ll eventually lose her, given her new healthy diet, our hope is that we won’t lose our mum before she is gone.
CHAPTER 4
How Not to Die from Digestive Cancers
Every year, Americans lose more than five million years of life from cancers that may have been prevented.1 Only a small percentage of all human cancers are attributable to purely genetic factors. The rest involve external factors, particularly our diet.2
Your skin covers about twenty square feet. Your lungs, if you were to flatten out all the tiny air pockets, could cover hundreds of square feet.3 And your intestines? Counting all the little folds, some scientists estimate that your gut would blanket thousands of square feet,4 vastly
more expansive than your skin and lungs combined. What you eat may very well be your primary interface with the outside world. This means that regardless of the carcinogens that could be lurking in the environment, your greatest exposure may be through your diet.
Three of the most common cancers of the digestive tract kill approximately one hundred thousand Americans each year. Colorectal (colon and rectal) cancer, which claims fifty thousand lives annually,5 ranks among the most commonly diagnosed of all cancers. Thankfully, it is also among the most treatable if caught early enough. Pancreatic cancer, on the other hand, is virtually a death sentence for the approximately forty-six thousand people who develop it every year.6 Few survive beyond a year after diagnosis, which means prevention is paramount. Oesophageal cancer, which affects the tube between your mouth and stomach, is also frequently fatal for its eighteen thousand annual victims.7 The foods you eat can indirectly affect cancer risk, for example, by exacerbating acid reflux, a risk factor for oesophageal cancer, or through direct contact with the lining of the digestive tract.
Colorectal Cancer
The average person has about a one-in-twenty chance of developing colorectal cancer over the course of his or her lifetime.8 Fortunately, it is among the most treatable cancers, as regular screening has enabled doctors to detect and remove the cancer before it spreads. There are more than one million colorectal cancer survivors in the United States alone, and, among those diagnosed before the cancer has spread beyond the colon, the five-year survival rate is about 90 percent.9
But, in its early stages, colorectal cancer rarely causes symptoms. If the cancer is not caught until later stages, treatment is more difficult and less effective. Starting at age fifty until age seventy-five, you should either get stool testing every year, stool testing every three years plus a sigmoidoscopy every five years, or a colonoscopy every ten years.10 For more on the risks and benefits of these options, see chapter 15. While regular screenings are certainly sensible to detect colorectal cancer, preventing it in the first place is even better.
Turmeric
India’s gross domestic product (GDP) is about eight times less than that of the United States,11 and about 20 percent of its population lives below the poverty line,12 yet cancer rates in India are much lower than in the United States. Women in the United States may have ten times more colorectal cancer than women in India, seventeen times more lung cancer, nine times more endometrial cancer and melanoma, twelve times more kidney cancer, eight times more bladder cancer, and five times more breast cancer. Men in the United States appear to have eleven times more colorectal cancer than men in India, twenty-three times more prostate cancer, fourteen times more melanoma, nine times more kidney cancer, and seven times more lung and bladder cancer.13 Why such a discrepancy? The regular use of the spice turmeric in Indian cooking has been proposed as one possible explanation.14
In chapter 2, we saw how curcumin, the yellow pigment in the spice turmeric, may be effective against cancer cells in vitro. Very little of the curcumin you eat gets absorbed into your bloodstream, however, so it may never come in sufficient contact with tumors outside the digestive tract.15 But what doesn’t get absorbed into your blood ends up in your colon, where it could impact the cells lining your large intestine where cancerous polyps develop.
The emergence of colorectal cancer can be broken up into three stages. The first sign may be what are called “aberrant crypt foci,” or abnormal clusters of cells along the lining of the colon. Next come polyps that grow from that inner surface. The final stage is thought to occur when a benign polyp transforms into a cancerous one. The cancer can then eat through the wall of the colon and spread throughout the body. To what degree can curcumin block each stage of colorectal cancer?
Studying smokers, who tend to have a lot of aberrant crypt foci, investigators found that curcumin consumption could reduce the number of those cancer-associated structures in their rectums up to nearly 40 percent, from eighteen down to eleven, within just thirty days. The only reported side effect was a yellow tint to their stools.16
What if polyps have already developed? Six months of curcumin, along with another phytonutrient called quercetin, which is found naturally in such fruits and vegetables as red onions and grapes, were found to decrease the number and size of polyps by more than half in patients with a hereditary form of colorectal cancer. Again, virtually no side effects were reported.17
What if the polyps have already transformed into cancer? In a last-ditch attempt to save the lives of fifteen patients with advanced colorectal cancer who didn’t respond to any of the standard chemotherapy agents or radiation, oncologists started them on a turmeric extract. In the two to four months of treatment, it appeared to help stall the disease in one-third of the patients, five out of fifteen.18
If we were talking about some new kind of chemotherapy drug that only helped one in three people, you’d have to weigh that against all the serious side effects. But when it’s just some plant extract shown to be remarkably safe, even if it just helped one in a hundred, it would be worth considering. With no serious downsides, a one-in-three potential benefit for end-stage cancer seems like it would spark further research, right? But who’s going to pay for a study of something that can’t be patented?19
The low cancer rate in India may be due in part to the spices they use, but it may also stem from the types of foods they are putting those spices on. India is one of the world’s largest producers of fruits and vegetables, and only about 7 percent of the adult population eats meat on a daily basis. What most of the population does eat every day are dark-green, leafy vegetables and legumes,20 such as beans, split peas, chickpeas, and lentils, which are packed with another class of cancer-fighting compounds called phytates.
Stool Size Matters
The bigger and more frequent your bowel movements are, the healthier you may be. Based on a study of twenty-three populations across a dozen countries, the incidence of colon cancer appears to skyrocket as the average daily stool weight drops below about a half a pound. Populations dropping quarter pounders appear to have three times the rate of colon cancer. You can measure the weight of your stools with a simple bathroom scale. No, not that way—by weighing yourself before and after you “go.”
The link between stool size and colon cancer may be related to “intestinal transit time,” the number of hours it takes for food to travel from mouth to toilet. The larger the stool, the quicker the transit time, as it’s easier for your intestines to move things along.21 People don’t realize you can have daily bowel movements and still effectively be constipated; what you’re flushing today you may have eaten last week.
How long it takes food to get from one end to the other can depend on gender and dietary habits. Food goes through men eating plant-based diets in just a day or two, but this transit time takes as long as five or more days among those eating more conventional diets. Women eating plant-based diets also average a day or two, but the average intestinal transit time in most women eating conventional diets may be four days.22 So you can be regular but four days late. You can measure your own oral-anal transit time by eating some beetroot and noting when your stools turn pink. If that takes less than twenty-four to thirty-six hours, you’re probably meeting the healthy half-pound target.23
Constipation is the most common gastrointestinal complaint in the United States, leading to millions of doctor visits each year.24 But beyond just the discomfort, the straining associated with trying to pass small, firm stools may play a role in a host of health problems, including hiatal hernia, varicose veins, hemorrhoids,25 and painful conditions with names like anal fissure.26
Constipation can be considered a nutrient-deficiency disease, and that nutrient is fibre.27 Just as you can get scurvy if you don’t get enough vitamin C, you can get constipation if you don’t get enough fibre. Since fibre is found only in plant foods, it’s no surprise that the more plants you eat, the less likely you are to be constipated. For example, a study comparing thou
sands of omnivores, vegetarians, and vegans found that those eating strictly plant-based diets are three times more likely to have daily bowel movements.28 Looks like vegans are just regular people.
Phytates
Colorectal cancer is the second-leading cause of cancer-related death in the United States,29 yet in some parts of the world, it’s practically unheard of. The highest rates have been recorded in Connecticut, and the lowest in Kampala, Uganda.30 Why is colorectal cancer so much more prevalent in Western cultures? Seeking answers to this question, renowned surgeon Denis Burkitt spent twenty-four years in Uganda. Many of the Ugandan hospitals Dr. Burkitt visited had never even seen a case of colon cancer.31 He eventually came to the conclusion that fibre intake was the key,32 as most Ugandans consumed diets centered around whole plant foods.33
Subsequent research has suggested that dietary prevention of cancer may involve something other than just fibre. For instance, colorectal cancer rates are higher in Denmark than in Finland,34 yet Danes consume slightly more dietary fibre than Finns.35 What other protective compounds might explain the low cancer rates among plant-based populations? Well, fibre isn’t the only thing found in whole plant foods that’s missing from processed and animal-based foods.
The answer might lie in natural compounds called phytates, which are found in the seeds of plants—in other words, in all whole grains, beans, nuts, and seeds. Phytates have been shown to detoxify excess iron in the body, which otherwise can generate a particularly harmful kind of free radical called hydroxyl radicals.36 The standard American diet may therefore be a double whammy when it comes to colorectal cancer: Meat contains the type of iron (heme) particularly associated with colorectal cancer37 but lacks, as do refined plant foods, the phytates to extinguish these iron-forged free radicals.
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