Avoiding diet fizzy drinks and those pastel paper packets seems easy enough, but artificial sweeteners are also present in more than six thousand products,56 including breath mints, cereals, chewing gums, jams and jellies, juice drinks, puddings, and even nutritional bars and yogurts.57 This prevalence has led researchers to assert that aspartame “is impossible to completely eradicate from daily encounters.”58 But, of course, that’s only true for people who eat processed foods. This is yet another reason to spend most of your time at the supermarket in the produce aisle. Discriminating shoppers make it a priority to read ingredients lists, but the healthiest foods in the supermarket don’t even have them.
Exercise versus Antidepressants
We’ve known for decades that even a single workout can elevate mood59 and that physical activity is associated with decreased symptoms of depression. One study of nearly five thousand people across the country, for example, found that people who exercised regularly had 25 percent lower odds of a major depression diagnosis.60
Of course, studies like these may not mean that exercise reduces depression. Maybe it means that depression reduces exercise. In other words, if you’re depressed, you might feel too lousy to get out of bed and go for a walk. What was needed to test this idea was an interventional study, one in which depressed subjects were split at random (randomized) into two groups, one that exercised and one that didn’t.
That’s what a team of researchers from Duke University attempted. They randomly assigned depressed men and women aged fifty or older to either begin an aerobic exercise program or take the antidepressant drug sertraline (Zoloft). Within four months, the mood of those in the drug group improved so much that they were, on average, no longer depressed. But the same powerful effect was found in the exercise group—that is, the group of people who weren’t taking any drugs. Exercise, it seemed, works about as well as medication.61
Let’s play devil’s advocate for a moment: The drug-free group in the Duke study met three times each week for an exercise class. Could the social stimulation rather than the exercise have improved their mood? With this question in mind, the same researchers subsequently conducted the largest-ever exercise trial of patients with depression. This time, they added a group, so one group took antidepressants, one group took an exercise class, and a new group did exercises by themselves at home. The results? No matter the setting—whether subjects were alone or in a group—exercise appeared to work about as well as drugs at bringing depression into remission.62
So before your doctor writes you a prescription for an antidepressant, ask about prescribing a daily workout instead.
Antioxidants and Folate
Accumulating evidence suggests that free radicals—those highly unstable molecules that cause tissue damage and contribute to aging—may play an important role in the development of various psychiatric disorders, including depression.63 Modern imaging techniques confirm autopsy studies showing a shrinkage of certain emotion centers in the brains of depressed patients that may be due to death of nerve cells in these areas caused by free radicals.64
This phenomenon may help explain why those who eat more fruits and vegetables, which are rich in the antioxidants that extinguish free radicals, appear protected against depression. A study of nearly three hundred thousand Canadians found that greater fruit and vegetable consumption was associated with lower risk of depression, psychological distress, mood and anxiety disorders, and poor perceived mental health. The researchers concluded that eating antioxidant-rich plant foods “may dampen the detrimental effects of oxidative stress on mental health.”65
The Canadian study relied on questionnaires asking people to self-report fruit and vegetable intake, a method that’s not always accurate. A nationwide American study took it one step further and measured the level of carotenoid phytonutrients in people’s blood streams. These phytonutrients include some of the yellow, orange, and red antioxidant pigments found naturally in some of our healthiest foods, including sweet potatoes and green leafy vegetables. Not only did people with higher levels of these nutrients in their bloodstreams have a lower risk of depression symptoms but there was also an apparent “dose-response relationship,” meaning that the higher the level of phytonutrients, the better people seemed to feel.66
Among the carotenoids, lycopene (the red pigment in tomatoes) has the highest antioxidant activity. Indeed, a study of nearly one thousand elderly men and women found that people who ate tomatoes or tomato products daily had just half the odds of depression compared with those who ate them once a week or less.67
If antioxidants are so helpful, why can’t we just pop a few antioxidant pills? Well, only food sources of antioxidants appear to be protectively associated with depression. The same can’t be said for dietary supplements.68 This finding may indicate that the form and delivery of the antioxidants we consume are crucial to ensure their best effects. Alternatively, antioxidants may just be a marker for other components of plant-rich diets, such as folate.
Folate is a B vitamin concentrated in beans and greens. (Its name comes from the Latin word folium, meaning “leaf,” because it was first isolated in spinach.) Early studies linking depression to low folate levels in the blood were cross-sectional in nature, meaning they were only snapshots in time. For this reason, we didn’t know whether low folate intake led to depression or if depression itself led to low folate intake.69 However, more recent studies following people over time suggest that low dietary folate intake may indeed increase the risk of severe depression by as much as threefold.70 However, once again, folate supplements (folic acid) do not appear to help.71
Vegetables—including antioxidant-rich tomatoes and folate-packed greens—may be good for the body and the mind.
Do Antidepressant Drugs Really Work?
We’ve seen that saffron and exercise compare favorably to drugs in treating depression, but how much is that really saying? Thousands of published studies seem to have demonstrated that antidepressant drugs are effective.72 The key word here, though, may be published. What if drug companies decided to publish only those studies that showed a positive effect but quietly shelved and concealed any studies showing the drugs didn’t work? To find out if this was the case, researchers applied to the Food and Drug Administration under the U.S. Freedom of Information Act (FOIA) to get access to the published and unpublished studies submitted by pharmaceutical companies. What they found was shocking.
According to the published literature, the results of nearly all antidepressant trials were positive. In contrast, FDA analysis of trial data—including the unpublished studies—demonstrated that roughly half of the trials showed the drugs didn’t work after all. When all the data—published and unpublished—was combined, antidepressants failed to show a clinically significant advantage over placebo sugar pills.73 This finding suggests that the placebo effect explains the apparent clinical effectiveness of antidepressants. In other words, improvements in mood may be a result of the patient’s belief in the power of the drug—not the drug itself.74
Even worse, the FOIA documents revealed that the FDA knew that these drugs—such as Paxil and Prozac—didn’t work much better than placebo yet made an explicit decision to shield drug companies by keeping this information from the public and prescribing physicians.75 How could drug companies get away with this? The pharmaceutical industry is considered one of the most profitable and politically powerful industries in the United States, and mental illness is considered a golden goose: chronic, common, and often treated with multiple drugs.76 Indeed, antidepressants are currently prescribed to more than 8 percent of the population.77
Just because antidepressant drugs may not work better than fake pills doesn’t mean they don’t work at all. Antidepressants offer substantial benefits to millions of people suffering from depression. And although the placebo effect is real and powerful, antidepressants do seem to beat sugar pills in reducing symptoms in the most severely depressed—perhaps about 10 percent of patients (alth
ough admittedly, this statistic also means that about 90 percent of depressed patients may be prescribed medication with negligible benefit).78
If doctors are willing to give patients placebo-equivalent treatments, some argue that it would be better for them to just lie to patients and give them actual sugar pills.79 Unlike the drugs, sugar pills do not cause side effects. For example, antidepressants cause sexual dysfunction in up to three-quarters of users. Other problems may include long-term weight gain and insomnia. And about one in five people have withdrawal symptoms when they try to quit.80
Perhaps most tragically, antidepressants may make people more likely to become depressed in the future. Studies show that patients are more likely to become depressed again after treatment with antidepressants than after treatment by other means, including placebos.81 So even if the mood-boosting benefit of exercise is also a placebo effect, at least it’s one with benefits rather than risks.
Just reading the dry statistics in all the studies, it’s hard to appreciate the suffering. Seeing a graph in which depression scores drop for even hundreds of people doesn’t hit me on the same gut level as seeing a single e-mail in my inbox of someone sharing his or her story of physical and emotional renewal.
Not long ago, a woman wrote to me about her battle with depression. Shay, in her forties, had always stuck to the standard American diet. In recent years, she had been suffering from severe migraines, unbearable constipation, and painful and irregular menstrual cycles. Meanwhile, her depression had become so bad that she was unable to go to work. Then Shay discovered my website and began educating herself about nutrition. Soon she came to understand how the Western diet was potentially contributing to her health problems, not to mention her unhappiness, and she became an ardent watcher of NutritionFacts.org videos.
Shay decided to switch to a whole-food, plant-based diet. She stopped eating animal products and junk and vastly increased her intake of fruits and vegetables. After four weeks, she had more energy and less-painful bowel movements. Within seven months, her bowel movements were effortless, her once-crippling migraines had stopped altogether, her periods were more regular, less painful, and shorter—and her depression was gone. Just months earlier, Shay had felt so bad that she couldn’t get out of bed in the morning. But by improving her diet, she is now much healthier, both physically and mentally.
That is a great example of the power of a healthy diet.
CHAPTER 13
How Not to Die from Prostate Cancer
When Tony, a regular reader of NutritionFacts.org, heard that I was writing this book, he asked me to share his story with you in the hopes of helping other men avoid what happened to him. A happily married father, engineer, and self-described fitness nut, he always tried to make good choices out of respect for his body and was lucky to have descended from long-lived, healthy ancestors. Tony was a runner who had always been at a healthy weight. He stayed away from tobacco, alcohol, and drugs. In the 1980s, based on health recommendations from the USDA, he convinced his family to switch from whole milk to skimmed milk and from beef to fish and chicken—lots and lots of chicken.
Tony was the kind of patient doctors love to take care of—the type who says, “What else can I do to be at my very best?” So no one was more surprised than Tony when, in his early fifties, he was diagnosed with an aggressive prostate cancer. He sought care at a world-renowned medical center and underwent a radical prostatectomy, which successfully removed his cancer but left him with the daily challenge of dealing with the consequences of that surgery—namely, urinary leakage and erectile dysfunction.
He says he wishes he’d known about the conflicts of interest within the USDA (which I elaborated in chapter 5) that have affected the federal agency’s ability to make recommendations in the best interests of the public independent of those of the food industry.
Eventually, Tony discovered the body of research you will be reading about in this chapter, and, being a scientist, he immediately understood the evidence that a healthy diet can improve male health. He has eaten a plant-based diet for the last several years, takes flaxseed every day, and has had no recurrence of cancer. As I will discuss, the same diet that may prevent prostate cancer has also been shown to potentially slow it down and even reverse its progression among those already diagnosed. So it is Tony’s (and my) wish that this chapter will help you see the importance of healthy eating for a healthy prostate.
The prostate is a walnut-sized gland located between the bladder and base of the penis, just in front of the rectum. It surrounds the urethra, the outlet from the bladder, and secretes the fluid portion of semen. Just as glandular tissue in the breast can become cancerous, so can glandular tissue in the prostate.
Autopsy studies show that about half of men over the age of eighty have prostate cancer.1 Most men die with prostate cancer without ever knowing they had it. That’s the problem with the emphasis on screenings—many prostate cancers that are detected may never have led to harm even if they’d gone undiscovered.2 Unfortunately, not all men are so lucky. Nearly twenty-eight thousand die each year from prostate cancer.3
Milk and Prostate Cancer
Since the U.S. National Dairy Board was first created by the Dairy and Tobacco Adjustment Act of 1983, it has spent more than $1 billion (£650 million) on advertising. By now, we’re all familiar with its various slogans, such as “Milk is a natural.” But is it? Think about it. Humans are the only species who drink milk after weaning. It also does seem a bit unnatural to drink the milk of another species.
What about “Milk: It Does a Body Good”? All foods of animal origin contain sex steroid hormones, such as estrogen, but today’s genetically “improved” dairy cows are milked throughout their pregnancies when their reproductive hormones are particularly high.4 These hormones naturally found even in organic cow’s milk may play a role in the various associations identified between milk and other dairy products and hormone-related conditions, including acne,5 diminished male reproductive potential,6 and premature puberty.7 The hormone content in milk may explain why women who drink it appear to have five times the rate of twin births compared with women who do not drink milk.8 When it comes to cancer, though, the greater concern may have to do with growth hormones.9
Mother Nature designed cow’s milk to put a few hundred pounds on a baby calf within a few months. A lifetime of human exposure to these growth factors in milk may help explain the connections found between dairy consumption and certain cancers.10 Leading Harvard University nutrition experts have expressed concern that the hormones in dairy products and other growth factors could stimulate the growth of hormone-sensitive tumors.11 Experimental evidence suggests that dairy could also promote the conversion of precancerous lesions or mutated cells into invasive cancers.12
Concerns about milk and other dairy products first arose from population-scale data, such as the twenty-five-fold increase in prostate cancer in Japanese men since World War II, which coincided with a sevenfold increase in egg consumption, a ninefold increase in meat consumption, and a twentyfold increase in dairy consumption.13 Though the rest of their diets remained comparatively stable and similar trends have been noted in other countries,14 there were myriad changes in Japanese society beyond eating more animal products that could have contributed to these rising cancer rates. So scientists took a closer look.
To control for as many variables as possible, researchers devised an experiment in which they dripped milk on human prostate cancer cells in a petri dish. The researchers chose organic cow’s milk to exclude any effect of added hormones, such as the bovine growth hormone, which is commonly injected into conventionally raised cows so they produce more milk.15 The researchers found that cow’s milk stimulated the growth of human prostate cancer cells in each of fourteen separate experiments, producing an average increase in cancer growth rate of more than 30 percent. In contrast, almond milk suppressed the growth of the cancer cells by more than 30 percent.16
What happens in a petri dis
h, though, doesn’t necessarily happen in people. Nevertheless, a compilation of case-control studies did conclude that cow’s milk consumption is a risk factor for prostate cancer,17 and the same outcome was found for cohort studies.18 A 2015 meta-analysis found that high intakes of dairy products—milk, low-fat milk, and cheese, but not nondairy sources of calcium—appear to increase total prostate cancer risk.19
But, you may be wondering, if you don’t drink milk, what will happen to your bones? Doesn’t milk help prevent osteoporosis? It turns out that the promised benefit may be just another empty marketing ploy. A meta-analysis of cow’s milk intake and hip fracture studies shows no significant protection.20 Even if you were to start drinking milk during adolescence in an attempt to bolster peak bone mass, it probably wouldn’t reduce your chances of fracture later in life.21 One recent set of studies involving one hundred thousand men and women followed for up to two decades even suggested milk may increase bone and hip fracture rates.22
Some babies are born with a rare birth defect called galactosemia, in which they lack the enzymes needed to detoxify galactose, a type of sugar found in milk. This means they end up with elevated levels of galactose in their blood, which can cause bone loss.23 A group of Swedish researchers figured that even among normal people who can detoxify the stuff, it might not be good for their bones to be drinking all that galactose in milk every day.24 And galactose may not just hurt bones. Scientists actually use galactose to induce premature aging in lab animals. When researchers slip lab animals some galactose, the “life-shortened animals showed neurodegeneration, mental retardation and cognitive dysfunction . . . diminished immune responses and reduction of reproductive ability.”25 And it doesn’t take much, just the human equivalent of one to two glasses worth of milk a day.26
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