Bone Health
The most surprising news about dairy may be its effect on bone density and health. We know that calcium is important to preserve bone density and prevent osteoporosis and that milk is an abundant source of calcium. But milk's acidic properties can affect our ability to fully utilize its calcium, and this can lead to some odd results. For example, a review of fifty-eight clinical studies evaluating the importance of dairy consumption to healthy bone growth in children and adolescents found no significant link between milk consumption—or calcium consumption—and healthy bone development.20 The authors of this study conclude:
Neither increased consumption of dairy products, specifically, nor total dietary calcium consumption, has shown even a modestly consistent benefit for child or young adult bone health. Conclusion: Scant evidence supports nutrition guidelines focused specifically on increasing milk or other dairy product intake for promoting child and adolescent bone mineralization.21
Among older populations, research has yielded even weirder findings about dairy and bone health. A Harvard study found that women who drank two or more glasses of milk daily had a significantly greater risk of hip fractures than those who drank one glass or less weekly.22 And a study of elderly Australians found that those who consumed the most dairy had twice the risk of hip fracture compared to those who consumed the least.23 Coincidentally, as with prostate and ovarian cancer risk, the critical level at which dairy is risky for bone health—two servings a day—is below both the three recommended by the USDA and the nearly four servings (in milk or equivalents) consumed by Americans daily.
There are two reasons why consuming dairy can lead to problems with bone density like osteoporosis. First, dairy's acidic pH causes the body to release calcium (an alkali) from bone to counter the acid's effects and restore healthy pH.24 Second, high levels of calcium consumption over long periods of time impair the body's ability to regulate production of the hormone calcitriol, which controls calcium absorption and excretion.25 Inappropriate calcitriol production can lead to excessive release of bone cells and reduction in bone mineral density.
The body tends to adjust to higher and higher levels of calcium intake, that is, to raise its point of balance to equal the level of calcium consumption. This compensation mechanism means those who consume calcium supplements can suffer the same bone density problems as those who consume large quantities of dairy.26 One of the leading scientists in this field, the late Harvard nutritionist D. Mark Hegsted, wrote of the irony of this phenomenon:
As we encourage people to consume more calcium, their calcium requirement—as defined by calcium balance—increases, with no end in sight. Numerous population studies in the U.S. and elsewhere have analyzed the relationship between dietary calcium intakes and fractures, finding that surprisingly, high calcium intakes do not protect against fractures.27
On the contrary, high intakes of calcium lead to high fracture rates. In Hong Kong, daily calcium consumption is less than 500 milligrams per day, and females suffer hip fractures at the rate of thirty-five cases per hundred thousand people. Americans consume at least twice as much calcium, averaging about 1,000 milligrams per day. Yet our per capita incidence of female hip fractures is three times higher than Hong Kong's.28 This research is consistent with other studies that find bone fractures are more common in Western countries, where dairy consumption is high, than in countries where little dairy is consumed.29
The studies on calcium and hip fractures are not exactly breaking news—they were published in the 1980s and '90s. Moreover, modern research suggests that people seeking to improve bone density should exercise more and eat plant-based calcium sources like kale and spinach (a plan that seems to work for herbivores like horses and elephants). Why then do Americans still turn, somewhat futilely, to dairy and calcium supplements for bone health? We do so because despite the high correlation between dairy consumption, calcium intake, and hip fractures, the dairy industry and the USDA continue to recommend that Americans aged nineteen to fifty consume 1,000 milligrams of calcium per day. This recommendation appears to have one goal: to sell dairy products.
Kids and Milk
For many, it will be astounding to learn that kids don't need cow's milk and would actually be better off without it. Why is this news so astonishing? Because just as we know the sun rises in the east, we know children need milk to grow up big and strong. Yet one of the pieces of information to emerge from recent studies is that kids grow up healthier when they don't consume significant amounts of dairy (other than their own mothers' milk) or other animal protein. Certainly, children need their own mothers' breast milk while in infancy. But otherwise, and after the age of weaning, there is little in the clinical literature to suggest that children need cow's milk or other animal foods for healthy development.
In fact, studies show the opposite. Girls who develop too quickly, for example—a phenomenon associated with drinking cow's milk—are more likely to develop breast cancer later in life.30 In one study of British girls, researchers found fast growth was associated with more than a 50 percent greater risk of breast cancer, leading the authors to conclude that “women who grow faster in childhood and reach an adult height above the average for their menarche [first menstruation] category are at particularly increased risk of breast cancer.”31 This heightened cancer risk may stem from the fact that other than in infancy, mammals' bodies are simply not designed to drink milk. After humans are weaned, we stop secreting both the enzyme rennin that breaks down milk protein and the enzyme lactase that digests lactose (milk sugar) and transforms it into sugars that our body can use (glucose and galactose).
Doctor Benjamin Spock wrote the bestselling book Baby and Child Care and, a decade after his death, remains one of the most influential pediatricians on the planet. Spock staunchly opposed feeding cow's milk or other animal foods to children of any age. In the “Foods to Avoid” section of his book, Spock wrote:
Meat: Children who grow up without developing a taste for meat, poultry, or fish will carry a tremendous advantage through life. Their tastes will not be oriented toward these products, all of which contain fat and cholesterol that can contribute to weight problems, heart disease and some cancers. They will also be at much less risk of infection with the bacteria that often taint meat products.
Dairy products: Nondairy milk, particularly soy milk has real advantages over cow's milk and other dairy products. These products are free of animal fat, animal protein, and lactose sugar, while still providing excellent nutrition.32
A number of children's doctors agree, including Dr. Frank A. Oski. While serving as director of pediatrics at Johns Hopkins University, Oski said, “There's no reason to drink cow's milk at any time in your life. It was designed for calves, not humans, and we should all stop drinking it today.”33
Egg-cess: Issues in Eating Eggs and Chicken
Are eggs really the “perfect protein”? They do provide protein and other nutrients. But they're also an abundant source of cholesterol; a single large egg contains 212 milligrams of the stuff. Because ingested cholesterol is never necessary but always harmful to our bodies, that's 212 milligrams more than we need and two-thirds more than the USDA's liberal, recommended daily maximum of 300 milligrams.34 The Jekyll-and-Hyde nutritional personalities of eggs seem to fit a pattern familiar in animal foods—they contain some helpful nutrients, but they also include plenty of disease-promoting substances. In the case of eggs, research has created controversy in the scientific community over whether their nutritional benefits outweigh the risks associated with their high cholesterol content.
Many studies show that egg consumption increases blood cholesterol, a phenomenon linked to increased risk of heart disease.35 On the other hand, a well-publicized 2007 paper by Adnan Qureshi and colleagues found that adults who eat more than six eggs per week have no greater risk of stroke or heart disease than those who eat no eggs.36 While some point to the first set of studies to argue that eggs cause heart disease, others�
�notably, the egg industry—cite the Qureshi article as evidence of eggs' harmlessness. Because this study's design and methodology are similar to those of other inquiries finding that animal foods are healthy, such as the Siri-Tarino piece discussed in chapter 1, it merits a closer look.
Using the cohort research model, Qureshi's team compared several populations of egg eaters to determine their incidence of disease over time. Qureshi's team adjusted for confounding factors like age, gender, race, and cigarette smoking. But just as the Siri-Tarino researchers did, the Qureshi team failed to adjust for the most important confounding factor: regular consumption of other animal foods. American males over the age of twelve routinely consume more cholesterol than recommended, in some cases by 100 milligrams or more daily.37 Since many Americans are already in a high-cholesterol category, which leads to heart disease for one in three, it's easy to see why adding an egg a day might not materially increase this risk.
In fact, in order to make their analysis representative of the US population, the Qureshi team chose cohorts whose members were overweight (with BMI over 25) and had blood cholesterol levels of 220 mg/dl or higher. That's 10 percent above the recognized safe cholesterol level of 200 mg/dl and 50 percent higher than the average of 146 mg/dl among vegans.38 In other words, this study looked at whether overweight people with high cholesterol, already substantially at risk for heart disease, would get any worse if they ate an egg a day. That's like studying the risk of cigar smoking among people who already smoke two packs of cigarettes a day.
Dietary cholesterol is present in animal foods but not in plant foods. So the only accurate way to measure the cholesterol-related effects of eating eggs is to compare a cohort of vegans with one whose only source of dietary cholesterol is eggs. Since the Qureshi study failed to control for the confounding effects of cholesterol intake, it's little wonder the study found no difference in disease risk between groups.
On the other hand, researchers do find a link between egg consumption and disease when they compare cohorts who eat less animal foods than Americans do and for whom a single egg is thus a more significant part of their diet. One study involving Japanese cohorts noted health benefits associated with “limiting egg consumption.”39 These researchers found links among egg consumption, blood cholesterol levels, and mortality rates among women “in geographic areas where egg consumption makes a relatively large contribution to total dietary cholesterol intake.”40 Plainly stated, the harmful effects of eggs are more clearly evident among those who eat less animal foods to begin with.
Despite the Qureshi study's design flaws, it's a favorite among egg industry marketers. The American Egg Board receives $21 million in yearly federal-mandated checkoff money.41 These funds power the website eggnutritioncenter.org, where the Qureshi study gives credibility to misleading messages like “An Egg a Day is MORE Than Okay!”42
Not to get too metaphysical, but is it possible to discuss eggs without mentioning chicken? Actually, chicken-related illnesses like cancer, heart disease, and food poisoning are discussed in the main text. As shown in chapter 6, there's little that's healthy about chicken.
Something's Fishy: Issues in Eating Seafood
Like eggs, fish are a nutritional paradox. On one hand, they're a good source of omega-3 fatty acids, which can improve infant brain development and reduce the risk of coronary heart disease.43 On the other hand, almost without exception, fish contain mercury, a neurotoxin that can damage the nervous system and cause cognitive disabilities.44 And they frequently contain polychlorinated biphenyls (PCBs), which cause cancer and, in infants, neurological and motor control problems.45 Like all animal foods, fish also invariably contain cholesterol (in some cases at levels as high as ground beef—see table 6.1 in chapter 6), and this substance causes heart disease. Finally, because all animal protein—including fish—promotes cancer, a diet high in seafood increases one's risk of cancer relative to a plant-based diet.46
Where does all this mercury and PCB come from? The mercury seems to come mainly from coal-fired power plants. PCBs, on the other hand, were used in manufacturing in the United States until they were banned in 1977, but they've lingered in our water and soil for decades and, as a result, persist in the environment. Both PCBs and mercury accumulate in the fatty tissues of fish and other animals, which means they are passed up the food chain until eaten by humans.
In a seven-year study of fish in 291 US waterways, the US Geological Survey found that every one of more than one thousand fish it examined contained some mercury. One-quarter of the fish contained mercury at levels unhealthy for human consumption, and two-thirds were contaminated at levels unhealthy for consumption by other mammals.47 It's not just fish in inland waterways that are toxic with mercury; high levels of mercury are routinely found in deep-sea fish as well.48 And PCBs are equally prevalent: another study found that thirty-nine of forty fish sampled contained PCBs in measurable quantities.49
The nutritional paradox surrounding fish leads to complicated advice on whether and when to eat it, dispensed in articles with titles like “Fish Is Good—Fish Is Bad” and “Americans Confused about Health Effects of Eating Fish.”50 In one particularly bizarre piece in the Journal of the American Medical Association, the authors note that omega-3s may help new or expectant mothers, but a few paragraphs later, warn that new or expectant mothers “should avoid four types of fish that are higher in mercury content.”51 Other articles contain charts advising which fish have acceptable levels of mercury and PCBs and how often one can eat them.52
If this seems like a lot of risk and effort to obtain omega-3s, consider a non-fish, nontoxic source for your beneficial fatty acids. Omega-3s are readily available in flax, hemp, soy, and walnuts. You won't need a chart to remember which you can eat and when, and none of these plant-based sources causes cancer, neurological defects, or developmental impairment.
¶ Milk, the source of all dairy, is the main ingredient in cheese, butter, cream, ice cream, yogurt, and whey.
Appendix B
Summary of the Annual Externalized Costs of US Animal Food Production (in billions)1
Appendix C
Economic Effects of Proposed Meat Tax and Support Changes
This appendix shows calculations for the main economic effects expected to result from this book's proposed changes to federal tax and support policy. These outcomes include: (1) reductions in subsidies and other support to the animal food industry, (2) a drop in consumption of animal foods, (3) a new tax burden for taxpayers, (4) a new tax credit for taxpayers, (5) an increase in tax revenue, (6) higher federal government outflows associated with the tax credit, (7) lower state and federal government outflows under Medicare and Medicaid programs, (8) a cash surplus for the federal government, and (9) decreases in externalized costs. As a reminder, economics is not a precise science, so while these figures may seem meticulously calculated, they are just estimates. You don't really know how something will play out until you try it, although you can certainly make predictions.
Weighted Average Elasticity Rate
The following calculations use a constant of 0.65 as the price elasticity of demand for animal foods. This constant is a weighted average based on the individual fair market values of animal foods produced yearly and their respective price elasticities, as shown in table C1. Note that “production value,” roughly analogous to wholesale value, is used rather than retail value because retail sales data for individual animal foods is not uniformly available.
TABLE C1 Animal Food Production Values, Elasticities, and Weighted Average Elasticity Rate (dollar amounts in billions)1, 2
Changes in Subsidies and Other Support
The proposed support changes affect two categories. First, there's the gross figure of $28.9 billion that the USDA spends supporting US farmers with loans, insurance, research, marketing assistance, and other help (the research and marketing subsidy).3 My recommendation is to eliminate the portion of this subsidy related to animal food production, which is rou
ghly $18.2 billion.4 Loss of this subsidy will have an effect on both producers and consumers.
From the producers' perspective, because the Meat Tax will cause consumption (and production) of animal foods to decline by 32.5 percent (see “Drop in Consumption” below), the portion of this subsidy on which producers would rely in order to maintain the status quo after adjusting sales for the effects of the Meat Tax is 67.5 percent (1 – 0.325) of $18.2 billion, or $12.3 billion. In other words, following the drop in consumption, a subsidy of only $12.3 billion will allow producers to maintain production at the new, lower level.
In the absence of data predicting how producers are likely to respond to the loss of certain services, it is reasonable to assume that they will choose to discontinue roughly half of these formerly subsidized services and continue half at their own expense ($6.1 billion). And in light of data showing that producers typically internalize some portion of increases in production costs (ranging from a minority to a majority of such costs), it is reasonable to assume further that producers will internalize roughly half of these costs and pass the other half ($3 billion) on to consumers.5 The resulting price increase is roughly 1.8 percent of the total retail sales of animal foods, after reducing this sales figure for the effects of the Meat Tax (see “Drop in Consumption” below). Table C2 shows the effect of applying the demand elasticity constant of 0.65 to this increase: eliminating this subsidy will cause consumer demand to decline by about 1.2 percent.
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