206 THE CHINA STUDY CHART 10.1: ASSOCIATION OF URINARY CALCIUM EXCRETION WITH DIETARY PROTEIN INTAKE (2) 100 (4) E • (1) ::J 'u m u (5) ~ (33) • (2) rc c § ~ 50 OJ Vl Y=0.50X r =0.85 rc ~ u f: ";R 0 100 200 % Increase in Protein Intake cium Chart 10.1 is taken from the 1981 publication 10 Doubling protein intake (mostly animal-based) from 35-78 glday causes an alarming 50% increase in urinary calcium This effect occurs well within the range of protein intake that most of us consume; average American intake is around 70-100 glday Incidentally, as mentioned in chapter four, a sixmonth study funded by the Atkins Center found that those people who adopted the Atkins Diet excreted 50% more calcium in their urine after six months on the diet 12 The initial observations on the association between animal protein consumption and bone fracture rates are very impressive, and now we have a plausible explanation as to how the association might work, a mechanism of action Disease processes are rarely as simple as "one mechanism does it all," but the work being done in this field makes a strong argument A more recent study, published in 2000, comes from the Department of Medicine at the University of California at San Francisco Using eighty-seven surveys in thirty-three countries, it compared the ratio of vegetable to animal protein consumption to the rate of bone fractures (Chart 10.2).1 A high ratio of vegetable to animal protein consumption was found to be impressively associated with a virtual disappearance of bone fractures These studies are compelling for several reasons They were published in leading research journals, the authors were careful in their analyses and WID E- RAN GIN G EF FE CT S: BON E,K ION EY EYE BRA I N I SE ASES 207 I I CHART 10.2: ASSOCIATION OF ANIMAL VERSUS PLANT PROTEIN INTAKE AND BONE FRACTURE RATES FOR DIFFERENT COUNTRIES 200 175 150 ~ Qlet> vQl c>QI I "C 125 v", c -QI QlCl 30 vo et> '-'-0 100 75 Cl.~ IQj s- 50 25 0_0 1_0 2.0 3.0 4.0 5.0 6.0 Vegetable-to-Animal Protein Intake Ratio (gig) interpretation of data, they included a large number of individual research reports, and the statistical significance of the association of animal protein with bone fracture rates is truly exceptional They cannot be dismissed as just another couple of studies; the most recent study represents a summary of eighty-seven separate surveys! The Study of Osteoporotic Fractures Research Group at the University of California at San Francisco published yet another study 13 of over 1,000 women aged Sixty-five and up Like the multi-country study, researchers characterized women's diets by the proportions of animal and plant protein After seven years of observations, the women with the highest ratio of animal protein to plant protein had 3.7 times more bone fractures than the women with the lowest ratio Also during this time the women with the high ratio lost bone almost four times as fast as the women with the lowest ratio Experimentally, this study is high quality because it compared protein consumption, bone loss and broken bones for the same subjects This 3.7-fold effect is substantial, and is very important because the I t 208 THE CHINA STUDY women with the lowest bone fracture rates still consumed, on average, about half of their total protein from animal sources I can't help but wonder how much greater the difference might have been had they consumed not 50% but 0-10% of their total protein from animal sources In our rural China study, where the animal to plant ratio was about 10%, the fracture rate is only one-fifth that of the U.S Nigeria shows an animal-to-plant protein ratio only about 10% that of Germany, and the hip fracture incidence is lower by over 99%.1 These observations raise a serious question about the widely advertised claim that protein-rich dairy foods protect our bones And yet we still are warned almost daily about our need for dairy foods to provide calcium for strong bones An avalanche of commentary warns that most of us are not meeting our calcium requirements, especially pregnant and lactating women This calcium bonanza, however, is not justified In one study of ten countries,14 a higher consumption of calcium was associated with a higher-not lower-risk of bone fracture (Chart 10.3) Much of the calcium intake shown in this chart, especially in high consumption countries, is due to dairy foods, rather than calcium supplements or non-dairy food sources of calcium Mark Hegsted, who produced the results in Chart 10.3, was a longtime Harvard professor He worked on the calcium issue beginning in the early 1950s, was a principal architect of the nation's first dietary guidelines in 1980 and in 1986 published this graph Professor Hegsted believes that excessively high intakes of calcium consumed over a long time impair the body's ability to control how much calcium it uses and when Under healthy conditions, the body uses an activated form of vitamin D, calcitriol, to adjust how much calcium it absorbs from food and how much it excretes and distributes in the bone Calcitriol is considered a hormone; when more calcium is needed, it enhances calcium absorption and restricts calcium excretion If too much calcium is consumed over a long period of time, the body may lose its ability to regulate calcitriol, permanently or temporarily disrupting the regulation of calcium absorption and excretion Ruining the regulatory mechanism in this way is a recipe for osteoporosis in menopausal and post-menopausal women Women at this stage of life must be able to enhance their utilization of calcium in a timely manner, especially if they continue to consume a diet high in animal protein The fact that the body loses its ability to control finely tuned mechanisms when they are subjected to continuous abuse is a well-established phenomenon in biology WID E- RAN GIN G EF FECT S: BON E,K I DNEY EY E BRA I N DIS EASE S 209 I I CHART 10.3: ASSOCIATION OF RATES OF HIP FRACTURES WITH CALCIUM INTAKE FOR DIFFERENT COUNTRIES 120 • UNITED STATES • NEW ZEALAND 100 0 • SWEDEN 0" (jj "- 80 • JERUSALEM Vl ~ ~ t ~ L.L • UNITED KINGDOM 60 0- £ • HOLLAND '0 OJ u c 40 • FINLAND • YUGOSLAVIA OJ -c ·0 E • HONG KONG 20 • SINGAPORE o o 500 1,000 1,500 Calcium Consumption (mg/day) Given these findings, it seems perfectly plausible that animal protein and even calcium-when consumed at excessive levels-are capable of increasing the risk of osteoporosis Dairy, unfortunately, is the only food that is rich in both of these nutrients Hegsted, backed by his exceptional experience in calcium research, said in his 1986 paper, " hip fractures are more frequent in populations where dairy products are commonly consumed and calcium intakes are relatively high." Years later, the dairy industry still suggests that we should be consuming more of its products to build strong bones and teeth The confusion, conflict and controversy rampant in this area of research allow anybody to say just about anything And of course, huge amounts of money are at stake as well One of the most cited osteoporosis experts-one funded by the dairy industry-angrily wrote in a prominent editoriaP5 that the findings favoring a diet with a higher ratio of plant-to-animal protein cited above could have been "influenced to some extent by currents in 210 THE CHINA STUDY the larger society." The "currents" he was referring to were the animal rights activists opposed to the use of dairy foods Much of the debate regarding osteoporosis, whether it is conducted with integrity or otherwise, resides in the research concerning the details As you shall see, the devil lurks in the details, the primary detail being that of bone mineral density (BMD) Many scientists have investigated how various diet and lifestyle factors affect BMD BMD is a measure of bone density that is often used to diagnose bone health If your bone density falls below a certain level, you may be at risk for osteoporosis In practical terms, this means that if you have a low BMD , you are at a higher risk for a fracture I 6-18 But there are some devilishly contradictory and confUSing details in this great circus of osteoporosis research To name a few: • A high BMD increases the risk of osteoarthritis 19 • A high BMD has been linked to a higher risk of breast cancer.20, 21 • Although high BMD is linked both to increased breast cancer risk and decreased osteoporotic risk, breast cancer and osteoporosis nonetheless cluster together in the same areas of the world and even in the same individuals.22 • Rate of bone loss matters just as much as overall BMD.23 • There are places where overall bone mass, bone mineral density or bone mineral content measurements are lower than they are in "Western" countries, but the fracture rate also is lower, defying accepted logic of how we define "big, strong bones."24 26 • Being fat is linked to greater BMD,H, 27 even though areas of the world that have higher rates of obesity also have higher rates of osteoporosis Something is wrong with the idea that BMD reliably represents osteoporosis and, by inference, indicates the kind of diet that would lower fracture rates In contrast, an alternative, but much better, predictor of osteoporosis is the dietary ratio of animal-to-plant protein I, 13 The higher the ratio, the higher the risk of disease And guess what? BMD is not significantly associated with this ratio.13 Clearly the conventional recommendations regarding animal foods, dairy and bone mineral density, which are influenced and advertised by the dairy industry, are besieged by serious doubts in the literature Here is what I would recommend you do, based on the research, to minimize your risk of osteoporosis: ... 210 THE CHINA STUDY the larger society." The "currents" he was referring to were the animal rights activists opposed to the use of dairy foods Much of the debate regarding osteoporosis, whether... greater the difference might have been had they consumed not 50% but 0-10% of their total protein from animal sources In our rural China study, where the animal to plant ratio was about 10%, the. .. dismissed as just another couple of studies; the most recent study represents a summary of eighty-seven separate surveys! The Study of Osteoporotic Fractures Research Group at the University of