A low-fat vegan diet may help people with Type 2 diabetes reduce physical pain related to the condition, suggests a small new study.
“This new study gives a ray of hope for a condition where there are no other good treatments,” said Dr. Neal Barnard, the study’s lead author and president of the Physicians Committee for Responsible Medicine, a non-profit organization that promotes a vegan diet, preventive medicine and alternatives to animal research.
Most people with Type 2 diabetes will develop peripheral diabetic neuropathy, the researchers write in Nutrition and Diabetes. People with the condition may feel pain, burning and numbness in their body’s extremities.
“For an individual patient, it can be miserable and depressing because there are no good treatments, and it just gets worse and worse,” said Barnard, who is also affiliated with the George Washington University School of Medicine in Washington.
“By setting aside animal products and oily foods, you can become healthier, and your pain can diminish and perhaps even go away,” he told Reuters Health in an e-mail.
Type 2 is the most common form of diabetes and is often linked to obesity. In Type 2 diabetes, the body’s cells are resistant to the hormone insulin, or the body doesn’t make enough of it. Insulin gives blood sugar access to the body’s cells to be used as fuel.
The disease is thought to interfere with the ability of nerves to signal the brain about pain, light touch and temperature. Anti-seizure medications and antidepressants help relieve nerve pain in some patients, but it may also have unpleasant side effects.
For the new study, the researchers recruited 35 adults with Type 2 diabetes and painful diabetic neuropathy. They randomly assigned 17 participants to follow a low-fat vegan diet and take B12 supplements for 20 weeks, with weekly support classes. The other 18 were instructed to take B12 supplements but maintain their normal diet.
The vegan diet focused on vegetables, fruit, grains and legumes. Over all, most participants on the vegan diet appeared to avoid animal products and about half stuck to low-fat diets throughout the study.
After 20 weeks, those on the vegan diet lost an average of about 15 pounds, compared with about one pound among those in the comparison group. Several other measures of health, including blood pressure, improved among the participants on the vegan diet compared with the control group.
Those on the vegan diet also reported a much greater drop in pain compared with the control group, the researchers report. A test of the nerves in the foot also suggested the vegan diet may have slowed or halted nerve function decline compared with the control group.
There was also a suggestion that the overall quality of life of those on the vegan diet improved compared with the control group. The difference may have been due to chance, however.
Barnard and his team acknowledged larger trials would still be needed to show a vegan diet helped relieve pain related to Type 2 diabetes.
Dr. Stuart Weiss, an endocrinologist at NYU Langone Medical Center in New York, said the study was “kind of cool,” though the number of participants was small and the length of the study was short.
“We always talk about diabetes and diabetes control being about diet and exercise, but we end up prescribing a lot of medications and don’t really focus that much on diet and exercise because that’s not easy,” said Weiss, who was not involved in the study.
Weiss told Reuters Health he typically advises patients to eat fewer processed and refined foods and not overeat.
“It might be that eating less of that in a plant-based diet might be helpful (in reducing inflammation), but again it was just 20 weeks and it takes years and years for neuropathy to develop,” Weiss said. “We need to see long-term [results], and nobody’s going to pay for that.”
While Weiss said it was exciting that researchers were looking for an alternative to medication, he cautioned that not everyone would go for a vegan diet.
Type 2 diabetes is becoming a global pandemic. We know the consumption of eggs is related to the development of some other chronic diseases, what about diabetes? There appears to be a stepwiseincrease in risk as more and more eggs are consumed. One study found that eating just a single egg a week increased the odds of diabetes by 76%. Two eggs a week doubled the odds, and an egg a day tripled the odds.
Recent studies, profiled in my video Eggs and Diabetes, have confirmed the link. In 2009, Harvard researchers found that a single egg a day or more was associated with an increased risk of Type 2 diabetes in men and women. This finding has since been confirmed in Asia in 2011 and in Europe in 2012. Reducing egg consumption should start early in life, though, as it appears once we get into our 70s, it may be too late.
For those with diabetes, eggs may then hasten our death. Eating one egg or more a day appears to shorten anyone’s lifespan, but may be even worse for those with diabetes, potentially doubling all-cause mortality, meaning egg-eating diabetics seem to live particularly short lives.
This is not good news for the egg industry. From a transcript of a closed meeting I got through the Freedom of Information Act, one egg industry advisor said, “Given the rate at which obesity and incidence of type II diabetes is growing in the US, any association between dietary cholesterol and type II diabetes could be a ‘showstopper’ that could overshadow the positive attributes in eggs.”
More Freedom of Information Act insights into the egg industry can be found in:
- Who Says Eggs Aren’t Healthy or Safe?
- Eggs and Cholesterol: Patently False and Misleading Claims
- Eggs and Choline: Something Fishy
- Eggs vs. Cigarettes in Atherosclerosis
Flax seeds may help control blood sugars (Flaxseeds for Diabetes) as well as Indian gooseberries (Amla Versus Diabetes), but our best bet may be a diet composed entirely of plants (How to Prevent Diabetes andHow to Treat Diabetes).
-Michael Greger, M.D.
Chances are good that you have diabetes or know someone who does. Even if you don’t, you’re paying for the care of millions of people with diabetes through your taxes. It’s a disease that affects people of all backgrounds, income levels, and, increasingly, ages, and it costs our country nearly a quarter trillion dollars every year — that’s well over the total yearly revenue of electronics giant Apple.
New statistics from the Centers for Disease Control and Prevention show that 29 million Americans have diabetes and another 86 million have prediabetes. Hardest hit are Native Americans, followed by African Americans and Latinos. They are at far greater risk for heart attacks, blindness, amputations, kidney failure, painful nerve symptoms, and loss of a decade of life compared with those who do not have the disease.
But a recent report has found that one simple prescription could help reverse diabetes, improve blood sugar, and lower weight, blood pressure, and cholesterol. It could allow the 115 million Americans with diabetes or prediabetes to dramatically reduce their medications or get off them entirely. And all this is possible, the analysis found, not with a new magic pill, but with tried-and-true, simple changes to diet.
A team of researchers from the United States and Japan, including the Physicians Committee’s Susan Levin, MS, RD and myself, published a new meta-analysis showing that a plant-based diet significantly improves diabetes management.
Combining the results of six prior studies, we found that a plant-based diet boosts blood sugar control considerably. Among the studies analyzed was our 2006 NIH-funded trial, which found that plant-based diets could improve a key indicator of blood sugar control called hemoglobin A1c as much as 1.2 points in 22 weeks. No drug comes close to offering those with diabetes this kind of relief.
The new meta-analysis focused on longer-term effects and combined the results of all available studies. The benefit of leaving meat out of the diet was as much as 0.7 points in some studies and averaged about 0.4 points overall. These numbers may seem small to those unfamiliar with the disease, but anyone with diabetes knows that such an improvement is truly profound.
If diet changes are so effective, why aren’t more doctors prescribing plants before pills?
Some wonder whether patients will stick to a plant-based diet. Well, studies show that patients are actually eager to make the switch. Why? Unlike conventional “diabetes diets,” vegan diets do not require counting calories or limiting carbohydrates. There’s no portion control or strenuous exercise routines. We tell our diabetes class and study participants that they can eat as much as they want — and as much whole wheat pasta, whole grains, and brown rice as they want — as long as they’re not eating animal products or lots of added oils. The diet is simple and clear, and it’s easier than ever to follow.
Plus, the “side effects” are all good. Weight comes down, blood pressure improves, and blood pressure and cholesterol drop. Best of all, low-fat, vegan diets provide freedom from the tedious routines of taking medications and injecting insulin.
That’s why doctors at Kaiser Permanente, the largest managed care organization in the United States, recently recommended that every patient receive information on plant-based diets. Doctors who lack the time or knowledge to prescribe a vegan diet can refer patients to registered dietitians and to plentiful online resources.
We can tackle diabetes at a policy level, too. Existing frameworks for improving nutrition in America, such as the National School Lunch Program and the Supplemental Nutrition Assistance Program (SNAP), could be better used to promote the consumption of disease-fighting foods like vegetables, fruits, whole grains, and legumes. Taxes could help curb consumption of unhealthful foods — the precedent has just been set by Berkeley’s soda tax and the Navajo Nation’s junk food tax.
As worrisome as the new statistics are, the solutions to the diabetes epidemic are at hand. With a plant-based diet, we could help tackle the disease once and for all.
Follow Neal Barnard, M.D. on Twitter: www.twitter.com/DrNealBarnard
Increased dietary fructose linked to elevated uric acid levels and lower liver energy stores
September 13, 2012
Obese patients with type 2 diabetes who consume higher amounts of fructose display reduced levels of liver adenosine triphosphate (ATP) — a compound involved in the energy transfer between cells. The findings indicate that elevated uric acid levels (hyperuricemia) are associated with more severe hepatic ATP depletion in response to fructose intake.
Obese patients with type 2 diabetes who consume higher amounts of fructose display reduced levels of liver adenosine triphosphate (ATP) — a compound involved in the energy transfer between cells. The findings, published in the September issue of Hepatology, a journal of the American Association for the Study of Liver Diseases, indicate that elevated uric acid levels (hyperuricemia) are associated with more severe hepatic ATP depletion in response to fructose intake.
This exploratory study, funded in part by grants from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), also suggests that uric acid levels may serve as a marker for increased fructose consumption and hepatic ATP depletion. Uric acid is produced by the breakdown of purines, natural substances commonly found in foods. According to the authors, increased dietary fructose can alter the body’s metabolism and energy balance. Energy depletion in the liver may be associated with liver injury in patients with non-alcoholic fatty liver disease (NAFLD) and in those at risk for developing this metabolic condition.
Fructose is a simple sugar that fuels the body, and is found in fruits and vegetables. High fructose corn syrup — a mixture of glucose and fructose — is used as a sweetener in consumer food products such as bread, cereal, and soda. Prior research reports that fructose consumption in the U.S. has more than doubled in the past 30 years. In fact, studies have shown that Americans’ fructose intake climbed from 15 grams per day in the early 1900s to 55 grams per day in 1994, which experts believe stems from an increase in soft drink consumption.
“There is an alarming trend of increased rates of obesity, type 2 diabetes and NAFLD in the U.S.,” said lead author Dr. Manal Abdelmalek from Duke University Medical Center. “Given the concurrent rise in fructose consumption and metabolic diseases, we need to fully understand the impact of a high-fructose diet on liver function and liver disease.”
For the present study, 244 obese and diabetic adults from the Look AHEAD Study were evaluated, with dietary fructose consumption estimated by the food frequency questionnaire. Liver ATP and uric acid levels were measured in 105 patients who participated in the Look AHEAD Fatty Liver Ancillary Study. Researchers assessed the change in liver ATP content using an IV fructose challenge in 25 subjects, comparing patients with low fructose consumption (less than 15 grams per day) to those with high fructose consumption (greater than 15 grams per day).
The team found that participants with a high intake of dietary fructose had lower liver ATP levels at baseline and a greater change in ATP content following the fructose challenge than those who consumed a lower amount of fructose. Patients with high uric acid levels (5.5 mg/dL or more) displayed lower ATP stores in response to fructose.
Dr. Abdelmalek concludes, “High fructose consumption and elevated levels of uric acid are associated with more severe depletion of liver ATP. Our findings suggest that increased dietary fructose intake may impair liver “energy balance.” Further research to define the clinical implications of these findings on metabolism and NAFLD is necessary.” The authors highlight the importance of public awareness of the risks associated with a diet high in fructose.
- Manal F. Abdelmalek, Mariana Lazo, Alena Horska, Susanne Bonekamp, Edward W. Lipkin, Ashok Balasubramanyam, John P. Bantle, Richard J. Johnson, Anna Mae Diehl, Jeanne M. Clark. Higher dietary fructose is associated with impaired hepatic adenosine triphosphate homeostasis in obese individuals with type 2 diabetes. Hepatology, 2012; 56 (3): 952 DOI: 10.1002/hep.25741
Various fraudulent products are often sold on the Internet as “cures” or treatments for diabetes. These dietary supplements have not been studied or approved. The FDA warns patients with diabetes not to be duped by bogus and unproven remedies.
“The following are the approved non fraudulent drugs that have been proven not to cure diabetes but do control the symptoms somewhat and with some very serious life threatening side effects.”
Orally administered agents used in the treatment of type 2 diabetes, which prevents the liver from breaking down glycogen into glucose and increases the sensitivity body tissues have to insulin.
Metformin (Glucophage) is a biguanide, which works by reducing glucose production in the liver and by making tissues more sensitive to insulin. Doctors recommend it as a first choice for most patients with type 2 diabetes who are insulin resistant, particularly if they are overweight. Metformin may also be used in combination with other drugs.
Metformin does not cause hypoglycemia or add weight, so it is particularly well-suited for obese patients with type 2 diabetes. Metformin also appears to have beneficial effects on cholesterol and lipid levels and may help protect the heart. Some research has suggested that it significantly reduces the risk for heart attack and death from heart disease. It is also the first choice for children who need oral drugs and is helpful for women with polycystic ovary syndrome and insulin resistance.
Sulfonylureas are oral drugs that stimulate the pancreas to release insulin. They are also first-line oral drugs. For adequate control of blood glucose levels, the drugs should be taken 20 – 30 minutes before a meal. A number of brands are available, including chlorpropamide (Diabinese), tolazamide (Tolinase), acetohexamide (Dymelor), glipizide (Glucotrol), tolbutamide (Orinase), glyburide (Micronase), glimepiride (Amaryl), and repaglinide (Prandin)
Meglitinides stimulate beta cells to produce insulin. They include repaglinide (Prandin), nateglinide (Starlix), and mitiglinide. These drugs are rapidly metabolized and short-acting. If taken before every meal, they actually mimic the normal effects of insulin after eating. Patients, then, can vary their meal times with this drug. These drugs may be particularly helpful in combination with metformin or other drugs. They may also be a good choice for people with potential kidney problems.
Thiazolidinediones, also known as peroxisome proliferator-activated receptor (PPAR) agonists, include pioglitazone (Actos) and rosiglitazone (Avandia). They improve insulin sensitivity by activating certain genes involved in fat synthesis and carbohydrate metabolism. These drugs are usually taken once or twice per day; however, it may take several days before the patient notices any results from them and several weeks before they take full effect. Thiazolidinediones are usually taken in combination with other oral drugs or insulin. Thiazolidinediones available as 2-in-1 pills include rosiglitazone and metformin (Avandamet), rosiglitazone and glimepiride (Avandaryl), and pioglitazone and glimepiride (Duetact).
Side Effects. Thiazolidinediones can have serious side effects. They can increase fluid build-up, which can cause or worsen heart failure in some patients. Combinations with insulin increase the risk. Patients with heart failure should not use them. People with risk factors for heart failure should use these mediciens with caution. Rosiglitazone may also increase the risk for heart attack. Patients who take rosiglitazone, especially those who have heart disease or who are at high risk for heart attack, should talk to their doctor about their treatment options.
In 2005, the FDA approved exenatide (Byetta), the first GLP-1 inhibitor drug. Exenatide is an injectable drug that is a synthetic version of the hormone found in the saliva of the Gila monster, a venomous desert lizard. Exenatide is injected twice a day, 1 hour before morning and evening meals. It is prescribed for patients with type 2 diabetes who have not been able to control their glucose with metformin or a sulfonylurea drug. It can be taken in combination with these drugs or alone
NEWS RELEASE June 9, 2014
Researchers Unveil Six Dietary Guidelines for Cancer Prevention
WASHINGTON—Six dietary guidelines – more aggressive than previous cancer prevention advice will be unveiled in the June 30 issue of the Journal of the American College of Nutrition.
The cancer prevention guidelines, emphasizing a diet rich in plant-based foods, such as soy beans and cruciferous, allium, and carotenoid vegetables, are based on the principle that diet changes are justified, even when evidence on certain issues are up for debate. The recommendations urge the same kind of precautionary approach health experts took against tobacco decades earlier, before smoking bans were enforced, and warn about the association between cancer and alcohol, red and processed meats, dairy products, and carcinogens in well-cooked meats, including beef, poultry, and fish.
“The key recommendation is to build meals around fruits, vegetables, and legumes,” says study author Neal Barnard, M.D., president of the nonprofit Physicians Committee and an adjunct associate professor of medicine at the George Washington University School of Medicine and Health Sciences. “Plant-based foods provide an antioxidant boost and help promote a healthy weight, reducing the risk for all types of cancer in the long run.”
The six dietary recommendations to reduce risk of several types of cancer are:
1. Limit or avoid dairy products to reduce the risk of prostate cancer.
Findings: Consuming thirty-five grams of dairy protein each day, the equivalent of one large cup of cottage cheese, increases risk of prostate cancer by 32 percent. Drinking two glasses of milk each day increases risk of prostate cancer by 60 percent.
Note: Calcium supplements appear to have the same effect as milk intake. Men who supplement with more than 400 milligrams of calcium per day increase risk for fatal prostate cancer by 51 percent.
2. Limit or avoid alcohol to reduce the risk of cancers of the mouth, pharynx, larynx, esophagus, colon, rectum, and breast.
Findings: One drink per week increases risk of mouth, pharynx, and larynx cancers by 24 percent. Two to three drinks per day increase risk of colorectal cancer by 21 percent.
Note: The alcohol itself (rather than additives) appears to be the cause of cancer, and all types of alcoholic beverages (wine, beer, and spirits) are problematic.
3. Avoid red and processed meats to reduce the risk of cancers of the colon and rectum.
Findings: Each 50-gram daily serving of processed meat, equivalent to two slices of bacon or one sausage link, increases risk of colorectal cancer by 21 percent. Each 120-gram daily serving of red meat, equivalent to a small steak, increases risk of colorectal cancer by 28 percent.
Note: The heme iron, nitrites, heterocyclic amines, and overabundance of essential amino acids in red and processed meats are all believed to contribute to cancerous cell growth in the body.
4. Avoid grilled, fried, and broiled meats to reduce the risk of cancers of the colon, rectum, breast, prostate, kidney, and pancreas.
Findings: Four types of heterocyclic amines (HCAs) are associated with cancer of the colon and rectum. HCAs form from creatine and amino acids in cooked skeletal muscle, increasing with higher cooking times and higher temperatures. When ingested, HCAs can disrupt DNA synthesis.
Note: In addition to the cancers listed above, HCAs are also associated, to a weaker extent, with cancers of the breast, prostate, kidney, and pancreas.
5. Consume soy products to reduce risk of breast cancer and to reduce the risk of recurrence and mortality for women previously treated for breast cancer
Findings: Evidence from Asian and Western countries shows that soy products are associated with reduced cancer risk. Chinese women who consume more than 11.3 grams of soy protein, equivalent to half a cup of cooked soybeans, each day during adolescence have a 43 percent reduced risk of premenopausal breast cancer, compared with women who consume 1.7 grams.
Research in Shanghai shows that women with breast cancer who consume 11 grams of soy protein each day can reduce mortality and risk of recurrence by about 30 percent. U.S. populations show similar findings: the higher the isoflavone intake from soy products, the less risk of mortality and recurrence in women with breast cancer.
Note: When choosing soy products, opt for natural forms, such as edamame, tempeh, or organic tofu, as opposed to soy protein concentrates and isolates, common in powders and pills.
6. Emphasize fruits and vegetables to reduce risk of several common forms of cancer.
Findings: Fruits and vegetables, especially leafy greens, help reduce overall cancer risk. A high intake of cruciferous vegetables, such as broccoli, kale, and cabbage, is associated with an 18 percent reduced risk of colorectal cancer and reduced risk of lung and stomach cancers.
Women who consume the most carotenoid-rich vegetables, such as carrots and sweet potatoes, lower their risk of breast cancer by 19 percent. Overall, women who consume the highest quantities of any kind of fruit or vegetable reduce breast cancer risk by 11 percent. A high intake of tomato products has been shown to reduce risk of gastric cancer by 27 percent. Garlic and other allium vegetables, such as onions, significantly reduce risk for gastric cancer, while a Western diet (high amounts of meat and fat with minimal amounts of fruits and vegetables) doubles the risk.
Note: Some components in soybeans, green tea, turmeric, grapes, tomatoes, and other plant foods have the ability to regulate apoptosis (a natural process for destroying unhealthy cells), an important pathway for cancer prevention.
Dietary Guidelines for Cancer Prevention (PDF)
“There’s considerable benefit–and no harm—in loading up with plant-based foods,” notes study author Susan Levin, M.S., R.D., C.S.S.D., director of nutrition education for the Physicians Committee. “Large bodies of research show fruits, vegetables, and legumes offer a variety of protective properties, so why not move these foods to the center of our plates?”
By JANE E. BRODY
Published: May 08, 1990
Published: May 08, 1990
EARLY findings from the most comprehensive large study ever undertaken of the relationship between diet and the risk of developing disease are challenging much of American dietary dogma. The study, being conducted in China, paints a bold portrait of a plant-based eating plan that is more likely to promote health than disease.
The study can be considered the Grand Prix of epidemiology. Sixty-five hundred Chinese have each contributed 367 facts about their eating and other habits that could ultimately help them and Americans preserve their health and prolong their lives. The data alone fill a volume of 920 pages, to be published next month by Cornell University Press. Among the first tantalizing findings are these: Obesity is related more to what people eat than how much. Adjusted for height, the Chinese consume 20 percent more calories than Americans do, but Americans are 25 percent fatter. The main dietary differences are fat and starch. The Chinese eat only a third the amount of fat Americans do, while eating twice the starch. The body readily stores fat but expends a larger proportion of the carbohydrates consumed as heat. Some of the differences may be attributable to exercise. The varying levels of physical activity among the Chinese were measured, but the data have not yet been analyzed.
Reducing dietary fat to less than 30 percent of calories, as is currently recommended for Americans, may not be enough to curb the risk of heart disease and cancer. To make a significant impact, the Chinese data imply, a maximum of 20 percent of calories from fat – and preferably only 10 to 15 percent – should be consumed.
Eating a lot of protein, especially animal protein, is also linked to chronic disease. Americans consume a third more protein than the Chinese do, and 70 percent of American protein comes from animals, while only 7 percent of Chinese protein does. Those Chinese who eat the most protein, and especially the most animal protein, also have the highest rates of the ”diseases of affluence” like heart disease, cancer and diabetes.
A rich diet that promotes rapid growth early in life may increase a woman’s risk of developing cancer of the reproductive organs and the breast. Childhood diets high in calories, protein, calcium and fat promote growth and early menarche, which in turn is associated with high cancer rates. Chinese women, who rarely suffer these cancers, start menstruating three to six years later than Americans. Dairy calcium is not needed to prevent osteoporosis. Most Chinese consume no dairy products and instead get all their calcium from vegetables. While the Chinese consume only half the calcium Americans do, osteoporosis is uncommon in China despite an average life expectancy of about 70 years, just five few years less than the American average.
These findings are only the beginning. Dr. T. Colin Campbell, a nutritional biochemist from Cornell University and the American mastermind of the Chinese diet study, predicts that this ”living laboratory” will continue to generate vital findings for the next 40 to 50 years.
The study, started in 1983 to explore dietary causes of cancer, has been expanded to include heart, metabolic and infectious diseases. Dr. Chen Junshi of the Chinese Institute of Nutrition and Food Hygiene organized the survey to cover locations from the semitropical south to the cold, arid north.
Exacting, Labor-Intensive Study
The extensive volume of raw data and its counterpart on computer tape will be available to any scientist to use as raw material for medical research.
It is an exacting, labor-intensive study, initially financed by the National Cancer Institute, that probably could not have been done anywhere except China. For nowhere else can accurate mortality statistics be combined with data from people who live the same way in the same place and eat the same foods for virtually their entire lives.
Nowhere else is there a genetically similar population with such great regional differences in disease rates, dietary habits and environmental exposures. For example, cancer rates can vary by a factor of several hundred from one region of China to another. These large regional variations in China highlight biologically important relationships between diet and disease.
And nowhere else could researchers afford to hire hundreds of trained workers to collect blood and urine samples and spend three days in each household gathering exact information on what and how much people eat, then analyzing the food samples for nutrient content.
‘The Whole Diet Panoply’
”The total cost in U.S. dollars of this project – $2.3 million plus 600 person-years of labor contributed by the Chinese Government – is a mere fraction of what it would have cost to do the same study here,” Dr. Campbell noted. And unlike typically circumscribed American studies that examine one characteristic as a factor in one disease, the Chinese investigation ”covers the whole diet panoply as it relates to all diseases.”
Dr. Mark Hegsted, emeritus professor of nutrition at Harvard University and former administrator of human nutrition for the United States Department of Agriculture, said: ”This is a very, very important study – unique and well done. Even if you could pay for it, you couldn’t do this study in the United States because the population is too homogeneous. You get a lot more meaningful data when the differences in diet and disease are as great as they are in the various parts of China.”
In the first part of the study, 100 people from each of 65 counties throughout China each contributed 367 items of information about their diets, lives and bodies. The responses from residents of each county were then pooled to derive countywide characteristics that could be measured against the area’s death rates for more than four dozen diseases.
By matching characteristics, researchers derived 135,000 correlations, about 8,000 of which are expected to have both statistical and biological significance that could shed light on the cause of some devastating disease.
In the poorer parts of China, infectious diseases remain the leading causes of death, but in the more affluent regions, heart disease, diabetes and cancer are most prominent, Dr. Campbell said.
Adding Taiwan to the Research
Although from an overall perspective of nutrient composition the Chinese diet is more health-promoting than ours, he said, there are some important limitations that result from a lack of economic development.
”Food quality and variety are not as good as ours,” he explained. ”With limited refrigeration, bacteria and mold contamination is more common, large amounts of salt and nitrites are used to preserve foods and hot spices are used to mask off-flavors.”
The study is now being expanded and revised. New mortality rates are being gathered to update the original mortality data from the early 1970’s and to reflect causes of death for 100 million people in the late 1980’s. The original 6,500 participants are being resurveyed and people from 12 counties in Taiwan are being included in the expanded survey, which will also measure many socioeconomic characteristics.
”We want to see how economics change and health factors follow,” Dr. Campbell explained in an interview. ”Taiwan should be interesting because it is intermediate between the United States and China in nutrient intake and plasma cholesterol levels. And since the Taiwanese gene pool is more like the Chinese, we can study the relative contributions of genetics and diet to risk of disease.”
Cholesterol as Disease Predictor
Dr. Campbell continued: ”So far we’ve seen that plasma cholesterol is a good predictor of the kinds of diseases people are going to get. Those with higher cholesterol levels are prone to the diseases of affluence – cancer, heart disease and diabetes.”
Contrary to earlier reports that linked low blood cholesterol levels to colon cancer, the Chinese study strongly suggests that low cholesterol not only protects against heart disease but also protects against cancer of the colon, the most common life-threatening cancer among Americans. In China, mortality rates from colon cancer are lowest where cholesterol levels are lowest.
Over all, cholesterol levels in China, which range from 88 to 165 milligrams per 100 milliliters of blood plasma, much lower than those in the United States, which range from 155 to 274 milligrams per 100 milliliters of plasma.
”Their high cholesterol is our low,” Dr. Campbell noted. He said the data strongly suggest that a major influence on cholesterol levels and disease rates is the high consumption of animal foods, including dairy products, by Americans.
‘Basically a Vegetarian Species’
”We’re basically a vegetarian species and should be eating a wide variety of plant foods and minimizing our intake of animal foods,” he said.
The Chinese have already begun to capitalize on these findings, using them to develop national food and agricultural policies that will promote health.
”Usually, the first thing a country does in the course of economic development is to introduce a lot of livestock,” Dr. Campbell said. ”Our data are showing that this is not a very smart move, and the Chinese are listening. They’re realizing that animal-based agriculture is not the way to go.”
The plant-rich Chinese diet contains three times more dietary fiber than Americans typically consume. The average intake in China is 33 grams of fiber a day, and it ranges as high as 77 grams in some regions. Dr. Campbell found no evidence to suggest that diets very high in fiber are in any way deleterious to nutritional well-being.
While American scientists worry that fiber may interfere with the absorption of essential minerals like iron, no reason for concern was found among the Chinese. Rather, those with the highest fiber intake also had the most iron-rich blood.
Iron From Vegetables
The study also showed that consumption of meat is not needed to prevent iron-deficiency anemia. The average Chinese adult, who shows no evidence of anemia, consumes twice the iron Americans do, but the vast majority of it comes from the iron in plants.
Nor are animal products needed to prevent osteoporosis, the study showed. ”Ironically,” Dr. Campbell noted, ”osteoporosis tends to occur in countries where calcium intake is highest and most of it comes from protein-rich dairy products. The Chinese data indicate that people need less calcium than we think and can get adequate amounts from vegetables.”
Another common health concern that could prove to be a red herring is the fear that aflatoxin, which is produced by a mold that grows on peanuts, corn and other grains, causes liver cancer. Rather, the Chinese study strongly indicates that chronic infection with hepatitis B virus and high serum cholesterol levels are the primary culprits.
”We did not find any relationship between aflatoxin and liver cancer, and we have the largest study on this question ever done,” Dr. Campbell said.
Among other intriguing findings are a relationship between infection with herpes simplex virus and coronary heart disease and a relationship between infection with the yeast candida and nasopharyngeal cancer.
”Lots and lots such relationships are turning up as we plot out the 367 characteristics on maps of China and try to match them up with maps of disease rates,” Dr. Campbell said. ”The data now need to be interpreted, and six Chinese scientists are working with us on this. The amount of information gathered in this study is kind of staggering,” he said, then proceeded to outline his interest in gathering more.