Presentation on theme: "Getting Rich Can Kill You! A Warning to Developing Countries… Learn from Our Mistakes! Robin Carr, Ph.D."— Presentation transcript:
Getting Rich Can Kill You! A Warning to Developing Countries… Learn from Our Mistakes! Robin Carr, Ph.D.
3 Requirements of Science 1.Look for evidence! (Especially peer-reviewed.) (And dont accept just evidence that fits your theories.) 2.Dont believe any one individual or any one scientific finding. Assess the weight of evidence. 3.While its sometimes necessary to focus on narrow questions and specific details, always step back now and then to see the broader picture.
Investigate the research yourself! PubMed Central (PMC) is the U.S. National Institutes of Health (NIH) free digital archive of biomedical and life sciences journal literature. http://www.ncbi.nlm.nih.gov/pubmed/ http://www.ncbi.nlm.nih.gov/pmc/ http://www.ncbi.nlm.nih.gov/pubmed/ http://www.ncbi.nlm.nih.gov/pmc/ Abstracts are almost always provided along with the references, and sometimes the entire article is provided free on-line, from a provided link.
Next…About Correlations A correlation is a measure of how closely 2 variables are related to each other. Correlations are the most frequently used tool in epidemiological and human dietary research. But they must be used with caution.
Example Did you know that a positive correlation was found between eating ice cream and getting divorced?
Which is the cause? Which is the effect? Summer Ice CreamDivorce Does eating more ice cream increase your risk of divorce?
Which is the cause? Which is the effect? Ice CreamDivorce Or, do you eat more ice cream when you get divorced?
The answer… Summer increases the chances of both! Summer Ice CreamDivorce
When Cause & Effect is Assumed Leg Length Pant Length Sometimes the context makes cause and effect obvious. But assumptions can sometimes be wrong.
He who does not know food, how can he understand the diseases of man? Hippocrates, the father of medicine (460-357 BC)
A Story about Proteins Protein is one of the basic components of food and makes all life possible. All of the antibodies and enzymes, and many of the hormones in the body are proteins. They provide for the transport of nutrients, oxygen and waste throughout the body. They provide the structure and contracting capability of muscles. They also provide collagen to connective tissues of the body and to the tissues of the skin, hair and nails. There are hundreds of thousands of different kinds of protein. 20 amino acids make up protein. 1.essential amino acids (9/8) – must be included in the diet. 2.nonessential amino acids (11/12) – the body can manufacture. For normal adults: 1.0 g protein / kg body mass per day. For active athletes: 1.4 g protein / kg body mass per day.
The Amino Acids Essential Amino Acids (must be obtained through the diet) Isoleucine Phenylalanine Leucine Threonine Lysine Tryptophan Methionine Valine Conditional Amino Acids (cant be made fast enough to support rapid growth) Arginine Histidine Nonessential Amino Acids (can be made by the body) Alanine Glutamine Asparagine Glycine Aspartic Acid Proline Cysteine Serine Glutamic Acid Tyrosine
Protein in Cultural History In the 19 th century, protein was synonymous with meat. Early scientists like the German Carl Voit (1831-1908) found that man needed only 48.5 grams/day, but he recommended 118 grams/day. (If something is good, more is better!) Well-known nutrition researcher Max Rubner stated that protein intake (meaning meat) was a symbol of civilization. A large protein allowance is the right of civilized man. The cultural bias was set. If you were rich, you ate meat. If you were poor, you ate staple plant foods like potatoes and bread.
The Protein Gap In the 1960s and 1970s, it was constantly asserted that there was a protein gap in the developing world. M. Autret of the Food and Agriculture Organization (FAO) of the United Nations reported a very strong association (correlation) between the consumption of animal-based foods and annual income, and he implied causation. What else could explain the association (correlation)? Animal- Based Foods Annual Income Increases ?
A More Realistic Explanation! Animal- Based Foods Annual Income Increases
Philippine Connection In 1967, while on the faculty at Virginia Tech, Dr. T. Colin Campbell began working on a ten-year project in the Philippines (funded by the U.S. Agency for International Development) to improve childhood nutrition among the poor. Ultimately, 110 nutrition mothercraft self-help education centers were established around the country, focussed on educating mothers of malnourished children about healthy local foods. The aim was to make sure that children of the poor were getting as much protein as possible, since there was a perceived protein gap in the developing world.
Protein and Cancer? Part of this project involved investigating the high prevalence of liver cancer, usually an adult disease, in Filipino children. It was thought to be caused by aflatoxin, a mould found in peanuts and corn, which is one of the most potent carcinogens known. Children who ate the highest-protein diets were the ones most likely to get liver cancer. They were the children of the wealthiest families. Campbell TC and Campbell TM (2006) The China Study. Dallas, Texas: Benbella Books, p.5
The Indian Study One group of rats was given aflatoxin and then fed diets of 20% protein. The other group was also given aflatoxin and then fed diets of only 5% protein. Every single animal fed a 20% protein diet got liver cancer or its precursor lesions. Not a single animal fed a 5% protein diet got liver cancer or its precursor lesions. 100% versus 0%? This seldom occurs in biological sciences. It was a very provocative finding! Madhavan TV and Gopalan C (1968) The effect of dietary protein on carcinogenesis of aflatoxin. Arch Path 85:133-7.
Three Stages of Cancer Initiation - A carcinogen enters a cell and is converted by cellular enzymes to highly reactive products that bind to the cells DNA, forming carcinogen-DNA complexes (adducts) that are often repaired. If not repaired before the cell divides, the daughter cells will have this new genetic defect (mutation). This occurs quickly and is usually irreversible. It represents a potential for cancer. Promotion - Some factors (promoters) may act to increase the growth and multiplication of these mutant cells over a longer period of time, while other factors (anti-promoters) work against this. Progression - Large foci (clusters of mutant cells) progress in the growth and may wander from their initial site (metastasize).
The Promotion Stage Many animal studies have shown that nutrition may be far more important in controlling the cancer promotion stage than the dose of the initiating carcinogen. OConnor TP, Roebuck BD and Campbell TC (1985) Dietary intervention during the post-dosing phase of L-azaserine-induced preneoplastic lesions. Journal of the National Cancer Institute 75:955-957 (cover article). Nutrients (esp. casein) from animal-based foods increased tumour development while nutrients from plant-based foods decreased tumour development. Hawrylewicz EJ, Huang HH et al. (1982) Enhancement of the 7,12- dimethylbenz(a) anthracene (DMBA)mammary tumorigenesis by high dietary protein in rats. Nutr. Reps. Int. 26:793-806.
What about the type of protein? What protein consistently and strongly promoted cancer? Casein (87% of cows milk protein) promoted all stages of the cancer process. What type of protein did not promote cancer, even at high levels of intake? The safe proteins were from plants, including wheat and soy.
Protein Excesses? Peer-reviewed biochemical research, funded by the National Institutes of Health, the American Cancer Society and the American Institute for Cancer Research, resulted in dozens of articles published in some of the best scientific journals. The results were shocking… Low protein diets inhibited the initiation of cancer by aflatoxin, regardless of how much of this carcinogen was administered …In fact, dietary protein proved to be so powerful in its effect that we could turn on and turn off cancer growth simply by changing the level consumed. The China Study, p.6
The Human Question So far, most of this research had involved laboratory studies performed on animals: rats and mice. Would similar results be found with humans?
The China Study Scientific Team Dr. T. Colin Campbell was Project Director; Dr. Junshi Chen, deputy director of Chinas premier diet & health research laboratory; Dr. Junyao Li, one of the authors of the China Cancer Atlas Survey and a key scientist in Chinas Academy of Medical Sciences; Dr. Richard Peto of Oxford University, one of the leading epidemiologists in the world, who has been knighted for his work. Campbell TC and Campbell TM (2006) The China Study. Dallas, Texas: Benbella Books.
Findings of the China Study The largest and most comprehensive study of human diet, lifestyle and disease in the history of biomedical research was organized through Cornell University, Oxford University and the Chinese Academy of Preventive Medicine, and involved 367 variables taken from questionnaires, blood tests, urine samples and 3-day diet inventories taken from 6500 adults from 65 Chinese counties. Called the Grand Prix of epidemiology by the New York Times, it produced more than 8,000 statistically significant correlations between various dietary factors and disease. People who ate the most animal-based foods got the most chronic disease. People who ate the most plant-based foods were the healthiest.
Disease Groupings in the China Study Diseases of Poverty (Nutritional Inadequacy & Poor Sanitation) Pneumonia, intestinal obstruction, peptic ulcer, digestive disease, pulmonary tuberculosis, parasitic disease, rheumatic heart disease, metabolic and endocrine disease other than diabetes, diseases of pregnancy and many others Diseases of Affluence (Nutritional Extravagance) Cancer (colon, lung, breast, leukemia, childhood brain, stomach, liver), diabetes, coronary heart disease (from The China Study, p. 76)
Rural Chinese versus U.S. Diets (normalized for a body mass of 65 kg) NUTRIENTRURAL CHINAUNITED STATES Calories (kcal/day) 26411989 Total Fat (% of calories) 14.534-38 Dietary fiber (g/day) 3312 Total Protein (g/day) 6491 Animal Protein (% of calories) 0.810-11 Total Iron (mg/day) 3418 (age-standardized rates from The China Study, p. 74)
From Underfed to Overfed In the year 2000, for the first time in human history, the number of overweight people in the world rivalled the number of underweight people. (While the world's underfed population had declined slightly since 1980 to 1.1 billion, the number of overweight people had surged to 1.1 billion.) Both the overweight and the underweight suffer from malnutrition. "Often, nations have simply traded hunger for obesity, and diseases of poverty for diseases of excess. Worldwatch (2000) Underfed and Overfed: The Global Epidemic of Malnutrition. Paper #150: Worldwatch Institute, Washington, DC.
Countries: Developing to Developed Major trends usually occur during this shift: increased longevity (life expectancy at birth) e.g. Canada 81.23, U.S. 78.11, Philippines 71.09 CIA World Fact Book https://www.cia.gov/library/publications/the-world-factbook/ https://www.cia.gov/library/publications/the-world-factbook/ improved sanitation and drinking water improved access to high quality medical care decrease in amount of daily physical activity shift from a plant-based diet to an animal-based diet increase in levels of obesity nutrient deficiencies & infectious diseases give way to chronic sedentary and degenerative diseases of excess
Diseases of Affluence hypoglycemia hyperglycemia type II diabetes high blood pressure coronary artery disease strokes autoimmune diseases (e.g. rheumatoid arthritis, gout, bursitis, neuritis, and some sciatica) osteoporosis many cancers
Cancer in China Counties with the highest incidence of some cancers had rates more than 100 times greater than counties with the lowest rates of those cancers. (In the U.S., cancer rates in one area are never more than about 3 times higher than in the lowest incidence areas.) Since 87% of Chinas population is the same ethnic group (the Han), why is there such a variation in the rates of cancer? It had to be due to environmental factors like poor nutrition, lack of exercise and unhealthy living environments. (Some U.S. scientists had already estimated that genetics only determines about 2-3% of the total cancer risk.) Doll R and Peto R (1981) The causes of cancer: quantitative estimates of avoidable risks of cancer in the United States today. J Natl Cancer Inst 66:1192-1265.
Blood Cholesterol & Cancer Blood cholesterol levels in rural China were far lower than expected (measured in mg/dL): Av. Rural ChinaAv. U.S.Minimal Safety (assumed) 127 215 150 As levels dropped from 170 to 90, there were associated decreases in cancers of the liver and colon (p<0.01), and rectum, male lung, adult leukemia and adult brain (p<0.5). NOTE: This correlation even at very low levels is surprising, due to a statistical phenomenon. Real relationships between 2 variables sometimes cannot be seen when the range of data is limited!
Breast Cancer The American death rate from breast cancer was 5 times higher than the rural Chinese rate. In fact, from an international perspective, breast cancer can clearly be seen as a disease of affluence that is highly related to animal fat (and, possibly just by association, animal protein). Carroll KK, Braden LM et al. (1986) Fat and cancer. Cancer 58:1818-25 This finding has been confirmed many times since then.
Carroll KK, Braden Lm et al. (1986) Fat and cancer. Cancer 58:1818-25
Colorectal Cancer A major American Cancer Society study finds people who reported the highest consumption of red and processed meat had a significantly higher risk of colorectal cancer than those who reported the least consumption. The study of nearly 150,000 Americans, the largest and most comprehensive to date, adds substantially to previous evidence linking highest consumption of red and processed meat to intestinal cancer.American Cancer Society Chao et al. (2005) Meat Consumption and Risk of Colorectal Cancer. JAMA (Journal of the American Medical Association) 293: 172-182.
A Major Recent Study! Red and processed meat intakes were associated with modest increases in total mortality, cancer mortality, and cardiovascular disease mortality. Sinha R, Cross AJ et al. (2009) Meat Intake and Mortality: A Prospective Study of Over Half a Million People. Archives of Internal Medicine 169(6), 562-571.
Nitrites and Nitrosamines Sodium nitrite: A meat preservative used since the 1920s, it kills bacteria, colours meat pink and adds to the taste. Nitrosamines: A family of chemicals of which at least 17 are reasonably anticipated to be human carcinogens. National Toxicology Program (2001) Ninth report on carcinogens, revised January 2001. Washington, DC: U.S Dept of Health and Human Services. http://ntp.niehs.nih.gov/index.cfm?objectid=72016262-BDB7- CEBA-FA60E922B18C2540 http://ntp.niehs.nih.gov/index.cfm?objectid=72016262-BDB7- CEBA-FA60E922B18C2540
Value of a Plant-Based Diet Recent scientific findings are suggesting that diets largely based on plant foods, such as some vegetarian, Mediterranean, or rural Asian diets, could best prevent nutrient deficiencies as well as diet-related chronic diseases. These diets contain no or very little meat. Diets largely based on plant foods, such as well- balanced vegetarian diets, could best prevent nutrient deficiencies as well as diet-related chronic diseases. Sabaté, Joan (2003) The contribution of vegetarian diets to health and disease: a paradigm shift? American Journal of Clinical Nutrition, Vol. 78, No. 3, 502S-507S.
Plant Protein Plant protein can meet requirements when a variety of plant foods is consumed and energy needs are met. Research indicates that an assortment of plant foods eaten over the course of a day can provide all essential amino acids and ensure adequate nitrogen retention and use in healthy adults, thus complementary proteins do not need to be consumed at the same meal. ADA Reports: Position of the American Dietetic Association and Dietitians of Canada: Vegetarian diets Journal of the American Dietetic Association Online June 2003, Volume 103, Number 6. Young VR, Pellett PL. Plant proteins in relation to human protein and amino acid nutrition. Am J Clin Nutr 1994;59:1203S-1212S. Beans & rice together provide plenty of all the essential amino acids.
Nutritional adequacy of plant-based diets Energy and protein intakes are similar for plant-based diets compared with those containing meat. Fe and vitamin B12 are the nutrients most likely to be found lacking in such diets. Bioactive substances present in foods of plant origin significantly influence the bioavailability of minerals and requirements for vitamins. Well-balanced vegetarian diets are able to support normal growth and development. It is concluded that meat is an optional rather than an essential constituent of human diets. Sanders TA (1999) Nutritional adequacy of plant-based diets. Proc Nutr Soc. May;58(2):265-9.
Phytochemicals Phytochemicals (there are thousands) are found naturally in plants, helping them to protect themselves from bacteria and disease. Some act as antioxidants, limiting and repairing cell damage caused by free radicals. Others act as hormone-like substances to prevent cancer or block the enzymes that promote the development of cancer and other diseases. Flavonoids, found in apples, strawberries, grapes, onions, green and black tea and red wine, may decrease atherosclerotic plaque and DNA damage related to cancer development. Carotenoids (beta-carotene, lutein, zeaxanthin, crytoxanthin and lycopene) protect the eye from harmful oxidation reactions. Lignans, found in flaxseed, seaweed, soybeans, bran and dried beans, are phytoestrogens that interfere with the action of the sex hormone estrogen and may help prevent hormone-related cancers, slow the growth of cancer cells, and lower the risk for heart disease.
Position of the American Dietetic Association and Dietitians of Canada: Vegetarian diets It is the position of the American Dietetic Association and Dietitians of Canada that appropriately planned vegetarian diets are healthful, nutritionally adequate, and provide health benefits in the prevention and treatment of certain diseases. ADA Reports: Position of the American Dietetic Association and Dietitians of Canada: Vegetarian diets Journal of the American Dietetic Association Online June 2003, Volume 103, Number 6. 256 mostly peer-reviewed references
The Mediterranean Diet The weight of evidence suggests that a Mediterranean style of eating may be the healthiest approach. In a population-based, prospective investigation involving 22,043 adults in Greece who completed an extensive, validated, food-frequency questionnaire… CONCLUSIONS: Greater adherence to the traditional Mediterranean diet is associated with a significant reduction in total mortality. Trichopoulou A et al. (2003) Adherence to a Mediterranean diet and survival in a Greek population. N Engl J Med. 26;348(26): 2599-608.
Mediterranean Diet and Longevity First, there appears to exist sufficient evidence that diet does indeed influence longevity. Second, an optimal diet for the prevention of both coronary heart disease and cancer is likely to extensively overlap with the traditional Mediterranean diet. It is not yet clear which components in the Mediterranean diet are more important for its apparent health effects, but olive oil, plant foods and moderate wine consumption are likely candidates. Trichopoulou A, Critselis E (2004) Mediterranean diet and longevity. Eur J Cancer Prev. 2004 Oct;13(5):453-6.
Mediterranean Diet Leads To Longer Life The Mediterranean diet has been associated with longer life expectancy among elderly Europeans. The diet typically involves a high intake of vegetables, legumes, fruits, and cereals; a moderate to high intake of fish; a low intake of saturated fats; a high intake of unsaturated fats (especially olive oil); a low intake of dairy products and meat; and a modest intake of alcohol, mostly wine. Current evidence suggests that such a diet may be beneficial to health. This study involved over 74,000 healthy men and women, aged 60 or more, living in nine European countries. When dietary exposures were calibrated across countries, the reduction in mortality averaged 7% (1% to 12%). Trichopoulou A, Orfanos P et al. (2005) Modified Mediterranean diet and survival: EPIC-elderly prospective cohort study. British Med J 330 (7498): 991. http://www.bmj.com/cgi/content/full/330/7498/991
Mediterranean Diet & CHD Epidemiological studies as well as randomised dietary trials suggest that Mediterranean diet may be important in relation to the pathogenesis and prevention of coronary heart disease (CHD). A striking protective effect of a Mediterranean diet rich in alpha-linolenic acid (ALA) was reported in the Lyon Diet Heart Study with a 50 to 70% reduction of the risk of recurrence after four years of follow-up in CHD patients. de Lorgeril M, Salen P (2006) The Mediterranean diet in secondary prevention of coronary heart disease. Clin Invest Med. June 29(3): 154-8.
Mediterranean Diet & Obesity The sample included 17,238 women and 10,589 men not obese and aged 29-65 y at baseline (1992-96)…High MD adherence was associated with significantly lower likelihood of becoming obese among overweight subjects…MD adherence was not associated with incidence of overweight in initially normal-weight subjects…results suggest that promoting eating habits consistent with MD patterns may be a useful part of efforts to combat obesity. Mendez MA, Popkin BM (2006) Adherence to a Mediterranean diet is associated with reduced 3-year incidence of obesity. J Nutr. Nov. 136(11): 2934-8.
Organizations Supporting Vegetarianism The American Institute for Cancer Research and the World Cancer Research Fund call for choosing predominantly plant-based diets rich in a variety of vegetables and fruits, legumes, and minimally processed starchy staple foods and limiting red meat consumption, if at all. The American Cancer Society recommends choosing most food from plant sources. The American Heart Association recommends choosing a balanced diet with an emphasis on vegetables, grains, and fruits. The Heart and Stroke Foundation of Canada recommends using grains and vegetables instead of meat as the centerpiece of meals. The Unified Dietary Guidelines developed by the American Cancer Society, the American Heart Association, the National Institutes of Health, and the American Academy of Pediatrics call for a diet based on a variety of plant foods, including grain products, vegetables, and fruits to reduce risk of major chronic diseases.
What is stopping the change? Most evidence suggests that a shift to largely plant-based diets would reduce chronic disease risks among industrialized and rapidly-industrializing populations. The accomplish this shift, it will be necessary to overcome market-place barriers and to develop new policies that will encourage greater consumption of fruits, vegetables and grains as a means to promote public health. Nestle M. (1999) Animal versus plant foods in human diets and health: is the historical record unequivocal? Proc Nutr Soc 1999;58:211–8.
The Broader Picture Rearing cattle produces more greenhouse gases than driving cars. Steinfeld H et al. (2006) Livestocks Long Shadow: Environmental Issues and Options. FAO (Food and Agriculture Organization) of the United Nations. On average, land requirements for meat-protein production are 10 times greater than for plant-protein production. Leitzmann C (2003). Nutrition ecology: the contribution of vegetarian diets. American Journal of Clinical Nutrition 78 (Suppl), 658S. Producing one kilogram of animal protein generally requires nearly 100 times more water than producing one kilogram of grain protein. Pimentel D, Piemental M (2003). Sustainability of meat-based and plant based diets and the environment. Am J Clin Nutrition 78(Suppl), 662S. Less than half the harvested acreage in the U.S. is used to grow food for people. For every sixteen pounds of grain and soybeans fed to beef cattle, we get back only one pound of meat on our plates. Gussow JD (1994). Ecology and vegetarian considerations: does environmental responsibility demand the elimination of livestock? American Journal of Clinical Nutrition 59 (Suppl), 1111S.
For your health… for your environment… for compassion to animals… Please…eat less meat!
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