"The history of medicine is largely a substitution of ignorance by fallacies." - Richard Gordon, The Alarming History of Medicine
The Food Guide Pyramid Program
Newsweek’s January 20, 2003 issue declared that present-day Americans are experiencing “obscene rates” of obesity, hypertension, diabetes and heart disease. Time’s March 1, 2004 and Fortune’s October 23, 2003 issues discussed the newly recognized role of inflammation as the common pathogenic mechanism for diabetes, heart disease, hypertension, arthritis, Alzheimer’s disease and cancer. Meanwhile, National Geographic, in August 2004, asked, “Why Are We So Fat?” - “we” referring to Americans. For four top popular U.S. magazines to devote lead articles to obesity shows the gravity of America’s epidemic of the new millenium.
Year 2002 marked the tenth year that the Food Guide Pyramid program (launched by the U.S. Department of Agriculture [USDA] in 1992) had served as the American people’s bible on what to eat and what not to eat. The program instructed Americans to shun saturated fats (coconut oil and animal and dairy fats) and to use nothing but polyunsaturated “vegetable oils,” such as corn and soybean oils and their margarines and shortenings for the preparation of all foods. The program recommended only carbohydrates and sugars as principal calorie sources, lean meats, vegetables, fruits and nuts. It carried no warning against transfatty-acid-containing foods, despite the demonstrated toxicity of these fats. This dietary recommendation shows how strong has been the influence and power of the U.S. edible-oil industry. They even succeeded in hiding for a time the toxic transfatty acids they produce in their margarines and shortenings.
Americans followed this guide faithfully. American food and confectionery producers removed the dairy and coconut fats in their products and replaced them with partially hydrogenated corn and soybean oil derivatives. Many Americans depend on easy-to-cook-and-serve processed foods and eat many of their meals in fast-food chains and restaurants that serve breads, pies, pizzas, potato fries and foods fried in polyunsaturated oils or enriched with shortenings rich in transfats. Reluctantly perhaps, they stopped taking butter and made do with flat-tasting margarine. Unknowingly, they substituted the toxic transfat-rich foods for the saturated fats they were told to be avoided. Their calories, in ever larger amounts, came from carbohydrates, sweets and polyunsaturated omega-6 oils. What about coconut oil? It vanished from all grocery and supermarket shelves.
From this diet, Americans got fat and sick. In just ten years on the Food Guide Pyramid diet, two-thirds (64 percent) of Americans, twenty years and older, are being reported to be overweight, and one-third (30 percent) of adults were obese with a body mass index (BMI) of 30 or more! There are plans to change the seats of planes and buses with more commodious ones. The Food Guide “is a disaster”, said Newsweek. What cardiologists and nutritionists had recommended as the most healthful diet was instead causing more diabetes, hypertension, heart disease and cancer. The advice, obviously, was wrong.
With this carbohydrate-linoleate-transfat-with-no-saturated-fat diet, the sensation of satiety is dulled, and the craving for food enhanced. The stomach simply dilates to accommodate all this additional bulk; obesity follows. A drastic corrective measure by surgeons for patients who consent, is stomach resection to restore the stomach’s normal capacity and help the patient to eat less. Another intervention is the insertion of a plastic ball into the stomach to partially fill it up. Liposuction is popular for removing fat collections under the skin (subcutaneous fat), but unfortunately, not the abdominal (visceral) fat whose adipocytes are the most active in secreting inflammatory cytokines and C-reactive protein (CRP). It goes without saying that these surgical remedies carry their own risks.
The systemic effects of obesity, especially visceral obesity, also result from the increased levels of inflammatory prostaglandins from excess omega-6 linoleates and transfatty acids that contribute to multi-organ involvement in diabetes: of the heart, brain, gut, kidneys, eyes (retinopathy, cataracts), peripheral nerves (polyneuropathy) and the whole body (accelerated aging). Two pathological mechanisms may be acting in tandem to produce this multi-organ disease: (1) metabolic syndrome/type 2 diabetes and (2) inflammation by linoleate overdose and/or transfatty-acid toxicity.
(a) Metabolic Syndrome
In metabolic syndrome or syndrome X, the prime features are calorie overload and insulin resistance that lead to hyperinsulinism, and, in diabetics, hyperglycemia. The consumption of excess calories from fats and carbohydrates (particularly, the simpler carbohydrates and sugar) dump ready calories into the organism. The response is more secretion of insulin to metabolize this overload. Repeated frequently, insulin efficiency falls and more insulin is needed to do the job. What happens in insulin resistance is not yet fully understood - whether the insulin receptors are down-regulated or they become insensitive because of a change in their structure. Japanese researchers suggest that the loss of insulin receptor sensitivity is due to a single gene mutation resulting in adipocytes secreting less adiponectin (which enhances insulin efficacy) and more resistin (which promotes resistance to insulin). Subjects may remain in a prediabetic state or may become frankly diabetic. Whether diabetic or only prediabetic, the complications are similar - multi-organ involvement due to chronic inflammation and obstruction of small arteries (microvasculitis) of the heart, brain, kidneys, eyes, nerve trunks and peripheral vessels. The older generation of diabetologists had wondered why diabetic complications were so unpreventable even in seemingly “adequately treated” diabetic patients. The explanation is now known to lie in this widespread inflammation of the smaller arteries of the body that develops with insulin-resistance syndrome.
(b) Essential Fats
The omega-6 fatty acids, e.g. linoleic acid and omega-3 fish oil, cannot be synthesized by the body and are called essential fatty acids (EFA). EFA deficiency leads to abnormal lipid levels and atherosclerosis. K.C. Hayes’s analysis of many studies in animals and humans is reproduced, slightly modified, in Fig. 1. HIs chart indicates that, as long as linoleic acid intake is adequate (3 to 4 percent or more) the coadministered fats do not affect low-density lipoprotein cholesterol (LDL-C) levels. At less than this intake, however, oleic acid (18:1), palmitic acid (16:0), and lauric plus myristic acids (12:0 + 14:0) may raise LDL-D, the latter quite significantly. This might explain why in all studies where animals were fed partially hydrogenated coconut oil without EFA supplementation, the animals developed hypercholesterolemia and vascular lesions, whereas when they were fed natural coconut oil with EFA supplementation and even cholesterol, they remained healthy. Hydrogenation either saturates the unsaturated fatty acids in coconut oil, or worse, converts them to transfatty acids. It is most surprising that stearic acid (18:0), the saturated fat of pork and beef, was found to have no effect on LDL-C in EFA deficiency. It is this fat of animals that was the primary target of the Seven Country Study, MRFIT and other studies that form the bases of the “Saturated are bad” slogan.
(c) The Essential Fats Are Bad in Excess
Hayes’s analysis did not go beyond 12 percent of 18:2 intake. What happens when linoleic acid is taken at 20,30 percent or more as many Americans must be doing? In the body, linoleic acid is elongated and desaturated to 20:4 (arachidonic acid) (Fig. 2). Arachidonic acid (AA) is then incorporated into the phospholipids that form the plasma membrane of all body cells. When needed by the cell, AA is detached by the enzyme phospholipase A2 (PLA2) and converted by other enzymes (lipoxygenases and cycloxygenases) into various active compounds. These are called eicosanoids because hey all contain twenty carbon atoms but they have different structures and functions. Blood platelets produce thromboxane (TxA2) that constrict blood vessels and cause platelets to aggregate and to initiate clotting. Many blood cells produce different prostaglandins (PGE2, PGF2a, PGD2); some of these, e.g. PGE2, promote inflammation for defense or reparative purposes. Bronchial muscles and other cells liberate leucotrienes that provoke broncho-constriction (asthma) and allergic reactions. In short, consumption of linoleate oils in large amounts saturates the body with too much arachidonic acid and leads to an increased tendecy towards inflammatory and allergic diseases. The diseases now plaguing the U.S. after ten years on the Food Guide Program may very likely be partly due to the consumption of linoleate oil from soybean, corn, safflower and sunflower oils.
(d) Transfats
Transfatty acids have long been shown to increase the atherogenic risk factors, namely, they increase the small dense LDl and lipoprotein (a), and decrease the HDL levels. The transposition of one unsaturated C-atom by the partial hydrogenation process converts the normally bent molecule to a straight one, like in saturated fats, but still unsaturated. Such an abnormal compound must interfere with the normal processes of the body (see Appendix A).
Transfats are bad in any amount, as is now becoming evident from several studies. Walter Willet and his Harvard University School of Public Health co-workers have reported positive relationships between transfatty acid intake and coronary heart disease in the 80,000 plus cohort of nurses they had been observing. Similarly, Pietinen et al. observed a significant association between transfatty acid intake and coronary disease among Finnish men and no association between coronary deaths and cholesterol or saturated-fat intake.
Margarines and shortenings, created by partial hydrogenation and rich in transfats, are used in the processing of many foods stocked up on the supermarket shelves of westernized civilizations. Fortunately, the U.S. Food and Drug Administration has finally awakened to the transfat danger and requires that by January 2006, all processed foods in the U.S. should state their transfat content on their labels. The transfat poisoning may decrease, but the linoleate toxicity will remain as long as these oils are used in excess.
(e) Saturated Fats and Overeating
Strange as it may seem, the lack of saturated fats may actually be contributory to America’s health problems. While smoking gun points directly to the carbohydrates, transfats and, omega-6 polyunsaturates, the desire to overeat may be induced by the very lack of saturated fats in the diet. Coconut oil and animal fats stimulate the feeling of satiety that makes a person stop eating. Omega-6 polyunsaturates and carbohydrates, on the other hand, are weak satiety stimulants. The fact that they constitute a large percentage of the American diet may be the principal cause for the ever larger food portions now being served. Never in the history of the U.S. has obesity been as pervasive and as severe, even in children.
Heart Disease in Early Twentieth-Century America
In the early 1900s, there was a very low incidence of heart disease in America. Paul D. White, the “dean” of American cardiologists and author of the first book on heart disease, started his cardiology practice in Boston in 1921 and is said to have seen his first coronary heart patient only in 1928. The total number of heart disease-caused deaths in 1930 was only 3,000 and these involved rheumatic and hypertensive disorders predominantly (Fig 3). What fats were America eating at that time? Americans were eating animal and dairy fats - lard, butter, tallow and coconut oil. Where were the vegetable oils - corn, soybeam, cottonseed, safflower, sunflower oils? They were not yet being marketed. This situation persisted till America’s entry into the war (WWII) and the Japanese occupation of coconut-producing countries, particularly in the Philippines. The U.S. could no longer get coconut oil. Thus was born the soybeam and linoleate oil industry. By the end of the war, soybeam and corn oils had taken up the market previously held by coconut oil. When coconut oil tried to reenter the U.S. market in 1946, the soybean-oil lobby started its campaign against coconut oil and other tropical oils. The American palate was now completely accustomed to the taste of the polyunsaturates, their margarines and shortenings.
In 1950, barely five years after the end of WWII, a frightening health problem suddenly reared its head. The U.S. Census startled America with the report that 51 percent of Americans were dying of heart disease, 90 percent of which were coronary. The total deaths from heart disease was 500,000. What could have caused this? Could it have been a lingering stress effect from the war? During the wartime food scarcity, the British, Dutch, Swedes, and Finns registered fewer cardiac deaths. After the war, with more food, heart-disease death rates started rising again - but not to such levels as this. This was a 167-fold increase over the 1930 heart-disease mortality rate.
No amount of increase in population, life expectancy or smoking could explain this. Neither could better diagnosis. Heart disease diagnosis in the 1950s did not differ much from that in 1930. The portable direct writing ECG machine was just developed and starting to replace the unwieldy photographic electrocardiograph. Enzyme tests for myocardial infarction were not even on the horizon.
The most significant change at this time was in the American diet: the widespread use of soybeam and corn oils, and products of their partial hydrogenation used as substitutes for butter and coconut oil. By 1950, according to Enig and Fallon, butter consumption had fallen by half - from 18 to 9.6 lbs per year - because butter had been displaced by polyunsaturated linoleate oils (corn, soybeam and other vegetable oils) and the margarines and shortenings from linoleate oils (Fig. 4 Table 2). Margarines and shortenings are artificially created by the partial hydrogenation of polyunsaturated oils, a process invented by a German chemist. Partial hydrogenation transforms the polyunsaturated liquid oils into a richer, creamier solid and more stable products for the baking of breads, cookies, biscuits, crackers, chips, pies, cakes and other foods. Partial hydrogenation does not saturate the double bonds; the oil remains unsaturated but the position of one of the carbon atoms making up the double bond changes from cis to trans (see Appendix A); thus, transfatty acids were consumed in liberal amounts in all processed foods, and in foods served in restaurants and homes. No one knew yet how toxic they were. When suspicion was directed towards the transfatty acids as the possible causative factors for the heart-disease mortality rate increase, the edible-oil group hastily pointed at the saturated fats instead, while promising to remedy the hydrogenation process to do away with the transfatty acids.
Till the ‘40s however, saturated animal fats and cholesterol had been the only fats on the American dining table and coronary heart disease was not a problem. In fact, when Dr. White was asked by the American Heart Association (AHA) panel (Drs. Irving Page, Jeremiah Stamler, and Ancel Keys) to endorse the launching of the “Prudent Diet” of corn oil, margarine, chicken and cereal to replace butter, lard, beef and eggs, Dr. White refused; he knew that saturated fats were not the bad fats; he had seen that they did not cause heart disease when he started his cardiology practice.
Ancel Keys, director of the Laboratory of Physiological Hygiene at the University of Minnesota, was mainly responsible for the “Fats cause heart disease” idea. In 1953, he formulated the Lipid-Heart Theory, which states that all fats, whether animal or vegetable, can cause heart disease. By 1957, he narrowed the blame to the transfatty acids and the saturated fats. The edible-oil industry, however, suggested that it was too much hydrogenation that produced the transfatty acids and promised to tone down on the process to avoid producing them, although this maneuver did nothing to decrease the production of transfats. However, for some reason, Keys still focused on saturated fats as the cause of heart disease.The transfatty acids, conveniently relegated to the background, remained there until Mensink and Katan and Enig showed how bad they really are. Mensink and Katan’s study proved that transfats raise the LDL-C level and lower HDL-C. Later, it was shown that, of the various LDL types, the small dense LDLs and lipoprotein (a) are the more atherogenic and that they are the ones increased by transfatty acids. The small dense LDL can more easily penetrate the endothelium and enter the subendothelial space than the larger LDL species. Lp(a) or lipoprotein(a) is an LDL with a long apo(a) protein attached to its apo-B protein; this makes the LDL more sticky and adhere better to the arterial wall. In addition, it also acts as an antifibrinolytic (pro-clotting agent) by preventing plasminogen from being changed to plasmin, the clot dissolver.
Summary
The history of heart disease in the U.S. may be summarized thus:
- Before the 1940s, when Americans were eating only saturated fats, there was a very low incidence of coronary heart disease.
- Polyunsaturated vegetable oils and their hydrogenated products supplanted saturated fats and coconut oil during World War II. By 1950, deaths from heart disease peaked to 50 percent of the total deaths in the country.
- Since then, the mortality rate from coronary disease has come down mostly because of better treatment - technological advances in surgical, interventional, and therapeutic management. But the incidence of coronary disease (morbidity) has remained high despite lowered saturated fat consumption, higher vegetable intake, and jogging and fitness addiction. In this period, butter and lard consumption went down by 75 percent but the consumption of vegetable oil products trebled (Table 2). Coconut oil use stopped completely.
"We learn from history that we do not learn from history!" - George Bernard Shaw