What causes heart disease — high fat or the over-consumption of sugar?
Humans have been eating all sorts of foods for more than 200,000 years, since we evolved from the African savannah. But what should we be eating to stay healthy in the 21st century?
Should we eat large amounts of protein, or avoid meat? Should we avoid carbohydrates, including vegetables and fruit? Should we avoid all fats or just some? Should we follow the Aitkin’s diet, the paleo diet, the low GI or high GI diet, or just go vegan?
It is very confusing.
What is finally making sense to millions of people is that sugar is bad for you and processed fructose is even worse. But that may be only half the story. The other half is the genetic question.
Obesity is at epidemic levels all around the world: some 170 million people worldwide suffer from diabetes and it is expected to rise to 336 million by 2030. For the first time in human history, there are now more obese than undernourished people in the world.
US pediatrician and endocrinologist Robert Lustig describes it as a social problem and says we need to stop blaming the individual. They are victims of the US food industry, in which 80% of 600,000 packaged food items in supermarkets contain added sweeteners.
History of sugar consumption
Industry letters stored at Illinois University show that the sugar industry knew in the 1950s that sugar was the major cause of teeth decay in children and other health problems.
But instead of advocating less sugar, they convinced governments to look for ways to break up dental plaque, fight tooth decay and encouraged the wider use of fluoride in drinking water.
During the second half of the 20th century, many health experts were concerned about the alarming increase of coronary thrombosis — a blood clot in the arteries supplying the heart muscle. It was widely attributed to high amounts of fat being consumed after the food shortages during World War II.
In 1957, British nutritionist John Yudkin found no evidence for the increase in intake of animal fats to be the direct cause of coronary mortality. Instead, he found that excess sugar contributed to atherosclerosis, a precursor to heart attack, dental caries, diabetes and obesity.
Pure, White and Deadly, Yudkin’s book published in 1972, showed that over consumption of sugar was involved in liver disease, causing cirrhosis, gout, indigestion as well as some cancers.
The sugar industry retaliated to destroy his reputation and research funding and paint him as an incompetent quack. This led to a 30-year drought of institutional funding for research into the health effects of sugar.
Ancel Keys, a US epidemiologist employed by the sugar industry, suggested that saturated fat was the primary cause of heart disease. The American Heart Association and the National Heart Foundation of Australia endorsed this view and recommended that fat be replaced by sugar.
Fat was then taken out of processed foods but, since it then tasted like cardboard, the industry added sugar. Sugar was cheap — even cheaper than oils or fats and people eat more.
US food advisors talk up the “bliss point” — not too much sugar but just enough. This is how 40 grams of sugar (or 9 teaspoons) ends up in a can of Coke. All the sugar-added food was advertised as “fat free”.
At the same time Robert Atkins published Diet Revolution, which advocated losing weight by restricting carbohydrates and eating lots of protein. Fat was considered harmless.
Atkins managed to sell millions of copies on the basis that eating steak, eggs and butter to our heart’s desire was fine because carbohydrates —pasta, rice, bagels and sugar — caused obesity and heart disease.
By 2003, 10% of Americans were on his diet. The sale of rice and pasta, and even donuts, went down. Atkins said people could eat, without limit, lobster with butter sauce, steak with béarnaise sauce and bacon cheeseburgers. But they could not eat starches or refined carbohydrates — no sugar or anything made from flour. Atkins even banned fruit juices and permitted just small amounts of vegetables.
The American Medical Association, which was advocating that people stop eating fats and cholesterol-rich food, attacked Atkins — who ended up defending his diet in Congressional hearings.
It now turns out Atkins may have been right in placing limits on our sugar intake.
It was partly due to his work that, during the 1980s, refined sugar was again seen as the new villain. Food manufacturers replaced sugar with the new healthy alternative — high fructose corn syrup (HFCS). It was cheaper than sugar and made huge profits.
In 2009, Robert Lustig, who had a special interest in childhood obesity, made the film Sugar: the bitter truth. Lustig and his colleagues had discovered, independently of Yudkin’s work, that sugar has serious deleterious effects particularly in the development of diabetes and obesity.
The popularity of the video, which has been now been viewed 6 million times, contributed to a resurgence of interest in Yudkin’s work. Lustig’s references to sugar include simple sugars, white or brown, cane sugar and high fructose corn syrup.
Chemical breakdown
Sucrose, known as sugar, is made of one molecule of glucose joined to one molecule of fructose and is a simple carbohydrate.
Complex carbohydrates, found in foods such as bread or potatoes, form polysaccharides which are only slowly broken down to glucose during digestion.
Fructose is found naturally in honey, maple sugar, fruits, berries, some vegetables such as cassava, onions, potatoes, sweet potatoes, sweet corn and some grains such as wheat, rice, barley and rye.
The enzyme sucrase breaks down sugar into glucose and fructose and it is absorbed rapidly into the blood stream and the liver.
Glucose responds to insulin and is used by every cell in the body. Fructose is mostly converted into fats and ends up in the liver. Fructose is not registered by the brain, through the hormone leptin, which means there is no trigger warning not to overeat.
HFCS is made up of 55% fructose and 45% glucose. As fructose is nearly twice as sweet as sucrose some processed foods have extra fructose making them extra sweet. HFCS makes every type of food — from soup to bagels, tomato sauce to bread — more sweet and palatable.
The high fructose in our diet induces insulin resistance, which is believed to instigate obesity, Type 2 diabetes as well as some cancers.
HFCS is not commonly found in Australian foods. Instead sucrose is the most common form of sugar added to food and soft drinks in this country.
In their switch away from sugars, food manufactures have gone for artificial sweeteners such as aspartame and a natural substance called stevia.
Stevia is 300 times sweeter than sugar, but needs maltodextrin added for taste. Coca Cola Life is sweetened by stevia. This shift also allows for a massive increase in manufacturers’ profits as stevia costs less than sugar or HFCS.
Genetics of obesity
Bad diets and bad genes contribute to obesity. However, biochemists are just learning about the effect of Epigenetic Transgenerational Inheritance (ETI) — the deleterious impact of minute traces of industrially-synthesised chemicals that are transmitted through food and water and which make genetic changes permanent in succeeding generations.
Nature has never before been exposed to these industrial chemicals and there is no pathway for their elimination from the environment.
In her 1962 book Silent Spring, Rachel Carson attacked chemical companies, warning of the dangers of these problems even though the biological mechanisms were then unknown.
ETI was only discovered in the last 3 years partly as a result of the Human Genome Project, which was finished in 2001. Our understanding of how the DNA sequence works and DNA methylation, which affects gene function, has increased enormously.
If the methylation pattern is not right, some genes can be switched off and some switched on in error which can lead to cancer.
Some 20 chemicals have been found to be responsible for obesity. They include phthalates, used as plasticisers to soften and increase the flexibility of Poly Vinyl Chloride (PVC) plastics. Exposure to these chemicals occurs through the prevalent use of plastic wrapping. Because phthalate plasticisers are not chemically bound to PVC they can easily leach and evaporate into food.
Endocrine disruptors
The use of diethylstilbesterol (DES) is one of the first-known examples of how a pharmaceutical could have permanent effects on a foetus.
DES is an endocrine disruptor, found to cause clear cell carcinoma, a vaginal cancer, and other health effects. From the 1940s till the 1980s, it was given to pregnant women in the mistaken belief it would reduce complications from pregnancy and miscarriages.
Bisphenol A (BPA) is another endocrine disruptor and is considered another source of ETI. In commercial use since 1957, BPA is used in the production of plastics and resins which are used in food and drink containers, flame retardants, dental sealants and dental fillings, thermal paper used in shopping receipts, sports equipment, CDs and DVDs and lining water pipes for industrial purposes.
The plastic is clear and tough and was used in a variety of popular consumer goods, including baby bottles and water bottles.
The health impact of exposure to 2,3,7,8 Tetrachlorodibenzo–p-dioxin (TCDD), the active agent in Agent Orange used extensively in the Vietnam War, has been well documented.
The negative developmental effects on the foetus from the mother’s exposure to dioxin through the food chain or water supplies may be much more significant than the effects in adults.
Dioxin promotes birth defects and congenital defects in the offspring including such problems as cleft lip, cleft palate, club foot, hydrocephalus, neural tube defects, fused fingers, muscle malformations and paralysis, kidney damage, Spina Bifida and some developmental disabilities.
Obesogens are chemical compounds that disrupt normal cell development and can lead to obesity. They can alter lipids, a group of naturally-occurring molecules that include fats, waxes, sterols, fat-soluble vitamins, fat storage and change metabolic set points, disrupt energy balance or modify the regulation of appetite and the feeling of being full to promote fat accumulation and obesity.
The mechanism of the obesogens is the same: permanent changes in cells which affect reproduction and future generations.
It is through the study of how environmental factors switch genes on and off and the affect this has on the DNA sequence that we now know that epigenetic adaptations can be permanent and passed on to future generations.
For the first time in the history of life on earth, we are being subjected to poisonous and toxic chemicals from the moment of conception to the day of our death. The chemicals which are changing the basis of our genetic inheritance are everywhere — from the remote Amazon jungles, to the African Sahara, to Iceland and Antarctica.
These stable chemicals are present in only tiny amounts, but are frighteningly potent. They are affecting, and will affect, all life on earth, eventually making it unlivable.
It is essential we change the method of production not just of industrial chemicals but in plastics and other processes that so far have not been investigated.
We must end the production of cheap and polluting plastic items that are used once and thrown away. This would entail a complete about face in manufacturing and economics, and include a rethink about how it can be done sustainably without damaging the food chain or the environment. It would necessitate the end of capitalism as we know it.
[Coral Wynter is a retired biochemist and member of the Socialist Alliance.]
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