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Trans fats are on their way out, but what about saturated fats? Are they still a problem? Official health guidelines say yes; decades of research say otherwise.
Questions on the amount and type of fat people should consume to stay healthy have been the subject of debate for decades. Recently the FDA called attention to these issues again when it ruled trans fats unsafe for consumption. Trans fats, which rose in popularity during the 1950s as a tasty and healthy alternative to butter, have become ubiquitous in food products. Since then, they have been found to raise bad cholesterol (LDL) and lower good cholesterol (HDL), which then increases the risk for heart disease, stroke, and type II diabetes. Health officials should have applauded the FDA’s having taken a major step towards eliminating trans fats, but instead, as reported in the New York Times, many voiced concerns that saturated fats would simply replace trans fats, leaving the public no better, or even worse off, then they were before. These concerns, however, may be misplaced. For years, saturated fats have been cited as the chief culprit in clogged arteries and fatal heart attacks. Yet decades-worth of research has been unable to establish a direct link between saturated fats and heart disease. Because health officials along with the U.S. Department of Agriculture and the American Heart Association continue to advocate for a low fat diet, one has to ask why saturated fats continue to have such a bad reputation.
The answer is a long story and comes from the desire to have a simple solution to a complex problem. (For the complete story read Gary Taubes’ article The Soft Science of Dietary Fat. The following information comes from his article). Starting in the 1950s, Americans saw a rise in heart disease-related deaths, and scientists started looking for the cause. Ancel Keys, a biochemistry professor, was one of the first to publish results suggesting saturated fats were to blame. In his famous Seven Countries study, Keys found that countries with low fat diets such as Japan had significantly lower rates of heart disease than countries with high fat diets such as Finland. Though his study lacked scientific evidence demonstrating the biological pathways that lead from saturated fat consumption to heart attacks, his breakthrough results precipitated the American Heart Association to push for a nationwide low fat diet – starting at age two. The missing pathway seemed to have been found in 1961 with the Framingham Heart Study, which concluded that high levels of cholesterol serum – the total amount of cholesterol – caused by saturated fat consumption, clogged arteries and caused heart attacks. Soon after, politicians and journalists looking to end heart disease established health guidelines for a low fat diet. The political committee in charge held several hearings before and after their publication, looking for scientific evidence that supported their plan. But when scientists explained the research was still inconclusive and needed more time, the politicians decided not to wait. The committee, also tended to disregard research in support of saturated fats because the members assumed it was influenced by the meat and dairy industry. In the end, the guidelines stated that a low fat diet was essential to reduce the risk of heart disease – and the recommendation has stayed the same to this day.
At this point you may be thinking if saturated fats increase cholesterol levels and high cholesterol levels lead to a heart attack, then where’s the controversy? The problem is that cholesterol serum measures the sum of two types of cholesterol, and to evaluate someone’s health, a doctor needs to know the amount of each one. This division is what distinguishes trans fats from saturated fats. Trans fats have no health benefits because they raise bad cholesterol (LDL) – particles that carry fat and cholesterol from the liver to the arterial cells among other tissues – and lower good cholesterol (HDL) – particles that carry cholesterol back to the liver. Saturated fats, on the other hand, raise both and the consequence of avoiding these fats all together can be as severe as over indulging in them. As an example, doctors in Japan are encouraging their patients to increase the amount of fat they eat because low levels of cholesterol have been linked to hemorrhagic stroke and shorter life spans.
Now the point of this post isn’t to free the reader to gorge on bacon and doughnuts (the trans fat free kind of course). The point is to question whether it makes sense to blame one thing for America’s health problems. No matter what dietary guidelines you choose to follow there are a few central points to consider. When people eliminate one thing from their diet, they tend to replace it with another instead of cutting their total calorie intake. Americans trying to cut saturated fats often replace them with carbohydrates, and studies have found that high carbohydrate diets are even worse than saturated fats because of the insulin resistance they can build and the weight gain they can cause. Rather then assign the blame to one unwholesome nutrient; it may be better to strive for a balanced diet. For example, as mentioned above, while a high saturated fat Finnish diet is associated with high rates of heart disease, the Mediterranean diet, which includes an equal amount of saturated fat but also includes fresh vegetables, is associated with a low rate of heart disease.
Given the history behind our current health guidelines, and examples of other diets, it seems that if saturated fats replace trans fats as some health officials fear, we may actually be better off, and may be even on our way back to a more balanced diet – until the next diet craze steps in.