The Lipid Hypothesis

Lipids are a biological term for fats, and Hypothesis means a theory. It comes from the English verb ‘to hypothesize’ meaning ‘to theorize’. So, the “Lipid Hypothesis” is basically a “theory” that proposes that dietary fats result directly in the increase of circulating fats (cholesterol) in the blood. And further, that these circulating fats, infiltrate the walls of the arteries and cause the buildup of plaque (blockages). In medical terms these arterial blockages are known as atherosclerosis which can result in its known complications – heart attack & stroke.

The world’s nutritional preferences have evolved on the basis of this hypothesis. And sadly, so has chronic ill-health & disease. This hypothesis changed the way we, and our doctors, look at our health and decide on a course of medication, which most of the times is completely unnecessary, and many a times causes more harm than good. So let’s take a brief look into the genesis of the lipid hypothesis, and examine the merits or demerits thereof.

The first seeds of the hypothesis were sown in the late 19th century, when Dr. Rudolph Virchow, a German pathologist, performed chemical analyses on arterial plaques taken from corpses. He discovered that they contained large amounts of cholesterol. His post mortems could not have ascertained how and why the cholesterol was deposited there in the first place, since he was dealing with dead bodies. Then, in 1925, it was found that the human body produces 80-90% of its own cholesterol and that diet is relatively unimportant. But the ensuing tensions of the World War II subdued the importance of this revelation, and this vital discovery was silenced by the guns of the big war.

After the war, in 1950, the hypothesis was revived by Dr. Ancel Keys an American epidemiologist. His Six Countries Study showed that the percentage fat in the national diet of six countries proportionately correlated with the incidence of death from coronary heart disease (CHD). His graph showed a near perfect correlation between the two. Much later it was found out that the same data was, in fact, available with him, for 22 countries at the time of his study. He picked the six that fit his theory and omitted the 16 that didn't. This is virtually a text book example of statistical fraud. In a later article (1997) he said - Cholesterol in food has no affect on cholesterol in blood and we’ve known that all along. But by then, the Lipid Hypothesis juggernaut was unstoppable.

Then came another well known advocate of the low fat diet called Dr. Nathan Pritikin. In fact what Pritikin advocated was the complete elimination of sugar, white flour and all processed foods from the diet. He recommended the use of fresh raw foods, whole grains and a strenuous exercise program. However, it was the low fat aspects of his regime that received the most attention in the media. Adherents found that they lost weight and that their blood cholesterol levels and blood pressure declined. When Pritikin died of cancer at a young age, many doubts were cast on his dietary doctrine.

The final proverbial nail in the coffin was delivered by a U.S Senate Committee on Nutrition headed by Sen. George McGovern. It was the first time in history for a government to officially advise its citizens on what to eat and what to avoid. Be that as it may, the Committee actually recommended an elimination of sugars & fats from diet, but “somehow” the sugars were erased from the final draft. It is said to have been the “hard work” of the sugar lobby which ensured that. Thus were born the U. S. Dietary Guidelines, which continue till today and maintain the same anti dietary-fats approach.

During the first meeting of the 2010 Dietary Guidelines Advisory Committee, Dr. Eric B. Rimm from Harvard testified that he is concerned about "the artificial limit on fat" in the Dietary Guidelines. He mentioned that “there is some concern” about excess carbohydrates elevating triglycerides because the ratio of TG to HDL is emerging as one of the most reliable risk factors for heart disease. Dr. Rimm's testimony was greeted with silence and he did not bring up the subject again!

In keeping with the guidelines, not just American citizens, but the world population deviated towards a diet based on High Carbs – Low Fat foods. The rate of chronic disease skyrocketed inspite of following this “sound advice”. Heart disease, the core concern of the Hypothesis has also refused to slow down as it was supposed to. Even though science and technology have grown by leaps and bounds, they have not succeeded in addressing the acceleration of the problem. Figures for obesity & chronic illnesses, like diabetes and hypertension, have also zoomed. Infant obesity has gone up over 6 times. Has infant diet changed from mother’s milk & formula foods to something new ? Do we expect them to start exercising more to reduce weight ? And what exercises would that be ?

Study after study, research after research, has failed to establish any link between dietary fats, cholesterol and heart health. But the dogma continues. At best, high cholesterol levels in the blood are one of the 300+ risk markers for heart disease. That is not the cause and so reducing those levels artificially, certainly is not the cure, neither an answer to the problem. Arterial plaque has been observed in 2500 year old intact bodies discovered in the snowy Alps, and in young 25 year old dead soldiers. The real issue is not the cholesterol in the plaque, but how it gets there, and why. I believe Dr. Rimm is right. I believe that elevated blood sugar & elevated triglycerides oxidize cholesterol and they are the real culprits. The cholesterol is just a poor victim – of our dietary choices.    

Healthy Regards.

No comments:

Post a Comment