Myth #1: People who eat less fat, live longer.

Facts: After over 50 years and hundreds of studies, researchers remain unable to prove that a low-fat diet is good for your health. A few years ago, researchers at the Cochrane Collaboration decided to review the medical literature and see what it said. They looked at the results of the 26 best studies and found that low-fat diets didn’t help people live longer. The researchers found that people on low-fat diets were 2% more likely to die than those in the comparison groups. Interestingly, they buried this important finding on page nine of their report.1 More recently, the Journal of the American Medical Association published their results of three huge studies attempting to show the benefits of a low-fat diet on breast cancer, colorectal cancer and coronary heart disease. Again, the studies failed to show significant benefit.2 In light of such findings, the British Medical Journal editorialized:

“Despite decades of effort and many thousands of people…there is still only…inconclusive evidence of the effects of modification of total, saturated, monounsaturated, or polyunsaturated fats on cardiovascular morbidity and mortality.”3

My opinion: The low-fat diet has never been proven to be good for most peoples’ health. In fact, low-fat diets may be the main cause for skyrocketing obesity and diabetes over the last 30 years. The increase in obesity rates began in the 1970s, about the same time that the original food pyramid was introduced. This starch-based pyramid was designed to help Americans avoid animal fats. Unfortunately, high intake of starch and other carbohydrates increases blood sugar and insulin levels. These increases can, in turn, lead to the production of more body fat. So, a low-fat, high carbohydrate diet could actually make you fatter and less healthy.

 

Myth #2: Salt is bad for your health.

Facts: Salt has been widely used by many people for thousands of years without any obvious harm. On the other hand, salt is considered harmful because it contains lots of sodium which is supposed to raise blood pressure, leading to heart disease. It is true that cutting salt can lower blood pressure slightly, but we still don’t know if cutting back on salt is actually good for your health. In fact, the British Medical Journal recently reported that overall, “data on the effect of dietary sodium intake on subsequent morbidity and mortality are limited and inconclusive.”4 Many studies even suggest that low-salt diets could be bad for you. In particular, two of the biggest studies found that people with the lowest salt intake had the shortest life spans.5,6 Yes, the people who ate the least salt, died the soonest, on average. But, how could cutting back on salt be harmful? Well, studies show that restricting salt can cause potentially harmful changes in metabolism, including increases in blood sugar, insulin and adrenalin levels.7, 8

My opinion: It is likely that some people can improve their health by consuming less salt, but is very unlikely that salt restriction is good for most people’s long-term health. Until someone can prove that cutting back on salt actually improves most people’s health, I believe that we’ve got more important things to worry about than getting everybody to restrict their salt intake.

 

Myth #3: Everyone with high cholesterol should take medicine to lower it.

Facts: Cholesterol is a natural substance in the human body. It is a component of every cell and a building block for many of our hormones. The “statin” drugs that are most commonly used to lower cholesterol work by disrupting normal cholesterol production. It is not surprising to learn then, that they have significant side effects including damage to muscle, the liver, and kidneys.

On the other hand, according to some of the best sources, statin drugs are only proven to help only one specific group of people live longer—men with heart disease. Researchers at the University of British Columbia concluded that “statins have not been shown to provide an overall health benefit in…prevention trials.”9 European researchers came to virtually the same conclusion, noting, “prevention with statins provides only a small and…hardly relevant improvement of cardiovascular morbidity/mortality.”10 And according to the Journal of the American Medical Association, taking medications for high cholesterol does not improve life expectancy for any group of women—even women with heart disease. 11

My opinion: Cholesterol-lowering medications have many side effects and should be used with caution. I believe that these medications should generally be reserved for people who are likely to improve their lifespan by taking them. Basically, that means middle-aged men who already have heart disease. For all the others with high cholesterol, I believe that addressing the underlying causes of their problem is more important. In most such cases, identifying and treating conditions such as hypothyroidism, insulin resistance and excess body weight is usually a better approach.

 

References:
1.     Reduced or modified dietary fat for preventing cardiovascular disease.  Hooper L, Summerbell CD, Higgins JPT, Thompson RL, Clements G, Capps N, Davey Smith G, Riemersma RA, Ebrahim S.
The Cochrane Library 2004, Issue 1. p9.
2.     JAMA. 2006 Feb 8; 295 (6): 629-642, 643-654, 655-666.
3.     http://www.bmj.com/cgi/content/full/322/7289/757?ck=nck
4.     BMJ, doi:10.1136/bmj.39147.604896.55 (published 20 April 2007)
5.     Am J Med. 2006 Mar;119(3):275.e7-14.
6.     Lancet. 1998 Mar 14;351(9105):781-5.
7.     Clin Sci(Lond). 2007 Aug;113(3):141-8.
8.     Klin Wochenschr.1991;69 Suppl 2:51-7.
9.     http://www.ti.ubc.ca/PDF/48.pdf
10. Int J Pharmacol Ther. 2003 Dec:41(12): 567-77.
11. JAMA. 2004 May 12;291(18):2243-52.