Mice thrive on carbs, but humans don't. (China Photos/Getty Images)
Notice I put human in the last sentence because this week the BBC Web site reported on a study, which appears to call into question the safety of low-carb diets that were given to mice [1,2]. In this study mice that had been bred to be particularly susceptible to atherosclerosis were used. The mice in this experiment were fed one of three diets. The diets were:
1. Regular mouse chow
2. A diet comparable with a standard Western diet in terms of fat and cholesterol
3. A lower-carb, higher-protein diet containing levels of fat and cholesterol comparable to diet 2
The study, which went on for 12 weeks, found that the Western diet produced 9 percent more atherosclerosis than the regular mouse chow diet. The lower-carb, higher protein diet, however, appeared to give even worse results (15 percent higher atherosclerosis than the mouse chow diet).
Not surprisingly, this study has been covered with a “low-carb diets are bad for the heart” message. Some researchers have tried to “prove” this over the years, despite overwhelming evidence, which shows that lower-carb diets are superior for cardiovascular health. Unable to find any decent human data to support the concept that low-carb diets are unhealthy, it seems some researchers will go to extreme lengths to demonstrate supposed hazards in animal models.
This study appears to be an example of this. It is vaguely reminiscent of the studies performed decades ago in which rabbits fed stacks of cholesterol were found to develop atherosclerosis. But rabbits are herbivores, and don’t have cholesterol naturally in their diet. No wonder, then, that feeding it to them in excess might not do them much good.
Mice are ostensibly herbivorous too, and by virtue of that eat a diet rich in carbohydrate. Feeding them a low carbohydrate is therefore taking them far away from the diet they are best adapted to, especially if it offers super-high levels of protein (45 percent of calories) that mice would not be accustomed to eating. Humans are not accustomed to eating such a protein-rich diet either.
Seems to me that these researchers chose an inappropriate animal model to test their theory and then fed the animals an inappropriate diet. These actions suggest that the researchers were doing what they could to design an experiment to produce a desired outcome. We get a little sense of that when it is revealed that the researchers “decided to investigate their [low-carb diets] impact on the cardiovascular system after hearing reports of people on the diets suffering heart attacks.” I wonder whether it ever occurred to these researchers that legions of people are dropping dead ever day while following low-fat diets. Perhaps start there?
Lead researcher Anthony Rosenzweig “said the findings were so concerning to him that he decided to come off the low-carb diet he was following.” I see, so this scientist has decided to turn his back on a huge stack of human evidence on the basis of one inappropriate animal study. The fact that it was his own study does not militate against the fact that this seems like he made a really dumb decision.
References:
1. news.bbc.co.uk/1/hi/health/8218780.stm
2. Foo SY, et al. Vascular effects of a low-carbohydrate, high-protein diet. Proceedings of the National Academy of Sciences Epub August 24, 2009
Dr. John Briffa is a London-based physician and health writer with an interest in nutrition and natural medicine. His Web site is drbriffa.com
