Rodent of the Week: Low-carb diets affect blood vessels

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Low-carb diets can help people lose weight. But the diets may have a downside if followed over the long term, according to a researcher whose curiosity was piqued after she observed a number of heart attack patients who had been on low-carb, high-protein diets. According to the study, published this week in the Proceedings of the National Academy of Sciences, rats on the diets had an increase of plaque in the arteries of the heart and also had an impaired ability to form new blood vessels in tissues deprived of blood flow.

Blood tests of people on low-carb diets suggest the diets are safe. But, said the lead author of the paper, Dr. Anthony Rosenzweig, ‘our research suggests that, at least in animals, these diets could be having adverse cardiovascular effects that are not reflected in simple serum markers.’

In the study, researchers fed mice a low-carb, high-protein diet; a standard mouse ‘chow’ diet or a typical Western diet (43% carbohydrate, 42% fat and 15% protein) for 12 weeks before examining their cardiovascular system. The rats’ cholesterol levels did not change, and the rats on the low-carb diet gained 28% less weight than mice on the Western diet. However, when researchers looked at the animals’ blood vessels, the low-carb mice had a 15.3% increase in plaque accumulation compared with 8.8% in the Western diet group.

The study suggests that there may be a disconnect between cholesterol levels and what is occurring in blood vessels. Moreover, vascular health may be directly influenced by the amount of protein and carbohydrate in a diet.

‘For now, it appears that a moderate and balanced diet, coupled with exercise, is probably best for most people,’ Rosenzweig said.

-- Shari Roan