Headed for surgery? hold the protein

Fast before surgery. That's a common recommendation doctors give patients to ensure a safe procedure. Now a new study in mice suggests that the advice may have benefits beyond the operation itself: Extensive presurgical fasting appears to protect organs from postsurgical damage. Although preliminary, the finding builds on evidence that short-term starvation helps the body guard against stress and may be a useful medical tool. Researchers have known for decades that drastically cutting calories can help animals live longer, although exactly why is uncertain. One popular idea is that when calories are curbed, the body has to adapt to the nutrient deficiency—and in doing so, it becomes more resistant to stress generally. The type of long-term calorie restriction tested in animals is too extreme to apply widely to people, but some scientists have wondered what effect very short-term restrictions, of just a few days, might have. James Mitchell, who studies stress resistance at the Harvard School of Public Health in Boston, was especially interested in ischemic reperfusion injury, a problem that often occurs with heart attacks and strokes, and sometimes even from heart and vascular surgery. When someone has a heart attack due to a blocked artery, the heart is deprived of oxygen (an effect called ischemia) and cells die. Counterintuitively, when blood flow is restored (called reperfusion) that can also do damage by triggering inflammation. This kind of double whammy can be induced experimentally in other organs, too. Mitchell focused on the kidney and liver in part because it's relatively easy to measure their function. Two years ago, he and his colleagues reported in Aging Cell that cutting the calories ingested by mice by 30% for up to 4 weeks protected the rodents' kidneys when their blood supply was cut off and then restored. Others have found that short-term calorie restriction does the same for the heart in mice.