Can curry save your life?

The healing powers of turmeric, a spice found in Asian foods such as curry, have been known anecdotally for centuries, though Western medicine has begun to acknowledge them only recently. A study by Drew Tortoriello and colleagues at Columbia University (New York, NY) now shows that turmeric may prevent some of the harmful effects of obesity, including type 2 diabetes (Endocrinology 149, 3549–3558; 2008).

The researchers mixed curcumin in with the diets of two groups of obese mice. Mice in one group were from a genetically modified obese strain that is used as a model for type 2 diabetes, and the other group comprised wild-type mice that became obese after being fed a high-fat diet. After 4–8 weeks of treatment, mice in both groups had better blood sugar control, weighed less and had less body fat compared with obese control mice that ate a normal diet, even though mice that ate curcumin consumed more food than did control mice. Curcumin's anti-inflammatory qualities probably have a role in its positive effects, as most obesity-related diseases are strongly associated with inflammation.

In short, as turmeric does not cause dose-related toxicity, it probably wouldn't hurt to eat a little more curry.

How worms sniff out salt

Many animals instinctively 'follow their noses' to get closer to savory dinner prospects. In roundworms (Caenorhabditis elegans), movement in response to smell is controlled by a neuron system that calculates the rate at which a smell or chemosensory stimulus becomes stronger or weaker. A new study led by Shawn Lockery (University of Oregon, Eugene) analyzed this computational system.

Worms' attraction to salt is controlled by one pair of chemosensory neurons. The researchers imaged these neurons' response to salt using genetically encoded calcium sensors that emitted fluorescent light when neurons were activated in the presence of salt (Nature 454, 114–117; 2008). When salt concentration increased, the left neuron became activated, and the worm moved forward towards the source. When concentration decreased, the right neuron was activated and the worm would turn, perhaps to search for salt elsewhere. These results indicate that the two neurons have opposite functions and that they respond to changes in salt concentration rather than to absolute quantities. In a second experiment, scientists used capsaicin to activate the individual neurons, showing that each neuron directly controlled a distinctive behavior (moving forward or turning).

The group's findings may help treatment of patients with taste and smell disorders.

Your mother was right

Scientists have long sought to better understand the workings of the immune system. New research from Lynn B. Martin II and colleagues (Ohio State University, Columbus) specifically addresses the link between reduced food intake and immune 'memory'. The results suggest that mothers everywhere were on to something: eating enough food is essential to proper immune function.

Immune activity varies among wild animals, for example, in response to changing exposure to pathogens. Martin's group considered that the physiological costs of maintaining immune defenses may also contribute to variation in immune function. They previously showed that mild food restriction reduced secondary antibody responses in deer mice (Peromyscus maniculatus). In their new work, they aimed to determine whether this reduction was associated with a decrease in the number of splenic B lymphocytes that produce immunoglobulin G (IgG), the cells responsible for maintaining immune memory.

Martin and colleagues reduced food intake by 30% in a group of deer mice and then examined their immune responses. After two weeks of food restriction, mice had lower numbers of total splenic cells, total splenic B lymphocytes and splenic B lymphocytes producing IgG (Physiol. Biochem. Zool. 81, 366–372; 2008). Their body mass remained unchanged, however, as did their numbers of circulating antibodies. These results indicate that keeping up immunity is costly and may therefore compete against other physiological processes for limited resources.