Consuming fish oil could help reduce weight gain in middle-aged people by transforming fat-storage cells into fat-burning cells, a new study has claimed.
Researchers from Kyoto University in Japan found that fish oil activates receptors in the digestive tract, fires the sympathetic nervous system, and induces storage cells to metabolise fat.
Fat tissues do not all store fat. So-called "white" cells store fat in order to maintain energy supply, while "brown" cells metabolise fat to maintain a stable body temperature. Brown cells are abundant in babies but decrease in number with maturity into adulthood, the researchers said.
A third type of fat cell - "beige" cells - have recently been found in humans and mice, and have shown to function much like brown cells.
Beige cells also reduce in number as people approach middle age; without these metabolising cells, fat continues accumulating for decades without ever being used.
The scientists investigated whether the number of these beige cells could be increased by taking in certain types of foods.
"We knew from previous research that fish oil has tremendous health benefits, including the prevention of fat accumulation," said senior author Teruo Kawada.
"We tested whether fish oil and an increase in beige cells could be related," Kawada said.
The team fed a group of mice fatty food, and other groups fatty food with fish oil additives.
The mice that ate food with fish oil, they found, gained 5-10 per cent less weight and 15-25 per cent less fat compared to those that did not consume the oil.
They also found that beige cells formed from white fat cells when the sympathetic nervous system was activated, meaning that certain fat-storage cells acquired the ability to metabolise.
"People have long said that food from Japan and the Mediterranean contribute to longevity, but why these cuisines are beneficial was up for debate. Now we have better insight into why that may be," said Kawada.
The study was published in the journal Scientific Reports.
