Fish oils and omega-3s may minimise the detrimental effects that ‘junk food’ has on the brain, according to a new research review by researchers at the University of Liverpool and published in the British Journal of Nutrition.

Researchers found that diets rich in omega-3s could prevent the negative effects of high-fat diets by stimulating the area of the brain that controls feeding, learning and memory. Research over the last 10 years has indicated that high-fat diets could disrupt neurogenesis, a process that generates new nerve cells in the brain.

The data revealed that while fish oils do not have a direct impact on this process in these areas of the brain they are likely to play a significant role in stalling the ability of refined sugars and saturated fats to inhibit the brain’s control on the body’s intake of food.

“Fish oils don’t appear to have a direct impact on weight loss, but they may take the brakes off the detrimental effects of some of the processes triggered in the brain by high-fat diets,” said Dr Lucy Pickavance, one of the study’s authors and a researcher at the University of Liverpool Institute of Ageing and Chronic Disease.

The research team reviewed more than 180 research papers from around the world to see if there was sufficient data available to suggest that omega-3s had a role to play in aiding weight loss.

“Body weight is influenced by many factors, and some of the most important of these are the nutrients we consume,” Dr Pickavance said. “Excessive intake of certain macronutrients, the refined sugars and saturated fats found in junk food, can lead to weight gain, disrupt metabolism and even affect mental processing,” she said.

The researchers said the changes can be seen in the brain’s structure, including its ability to generate new nerve cells, “potentially linking obesity to neurodegenerative diseases”.

“Research, however, has suggested that omega-3 fish oils can reverse or even prevent these effects,” Dr Pickavance said. “We wanted to investigate the literature on this topic to determine whether there is evidence to suggest that omega-3s might aid weight loss by stimulating particular brain processes,” she said.

Research papers reviewed by the University of Liverpool team showed that on high-fat diets hormones that are secreted from body tissues into the circulation after eating, and which normally protect neurons and stimulate their growth, are prevented from passing into the brain by increased circulation of inflammatory molecules and a type of fat called triglycerides.

The data showed that molecules that stimulate nerve growth are also reduced, but animal studies seem to indicate that omega-3s restore normal function by interfering with the production of the inflammatory molecules, suppressing triglycerides, and returning these nerve growth factors to normal.

“They seem to mimic the effects of calorie restrictive diets and including more fish or fish oil supplements in our diets could certainly be a positive step forward for those wanting to improve their general health,” Dr Pickavance said.

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