Fish oil can counter the negative effect junk food has on the brain, say scientists.
More than a decade of research has shown that high-fat diets can impact the brain by disrupting ‘neurogenesis’, a process that generates new nerve cells.
Now University of Liverpool researchers have discovered that diets rich in omega-3s, such as fish oil, can prevent these negative effects by stimulating the area of the brain that controls feeding, learning and memory.
The team from the University’s Institute of Ageing and Chronic Disease originally set out to look at research from across to world to see whether the data suggested that omega-3s had a role to play in aiding weight loss.
However, although data from the 185 research papers indicated fish oils do not have a direct impact on this process, it found that they play a significant role in reversing the damage high fats can cause the brain.
Researcher Dr Lucy Pickavance explained: ‘Body weight is influenced by many factors, and some of the most important of these are the nutrients we consume.
‘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.
‘These 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. 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.’
The research papers showed that on high-fat diets hormones that are usually secreted from body tissues into the circulation after eating – which 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.
Molecules that stimulate nerve growth are also reduced.
But it appears – in studies with animal models – that omega-3s restore normal function by interfering with the production of these inflammatory molecules, suppressing triglycerides, and returning these nerve growth factors to normal.
Dr Pickavance added: ‘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.
‘They seem to mimic the effects of calorie restrictive diets and including more oily fish or fish oil supplements in our diets could certainly be a positive step forward for those wanting to improve their general health.’