Fish oil and brown fat: an interesting lead, to be followed closely

A discovery in mice is a research lead, not yet advice for humans.

The study

In 2015, a team from Kyoto University fed mice a high-fat diet, with or without fish oil. The mice given fish oil gained about 5 to 10% less weight and stored less fat than the others.

The explanation put forward: the omega-3 fatty acids in fish oil may stimulate, via the nervous system, the appearance of cells able to burn fat to produce heat, instead of storing it. This is known as "brown" or "beige" fat.

What to take away

• This is a study in animals: we do not know whether the effect is the same in humans, nor at what dose.
• Food supplements are not harmless: they can interact with certain medicines, such as anticoagulants. Ask your doctor or pharmacist before taking any.
• The safest and most enjoyable way to benefit from omega-3s is on your plate: French nutritional guidelines advise eating fish twice a week, including one oily fish (sardine, mackerel, herring, salmon). Walnuts, rapeseed oil and flaxseed also provide them.

For runners, omega-3s are part of a balanced diet. But no oil replaces regular training, sleep and a varied plate.

Sources

• Kim M. et al., "Fish oil intake induces UCP1 upregulation in brown and white adipose tissue via the sympathetic nervous system", Scientific Reports, 2015. See on PubMed
• Programme national nutrition santé (French national nutrition programme), guidelines on fish and seafood, mangerbouger.fr.