A new study suggests that including oily fish like salmon and trout or fish oil supplements in one's diet can significantly improve memory in older adults.

It is believed that DHA found in fish oil supplements could be key in preventing Alzheimer's disease, one of the most common forms of dementia.

Researchers at Rhode Island Hospital examined the relationship between fish oil supplements during the US Alzheimer's Disease Neuroimaging Initiative (ADNI) and indicators of cognitive decline.

In this retrospective study, older adults were assessed with neuropsychological tests and brain magnetic resonance imaging (MRI) every six months.

The group included 229 older adults who were cognitively normal; 397 who were diagnosed with mild cognitive impairment; and 193 with Alzheimer's disease (AD).

The study found that fish oil supplement use was associated with significantly lower rates of cognitive decline and brain atrophy in older adults.

"Participants with normal cognition who reported taking fish oil supplements demonstrated less brain shrinkage in key neurological areas, compared to those who did not use the supplements," explained principal investigator Lori Daiello from Rhode Island Hospital.

The findings were published online in the journal Alzheimer's & Dementia.