Have Fruitflies Shown Us How To Cure Memory Loss?

Memory loss is annoying. It affects most of us to some degree, even when we're young and healthy, and research has found that the problem often worsens as we age.

There are ways to slow the onset of this age-related memory impairment (AMI) and mitigate it once it shows up. But new evidence suggests that there may be a way to prevent or reverse memory loss, and our diets could be the pivotal factor.

Researchers writing in Nature Neuroscience conducted an experiment in which they trained fruit flies to associate a particular odor with an electric shock. The younger flies quickly learned to avoid the odor, while the older insects learned more slowly. After adding polyamines to the second group's diet, however, the study's authors found that “the age difference in learning and memory was nearly wiped out,” Nature reported two weeks ago.

The experiment was repeated by another team of researchers to verify the results. But instead of changing the flies' diet, the second team increased the activity of an enzyme responsible for manufacturing polyamines. Both approaches reversed the age-related memory loss.

This research is unlikely to yield a pill for memory loss in the near future, but the researchers are probably onto something by suggesting that diet can influence memory loss. We have pretty good evidence suggesting that our eating habits affect our mental health in a variety of ways, and a little digging on PubMed reveals that our diets can also impact our ability to remember information.

The connection between healthy eating and memory enhancement isn't shocking by itself; the link between the two has been investigated extensively over the years. But the degree to which certain foods may influence our memory might surprise you a little bit. One 2008 study, for example, found that many elderly people (aged 85 and older) with higher total and LDL cholesterol experience better memory function. The study only involved 185 people, and the researchers had no way of knowing if higher cholesterol was responsible for the improved memory function observed in the study, but a 2001 paper published in Science offers a good explanation. According to that research, cholesterol plays an important role in the formation of synapses, connections between neurons which are essential to all the information processing our brains do, including memory formation. 

So while eating an egg a couple of times a week might help you keep your memory intact as you age, eating too much sugar probably has the opposite effect. Last year, scientists at the Brain Research Institute at UCLA conducted a study which suggests that sugar, along with causing diabetes and weight gain, can damage synapses through insulin resistance, thus causing memory loss. It's an interesting argument and other earlier research seems to support the idea that insulin resistance is bad for our brains, but we can't know for sure yet. The UCLA researchers studied rats, and none of us are rats.

Whatever effect particular foods may have, another possibility is that eating less in general may help to preserve our memories. Previous research has shown that obese people have impaired episodic memory, but a paper published in June found that obese women who lost an average of 20lbs performed better on a memory test after they lost the weight. The researchers were able to track their progress using functional magnetic resonance imaging. “After weight loss, brain activity … increased during memory encoding … [and] decreased after weight loss in the regions that are associated with retrieval of episodic memories,” which suggests more efficient retrieval, according to one of the researchers.

Experiments like these are far from a cure for memory loss. Nonetheless, new evidence continues to suggest that what we eat and how much we eat may have a major impact on our memory. So along with keeping your brain active, add eating better to the list of things you do for the sake of your memory. If nothing else happens, you might lose some weight.