When you eat a scoop of chocolate chip ice cream, you’re consuming fat, but you’re also getting fat when you eat healthier foods like grilled salmon and when you sauté your vegetables in olive oil. These foods all contain fat. On the other hand, not all fats are the same. Chocolate chip ice cream contains mostly saturated fat – the type of fat that many experts believe raises LDL-cholesterol and is linked with heart disease. In contrast grilled salmon contains more polyunsaturated fats.
One sub-type of polyunsaturated fat called omega-3s is linked with heart health. Omega-3s have favorable effects on blood lipids. They exert their heart-healthy effects by lowering triglyceride levels and raising HDL, the “good” form of cholesterol that protects against heart disease. Plus, omega-3s have anti-inflammatory benefits that reduce inflammation inside blood vessels, another way it may lower the risk for a heart attack or stroke. There’s another type of fat called monounsaturated fats. These fats are abundant in olive oil, nuts avocados. It’s a heart-healthy form of fat because it reduces LDL-cholesterol and raises HDL.
Now you know the effect each type of fat has on blood lipids, but what impact does each have on the function of your brain – processes like memory and cognitive processing? A recent study looked at this issue and shed some light on how different types of fat impact memory and cognitive function.
Dietary Fat: Does the Type You Choose Affect Your Memory?
As part of a large national study called the REGARDS study, researchers looked at the dietary habits of almost 18,000 people, both men, and women while testing their memory and cognitive function over a 4-year period. By the end of the study, almost 7% of the participants had experienced a decline in memory.
The good news? Eating a diet higher in monounsaturated and omega-3 fats from olive oil, fish and nuts relative to saturated fat in meat and dairy was linked with an almost 20% reduction in memory and cognitive decline in this study. The participants that ate healthy fats were essentially followed a Mediterranean-style diet, and the more closely they adhered to this type of diet the less likely they were to develop cognitive problems over time.
Why Are Certain Types of Fat Better for Cognitive Function?
This study doesn’t prove that dietary fat was the only factor that explains the differences between the two groups. The Mediterranean diet also emphasizes fruits and vegetables, rich in brain-protective antioxidants, which likely played a role as well. But other research shows omega-3s are good for your brain. Another study focused on young adults under the age of 25, looking at the effects omega-3 fats have on memory in a younger population. Participants took omega-3 supplements for 6 months and underwent blood tests, brain scans and memory, and cognitive test. Those that took the supplements showed documented improvements in their working memory.
There’s a growing body of literature suggesting that omega-3s, a brain and heart-healthy type of polyunsaturated fat, improves memory and helps to ward off cognitive decline with aging. In addition, some studies show that monounsaturated fats in nuts and olive oil help to slow down brain aging as well. What could be more important than protecting your brain cells? One form of omega-3 called DHA plays an important role in transmitting signals between brain cells and keeps the membranes of brain cells fluid so messages flow more easily. That translates into better cognitive function.
Why might a diet that emphasizes monounsaturated and polyunsaturated fats like omega-3s over saturated fats be healthy for your brain? Saturated fats in full-fat dairy products and meat raise LDL-cholesterol levels in some people. This leads to an increased risk for atherosclerosis or the build-up of plaque inside blood vessels. One of the places plaque builds up is in blood vessels in the brain. This reduces blood flow to areas of the brain involved in memory and cognitive function. In extreme cases, this can lead to a stroke, if it involves blood vessels in the brain, or a heart attack if it involves vessels that carry blood and oxygen to the heart.
Some Types of Fat Also Have Anti-Inflammatory Benefits That Are Brain-Healthy
Another reason omega-3 fats may be protective, other than their effect on lipids, is by reducing inflammation. There’s evidence that brain degenerative diseases like Alzheimer’s disease are linked with low-grade inflammation. Omega-3 fats help to reverse the inflammatory cascade that leads to degenerative changes in the brain that cause cognitive impairment. Where omega-3s seem to be most beneficial is for people who have mild cognitive dysfunction – a few too many “senior moments” – but don’t have Alzheimer’s disease. Based on some studies, omega-3s improve memory and cognition in people who fall into this category.
The Bottom Line?
Choose your fats carefully. What’s healthy for your heart is also good for the health of your brain. You can pamper them both by replacing some of the red meat in your diet with fatty fish and by choosing lean sources of poultry as a red meat replacement. Don’t forget about eating more plant-based sources of protein like lentils, beans, nuts and fermented soy products like tempeh. Meat isn’t the only source of protein.
When you choose dairy, choose low-fat over full-fat to reduce the amount of saturated fat in your diet. Some studies show that some types of saturated fats like coconut oil may not be as bad as previous research suggested, but you’ll get more benefits from increasing the ratio of monounsaturated and omega-3s in your diet relative to saturated fat. Think olive oil over butter – and definitely stay away from margarine that contains trans-fat.
References:
FoodNavigator.com. “Trimming the Fat: For a Better Memory Avoid Sat Fats, Meat and Dairy and Increase Omega-3”
Neurobiol Aging 33 (7): e17–29.
Reprod Nutr Dev. 2005 Sep-Oct;45(5):559-79.
The University of Pittsburgh. “Omega-3 Intake Heightens Working Memory in Healthy Young Adults”
Medscape Family Medicine. “Raising HDL in Clinical Practice: Clinical Strategies to Elevate HDL”
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