Food n Mood

How eating the right kind of fat is good for the brain.

By Willow Lawson, published November 1, 2002 - last reviewed on June 9, 2016

When it comes to your diet, there's the school of thought that it all comes down to calories. And if you're just measuring your waistline that may be true.

But if it's your mental health you're monitoring, a growing number of scientists want you to pay attention to something else: eating the right kinds of fat. This doesn't mean just monitoring the fat grams in your blueberry muffin or how many times you've had red meat this week. It's about eating the fats that your brain can use for routine maintenance.

Our brains are literally made of fat and our nerves are sheathed in thin membranes of it. The signals that travel through our flesh--our feelings, thoughts and commands to our bodies skip along cells and their long arms made of fat.

But not just any fat. Omega-3 fatty acids are one of the basic building blocks of the brain. Found mainly in seafood, but also in walnuts, leafy greens and ground flaxseed, these are polyunsaturated fats that also promote cardiovascular health and protect against cancer.

Omega-3 fatty acids are also increasingly seen as key to the deterioration of mental processes that mark a large variety of mental disorders. Brain cell membranes are about 20 percent fatty acids and they seem to be crucial for keeping brain signals moving smoothly along the folds of the brain.

Studies have shown that countries with diets rich in omega-3s have lower rates of depression, homicide, bipolar disorder, postpartum depression and suicide.

The fatty acids in cell membranes need constant replenishment by diet. And that's where complications set in. The omega-3s exist in a delicate balance with another group of needed fats, the omega-6s.

The trouble is, most Americans appear to be consuming too much of the omega-6s, and they're crowding out the omega-3s that we need. The omega-6s are found in many vegetable oils that permeate processed foods. Think of the cake and cookies found in your local deli or gas station, the ones that seem to stay fresh forever.

Joseph Hibbeln, M.D., a psychiatrist at the National Institutes of Health, says the overabundance of omega-6s in our diet is one of the most critical issues facing U.S. public health. Over the last century, our consumption of soybean oil has increased a thousand-fold, so that each of us now eats about 25 pounds of the stuff a year.

"There's good data that this soybean oil has literally been flooding our bodies and brains," Hibbeln says. He believes that many health problems, including the steep rise in depression, might be due to this radical change in our diet, although Hibbeln says more studies need to be done.

So next time you are in the grocery store, take a look at the ingredients on boxes of crackers and cookies and even jars of peanut butter. Most likely they are packed with soybean, cottonseed or corn oil. Instead, do your brain and your mood a favor and feed it a walnut or a sardine.