You are what you eat has never appeared to be more true than it has recently, if you take the results of certain mental health studies under consideration. It would seem that our brains -- the very essence of who we are -- are affected quite a bit by our nutritional intake. Case in point: new mental health research from Brigham and Women's Hospital in Boston found that the type of fats we consume influences our memory and other brain functions.1
The scientists pored over data on 6,000 women who were involved in the Women's Health Study. All of the participants were at least 45 years old. They were given a test of cognitive function in two-year intervals during a four-year time span and answered questionnaires about their eating habits as the study commenced. The researchers compared the good fats and bad fats the women reported eating with their mental abilities.
They were able to draw a parallel between eating "bad" fats and decreased brain performance. The volunteers who most frequently ate "bad" fats consistently displayed lower scores on their memory and brain function testing during the experiment period. The types of fats in this category include saturated and manmade trans fats, which in general have been linked to numerous health issues, particularly heart disease. Saturated fats are derived from animals, such as meat and dairy items. Artificial trans fats are found in all kinds of commercially prepared fried and baked goods, and anything that has partially hydrogenated vegetable oil.
The participants who typically ate the most "good" fats, conversely, received much higher scores on their cognitive testing throughout the trial. These types of fats, like monounsaturated fats, are typically associated with health benefits. They are found in seeds, nuts, fish, and avocados. The quantity of overall fat consumed didn't make a difference; the results were clearly dependent on what types of fat the woman generally ate.
This would seem to confirm the results of a 2011 study at Oregon Health and Science University, Portland, which found that individuals with measurably high levels of trans fat in their bloodstream scored lower on tests of mental acuity than others with lower trans fat levels.2 In that research, the participants with higher trans fat levels also were found to have a reduced brain volume.
Now, certainly the majority of trans- and saturated- fats are bad for you. But it is a little simplistic to say that they are all bad. The researchers didn't break down the study by exactly which trans fats and saturated fats were being consumed. A certain amount of saturated fat in the diet is actually essential, and some saturated fats are extremely health promoting. Plus, our experience with the high meat/high fat/low carb diets has shown that natural saturated fat does not necessarily raise cholesterol levels and clog arteries. For example, coconut oil is the highest source of saturated fats (92 percent), yet included in that number are the medium-chain triglycerides, which are extremely beneficial to the body.
Artificial trans fats are major contributors to cancer, heart disease, and diabetes and have no place in your diet if you wish to be healthy. But naturally occurring trans fats can be healthy. Conjugated linoleic acid is both a trans-fatty acid and a cis-fatty acid that has major health benefits. Studies have indicated it is a potent cancer fighter across a wide variety of tumors, can lower LDL cholesterol levels, prevent bone loss and atherosclerosis, and is actually brain protective.3
Also, when it comes to omega-6 and omega-3 fats, the study didn't break down the ratio between the two in the women's diets, which is actually a major determinant of your state of health.
So, while in general it's probably good advice to cut back on your intake of saturated fats and eliminate virtually all artificial trans fats from your diet, it's not quite so black and white as it can be made to appear. Knowledge is the best weapon in living a healthy lifestyle, and becoming accustomed to reading food labels on a regular basis helps too. And when you're feeling tempted, always remember that eating fresh foods is safer and will keep you feeling healthier and more energetic than eating processed foods every single time.
1 Chan, Amanda L. "Good and Bad Fats Affect Brain Health, Too." Huffington Post. 19 May 2012. . Accessed 20 May 2012. <http://www.huffingtonpost.com/2012/05/19/fat-brain-health-monounsaturated-saturated-trans_n_1527437.html>.
2 Bowman, G.L. et al. "Nutrient biomarker patterns, cognitive function, and MRI measures of brain aging." Neurology. 28 December 2011. Accessed 20 May 2012. <http://www.neurology.org/content/78/4/241.abstract?sid=248e9e6b-4dd9-4a1b-b8e7-9f094853e6bb>.
3 Hunt WT, Kamboj A, Anderson HD, Anderson CM. "Protection of cortical neurons from excitotoxicity by conjugated linoleic acid." J Neurochem. 2010 Oct;115(1):123-30. doi: 10.1111/j.1471-4159.2010.06908.x. Epub 2010 Aug 3. <http://www.ncbi.nlm.nih.gov/pubmed/20633209>