Your brain loves fat. But it’s a picky eater.
A recent study (1) compared cognitive function in middle-aged adults who, for the previous 20 years, had adhered to either a Mediterranean diet (MD) or a DASH (Dietary Approaches to Stop Hypertension) diet. While both are considered to be healthy diets, only the Mediterranean diet was shown to preserve brain function.
There’s been plenty of data showing that people who eat greater quantities of oily fish are less likely to suffer cognitive decline and even Alzheimer’s Disease (2). This was the first study, though, that evaluated these two healthy diets head-to-head.
An important difference between the MD and the DASH is that the MD consists of higher amount of healthy fat, largely from fish and extra virgin olive oil. DASH emphasizes saturated fat (along with decreased salt), but does not emphasize fish as the preferred source of animal protein or extra virgin olive oil as an important nutrient. It now appears that the abundant omega-3 fatty acids in oily fish and the antioxidants in extra virgin olive oil may be important contributors to brain health.
The Mediterranean Diet. Finally, A Diet That’s Not a Gimmick
I have read literally hundreds of scientific and medical articles about diet and diets; and I am more convinced than ever that the Mediterranean diet is the healthiest, most sustainable, and least gimmicky way to eat (3). There are several versions of this diet, but they all emphasize vegetables, fruits, whole grains, legumes, fish, extra virgin olive oil, nuts and seeds. Red wine, thankfully, is also included.
This is what MD has to offer:
Compared with low-fat and low-carbohydrate diets, people who eat a MD lose more abdominal fat and have better blood levels of glucose, insulin, and lipids (4). Eating a Mediterranean diet does not result in weight gain even if you don’t restrict calories (5).
Metabolic Syndrome Reversal and Type 2 Diabetes Prevention
Metabolic Syndrome is a combination of related risk factors for heart disease and type 2 diabetes: high blood pressure, low HDL (”good”) cholesterol, high triglycerides, high fasting glucose, and abdominal obesity. More than a third of all Americans have metabolic syndrome (6) If you eat a consistent MD, and especially if you’re also physically active, you have the capacity to actually reverse all those risk factors (7,8). Even for people who already have type 2 diabetes, their disease is better controlled if they eat in this way. (9).
Heart Disease & Stroke Prevention
Numerous studies have demonstrated the effectiveness of the Mediterranean diet in decreasing the risk of heart disease and stroke (10-12).
I’ve always been concerned by how many of my patients have trouble taking diabetes and hypertension seriously. After all, they’re common, painless (at least at first), and invisible. It can be difficult to fully appreciate that these conditions represent a direct line to heart attack and stroke. And anyway, heart attack and stroke can sound so far away, and we all have to die of something, right? Well, the big problem may not be dying: with severe heart disease, it’s possible to end up being a “cardiac cripple,” with the high point of your day being a walk from the bed to the toilet. And life after a stroke? Oy vey.
Because of the decreased chronic inflammation, the improvement in the body’s hormonal balance, and the weight loss itself, staying on a Mediterranean diet lowers your risk of developing cancer, including breast and colon cancer (13).
Improved Brain Health and Prevention of Cognitive Decline
The Mediterranean diet is associated with reduced rates of depression (14),, cognitive decline (15), and even Alzheimer’s Disease (2).
You Are What You Eat: The Intestinal Microbiome
Some of these seemingly-miraculous effects have to do with the positive changes the MD facilitates in the intestinal microbiome. The bacteria in your gut play a large role in how easily you gain weight (16), how much inflammation you have in your body, how well your immune system performs, and how your nervous system works to affect brain function, mood, and behavior (17).
The inferior microbiome (18) that is associated with the typical Western Diet (lots of meat, processed foods, and refined sugar; not enough vegetables, fruit, and fiber) is strongly correlated with not just intestinal disorders such as irritable and inflammatory bowel diseases (19), but also with atherosclerosis, allergies, autoimmune illnesses, asthma, diabetes, and some cancers — all of which are related to chronic low-grade systemic inflammation (20).
Do not despair, however: switching to a healthier diet has dramatic and rapid positive effects on the microbiome, with regard to both more beneficial and more varied bacteria that make their home inside you. That’s true for children, too (21).
To summarize, people who adhere to a Mediterranean-type diet live a longer, more vital life. Incredibly, even if they don’t start the Mediterranean diet until they’re over the age of 70, they still have a 50 percent decrease in mortality over a ten-year period (22). It’s never too late to start!
Maybe you want to incorporate the MD into your life gradually. That’s fine. Perhaps one meatless dinner a week? One fewer restaurant meal a week? A glass of red wine instead of a shot of vodka? See what works for you, and be open to making changes. The important thing is that you feel like you’re adding something worthwhile to your life and that it’s worth the effort, rather than feeling like you’re giving up tantalizing (but potentially destructive) foods. This change will become so much easier as you go along — I guarantee it.
You can’t control your genetic inheritance. You may have inherited genes that increase the risk of getting certain diseases (23). But you can definitely lower that risk, depending on the way you live. When it comes to weight and disease susceptibility, “Although genetic factors play a large role, heritability is not destiny,” (24).
So let’s eat some fat! Here’s a delicious, good-for-your heart and-brain recipe:
Spicy Grilled Salmon
4 6-ounce salmon (preferably wild) fillets or steaks
For the Marinade:
1/4 cup olive oil
2 Tbl tamari or soy sauce
2 Tbl balsamic or red wine vinegar
2 Tbl green onions (chopped)
1-3 tsp sambal chili paste (or 1-3 tsp sriracha sauce plus ½ tsp rice vinegar)
2 tsp maple syrup
1-2 cloves garlic (minced)
1 tsp grated ginger
1 tsp sesame oil
Combine marinade ingredients in a small bowl.
Place salmon in a large resealable bag. Pour the marinade mixture in the bag. Seal the bag, and flip it around a few times to make sure the salmon is completely coated.
Place in the refrigerator to marinate for 30-60 minutes.
Heat the grill at medium heat. Clean and oil the grill grates.
Remove fish from bag and place on the grill.
If you’re using steaks, cook them for 4-5 minutes per side or until done (between 145-150 degrees F.).
If you’re using fillets, place the fish on a sheet of foil on the grill. Cook for about 10 minutes without turning.
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(2)Wu S et al. Omega-3 fatty acids intake and risks of dementia and Alzheimer’s disease: a meta-analysis. Neurosci Biobehav Rev 2015; 48:1-9.
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(11)Martinez-Gonzalez MA et al. Benefits of the Mediterranean diet: insights from the PREDIMED study. Progress Cardiovasc Dis 2015; 58(1):50-60.
(12)Widmer RJ et al. The Mediterranean diet, its components, and cardiovascular disease. Am J Med 2015; 128:229-38.
(13)Barak Y, Fridman D. Impact of Mediterranean diet on cancer: focused literature review. Cancer Genomics Proteomics 2017;14(6):403-8.
(14)Garcia-Tora M et al. Obesity, metabolic syndrome and Mediterranean diet: impact on depression outcome. J Affective Disord 2016; 194:105-8.
(15)Valls-Pedret C et al. Mediterranean diet and age-related cognitive decline: a randomized clinical trial. JAMA Intern Med 2015; 175(7):1094-1103.
(16)Tilg H, Adolph TE. Influence of the human intestinal microbiome in obesity and metabolic dysfunction. Curr Opin Pediatr 2015; 27(4):496-501.
(17) Sherwin E. A gut (microbiome) feeling about the brain. Curr Opin Gastroent 2016; 32(2):96-102.
(18)De Filippis F et al. High-level adherence to a Mediterranean diet beneficially impacts the gut microbiota and associated metabolome. Gut 2016; 65(11):1812-8.
(19)Distrutti E et al. Gut microbiota role in irritable bowel syndrome: New therapeutic strategies. World Gastroent 2016; 22(7):2219.
(20)Kataoka K. The intestinal microbiota and its role in human health and disease. J Med Inves 2016; 63(1-2):27-37.
(21))David LA et al. Diet rapidly and reproducibly alters the human gut microbiome. Nature 2014: 505(7484):559-63.
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(24)Casazza, K et al. Myths, presumptions, and facts about obesity. N Engl J Med 2013; 368(23):2236-7.