Wednesday, March 26, 2008

brain food: the good fats

The brain is extremely metabolically active, and so what we eat very much fuels it well (or not). The fats we consume play a major role in brain health. I found quite a bit of information about fats and the brain. I'll include some findings, and at the end of this post, list the foods with fats that positively influence brain health.

Brain performance requires omega-3 fatty acids, commonly found in fish. Omega-3s are major constituents of brain cell membranes, through which all nerve signals must pass. And, for new nerve connections to be made, new cell membranes must be formed. And, brain cell membranes are in constant need of replenishment. So keep those cell membranes fueled with fish. And fresh or canned fish gets more omega-3s into bodies than omega-3 supplements or refined fish oils.

Warning about fish: a lot of it is high in mercury or PCBs. The Environmental Defense Fund (see www.edf.org/seafood) lists best, okay, and worst choices and notes which of the best choices are both high in omega-3s and low in contaminants.

How often should you eat fish? Two or three times a week.

Note that farm-raised fish are more likely to have been given antibiotics. Also, a lot of fish is sprayed with preservatives. It seems like a prudent idea to rinse fish before cooking.

Walnut oil and canola oil are highly recommended non-fish sources of omega-3s. Other sources include flax seeds***, walnuts***, cooked soybeans***, hemp seeds, pumpkin seeds, chia seeds, sea vegetables, spirulina, and dark green leafy vegetables (the usual suspects, I suppose, like kale, spinach, collards, romaine, etc.). Chia seeds! Aren't those the little seeds used in chia pets--you stick them into grooves on a ceramic animal-shaped vessel, fill the vessel with water, and sprout a green creature? I've never heard of eating them or seen them sold as a food in a grocery store! Who knew?

A 1:1 balance of omega-3s and omega-6s is required. Most Americans are lacking the omega-3s. Omega-6 is found in red meat and dairy. Americans tend to consume 10 to 20 times more omega-6s than omega-3s. So if you eat dairy, nonfat is best, and limit red meat while boosting sources of omega-3s. Avoid transfats and supermarket oils and salad dressings unless they say cold-pressed or olive oil is labeled extra-virgin.

Really avoid transfats! Transfats are unnatural oils, nearly all man-made. They are partially hydrogenated for longer shelf life, and thus are cheaper. They have a different shape than healthy fatty acids and adversely affect brain cell membranes. The western diet has included them for 50 years without much ado until recently. Who knows the long-term effects of a couple of generations of people blithely consuming them? Which reminds me, have you seen Idiocracy? That movie might turn out to be true, only instead of water being the reason for the dumbing down of the human race, it's transfats.

Another important fat-related brain nutrient is choline. It is a precursor of many neurotransmitters. Choline is a fat-like B vitamin found in eggs. (Sort of gives new meaning to the commercial of the frying egg with voiceover saying, "This is your brain on drugs." Actually, this egg is good for your brain--especially if fried in canola or walnut oil!)

Choline enhances memory and minimizes fatigue.

Oleic acid is a primary constituent of the myelin sheaths in our brains. Sources of oleic acid include oils from olives, almonds, pecans, macadamias, peanuts, and avocados. I imagine you could just eat these foods to get the benefit, but it must be nice to have all these oils on hand in the kitchen. Mmm, salad dressing made with avocado oil. I must try that! A salad of green leafy vegetables, avocados, wild Alaska salmon, and one of the aforementioned oils with lemon juice sounds like a great way to get some great brain food.

DHA is the most prevalent fat in the brain. The rise in depression in the 20th century has been associated with a decline in DHA consumption. There's also a link between DHA deficiency and hostility and aggression. It's most important for pregnant women and babies, when the brain is forming.

Fish contains DHA. Now there are two good reasons to eat fish--omega-3s and DHA.

My list of brain foods with good fats:
fish (best are anchovies, Atlantic mackerel, farmed oysters, wild Alaska salmon***, canned pink/sockeye salmon***, sardines, farmed rainbow trout, and U.S. and Canadian albacore tuna; good are Pacific halibut, Pacific cod, U.S. farmed shrimp, farmed bay scallops, U.S. yellowfin tuna)

oils, seeds, and nuts: canola oil, walnuts and walnut oil***, flax seeds and flax seed oil***, chia seeds (if you find them in a store, let me know, please!), olives and olive oil, almonds, pecans, macadamia nuts, peanuts, avocado oil

note: do not cook with these oils--use them for dressings--and store them in dark containers in the fridge--they are sensitive to heat and light

sea vegetables (dulse, kelp, wakame, kombu, arame)

dark green leafy vegetables, cauliflower, cabbage, broccoli, brussels sprouts, winter and summer squash, avocados, cooked soybeans including tofu***

cloves, oregano, mustard seeds

eggs, in moderation

*** very high

Avoid transfats!

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