What do you use to oil a rusty brain?
October 3rd 2010 22:48
Signature Tune
Oil it with fish, blueberry juice
Now think about this: A room has three reading lamps with each one connected to a separate switch, all switches being outside the room. Your task is to identify which switch turns on which bulb. You can turn the switches off and on as many times as you like, and leave them in any position you like, but you can enter the room only once. How would you solve the problem?
Having a little trouble? You're not alone. And the more senior you are, the more likely you are to experience difficulties. That, I'm afraid, is a fact.
Just like every other part of the body, our brain is also subject to the ravages of age. As we get older, our mental acuity declines, our memory begins to fade. But wouldn't it be great if science could do something about that? Researchers all over the world are racking their brains to find ways of maintaining higher mental function in the elderly, the most rapidly growing segment of the population. Of course, people of all ages could benefit from a little lubrication of their mental machinery. And that lubricant could be an oil, applied through a readily available orifice, the mouth.
"Oiling" the brain can be taken quite literally. But it does have to be the right kind of oil, namely one that features a solid dose of docosahexaenoic acid. DHA, as it is commonly abbreviated, belongs to the omega-3 family of fats, found mostly in fish, with salmon being a particularly good source. Why should a dietary fat improve brain function? Because DHA is the most abundant fat in brain cell membranes where it contributes to "synaptic plasticity," a measure of how well cells communicate with each other.
Nerve cells transmit messages by releasing chemicals called neurotransmitters into the synapse, the gap that separates the cells. The effectiveness of such cellular communication depends on the quantity of neurotransmitters released as well as on the response of receptors on neighbouring cells to those neurotransmitters. DHA makes the cell membrane more fluid and makes receptors more responsive. Since it is postulated that memory and learning are determined by the extent of connections between the vast array of nerve cells in the brain, it is clear that synaptic plasticity represents one of the foundations of learning and memory.
In theory, then, any increase in DHA in cell membranes should lead to improved synaptic plasticity and better brain function. Although our bodies can make DHA from other fats in the diet, they do not do so very efficiently. It is far better to oil the brain directly with DHA. But what evidence is there, other than anecdotes about fish being "brain food," that an increase in DHA really does lubricate the mental gears?
Rodents are a good starting point, even though their mental capabilities are significantly less than that of most humans. When rats are put on a diet deficient in omega-3 fatty acids, their memory and learning ability are clearly impaired. They just don't solve those little mazes as well.
In humans, dietary deficiencies in omega-3 fats have been associated with an increased risk of dementia, dyslexia, depression, bipolar disease, attention-deficit disorder and even schizophrenia. But these, of course, are just associations, although there have been preliminary studies in which children's school performance seemingly improved with DHA supplements. Some critics, however, argue that these results were interpreted over-zealously by the researchers.
As far as adults go, a few trials have examined DHA's link to memory. In one placebo-controlled study, healthy subjects with memory complaints who took 900 mg of DHA daily for six months reduced the errors they made on tests of learning and memory. The researchers claimed that in terms of learning and memory, the benefits were equivalent to turning the clock back three years!
DHA is not the only food component to be associated with memory enhancement. Epicatechin, a natural compound found in tea, grapes, chocolate and blueberries, has been shown to enhance blood vessel growth in an area of the brain involved in learning and memory. More blood vessels mean more oxygen delivered to the brain and better utilization of glucose, the brain's main source of energy. Nerve cells in this area are also better developed, suggesting an enhanced ability of communication between cells, implying better memory.
These benefits were even more evident in mice that were allowed to run on a treadmill for two hours a day. The epicatechin-treated and well-exercised mice showed great improvement in remembering the location of a platform hidden in a pool of water.
Humans rarely have a need to find platforms hidden under water, but better memory for words and names comes in handy. And since blueberries have a hefty amount of epicatechin along with many other related anthocyanins, blueberry juice is an excellent candidate for trials aimed at improving memory. In one such, nine subjects in their 70s with early signs of memory
changes were asked to drink 440 to 620 millilitres of blueberry juice daily, depending on their body weight. After 12 weeks, there was a measurable improvement in a word recall test.
But in the end, as far as improving memory goes, it may not be what we eat or drink that counts, but what we don't. In a group of adults with normal memory, a 30-per-cent reduction in daily calorie intake over three months resulted in a 20-percent increase in word recall!
Now back to our light bulb problem. Switch on one bulb and leave it on for a few minutes. Turn it off and switch on another. Enter the room. One bulb will be on, so you've identified it. Touch the other two to see which one is warm. The warm one is the one you had previously turned on. The third one is identified by elimination.
Missed that? Then go and eat your fish and drink your blueberry juice. Forget the dessert. Follow with a run on a treadmill. That should make your mental light bulb glow more brightly.
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