Your neurons – the cells that transmit information – look like mops with shaggy strings that reach out to one another, while the handles of the mops act like cables that carry the information. These neurons talk with one another with the frequency of eleven-year-old girls at a sleepover party; a lot of information is exchanged very quickly.
The hippocampus, which is shaped a little like a seahorse and is buried deep inside your brain (see Figure 1.1), is the main driver of memory. (The other two memory-related areas of the brain are the prefrontal cortex, which controls the executive function of your brain, and the cerebellum, which controls balance.) Your hippocampus processes information before it is stored. It works best when you’re either emotionally interested in the material or alert when you’re learning about it. That’s one reason why coffee may aid memory; it seems to increase your alertness the first time you learn something, which increases the chance you’ll deposit it in your long-term memory bank.
But for the purposes of ageing, we’re mostly concerned about what happens to the power lines within your brain. So flip on your hippocampus (or grab a cup of coffee) and remember this: there are protein fragments in your brain that sound like the name of a Star Wars droid – beta-amyloid – and they’re responsible for gunking up your power lines like overgrown vegetation or fallen branches. They’re probably responsible for causing Alzheimer’s. The primary defect in Alzheimer’s affects the input and output power lines of the hippocampus. Memory starts to fade. (The other physiological sign of Alzheimer’s is the buildup of what are called neurofibrillary tangles. They’re insoluble twisted fibres that build up inside neurons, like power lines getting crossed up and sending energy to the wrong location. These tangles influence intelligence.) Now, a downed branch here and there won’t do much to disrupt the flow of energy through your entire city, but what happens when a lot of branches or shrubs or trees fall on the same part of the grid? You’re out of commission.
Figure 1.1 Storage Units Memories are stored in the hippocampus. The other two major memory-related areas of the brain are the prefrontal cortex (controlling the executive function of your brain) and the cerebellum (used for balance). Craving memories are found in the insula.
In general, genes control how much beta-amyloid you have. Some branches may be knocking out those notes from your course in eighteenth-century Roman history, while others may be causing you to forget to pick up the very thing that you went to the supermarket for in the first place. But your genes don’t have complete control. You can alter the amount of gunk you have weighing down your power lines by altering the expression of one of your genes: the Apo E gene, to be exact. Apo E protein acts like the power company crew that removes the branches and sap from the power lines after the storm. It sweeps through and removes the beta-amyloid so that your synapses can keep functioning and you don’t lose the ability to remember what year Diane Keaton won an Oscar for best actress (1977). Whenever we create new synapses to help our brain improve itself, some of this beta-amyloid remains behind, and the Apo E workers clear the gunk to ensure a clean connection.
One group in the union, however, local Apo E4, sabotages the effort to restore power and even gunks up the power lines further (see Figure 1.2). Research shows that an elevated level of the E4 protein is correlated with a higher incidence of Alzheimer’s. Fortunately, there are things you can do to turn down the activity of the E4 gene and allow the rest of the Apo E team to clear your power lines. Eating turmeric, which is found in Indian foods, seems to reduce expression of the E4 gene (India, by the way, has a relatively low incidence of Alzheimer’s). Exercise has a similar effect.
Your Blood Supply: While there’s a strong genetic component to memory problems, we’d be remiss if we didn’t address the arterial component of an ageing brain. A lack of healthy blood flow to the brain is one of the other main causes of forgetfulness. Each side of the brain has a separate blood supply that looks like several large trees during winter. Between the twigs at the tips of the major branches are areas of brain that are dependent on blood from each of the surrounding trees. The area farthest from two blood-supply lines is the watershed area where we tend to have ministrokes when the branches of surrounding trees are pruned by atherosclerosis or the tree trunks themselves wither from poor maintenance (see Figure 1.3). Cholesterol-lowering statin drugs may help maintain memory by preserving tree architecture, while also reducing inflammation that ages the brain cells directly (more on arterial health in the next chapter).
Figure 1.2 Power Outage Apo E proteins that bind cholesterol are like workers clearing junk to ensure a good connection between neurons. Apo E4 gets in the way, and the power lines sag under a substance called beta-amyloid.
Figure 1.3 Delivery Failed When blood (and the nutrients it’s carrying) can’t get to the brain, tissues shrink – and you start to lose memories.
Brain Pills?
It’d be nice if there were such a thing as mental Viagra – just swallow a pill and get a little lift where you need it. But the verdict’s still out on many pills, supplements and vitamins that purport to make your memory stronger. Here’s our take on the ones that get most of the attention:
| Pill | Do We Recommend It? | The Fine Print |
| Aspirin | Yes | Research shows a 40 percent decrease in arterial ageing, a major cause of memory loss, for those who take 162 milligrams of aspirin a day. Though science isn’t sure of the mechanism protecting against memory loss, it may happen because aspirin helps decrease that gunky beta-amyloid from your wiring, and because it improves circulation. |
| Vitamin E | In your diet, ideally | People who consume the highest amount of vitamin E are 43 percent less likely to get Alzheimer’s. You can get the vitamin E you need by eating just 3 ounces of nuts or seeds a day (about 15.5 milligrams), which is our preferred method. Alternatively, you can take a 400 IU (international unit) supplement daily if you take it with vitamin C and are not taking statin drugs like Lipitor. |
| Vitamins B6, B12, folic acid | Yes | Without B vitamins, your neurotransmitters don’t work efficiently. To compound matters, without B vitamins, your homocysteine levels rise, and that doubles the risk of developing Alzheimer’s. Homocysteine is an amino acid associated with stroke, heart disease and Alzheimer’s. Although no study has demonstrated a benefit of supplementation to your thinking process, the products are generally safe, and anecdotal evidence is enticing. We recommend a supplement with 400 micrograms of folic acid, 800 micrograms of B12 and 40 milligrams of B6 a day. |
| Aceytl-L-carnitine/ alpha-lipoic acid | Not yet |
There are lots of strong theoretical reasons why this should enhance brain health – specifically, by improving
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