The catch: once that peak is reached, it doesn’t last long and it’s all downhill from there. Fortunately, it’s possible to avoid or at least slow the decline that could eventually turn us into angry old grumps.
The brain functions at top speed for around five years. That’s really short!
Before you hit 30, brain function is already declining. That may seem depressing, but as it ages, your brain adapts and will not necessarily be the worse for the wear. Young adults have the ability to think faster and they have better short-term memory, while adults in their forties and fifties are better at deciphering the emotional signals of their conversation partners, and elderly people are more knowledgeable. If it were a competition, who do you think would be the winner?
Remarkably, one of the faculties that takes the longest to acquire is also the first to go, and that’s the ability to plan and coordinate tasks. This ability, which is essential in the workplace, is associated with the prefontal and temporal cortices, which continue developing until the early twenties. Remember cramming into the wee hours of the night when you were in college or university?
Among the different kinds of memory we have, episodic memory, the one responsible for recording the time and place of important events, tends to decline before the others. Your brain takes longer to manage information, so your memory stores less information.
If you’re starting to worry right about now, don’t! While things start declining in your late twenties, the slide is neither fast nor across the board, and above all, the phenomenon won’t leave you helpless. According to a study involving the Mini-Mental State Questionnaire, we lose one point every ten years starting in our mid-twenties. The 30-point test measures arithmetic, language and basic motor skills. A drop of three to four points is considered clinically significant. If you do the math, between the ages of 20 and 60, you tend to lose four points, which should translate into a noticeable aging of your faculties.
Physically too, the decline is perceptible: your brain loses around 5% of its mass every decade as of your forties, a process that accelerates after your 70th birthday. Apparently, loss of faculty is not the same for everyone and ranges from memory lapses to dementia… to sharp-wittedness.
Why is it that some people maintain a keen eye, excellent memory and all their wits, while others don’t?
First, there’s blood flow. Of course it’s an essential factor in cardiovascular health, but it affects the brain too. Blood transports oxygen, glucose and all the other nutrients cells need to carry out their functions. Apparently, cerebral microcirculation is directly related to the cognitive functions and to regeneration of nerve cells (including those of the brain).
The body’s glycemia, or blood sugar level, also affects the brain. Abnormal glycemic fluctuations lead to peaks in blood sugar, which affect a region of the hypothalamus (the dentate gyrus), which plays a role in creating memories and in the faculty of memory itself.
The third factor is the hardest to control. It appears that the drop in levels of estrogen and neurotransmitters (serotonin and dopamine) affects the cognitive faculties. The decline in estrogen levels during menopause at least partly explains the greater incidence of Alzheimer’s disease among women.
Lastly, excess weight and obesity in middle-aged people also affect the way the brain ages. In fact, it has been observed that people who are obese have less white matter. According to the theory, fat cells generate more inflammatory substances, which white matter is sensitive to.
So what can you do to stay sharp?
Whatever you do, don’t stop using your brain! Learning, reading, teaching yourself something and cultivating intellectual curiosity are just a few ways to stimulate the mind.
Keeping physically active throughout your life is vital. Exercising boosts the oxygen supply to the brain and slows the decline in the density of the brain’s grey and white matter. It also helps stabilize blood sugar levels and memory, helps cells regenerate and improves concentration. Coordination exercises that focus on balance and motor control also help cognitive function. That explains why tai chi is so popular!
And lastly, eat right. The nutrients your brain needs are readily available in your food:
- Fish and other omega-3-rich foods, which support cognitive function and prevent strokes
- Foods and supplements rich in antioxidants, including blueberries, açai berries, pecans, hazelnuts, strawberries, Granny Smith apples, plums, kidney beans, spinach, broccoli and, in supplement form, ginkgo biloba
- Drink alcohol in moderation
In fact, the same lifestyle advice you get on how to maintain heart health applies equally to your brain—there’s no need to complicate things!
R Peters. Postgrad Med J. 2006 Feb; 82(964): 84-88.
Wu W. et al. Ann Neurol 2008;64:698–706