Why your memory goes downhill after 30 – and how to reboot it

Forgetting names, finding myself on the wrong tube, searching for my keys while holding them – as I’ve hit middle age I find memory lapses seem to have become increasingly frequent.  

It’s almost comical how long it can take my friends and I to remember the name of an actor, a movie title or the plot of a book. What is going on? Am I on the grim road to dementia? And is it possible to reboot my memory and restore it to an earlier, sharper form?

Dr Tim Beanland is head of knowledge at the Alzheimer’s Society and author of the puzzle book, Mind Games.  

“People think if their memory is getting a little bit worse they must have dementia. But a bit of memory loss is normal. Your brain is part of your body and you wouldn’t expect your skin, for example, to be the same as when you were 20 –  it’s the same for your brain. It’s normal to become a bit more distractible and to find it harder to hold onto things like names,” he says. 

Dementia is on a different scale from normal memory loss, however. “If I just told you something and you then asked me for the same information within 2 to 5 minutes, that would be dementia – when people stop being able to form memories. Instead of forgetting where you parked your car, people with dementia would ask, ‘Did I come by car or bus?’ 

“Dementia affects your ability to do your job and socialise – there’s a big difference in scale,” says Beanland.

The good news is that some of the brain’s memory power improves with age. “There are at least five types of different memories and they all age at different times. Our working memory, the ability to hold a phone number or do a bit of maths, peaks early at age 30 and starts going downhill after that. Your memory for events and things like where you parked your car doesn’t start to decline until around 50 to 60 years old, and your semantic memory – your knowledge of facts, like Paris being the capital of France – that keeps getting better until about the age of 70,” says Beanland. 

It is also possible to give your memory a workout – to train it and sharpen it – and this will bolster your protection against dementia in later life. 

“We’ve realised that 40 per cent of the risk of getting dementia is down to things you can control. If you stimulate your brain and do brain workouts you can build up cognitive reserve, which strengthens the pathways across the brain. This will delay normal memory ageing and make it less likely that you will get dementia when you’re older,” he says. 

I decided to test Beanland’s claims and put my memory into the equivalent of a brain bootcamp. Over a month I embarked upon a memory strength training regime, trying a range of interventions from diet changes to puzzles. First, I took a test to see how my memory is performing now. 

The Test

Muhdo Health is a science company offering epigenetics (tests for how your behaviours and environment affect the way your genes work) and DNA testing to get a picture of your current health. Their app also offers brain training to improve your cognitive score. 

James Brown, clinical dietician and director of nutrigenetics at Muhdo Health explains: “Your DNA is genetically fixed, but your epigenetics – the chemicals that sit above the DNA – change on an hourly basis and influence how your genes express themselves. So we can look at this for the genes associated with your memory, and whether that makes you slightly older or younger than your chronological age,” he explains. 

I sent a sample of my saliva, and two months later the results arrived. 

According to my results, my brain age is 49, which is good news as I am 52. My memory age is 49.3, which is also healthy.

However, Brown, whose brain age is five years younger than his biological age, says it’s possible to improve my memory further, although I would need a year to see a big change in my epigenetic results. However, Muhdo Health also offers brain training on the app, and if I do that regularly I should see an improvement in my brain training scores faster. My test results also offer some more specific clues and suggestions for interventions to try – a sort of holistic memory workout including changes to diet, supplements, exercise and learning new skills. Here are my brain boot camp suggestions:

Eat more blueberries 

We know that blueberries are good for us in multiple ways, but studies have shown they also improve our memories and cognitive function. Most recently researchers from King’s College and the University of Reading discovered that men and women aged 65-80 who consumed blueberries daily experienced a better memory, improved accuracy on attention tasks, and lower blood pressure.

“We think the blue pigments in blueberries, the anthocyanins, which are a type of polyphenols also present in other foods such as strawberries, raspberries, red grapes and purple vegetables, are behind these effects,” says Dr Ana Rodriguez-Mateos, a reader in nutrition at the Department of Nutritional Sciences.

Blueberries are also one of the most nutrient-dense berries as they are full of fibre, vitamin C, vitamin K and manganese so it’s a win-win. Blueberries can be expensive, so I buy a large bag of frozen blueberries and have them daily with Greek yogurt, which quickly becomes a much-loved snack. 

Take vitamin supplements

Brown says my test results show that the genes involved with metabolising and absorbing B12 may not be functioning quite as well as they should be. “B12 is massively important for cognitive memory. If you’re eating animal products like dairy, chicken and beef you should be okay, but if you’re feeling tired and have brain fog, it’s worth getting a blood test to see if you’re deficient,” he says. 

Given that my chances of getting a GP appointment quickly are slim, I add a B12 supplement just to be safe, as any excess B12 we don’t need is excreted by the body. 

Brown also advises I add an omega-3 supplement to my diet, as my tests also show that I don’t metabolise it well. Multiple studies have shown that omega-3s may improve memory, brain fog and mood disorders. 

Finally, my results also show some chronic inflammation, which might explain why my immunity is not robust and I pick up viruses regularly. Chronic inflammation can also increase the risk of contracting dementia. Omega-3 can help with inflammation, as can selenium – and  according to my DNA results I am at an increased risk of selenium deficiency. 

Brown recommends I help this by eating a handful of Brazil nuts daily, accompanied by a vitamin C effervescent tablet dissolved in water as this helps with selenium absorption. 

Learning languages and doing puzzles

Keeping your memory sharp and young is a bit like keeping your body fit – you have to work at it. “It’s a case of use it or lose it,” says Beanland, whose book, Mind Games, features more than 150 puzzles to stimulate your brain. 

“Ideally you keep learning as long as you can. It’s helpful if you have a complicated job, but you can also do puzzles, learn a new language or play a musical instrument. You’ve got to do something that activates and stimulates your brain to build more efficient pathways,” he says. 

For about a year I’ve been hearing the pings from my husband’s Duolingo app as he learns German. Now I’m joining him by learning Italian. The lessons are super speedy – just five minutes – so they’re easy to fit in. If you forget to do the lesson the app sends you a reminder and soon I’m confidently ordering cappuccinos. 

What is less fun is Sudoku. Where I enjoy Wordle and crosswords, I tend to avoid anything that involves numbers. But Beanland says I need to get out of my comfort zone. Even starting at an easy level is a brain workout for me and adding it to my daily routine feels a bit like eating greens. Hopefully, the pain of the process is the brain equivalent of muscle soreness after a session in the gym. 

I also start weekly brain training on the Muhdo app, where a series of computer games extensively researched by the company CogniFit claim to train your brain and test seven different memory skills. I do this training weekly and hope that by the end of the month my scores will have improved. 

Another reason for weight management

Being overweight has been shown to shrink your brain, impair cognitive function and reduce blood flow to the brain, increasing your risk of dementia. 

My BMI puts me at the lower end of the overweight margin, and I know that I need to shed at least a stone. 

Soberingly, my Muhdo test results also show an impaired response to blood sugar and saturated fats, and a risk of type two diabetes.

I sign up for the diet that seems to have had the most success amongst my friends – the rather optimistically named Six Pack Revolution. This is a high-protein diet, with a daily workout of strength training and a weekly exercise challenge, and I find it relatively easy to stick to. 

The diet lasts for 75 days, but after a month I can fit into my small jeans, I’m sleeping better, and many people are telling me I look well, which I think is a polite way of saying I’ve lost weight. 

Getting on top of stress and sleep

Managing stress is easier said than done, but when you’re stressed your body releases cortisol which, studies have shown, impairs the brain’s memory process. Stress can also lead to poor sleep, which in turn makes you less able to deal with stress and increases your risk of dementia.

“Your tests show an increased risk of stress leading to physical symptoms like not being able to sleep. Stress is also tremendously ageing. My biological age test went up five years in six months when my mum had a stroke,” says Brown.

It’s true that I’ve never been a great sleeper, and middle age has made this worse – when something is worrying me I can wake up at 4am and struggle to go back to sleep, exacerbating the vicious circle the next day. 

To get on top of this, I follow Brown’s recommendations: I dim the house lights after 9pm, put away my phone at least an hour before bed, take magnesium supplements and have regular baths in magnesium bath salts. I also increase the amount of exercise I am doing as, according to the Muhdo app: “Exercise increases the expression of BDNF (brain derived neurotrophic factor) which will improve your cognitive performance and memory and help alleviate anxiety and the physical symptoms of stress.” 

Studies have also shown that a short nap can boost cognitive performance, provided you don’t sleep for too long. So if I’m really tired I have a short nap of five to 20 minutes in the afternoon. 

Being mindful of stress and prioritising sleep definitely increases my mental stamina during the day. 

The results: One month later 

After just four weeks I’ve lost weight, I am sleeping better, and rarely get the afternoon dip in energy and brainpower of old. I take the Muhdo epigenetics test again, and the results came back… basically the same. Brown explains that it would take six months to a year to see a big drop in my brain and memory age. 

However, the cognitive brain training results are far better. My working memory, visual recall memory, short-term memory, non-verbal memory and contextual memory have all improved and the computer games seem easier, which is incredibly satisfying. 

Given my unscientific methodology, it’s hard to know if this is the result of the brain training on the app or the other changes I’ve made, but I’m guessing it’s all worked together to sharpen up my memory. I no longer struggle to recall names and events, and even signed up to participate in the quiz at my daughter’s school, something I would have baulked at before. More importantly, the brain training has improved my overall wellbeing, proving that when it comes to our health, nothing works in isolation and small changes can make a big difference. 

Give your own brain a workout at Telegraph Puzzles, your home for crosswords, sudoku, word games and puzzles online