How to reduce your risk of Alzheimer’s today...
Experts claim that lifestyle changes alone could cut our chances of developing the disease by two-thirds. Patrick Holford, author of The Alzheimer’s Prevention Plan, reveals the small things we should do in midlife that will make a huge difference to our brain health as we get older
Ask the average person how much the risk of developing Alzheimer’s disease is dictated by our genes and most will estimate a third. But less than one in a hundred people develop the condition because of a familial link.
Even better news is that a recent conference of the world’s leading experts in the degenerative brain disorder, which slowly destroys memory and thinking skills, revealed most people can cut their chance of getting the disease by two-thirds by making a few simple diet and lifestyle changes midlife.
“It is largely a preventable disease and we know quite a lot about what people need to do to help prevent it,” says Professor David Smith, former deputy head of the Faculty of Medical Science at Oxford University. “It is not an inevitable consequence of ageing.”
Bitter truth
Let’s start with sugar. A US study at Boston University earlier this year reported that having a blood sugar level in the high end of the normal range at age 35 increased a person’s risk of developing Alzheimer’s later in life by 15 per cent.
Research by paediatric endocrinologist Professor Robert Lustig, from the University of California, has shown that sweet-toothed teenagers already have shrinking brains and worsening memory.
While more research is needed to fully explain the reason for this impact, high blood sugar levels have been linked to inflammation, which damages blood vessels, as well as higher levels of a protein, beta-amyloid, which can block nerve signals in the brain.
The dynamic duo
At the other end of the spectrum, the two hardest hitters for fighting the onset of the disease are B vitamins and omega-3 fats found in oily fish. Prof Smith’s research at Oxford has shown that giving B vitamins stops the accelerated brain shrinkage which is the hallmark of Alzheimer’s.
Researchers at the US National Institutes of Health attribute 32 per cent of risk to an inactive lifestyle, 22 per cent to smoking, 22 per cent to lack of omega-3, and another 22 per cent to a raised blood homocysteine level, which is a measure of B-vitamin status. “Lowering homocysteine with B vitamins, as we trialled at Oxford, resulted in up to 73 per cent less brain shrinkage and slowed memory decline,” says Prof Smith. “This placebo-controlled trial was in people over 70 with pre-dementia.”
One in three ended the trial with no clinical signs of dementia at all.
Often I’m asked if you can simply get all the vitamins you need from a well-balanced diet. But the truth is, as we age, our ability to absorb vitamin B12 ( found in animal products such as eggs, meat, fish and milk) declines. As a
‘‘ Two in five people over 60 have insufficient vitamin B12 in their blood
consequence, two in five people over 60 have insufficient B12 in their blood, despite often having adequate levels in their diet. This pushes up the toxic amino acid called homocysteine, which leads to brain cell destruction.
Raised homocysteine levels also mess up circulation and those who have this are 17 times more likely to have brain blood vessel damage.
Vascular dementia, which accounts for one in five cases of dementia, is caused by reduced blood flow to the brain. Raised homocysteine, which any GP can test for, can be lowered with a vitamin supplement high in B12 costing 10p a day, and can make a massive difference to dementia risk .
Next, look at your fish intake. A study of almost half a million people from the UK's Biobank found that those taking fish oil supplements had a seven per cent lower risk of dementia. The same was true for those with higher blood levels of omega-3.
Eating three servings of fish each week cuts Alzheimer’s risk by a third. Why? Both fish and fish oils are high in a type of omega-3 fat called DHA. This makes up half of the membrane of brain cells through which all “memory” signals have to pass.
More fascinating yet, it turns out that B vitamins and omega-3 are a dynamic duo. Prof Smith’s team at Oxford discovered that omega-3 fats don’t work nearly so well without B vitamins – and the benefits of B12 aren’t seen in people with low intake of omega-3. You need both.
This discovery provoked a major US trial, B-PROOF, which had shown modest benefits of B vitamins, to re-analyse their results. Sure enough, those trial participants with low omega-3 blood levels at the start of the trial had little benefit from the B vitamins, but those with high omega-3 status saw major benefits.
Conversely, a study in Sweden giving fish oil supplements re-analysed their results and found that those with good B-vitamin status, confirmed by a lower homocysteine level, had a highly significant reduction in cognitive decline, but those with poor B vitamin status derived no benefit at all from the fish oils.
Keep on keeping on
Your brain needs exercise, so keep on moving. Research by University of Washington neuroscientist Thomas Wood showed that your muscle mass impacts brain volume. “Exercise, especially resistance, is important as it makes the brain do things that keep it healthy, such as growth and repair,” he says. “When they aren’t stimulated, the health of brain tissues deteriorates, with a knock-on effect on memory and thinking.”
It’s not just physical exercise we need though – we also benefit from mental exercise in activities like solving puzzles. “For many the worst thing they can do for their brain is to retire,” says Wood. “They lose the stimulation that kept it healthy.” A study on trainee London taxi drivers learning the Knowledge, which involves memorising 26,000 streets, found those who passed had physically built more brain tissue and connections than those who failed. And it’s good to learn things you’re bad at. Those learning a new instrument show greater brain health than professional musicians, for example.
And just as your muscles need rest after exercise, your brain needs sleep after a period of cognitive activity – but quantity and quality is everything. Research has shown that sleeping only five hours, or nine or more, doubles your dementia risk.
“Owls” who drop off late have a higher Alzheimer’s risk than early birds. The less disrupted sleep is, the better, with the optimal duration being seven hours from 10pm.
■ Patrick Holford is a founder of foodforthebrain.org which has a free online cognitive test to help you dementia-proof your diet and lifestyle.