At what age should we be considering nutrition and lifestyle interventions to reduce the risk of developing Alzheimers?
Rates of Alzheimer's are rapidly on the rise, with women twice as likely to develop the condition as men. Studies show they comprise two-thirds of people living with this debilitating disease, regardless of age and ethnicity (1,2). Neuroimaging shows changes to the brain begin decades before the onset of symptoms and action can be taken from our 40’s to help reduce the risk of developing Alzheimer's and other forms of Dementia.
Longer female life expectancy may be part of the explanation for the disparity between female and male incidence of Alzheimer's and Dementia; recent research, however, suggests changes in a woman’s hormone levels as she transitions through the menopause (particularly falling oestrogen levels) may also play a role in cognitive decline later in life (3).
Although ageing, sex, genetic tendency and hormonal changes are all possible risk factors, the development of Alzheimer's is generally multifactorial. Recent studies estimate that a third of all Alzheimer's cases could be prevented by dietary and lifestyle changes. These include cutting down on sugar, increasing fibre rich plant foods, good quality fats and proteins in our diets, as well as prioritising sleep, stress reduction, regular exercise, avoiding smoking and limiting toxin exposure to support our bodies as they try to regulate our hormones.
From a dietary perspective, we are all biochemically individual so optimal dietary composition will vary from person to person, but from a population perspective, the Mediterranean diet has been shown to improve cognition in an older population (4). Eating a wholefood diet is vital to nourish our bodies and maintain hormonal balance; here are some steps we can all take to up the chances of maintaining cognition and memory into old age:
Keep blood sugar and insulin levels stable by reducing sugar consumption, eliminating refined carbs, including moderate amounts of complex carbs (amounts tolerated will vary from person to person) and including protein and fat with every meal or snack.
Include plenty of fibre in your diet to support digestion and hormone detoxification (and so help balance your hormone levels).
Eat the rainbow! This phrase is often used by nutritionists for good reason. Eating a diversity of plant foods will not only support a healthy gut microbiome (which in turn supports brain health), but also supplies your body with a broad range of antioxidants and phytonutrients. Large scale studies show that people who eat at least 1 serving of leafy green veg every day have fewer memory problems and cognitive decline than those who rarely eat them (5). Additionally, a study of over 16,000 women showed that those who regularly ate flavonoid rich berries had slower rates of cognitive decline than those who didn’t eat the berries (in the study at least one serving of blueberries and two servings of strawberries were eaten weekly)(6). Think bright, dark colours and as many different types as possible.
Enjoy a daily handful of nuts and generous amounts of extra virgin olive oil daily and aim to include oily fish in your diet 2-3 times a week to give your brain the healthy fats it needs to function optimally.
Reduce alcohol consumption. The liver’s capacity to detoxify declines after the age of 40 so we don’t process alcohol as effectively. The more pressure we put on our detoxification system, the harder it has to work to metabolise and balance our hormones. If you enjoy a glass of wine, choose a glass of resveratrol rich red wine and have evenings off – your body will thank you.
Stay well hydrated – the brain is comprised of up to 80% water and dehydration compromises cognitive function.
Scheyer O, Rahman A, Hristov H, et al. Female Sex and Alzheimer's Risk: The Menopause Connection. J Prev Alzheimers Dis. 2018;5(4):225-230. doi:10.14283/jpad.2018.34
Mosconi L, Brinton RD. How would we combat menopause as an Alzheimer's risk factor?. Expert Rev Neurother. 2018;18(9):689-691. doi:10.1080/14737175.2018.1510320
Valls-Pedret C, Sala-Vila A, Serra-Mir M, et al. Mediterranean Diet and Age-Related Cognitive Decline: A Randomized Clinical Trial. JAMA Intern Med. 2015;175(7):1094–1103. doi:10.1001/jamainternmed.2015.1668
Martha Clare Morris, Yamin Wang, Lisa L. Barnes, David A. Bennett, Bess Dawson-Hughes, Sarah L. Booth. Nutrients and bioactives in green leafy vegetables and cognitive decline. Neurology Jan 2018,90 (3) e214-e222; doi:10.1212/WNL.0000000000004815
Devore EE, Kang JH, Breteler MM, Grodstein F. Dietary intakes of berries and flavonoids in relation to cognitive decline. Ann Neurol. 2012;72(1):135-143. doi:10.1002/ana.23594