Alzheimer’s disease and nutrition
While there are no guarantees about total prevention of chronic diseases, you can always do your best to minimise your risk. One of the factors that influences Alzheimer’s disease (AD) outcomes is directly linked to your diet. You may be asking “what should I eat to lower my risk of developing AD”? Let me give you some evidence-based answers.
Good nutrition plays an important role in promoting longevity and healthy cognitive function, and studies show that whether your risk of AD is genetic, environmental or lifestyle based, you can significantly change the projected outcome by changing your diet. The World Dementia Council found that cognitive decline and cardiovascular health are potentially linked, and they state there is strong evidence linking a healthy diet with a reduced risk of cognitive decline (1).
Many compounds found in plant foods can have a dramatic positive impact on the ageing brain, with the potential to improve cognition and motor skills. This is due to the high quantities of antioxidants and anti-inflammatory compounds found in a plant-based diet (2). I do not believe that we should be singling out individual vitamins or foods as this encourages a reductionist approach to nutrition, and dangerous (and expensive) over-supplementation.
Omega 3 and other compounds
Yes it is true that Omega 3 is good for brain health. But if you eat a well-rounded diet, that is predominantly whole food plant-based, you will get all the Omega 3 you need and in the correct ratios to Omega 6. While there is some evidence to show that including Omega 3 rich foods may reduce your risk of cognitive decline, there is no evidence that supports taking Omega 3 supplements has the same effect. A study completed in 2015 showed that supplemental Omega 3 did not slow or reverse cognitive decline (3). A 2017 study found that people who have the APOE4 gene (a gene associated with a heightened risk of developing AD) may benefits from Omega 3 (DHA) if they start taking it before developing sings of AD (4).
Several studies have been done on vitamins A, C, E and B and cognition, and while dietary sources showed improvements, the results of trials where supplements were used are inconclusive in improving cognitive function in older adults.
Polyphenols are substances found only in plant foods and include foods such as green tea, grapes, blueberries, turmeric and gingko biloba. Polyphenols are antioxidant, anti-inflammatory, they regulate pathways for intracellular signalling, and have been found to improve learning and memory (5). Therefore, eating a diet rich in fruits, vegetables, nuts, seeds, whole grains, legumes, and seaweeds will ensure you are ingesting nearly every nutrient you need for longevity and a healthy brain. Vit B12 is an exception and should be supplemented as it is vital to good health. It is a bacteria rather than a vitamin as such, and can be found in fortified cereals and other foods.
Keto diet – no way!
You may have seen headlines such as “Keto Diet cures Alzheimer’s”. Let me be absolutely clear that there is no evidence to support this at all. In fact, a long-term ketogenic diet has been shown to be detrimental to cognitive function. Prof T Colin Campbell states that ketogenic diets create harmful by-products, “…as well as deposition of amyloid and tau proteins which are known to be strongly associated with end-stage Alzheimer’s disease” (6).
7 steps to prevention
In 2013 the International Conference on Nutrition and the Brain, was held in Washington, DC. Speakers presented seven practical steps as possible factors in AD prevention (7). These include:
- Minimise (or better still avoid) saturated fats (dairy, meat, coconut oil, palm oil) and trans fats (processed foods, snack foods, fried foods, junk foods).
- Whole food plant-based diet should replace meat and dairy as dietary staples.
- Vitamin E should come from nuts, seeds, whole grains and leafy greens, not from supplementation (supplements have been shown to have some detrimental effects on health).
- Have blood levels of B12 checked yearly and find a reliable source (either good quality supplement or eating fortified foods such as cereals, nut milks or nutritional yeast – read packaging to ensure it is fortified).
- If taking multi-vitamins, select those without iron and copper. Only supplement with iron if your doctor prescribes it for you. (If eating a whole food plant-based diet you should not need a multi-vitamin unless prescribed by your doctor).
- The evidence linking aluminium to AD is inconclusive, but if you are concerned use cookware, antacids, baking powder and deodorants that are aluminium-free.
- Go for a brisk 40 minute walk at least 3 times per week.
Although research into the area of nutrition and preventing AD still has a way to go, it is certainly promising to consider nutritional intervention as a simple and inexpensive strategy to reduce, or even reverse, AD.
*Author’s note: Yes, Omega 3 is found in seafood. But as our oceans are largely toxic now due to pollution, and fish supplies are in dire straits of being wiped out across the globe from over fishing, I do not find it ethical or sustainable to consume seafood. Foods such as walnuts and other nuts, flaxseeds/linseeds and other seeds, avocado, cabbage and other cruciferous vegetables, pumpkin and other squashes, seaweeds (like nori), spirulina, beans are all excellent sources of Omega 3 essential fatty acids.
This is why a whole food plant based way of eating is so beneficial as not only are walnuts, flaxseeds, avocados etc… high in Omega 3, they are also high in many other vitamins, minerals, anti-oxidants, fibre and so on, so when we eat a plant-rich diet we are consuming many healing and nutritious compounds at the same time.