I’m devoting this, my fifth update on the 5th International Plant-Based Nutrition Healthcare Conference, held in Anaheim, California in September 2017, to just one presentation – ‘Alzheimer’s and Diet: New Research Frontiers’, by husband-and-wife researchers Drs Ayesha and Dean Sherzai.
Dementia in general, and Alzheimer’s disease in particular, is probably the condition that people fear the most as they get older. Anyone who has ever watched a loved one succumb to the ravages of dementia would probably give their right arm to avoid it.
As it turns out, you don’t need to sacrifice a limb to stave off dementia. You just need to implement the same healthy lifestyle strategies that protect you against heart attack, stroke, type 2 diabetes and many common cancers.
Ayesha and Dean Sherzai are co-directors of the Brain Health and Alzheimer’s Prevention Program at Loma Linda University, in the heart of the only ‘Blue Zone’ in the United States.
The Blue Zones are 5 regions in the world that boast the highest percentages of centenarians. In the Blue Zones, people don’t only have unusual longevity; they remain in unusually good health until very near the end of their lives.
Loma Linda is home to a large population of Seventh Day Adventists (SDAs), a Christian denomination whose religious teachings emphasise the importance of caring for the health of the body, as the temple of the soul. Rates of cigarette smoking and alcohol use are extraordinarily low among SDAs, and up to 50% of them practise vegetarianism in some form.
Strikingly, of the more than 2500 patients that the Sherzais are currently tracking in their brain health clinic, less than 1% of those with cognitive decline were vegetarians already following a healthy lifestyle at the time they enrolled in the Sherzais’ program.
The poster-child (if ‘child’ is the right word for a 103-year-old-man) for the benefits of a healthy plant-based diet and active living is Dr Ellsworth Wareham, a pioneering cardiothoracic surgeon who, as the Sherzais explained, continued to perform open-to-close surgeries at Loma Linda University’s medical centre until well into his 90s… before retiring to spend more time with his wife, and to travel. Dr Wareham, a practising SDA, credits his long and healthy life largely to having adopted a vegan diet in his 50s.
While Dr Wareham’s story is uplifting, the Sherzais had some depressing news to share about dementia. In the US, as in other developed countries, an aging population is leading to increased rates of Alzheimer’s disease, vascular dementia, stroke and Parkinson’s disease. However, it’s important to understand that aging does not cause these diseases, it increases the risk of developing them, because older people have been exposed to the causes of these diseases for a much longer period of time than younger people.
Alzheimer’s disease (AD) is now the 6th (and, based on new data, possibly the 3rd) leading cause of death in the US. 1 in 10 Americans over the age of 65 has AD, and nearly 1 in 2 of those aged over 85.
And while mortality from other chronic diseases such as cardiovascular disease and cancer has been declining despite an increased incidence of these conditions, mortality from AD is rising – in fact, there was an 89% increase in deaths due to AD between 2000 and 2014.
There is no successful medical treatment for AD. The failure rate of drugs developed to treat it, in over 400 clinical trials from 2000-2012, was 99.6%. In reality, as the Sherzais pointed out, the failure rate is actually 100%, because no drug actually slows or stops AD. Even ‘successful’ drugs only treat disease processes – such as accumulation of β-amyloid protein – without restoring function of affecting the clinical outcome in any way. The Sherzais stressed that the amyloid plaques and neurofibrillary tangles that have been the major targets of AD research are the wrong targets – these phenomena are the result of the AD process rather than the cause of it.
So what causes so many people to lose their cognitive function as they get older… and what can we do to prevent this process?
The first thing to realise is that dementia is not a normal part of getting older. Normal aging does cause a mild slowing of processing speed – it takes a little longer than before to find things in your mental ‘filing cabinet’ – but all of those things are still in there. Mild cognitive decline or MCI is an intermediate stage between normal aging and dementia, and is reversible whereas at this stage, the Sherzais do not believe that full-blown dementia can be reversed.
The Sherzais explained that the brain is under much more stress than other organs in the body due to its incredibly high energy and waste disposal needs relative to its weight. That’s the bad news. The good news is that the brain also has great resilience due to its high capacity to make new neuronal connections – the phenomenon known as neuroplasticity – and changes in lifestyle have a huge impact on brain health and therefore on cognitive function.
Here’s a summary of the research the Sherzais presented:
- In the 1993 Adventist Health Study, consumption of animal products – including white meat, such as chicken and fish – doubled the risk of dementia.
- The Chicago Health and Aging Project found a 2.2 times higher risk of AD in those with the highest saturated fat intake.
- The Women’s Health Study found that those with the highest saturated fat intake had a 70% faster rate of cognitive decline.
- In general, saturated and trans fat intake increases the risk of dementia, while plant fats decrease it.
- Sleep apnoea – which is usually associated with obesity – increases the risk of AD by 70%.
- Insulin resistance is strongly linked with dementia; in fact some researchers are now describing AD as ‘type 3 diabetes’ in recognition that insulin resistance within the brain, and disturbances to brain glucose metabolism, severely impact cognitive status.
The Sherzais cautioned against adopting a ketogenic (very low carbohydrate, high fat) diet, which has been promoted as ‘good for the brain’ and even a therapy for AD. They acknowledged that in the short term, people may feel better on a ketogenic diet because ketone bodies increase alertness. However, in the longer term, ketogenic diets causes microvascular damage, inflammation, and harm the microglia – the brain’s immune cells – and, as previous research has shown, the saturated fats in which ketogenic diets are rich, are strongly related to the abnormal proteins involved in AD.
The Sherzais referred to research on the MIND Diet, a hybrid of the Mediterranean and DASH (Dietary Approach to Stop Hypertension) diets which emphasises fruits (especially berries), vegetables (especially green leafies), legumes, whole grains, nuts and seeds, and limits animal products. People who adhered most closely to the MIND dietary pattern were found to have a 54% lower risk of developing AD.
In their program at Loma Linda University, the Sherzais take an integrated approach to prevention of cognitive decline. They teach people with MCI to adopt a wholefood plant-based diet along with regular exercise, meditation, restful sleep and cognitive stimulation, and they have achieved remarkable results with arresting and even reversing cognitive decline.
It should come as no surprise that we can prevent age-related cognitive decline with a healthy diet and lifestyle. After all, the brain is an organ like any other in the body, dependent on a constant supply of nutrients and requiring constant removal of its metabolic wastes and protection against external toxicants. That’s bad news for the pharmaceutical industry, which is never going to find a ‘cure’ for Alzheimer’s disease, but good news for us because we’re in charge of what we eat, and how much we move, rest, sleep, and use our brains.
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