Alzheimer’s Research Shifts to Prevention
As a practicing physician in 2010, I did not have much to offer my patients who wanted to prevent Alzheimer’s disease. Back then, the two primary known risk factors — getting older and having a family history of dementia — were two things we just couldn’t change. Despite more than 100 ongoing clinical trials, no cure or drug had been proven to halt the course of the disease. In fact, more than 200 experimental drugs over 30 years have failed. It’s no wonder that when the National Institute of Health (NIH) met in 2010 for a summit of Alzheimer’s experts, they basically threw up their hands in frustration. Their conclusion: “Evidence is insufficient to support the use of pharmaceutical agents or dietary supplements to prevent cognitive decline or Alzheimer’s disease.”
But something incredibly positive came out of that same 2010 state-of-the-science Alzheimer’s meeting: the NIH sent out a plea to the scientific community to focus their research on prevention. They encouraged researchers to determine the impact of factors we have the power to change, such as blood cholesterol, high blood pressure, physical exercise, and nutrition.
Thanks to this new focus on prevention, we now have a better understanding of how to reduce a person’s Alzheimer’s risk. And even though all those decades of research failed to bring an effective drug to market, there were critical breakthroughs. For example, we now have a tool to detect the buildup of amyloid-beta in the brain, a key pathological feature of Alzheimer’s disease. Just 10 years ago, the only way to diagnose Alzheimer’s disease was by autopsy after the patient died. Now we can study living brains with positron emission tomography (PET) scans. Discovering amyloid-beta in the brains of patients 20 to 30 years before the onset of Alzheimer’s symptoms has helped us understand how the disease evolves, and how better to delay it.
Understanding the Genetics of Alzheimer’s
Changing technology in the field of genetics was another game changer for Alzheimer’s researchers. Back in 2010, the only identifiable genetic risk factor we knew of was Apolipoprotein E (APOE) 4, one form of the APOE gene. Now researchers have identified a growing list of genetic mutations that are linked to Alzheimer’s disease. Some genes, like APOE4 are associated with late-onset (after age 60) Alzheimer’s. Others are linked to the devastating early-onset form in which multiple family members are diagnosed in their 30s, 40s, and 50s. There are so-called “genetic regions of interest” that affect the brain’s inflammatory response to aging, the metabolism of lipids, and cellular functions that transport tau protein, a key substance that accumulates in the brains of Alzheimer’s patients. In fact, at the time of the NIH’s last Alzheimer’s Disease Progress Report in 2014, there were a whopping 24 genetic mutations being actively studied. (Read the full report here.)
What could be more exciting than discovering genes linked to Alzheimer’s disease? How about the discovery that environmental factors can determine whether or not those genes are expressed. Our knowledge of epigenetics — chemical modifications, or marks, on DNA that turn gene activity on and off — has exploded in recent years. Researchers are figuring out how we can keep these newly discovered Alzheimer’s genes from getting turned on by modifying our lifestyle and environmental factors. We’re talking about diet, exercise, how we deal with stress — factors we have the power to change.
The Case for Brain Healthy Food
All of this brings us back to the rationale behind eating a diet packed with brain healthy foods to reduce the risk of Alzheimer’s. Nutrition science has exploded in the last several years in three general areas. First, epidemiologists are studying groups of people over time to see if what they eat, or a certain dietary pattern like the Mediterranean diet, is linked to Alzheimer’s disease.
Secondly, researchers are looking at single or multiple nutrients to see if they play a role in Alzheimer’s — things like omega-3 fatty acids, caffeinated foods, vitamin D, and curcumin, one of the active ingredients in turmeric.
Thirdly, researchers are trying to figure out if the way we eat — by restricting calories or fasting periodically — will change our risk of Alzheimer’s. Proponents of the ketogenic diet, a low carbohydrate/high fat diet that mimics starvation, believe ketones are a more brain healthy fuel than glucose. A few small studies on the effects of the ketogenic diet on memory in those with early dementia are intriguing — some patients did improve. We need more studies to determine if flooding the brain with ketones is actually a good thing to do.
The Mediterranean Diet: Good for the Heart and the Brain
What’s the best diet on the planet? No one knows the answer to that question. But the one with the most data to back it up is the Mediterranean diet. You’ve likely seen the Mediterranean Diet Pyramid with its base of abundant fruits, vegetables, grains, nuts, legumes, and generous amounts of olive oil. Fish and seafood are recommended several meals per week. Poultry, eggs, cheese and yogurt are eaten less frequently, and meats and sweets are considered occasional treats. All is taken in the company of friends and family, at a leisurely pace, and washed down with a moderate amount of red wine.
As a practicing physician, when patients asked me what they should eat, I would give them a copy of the Mediterranean Diet Pyramid. Hundreds of studies have shown it to be associated with a reduced risk of cardiovascular disease, diabetes, stroke, and obesity. Now researches are taking a look at how the Mediterranean diet can help prevent Alzheimer’s too.
A meta-analysis of prospective cohort studies, published in the British Medical Journal in 2008, showed that those who mostly ate a Mediterranean diet had less Alzheimer’s disease and less Parkinson’s, another chronic neurodegenerative disease.
One Med diet study in particular, the PREDIMED study, published in the New England Journal of Medicine in 2013, showed an incredible reduction in heart attack and stroke in over 7000 men and women who were at high risk for cardiovascular disease. They were divided into three study arms: general dietary advice about a low fat diet, a Mediterranean diet supplemented with extra olive oil, or a Mediterranean diet supplemented with nuts. Those on the Mediterranean diet had 30% less heart attacks, strokes and death from all causes of cardiovascular disease. The results were so compelling that the researchers stopped the study ahead of time so that the low fat diet group could switch to a Mediterranean diet too.
An emerging theme of Alzheimer’s prevention builds on what we already know about preventing heart disease: What’s good for the heart is good for the brain. We have known for decades the recipe for good cardiovascular health: a plant-based diet (like the Mediterranean diet), regular exercise, smoking cessation, stress reduction, and maintaining a healthy weight. The same is holding true for Alzheimer’s prevention. That’s because maintaining healthy blood vessels also impact brain health. Up to 20% of all dementias are caused by blood vessel diseases, like hardening of the arteries, that leads to multiple small strokes. And healthy blood vessels prevent Alzheimer’s in ways we are just starting to understand.
The MIND Diet Study Defines 10 Brain Healthy Food Groups
Brain Works cooking curriculum teaches findings from the MIND diet study out of Rush University in Chicago, published in 2015 in the journal of Alzheimer’s and Dementia. Researchers in the department of nutritional epidemiology, led by Dr. Martha Clare Morris, created a small sensation with their 4.5 year study of 758 dementia-free participants who kept diligent food diaries for the duration of the study. MIND stands for the “Mediterranean-DASH Intervention for Neurodegenerative Delay.” It’s a combination of the Med diet and the DASH diet, a plan designed to reduce hypertension. The researchers divided foods into 10 brain-healthy food groups and 5 brain-unhealthy ones, and a MIND diet score at the end of each week was calculated to assess how participants ate.
Those with the highest MIND diet score, eating more brain healthy and less brain unhealthy foods, had a 53% reduction in Alzheimer’s risk. Those that did not follow the guidelines rigorously — meaning they cheated on the diet about half the time — still had a significantly reduced risk of Alzheimer’s of 35%. These numbers stunned the scientific community. Never before had a study shown such a dramatic impact on Alzheimer’s risk. Reducing Alzheimer’s risk by this degree is equivalent to adding 7.5 years to one’s brainspan (the number of years a brain is functioning at a high level.)
Not only did MIND diet participants get less Alzheimer’s, they had less decline in global, episodic, and working memory, and in perceptual speed and organization. In other words, following the MIND diet helped them improve their cognitive function.
It will be important to see if these findings hold water once they are subjected to a more rigorous randomized, controlled trial. The MIND diet study is entering its phase III trial this year, which means one group of participants will follow the MIND diet, while another control group will not.
Learn more about the 10 brain healthy food groups, and the 5 to avoid, here.
FINGER Study Combines Exercise, Good Nutrition, and Cardiovascular Risk Monitoring
I have one more study to tell you about and thisone is Brain Works also draws inspiration from the FINGER study in Finland in which a large group of participants reduced dementia risk by following a low fat Mediterranean diet along with exercise. And the data from the Blue Zones, a National Geographic project conducted by Dan Buettner who examined the food and lifestyle in the parts of the world with the highest density of centenarians. In the Brain Works Kitchen, we aspire to be high functioning 100-year olds, and we want to eat like them too. So we use lots of the foods Buettner has compiled that are universal in Blue Zones.