Can Diet Prevent Alzheimer’s

Written by Dr. Steve Chaney on . Posted in Diet and Alzheimer's

Preserving Your Memories In Your Golden Years

Author: Dr. Stephen Chaney

 

can diet prevent alzheimer'sAlzheimer’s is a scary disease. There is so much to look forward to in our golden years. We want to enjoy the fruits of our years of hard work. We want to enjoy our grandkids and perhaps even our great-grandkids. More importantly, we want to be able to pass on our accumulated experiences and wisdom to future generations.

Alzheimer’s and other forms of dementia have the potential to rob us of everything that makes life worth living. What is the use of having a healthy body, family, and fortune if we can’t even recognize the people around us?

That is why anything that might reduce the risk of Alzheimer’s is BIG news, which brings me to the recent buzz about the MIND diet.  Can diet prevent Alzheimer’s.

 

What Is The MIND Diet?

the mind dietThe MIND diet is the brainchild of Dr. Martha Clare Morris, a nutritional epidemiologist at Rush University Medical Center. She started with the Mediterranean and DASH diets, which I have described in a previous issue of “Health Tips From the Professor,” because both of those diets have been shown to reduce the risk of dementia. Then she researched the literature for studies linking specific foods and nutrients to improving cognition and/or preventing dementia.

In short, she combined the brain-healthy features of the Mediterranean and DASH diets and further modified them based on the best scientific data available. She emphasized some components of those two diets and minimized others. She also modified the number of servings of some foods, based on the best available evidence.

She acknowledged that when she eliminated or reduced foods that were parts of those two diets, it did not mean those foods might not play an important role in preserving cognitive function as we age. It simply meant we don’t currently have strong evidence to prove their beneficial effects in preserving cognition.

The MIND diet is a whole food, plant-based, diet.

 

  • It includes 10 “brain-healthy” food groups: green leafy vegetables, other vegetables, nuts, berries, beans, whole grains, fish, poultry, olive oil, and wine (in moderation, too much alcohol kills brain cells).
  • It limits red & processed meats, butter and margarine, cheese, pastries & sweets, and fried & fast foods.
  • It neither recommends nor discourages low fat dairy foods and fruit other than berries. Dr. Morris notes that while those are healthy foods, they have no proven benefit for preventing cognitive decline.

 

Can Diet Prevent Alzheimer’s?

 

As you can tell, a lot of thought went into the design of the MIND diet, but does it work? Dr. Morris partnered with 5 of her colleagues at Rush University Medical Center to test the hypothesis (Morris et al., Alzheimer’s & Dementia 11: 1007-1014, 2015). They enrolled 923 participants, ages 59 to 98 years (average age = 81) from retirement communities and senior public housing units in the Chicago area. All participants were free of Alzheimer’s disease when the study began.

doctor's studyAt the beginning of the study each participant filled out a detailed food frequency questionnaire. Participants were given an extensive physical and neurological exam designed to diagnose the onset of Alzheimer’s disease and/or dementia on an annual basis. Participants were followed for an average of 4.5 years, during which time 144 of the participants developed Alzheimer’s and another 14 developed non-Alzheimer’s dementia.

At the end of the study the food frequency data were analyzed to determine how closely participants adhered to the MIND diet, the Mediterranean diet, and the DASH diet.  Adherence to each of these diets was then correlated with the onset of Alzheimer’s disease. [To be perfectly clear, none of the participants were given any dietary instruction. Nor were they advised to change their diet. This study simply looked at the diets they were already eating and determined how closely their diet matched the standards set for MIND, Mediterranean, and DASH diets.] The results were striking:

  1. Strict adherence to all 3 diets significantly decreased the risk of developing Alzheimer’s disease. The decreased risk was:
    • 53% for the MIND diet.
    • 54% for the Mediterranean diet.
    • 39% for the DASH diet.
  2. When the investigators looked at moderate adherence to each of the diets, the MIND diet performed slightly better than the other two diets:
    • Moderate adherence to the MIND diet decreased Alzheimer’s risk by 35%.
    • Moderate adherence to the Mediterranean and DASH diets had no significant effect on Alzheimer’s risk.

What Does This Study Mean For You?

Dr. Morris concluded that healthy diets, such as the Mediterranean and DASH diets, provide substantial protection against dementia. She stated that as new studies come along, these diets can be modified to provide even better protection. She considers the MIND diet is the first step in that process.

alzheimer's riskA 53% decrease in Alzheimer’s risk is impressive. However, if you are really concerned about dementia and Alzheimer’s disease, you should think of diet as only one component of a holistic approach. As I described in a recent article How to Prevent Memory Loss, a holistic approach to preserving your cognitive function includes:

  • A healthy diet
  • B vitamins & omega-3s
  • Weight control
  • Exercise
  • Adequate sleep
  • Socialization
  • Memory training (mental exercise)

The Bottom Line

 

  1. The Mediterranean and DASH diets have already been shown to preserve mental function as we age, thus reducing the risk of developing dementia and Alzheimer’s.
  2. Martha Morris at Rush University Medical Center used the latest studies on specific foods and nutrients that preserve mental function to modify those diets into something she calls the MIND diet.
  3. Morris and colleagues at Rush then evaluated the effectiveness of all 3 diets on reducing Alzheimer’s risk. Strict adherence to all 3 diets significantly decreased the risk of developing Alzheimer’s disease. The decreased risk was:
    • 53% for the MIND diet.
    • 54% for the Mediterranean diet.
    • 39% for the DASH diet.
  4. When the investigators looked at moderate adherence to each of the diets, the MIND diet performed slightly better than the other two diets:
    • Moderate adherence to the MIND diet decreased Alzheimer’s risk by 35%.
    • Moderate adherence to the Mediterranean and DASH diets had no significant effect on Alzheimer’s risk.
  5. Morris concluded that healthy diets, such as the Mediterranean and DASH diets, provide substantial protection against dementia. However, she feels that as new studies come along, these diets can be modified to provide even better protection. She considers the MIND diet as the first step in that process.
  6. Healthy diet is only one component of a holistic approach for preserving mental function. Other components include:
    • B vitamins & omega-3s
    • Weight control
    • Exercise
    • Adequate sleep
    • Socialization
    • Memory training (mental exercise)

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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Comments (2)

  • Barbara Wagner

    |

    I have a Shaklee distributor and have received your newsletter for years. I was at the recent Science Symposium in Portsmouth, NH.

    Re the Mind diet, I included an excerpt from your newsletter below. How do you reconcile a’ whole foods plant based diet’ and then include fish, poultry, meat and dairy as you’ve done below. I have found the research/writing done by T. Colin Campbell to be the most convincing case for a healthy diet (including for the brain). He recommends a whole foods plant based diet without animal products. Michael Greger, MD, and his book ‘How Not to Die’ also recommends a whole food plant based diet without animal products.

    ‘The MIND diet is a whole food, plant based, diet.

    • It includes 10 “brain-healthy” food groups: green leafy vegetables, other vegetables, nuts, berries, beans, whole grains, fish, poultry, olive oil, and wine (in moderation, too much alcohol kills brain cells).

    • It limits red & processed meats, butter and margarine, cheese, pastries & sweets, and fried & fast foods.

    • It neither recommends or discourages low fat dairy foods and fruit other than berries. Dr. Morris notes that while those

    Reply

    • Dr. Steve Chaney

      |

      Dear Barbara,

      As Joe Friday used to say in the TV show “Dragnet”: “Just the facts, mam.” I am a big fan of a Vegan diet and the writings of T. Colin Campbell. However, the data are very clear that a plant based diet with some healthy animal proteins, such as the Mediterranean diet, also dramatically decreases the risk of heart disease, diabetes, cancer, and dementia. The MIND and DASH diets are very closely related to the Mediterranean diet. I consider all of them healthy diets. Whether you want to go Vegan, Mediterranean, MIND or DASH is a matter of personal preference.

      Dr. Chaney

      Reply

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Latest Article

A Low Carb Diet and Weight Loss

Posted January 15, 2019 by Dr. Steve Chaney

Do Low-Carb Diets Help Maintain Weight Loss?

Author: Dr. Stephen Chaney

 

low carb dietTraditional diets have been based on counting calories, but are all calories equal? Low-carb enthusiasts have long claimed that diets high in sugar and refined carbs cause obesity. Their hypothesis is based on the fact that high blood sugar levels cause a spike in insulin levels, and insulin promotes fat storage.

The problem is that there has been scant evidence to support that hypothesis. In fact, a recent meta-analysis of 32 published clinical studies (KD Hall and J Guo, Gastroenterology, 152: 1718-1727, 2017 ) concluded that low-fat diets resulted in a higher metabolic rate and greater fat loss than isocaloric low-carbohydrate diets.

However, low-carb enthusiasts persisted. They argued that the studies included in the meta-analysis were too short to adequately measure the metabolic effects of a low-carb diet. Recently, a study has been published in the British Medical Journal (CB Ebbeling et al, BMJ 2018, 363:k4583 ) that appears to vindicate their position.

Are low carb diets best for long term weight loss?

Low-carb enthusiasts claim the study conclusively shows that low-carb diets are best for losing weight and for keeping it off once you have lost it. They are saying that it is time to shift away from counting calories and from promoting low-fat diets and focus on low-carb diets instead if we wish to solve the obesity epidemic. In this article I will focus on three issues:

  • How good was the study?
  • What were its limitations?
  • Are the claims justified?

 

How Was The Study Designed?

low carb diet studyThe investigators started with 234 overweight adults (30% male, 78% white, average age 40, BMI 32) recruited from the campus of Framingham State University in Massachusetts. All participants were put on a diet that restricted calories to 60% of estimated needs for 10 weeks. The diet consisted of 45% of calories from carbohydrate, 30% from fat, and 25% from protein. [So much for the claim that the study showed low-carb diets were more effective for weight loss. The diet used for the weight loss portion of the diet was not low-carb.]

During the initial phase of the study 161 of the participants achieved 10% weight loss. These participants were randomly divided into 3 groups for the weight maintenance phase of the study.

  • The diet composition of the high-carb group was 60% carbohydrate, 20% fat, and 20% protein.
  • The diet composition of the moderate-carb group was 40% carbohydrate, 40% fat, and 20% protein.
  • The diet composition of the low-carb group was 20% carbohydrate, 60% fat, and 20% protein.

Other important characteristics of the study were:

  • The weight maintenance portion of the study lasted 5 months – much longer than any previous study.
  • All meals were designed by dietitians and prepared by a commercial food service. The meals were either served in a cafeteria or packaged to be taken home by the participants.
  • The caloric content of the meals was individually adjusted on a weekly basis so that weight was kept within a ± 4-pound range during the 5-month maintenance phase.
  • Sugar, saturated fat, and sodium were limited and kept relatively constant among the 3 diets.

120 participants made it through the 5-month maintenance phase.

 

Do Low-Carb Diets Help Maintain Weight Loss?

low carb diet maintain weight lossThe results were striking:

  • The low-carb group burned an additional 278 calories/day compared to the high-carb group and 131 calories/day more than the moderate-carbohydrate group.
  • These differences were even higher for those individuals with higher insulin secretion at the beginning of the maintenance phase of the study.
  • These differences lead the authors to hypothesize that low-carb diets might be more effective for weight maintenance than other diets.

 

What Are The Pros And Cons Of This Study?

low carb diet pros and consThis was a very well-done study. In fact, it is the most ambitious and well-controlled study of its kind. However, like any other clinical study, it has its limitations. It also needs to be repeated.

The pros of the study are obvious. It was a long study and the dietary intake of the participants was tightly controlled.

As for cons, here are the three limitations of the study listed by the authors:

#1: Potential Measurement Error: This section of the paper was a highly technical consideration of the method used to measure energy expenditure. Suffice it to say that the method they used to measure calories burned per day may overestimate calories burned in the low-carb group. That, of course, would invalidate the major findings of the study. It is unlikely, but it is why the study needs to be repeated using a different measure of energy expenditure.

#2: Compliance: Although the participants were provided with all their meals, there was no way of being sure they ate them. There was also no way of knowing whether they may have eaten other foods in addition to the food they were provided. Again, this is unlikely, but cannot be eliminated from consideration.

#3: Generalizability: This is simply an acknowledgement that the greatest strength of this study is also its greatest weakness. The authors acknowledged that their study was conducted in such a tightly controlled manner it is difficult to translate their findings to the real world. For example:

  • Sugar and saturated fat were restricted and were at very similar levels in all 3 diets. In the real world, people consuming a high-carb diet are likely to consume more sugar than people in the other diet groups. Similarly, people consuming the low-carb diet are likely to consume more saturated fat than people in the other diet groups.
  • Weight was kept constant in the weight maintenance phase by constantly adjusting caloric intake. Unfortunately, this seldom happens in the real world. Most people gain weight once they go off their diet – and this is just as true with low-carb diets as with other diets.
  • The participants had access to dietitian-designed prepared meals 3 times a day for 5 months. This almost never happens in the real world. The authors said “…these results [their data] must be reconciled with the long-term weight loss trials relying on nutrition education and behavioral counseling that find only a small advantage for low carbohydrate compared with low fat diets according to several recent meta-analyses.” [I would add that in the real world, people do not even have access to nutritional education and behavioral modification.]

 

low carb diet and youWhat Does This Study Mean For You?

  • This study shows that under very tightly controlled conditions (dietitian-prepared meals, sugar and saturated fat limited to healthy levels, calories continually adjusted so that weight remains constant) a low-carb diet burns more calories per day than a moderate-carb or high-carb diet. These findings show that it is theoretically possible to increase your metabolic weight and successfully maintain a healthy weight on a low-carb diet. These are the headlines you probably saw. However, a careful reading of the study provides a much more nuanced viewpoint. For example, the fact that the study conditions were so tightly controlled makes it difficult to translate these findings to the real world.
  • In fact, the authors of the study acknowledged that multiple clinical studies show this almost never happens in the real world. These studies show that most people regain the weight they have lost on low-carb diets. More importantly, the rate of weight regain is virtually identical on low-carb and low-fat diets. Consequently, the authors of the current study concluded “…translation [of their results to the real world] requires exploration in future mechanistic oriented research.” Simply put, the authors are saying that more research is needed to provide a mechanistic explanation for this discrepancy before one can make recommendations that are relevant to weight loss and weight maintenance in the real world.
  • The authors also discussed the results of their study in light of a recent, well-designed 12-month study (CD Gardener et al, JAMA, 319: 667-669, 2018 ) that showed no difference in weight change between a healthy low-fat versus a healthy low-carbohydrate diet. That study also reported that the results were unaffected by insulin secretion at baseline. The authors of the current study noted that “…[in the previous study] participants were instructed to minimize or eliminate refined grains and added sugars and maximize intake of vegetables. Probably for this reason, the reported glycemic load [effect of the diet on blood sugar levels] of the low-fat diet was very low…and similar to [the low-carb diet].” In short, the authors of the current study were acknowledging that diets which focus on healthy, plant-based carbohydrates and eliminate sugar, refined grains, and processed foods may be as effective as low-carb diets for helping maintain a healthy weight.
  • This would also be consistent with previous studies showing that primarily plant-based, low-carb diets are more effective at maintaining a healthy weight and better health outcomes long-term than the typical American version of the low-fat diet, which is high in sugar and refined grains. In contrast, meat-based, low-carb diets are no more effective than the American version of the low-fat diet at preventing weight gain and poor health outcomes. I have covered these studies in detail in my book “Slaying The Food Myths.”

Consequently, the lead author of the most recent study has said: “The findings [of this study] do not impugn whole fruits, beans and other unprocessed carbohydrates. Rather, the study suggests that reducing foods with added sugar, flour, and other refined carbohydrates could help people maintain weight loss….” This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.

The Bottom Line

 

  • A recent study compared the calories burned per day on a low-carb, moderate-carb, and high-carb diet. The study concluded that the low-carb diet burned significantly more calories per day than the other two diets and might be suitable for long-term weight control. If confirmed by subsequent studies, this would be the first real evidence that low-carb diets are superior for maintaining a healthy weight.
  • However, the study has some major limitations. For example, it used a methodology that may overestimate the benefits of a low-carb diet, and it was performed under tightly controlled conditions that can never be duplicated in the real world. As acknowledged by the authors, this study is also contradicted by multiple previous studies. Further studies will be required to confirm the results of this study and show how it can be applied in the real world.
  • In addition, the kind of carbohydrate in the diet is every bit as important as the amount of carbohydrate. The authors acknowledge that the differences seen in their study apply mainly to carbohydrates from sugar, refined grains, and processed foods. They advocate diets with low glycemic load (small effects on blood sugar and insulin levels) and acknowledge this can also be achieved by incorporating low-glycemic load, plant-based carbohydrates into your diet. This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.
  • Finally, clinical studies report averages, but none of us are average. When you examine the data from the current study, it is evident that some participants burned more calories per hour on the high-carb diet than other participants did on the low carb diet. That reinforces the observation that some people lose weight more effectively on low-carb diets while others lose weight more effectively on low-fat diets. If you are someone who does better on a low-carb diet, the best available evidence suggests you will have better long-term health outcomes on a primarily plant-based, low-carb diet such as the low-carb version of the Mediterranean diet.

For more details read the article above.

 

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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