Why No Cheese?

When we discuss the distinctions between the MIND diet and the Mediterranean diet, the topic of cheese, stick butter, and stick margarine comes up. They are not allowed in the MIND diet. When I speak about this, I might hear a groan from the audience. But what’s wrong with enjoying these common foods? 

The issue was identified by the late Dr. Martha Clare Morris in the longitudinal studies she and her team conducted that led to the development of the MIND diet. She saw a correlation between consumption of these foods and the development of Alzheimer’s disease. And so they were tagged as bad. So that’s correlation. But what does that tell us about causation? 

When asked about causation, dietitians usually point to the saturated fat content of these products. But I’m not sure we know that’s the case. According to some recent research, the story may have more to do with a negative effect that cheese has on the gut microbiome. In fact, while cheese may kill off some beneficial microbes, other dairy products may benefit the microbiome. Quite a paradox. 

In understanding why this might be relevant to our interest in Alzheimer’s disease, we need to recall the mystery of the gut-brain axis. There is some kind of communication between the gut microbiome and the brain, and the brain is in some ways actually controlled by the gut microbiome. The gut is sometimes called “the second brain.” How does that work? If you find out, please let me know! Nevertheless, we associate a healthy gut microbiome with a healthy brain. Eating fermented foods, like sauerkraut and kimchi, are probiotic and are associated with better brain health, because they replenish important bacteria and archaea which may have died at the hands of antibiotics and artificial sweeteners. And, perhaps, cheese. 

The research in question was published in the journal, Nutrients. It studied a relatively small cohort of older men but led to some interesting conclusions. Essentially, dairy, in general, is probiotic and increased the population of beneficial bacteria and archaea in the gut. So dairy is generally good. But cheese, on the other hand, decreased the population of beneficial microbes. Surprisingly, yogurt seemed to be neutral. Yogurt contains some microbes important to a healthy gut, but they may all get destroyed by the digestive juices in the stomach. Or so some believe. On the other hand, older men don’t eat much yogurt, so this may have been the wrong population to use for studying yogurt. (I guess I’m an exception, since I consume plenty of yogurt – mixed with blueberries, walnuts, and monkfruit sweetener.) 

So I’ll speculate. It may well be that saturated fat in butter and cheese is directly detrimental to the brain, promoting the development of Alzheimer’s disease. But also, it may be that the damage to the gut microbiome caused by cheese increased the incidence of Alzheimer’s significantly enough to influence Dr. Morris’s results. 

The research was conducted at Baylor College and involved 34 older men. They basically counted microbes in material taken from their colon mucous and correlated the counts with dairy consumption. Since the study involved such a small population of older men (who didn’t like yogurt) – you guessed it – more research is necessary.

Here's some more, perhaps simpler reading on this.

The MIND Diet -- Dead and Buried -- or Reborn?

In Beating the Dementia Monster, we looked forward to what was to be the definitive study on the MIND diet. The research project was looking to recruit 600 participants, and it appeared that we could expect to see results in April, 2021. The research was a collaboration of Rush University, T. H. Chan School of Public Health, Brigham and Women’s Hospital, and the National Institute on Aging. I was very hopeful for some solid, scientific support for the validity of the MIND diet.  

And then covid happened.

Covid threw a monkey wrench into a lot of plans, including this one. In fact, if you go to the study’s web site, you’d think the research is still underway. The web site stands frozen in time. But they did finally publish the results in July 2023, and the results were disappointing. Some vegan YouTubers were a bit gleeful about this, primarily (it seems to me) because the diet allowed for consumption of some fish and poultry. 

I wrote before that I was disappointed in the quality of the study, because it was compromised by covid restrictions. In my view, some of the adjustments they made to the research protocol impaired data collection and assurance of the validity of the data. After reading the research, it didn’t appear to me that they really knew what people were actually eating with an appropriate level of accuracy. Some took the research results to indicate that the diet really didn’t work to reduce the risk of Alzheimer’s, at least not any better than the Mediterranean diet. But not me.  

So perhaps I’m vindicated in resisting the negative interpretation of the results. Recent research at the University of Hawaii (my wife’s alma mater) used data drawn from 93,000 US adults, of which 21,000 developed Alzheimer’s. The study found that adherence to the MIND diet by members of the general population resulted in a 9% reduction in Alzheimer’s risk. But those of White, Black, and Latino descent experienced a 13% reduction. However, people who improved their adherence to MIND over 10 years (including those who didn’t follow the diet closely at first) had a 25% lower risk of dementia compared to those whose adherence declined. Data for the study was drawn from the research cohort known as the Multiethnic Cohort Study which began in the 1990s. This study was also an initiative of the University of Hawaii, but its original goal was to study the demographics of cancer.  

Now, the MIND diet had not yet been formulated in the 1990s. So this is obviously a longitudinal study in which they analyzed information regarding a large population and looked for correlations between diet and the development of Alzheimer’s. The late Dr. Martha Clare Morris developed the MIND diet based on similar research that she and her team conducted. She describes her research in her book, Diet for the Mind.  

Noteworthy about this new research is that adherence to the diet had relatively little effect on Americans of Asian and Native Hawaiian descent. Positive results were seen in White, Black, and Latino populations. The researchers speculated that this may be because the ethnic foods of Asian and Native Hawaiian cultures was already somehow protective of the brain. And you’re looking for the difference in outcome between what people normally eat and a specialized diet. But if both diets are protective of the brain, you won’t see anything that suggests the MIND diet improved anything. But … as they always say ... more research is necessary.  

The new research hasn’t been published, but it was to have been presented at NUTRITION 2025, the conference of the American Society for Nutrition, this past Monday, June 2, in Orlando. I presume all went according to plan.