The Mediterranean diet is one of the most heavily researched types of diets out there and studies consistently point to the health benefits that it offers.
In particular, it has been connected to reducing the risk of heart disease, metabolic syndrome and even dementia, while it is also considered a good approach for weight loss.
At its heart, this powerful diet is simple.
It relies on eating higher amounts of fish, vegetables (including green leafy vegetables) and fruit (including berries and figs), along with healthy fats like olive oil. Other components of the diet include nuts, seeds, beans, legumes and wine. In contrast, people following the Mediterranean diet tend to eat less dairy, red meat, sugars and processed foods.
Because of the benefits that this diet type offers, there has been considerable interest in looking at the precise impacts that the diet has, particularly over time.
One such study took a look at research into the impacts of a Mediterranean-style diet on cognition in adults (Hardman et al., 2016). In this post, we’re going to take a look at what the study found and its implications for our own eating patterns and health.
The Study Itself
This particular study made use of a process called meta analysis. This means that the authors were not conducting research of their own. Instead, they were collecting and evaluating the outcomes of other studies on the topic.
This type of research can be particularly powerful because research studies often vary in their outcomes, even when they’re considering the same general topic. This can happen for a range of reasons, including variations in experimental design and the sample chosen. A meta analysis provides a way of examining what the balance of evidence is and the overall perspectives that current research supports.
In this particular case, the authors looked at 18 individual articles that considered the food that people ate along with cognitive outcomes, such as levels of cognitive decline and cognitive function. Within these studies, food consumption was determined through food diaries or food frequency questionnaires.
The studies that the authors considered also looked at food consumption and cognitive outcomes based on an extended period of time.
This allowed the authors to look at the long-term impacts of a Mediterranean diet.
That information was then used to determine how well participants followed the Mediterranean diet, through the use of a Mediterranean diet score. A higher score meant a greater level of adherence to the Mediterranean diet pattern.
Overall, the authors found that an increased Mediterranean diet score was associated with improvements in cognitive outcomes and decreased cognitive decline.
Likewise, higher adherence also reduced the risk of Alzheimer’s disease.
It's also important to note that these positive benefits were not just found in the older population. Instead, two of the studies looked at outcomes in young adults and both indicated improvements in cognition associated with Mediterranean diet adherence.
Likewise, positive patterns have been found throughout the world, rather than just in countries in the Mediterranean region.
However, it is important to note that those outcomes were for the 18 studies collectively. On an individual basis, 13 studies showed a relationship between the Mediterranean diet and improved cognitive outcomes, while 5 did not.
Strengths and Limitations
By considering a range of different studies, the authors of the meta analysis were able to reduce the impact of research design and sample population and instead focus simply on the relationship between the Mediterranean diet and cognition. That design is a powerful approach and is one of the key strengths of the study.
At the same time, other strengths included the significant sample population that was included along with the long-term nature of the research.
Despite these strengths, there are also some limitations to consider in the research.
One limitation is that the research is still observational.
Observational research is interesting. It’s a powerful tool that lets researchers see patterns across large populations and over an extended period of time. But, the approach lacks the ability to test cause and effect.
In this case, the limitation means that the research can see an association between Mediterranean diet adherence and improved cognitive outcomes, but the research can’t prove that the diet adherence caused the cognitive improvements.
This is a fairly major limitation because it obscures other potential causes, such as lifestyle differences and variations in behavior.
When considering studies like this it is important to be aware of this limitation and interpret the results with caution. Nevertheless, it is important to note that the observational approach is the most effective and practical way to study the topic at hand.
Indeed, doing an intervention study with the Mediterranean diet would be extremely difficult because of the complexity of the diet. Even if an intervention study was done, it would still be unrealistic to look at long-term outcomes, especially outcomes like the incidence of Alzheimer’s disease.
As such, despite the limitations of observational research, this approach was the best one for the study at hand.
This study offers another piece of evidence about the power of the food we eat and the advantages of the Mediterranean diet. In particular, it suggests that greater adherence to the Mediterranean diet is associated with improved cognition, which is an appealing outcome.
The nature of the study means that it considers the Mediterranean diet as a whole, rather than specific foods. So, it isn’t clear which food or foods are contributing to the observed outcomes and the mechanisms behind the observed effects are not known.
Nevertheless, the study does provide important information about and direction for future research. It also shows that the Mediterranean diet can be a good approach for people worried about their cognitive health or about the risk of Alzheimer’s disease.
At the same time, the outcomes do reinforce the idea that whole foods may offer many health benefits, as opposed to the heavily processed and sugar-filled foods that are prevalent within the United States.
As such, moving away from chemicals and towards simpler and more natural foods may have important implications for health, including cognitive health.
Likewise, relying on specific components of the diet, like olive oil, is also a good positive step for promoting better health and longevity overall.
Indeed, the reasons for the observed benefits of the diet include the significant amount of micronutrients that are included within the Mediterranean diet, along with the various vitamins and minerals, and the way that this diet replaces unhealthy fats with healthy ones. Likewise, there are other potentially relevant areas, such as reducing inflammation and even potentially improving bacteria in the gut.
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