The Mediterranean Diet and A Healthy Mind

The recent article that came out stating that people who adhere to a Mediterranean diet supplemented with olive oil or nuts had improved function over time hit the presses with vigor. The ability to have an early intervention - a diet intervention, to delay onset of cognitive decline is a priority for all, but to do it with a diet as lovely as this? That is amazing.

You can imagine -living here, looking over the sea, eating olives and drinking red wine and knowing your brain and your heart are better off for it. Who wouldn't be in for that?

What Is The Theory about Mediterranean Diet and Memory?

The theory of cognitive decline as we age has to do with "oxidative stress," much like a nail that becomes rusty by oxidative stress, it is felt that this has a long-term effect on the brain. The theory being that if a person were to eat an antioxidant-rich food that there might be some protection against that slow decline, and perhaps even delay the onset of progressive degenerative diseases.

In addition, it has long been noted that pregnant mothers who diets rich in polyunsaturated fats,  specifically omega-3 fatty acids, have children that are smarter and perform better than mothers who do not. The other observation was from parents who enforce a vegan lifestyle to their children - those children have more difficulty with learning than those children who have more fat in their diet.  Fats are an important part of the brain and nervous system function, so not only are the antioxidants needed but additionally fat is needed to promote that function.

Previous Work Pointed The Way to Healthy Mediterranean Brain

There have been a number of studies, both observational and epidemiological- looking at populations that adhere to a Mediterranean-type diet that have better memory and cognitive abilities as they age as well as less dementia.  

Some work in rodents found that while there was a steep cognitive decline with refined fructose, omega-3 fatty acids appeared to protect against this decline. So if you don't want your rats to remember your house be sure to put out a lot of fructose and don't let them get into your salmon. 

What This Study Adds 

This study randomized older people to different diets and followed them, checking for memory loss, dementia, and cognitive decline (decreasing ability to process with the brain).  What was interesting was a previous study looking at patients who were on the Mediterranean diet found high scores on neuropsychological testing, but without a baseline study to compare.

Study Design

The study took 447 volunteers whose average age was 66.9 years and followed them for five years. This study took baseline data, from lifestyle and blood work to medication use. The participants were randomized into three diet groups: A Mediterranean diet supplemented with extra virgin olive oil, a Mediterranean diet supplemented with mixed nuts, and a control diet where the advice was to reduce dietary fat. 

The Results

There was cognitive improvement in those who had the Mediterranean diet, either supplemented with nuts or with olive oil and cognitive decline with the "control" group. 

Specifically the scores for the Mediterranean diet plus supplement were better with high statistical probablility when compared to controls (P of 0.049 and 0.04) in the Color Trail test and the Rey Auditory Verbal Learning Test (RAVLT). All cognitive scores were significantly decreased from baseline in the control diet group - (P < 0.05).

From the paper: Error bars indicate 95% CIs. P values by analysis of covariance were adjusted for sex, baseline age, years of education, marital status, APOE ε4 genotype, ever smoking, baseline body mass index, energy intake, physical activity, type 2 diabetes mellitus, hyperlipidemia, ratio of total cholesterol to high-density lipoprotein cholesterol, statin treatment, hypertension, use of anticholinergic drugs, and time of follow-up, with the Bonferroni post hoc test. For each cognitive composite, the changes between the 2 Mediterranean arms were not statistically different (P >.99 for all). The changes for memory between the Mediterranean diet plus olive oil and control groups and for frontal and global cognition between the Mediterranean diet plus nuts and control groups had values of P < .25.

Other Studies Comparison

In an Italian  Longitudinal Study on aging, it was noted that people who had greater intake of mono and poly unsaturated fats had better cognitive function in an 8 year follow up. One study showed a weak association with olive oil and cognitive function. So the evidence has pointed to this for years. 

Conclusions

The diet is a healthy way, and delicious way to eat and this study suggests that a healthy Mediterranean diet supplemented with olive oil or nuts may help counteract age-related memory and cognitive decline. 

Since we do not have an effective treatment for cognitive decline- this diet is the best weapon currently for adults.

References:

Mediterranean Diet and Age-Related Cognitive Decline: A Randomized Clinical Trial. Valls-Pedret C, Sala-Vila A, Serra-Mir M, Corella D, de la Torre R, Martínez-González MÁ, Martínez-Lapiscina EH, Fitó M, Pérez-Heras A, Salas-Salvadó J, Estruch R, Ros E. JAMA Intern Med. 2015 PMID: 25961184

Mediterranean diet, cognitive function, and dementia: a systematic review.

Lourida I, Soni M, Thompson-Coon J, Purandare N, Lang IA, Ukoumunne OC, Llewellyn DJ.

Epidemiology. 2013 Jul;24(4):479-89 PMID: 23680940

Brain foods: the effects of nutrients on brain function. Gómez-Pinilla F1.Nat Rev Neurosci. 2008 Jul;9(7):568-78 PMID: 18568016

Association of mediterranean diet with mild cognitive impairment and Alzheimer's disease: a systematic review and meta-analysis.Singh B, Parsaik AK, Mielke MM, Erwin PJ, Knopman DS, Petersen RC, Roberts RO.J Alzheimers Dis. 2014;39(2):271-82.PMID: 24164735