Mediterranean diet tied to reduced cardiometabolic, frailty risk in older adults

A secondary analysis of the ASPREE* and ALSOP** studies found an association between a Mediterranean Diet (MedDiet) pattern and reduced risks of cardiometabolic conditions and frailty in older Australian adults.

“[We] aimed to develop MedDiet and ultra-processed food (UPF) scoring tools for use in a population of community-dwelling older Australian adults [and to] determine the relationship between the scores generated from these tools with prevalent cardiometabolic diseases and markers of frailty,” the researchers said.

In ASPREE, 16,703 individuals were enrolled in a randomized trial comparing aspirin 100 mg against placebo for reducing the risk of disability-free survival, physical disability, dementia, mortality, and cardiovascular disease. ALSOP was then initiated to further evaluate the participants’ lifestyle factors with three waves of questionnaire data collection.

The second wave (~3 years after ASPREE started; n=12,416; median age 76.9 years, 54.4 percent women, mean BMI 27.6 kg/m²) included a 54-item food frequency questionnaire (FFQ), which was the basis of this analysis. The FFQ was used to generate the ASPREE-MedDiet Score (MDS) and ASPREE-UPF dietary scores. [Nutrients 2024;16:2978]

Quartile (Q)4 saw higher scores than Q1 across all ASPREE-MDS*** and ASPREE-UPF^# dietary components (p<0.001). Higher scores meant greater adherence to the respective eating patterns evaluated for each group.

ASPREE-MDS

On univariate analysis, compared with Q1, Q4 saw fewer participants with BMI >33 kg/m² (10.2 percent vs 13 percent), central adiposity (52.2 percent vs 57.4 percent), type 2 diabetes (T2D; 9.1 percent vs 11.9 percent), hypertension (70 percent vs 76.8 percent), chronic kidney disease (CKD; 25 percent vs 33.6 percent), and frailty (9.4 percent vs 13.6 percent; p<0.001 for all).

Conversely, the percentage of participants with dyslipidaemia was marginally higher in Q4 than Q1 (83.2 percent vs 80.5 percent; p=0.005). About 57 percent were deemed non-frail by Q4, which was quite a jump from the 46.7 percent reported in Q1.

Higher ASPREE-MDS was associated with lower odds of CKD (adjusted odds ratio [aOR], 0.94) and hypertension (aOR, 0.96) and lower risk of prefrailty (adjusted relative risk [aRR], 0.93) and frailty (aRR, 0.88) after adjusting for confounders.

“There are multiple proposed explanations exploring the effects of the MedDiet on cardiometabolic markers and overall healthy ageing. In the older population, microbiome modulation has been proposed as one possible driver,” the researchers said.

Another plausible explanation is some of the diet’s specific components. For instance, olive oil may act by regulating systemic inflammation and oxidative stress at the genomic level, consequently generating epigenetic change, while legumes are low in saturated fats. [Cells 2020;9:478; Cochrane Database Syst Rev 2020;8:CD011737]

“[S]ome of the benefits of the MedDiet may also be about what is not included, rather than what is … [I]n this population of older adults, the positive MedDiet associations seem to be – at least in part – contributed to by the overall variety of polyphenols, fibre, mono- and poly-unsaturated fats, and lean proteins seen with higher ASPREE-MDS scores,” the researchers explained.

ASPREE-UPF

In this group, Q4 and Q1 had similar percentages of participants with BMI >33 kg/m² (11.4 percent and 12.2 percent), central adiposity (53.6 percent and 56.1 percent), T2D (10 percent and 9.8 percent), hypertension (72.9 percent and 74.2 percent), CKD (30 percent and 28.3 percent), and frailty (11.5 percent and 10.5 percent).

A higher ASPREE-UPF score was tied to greater risk of prefrailty (aRR, 1.04) and frailty (aRR, 1.10) in the adjusted analysis, and lower odds of hypertension (aOR, 0.97).

Notable observations

“Interestingly … our study demonstrated that higher ASPREE-MDS and ASPREE-UPF scores were both associated with reduced rates of hypertension,” the researchers noted. “This unexpected outcome may be partly explained by the adjustment for confounding risk factors, particularly excess body weight, which is inextricably linked to both high dietary intakes of UPF and hypertension.”

Another noteworthy finding was that high UPF intake did not preclude high MedDiet adherence, which deviates from evidence on younger adults. [Nutrients 2022;14:2073] “[The contrast may be] due to UPF intake being based on the total energy percentage attributable to UPFs, which we were unable to perform with our FFQs. It is also possible that in our older population … the total energy consumption attributable to UPFs is relatively lower compared with younger adults, perhaps due to lower overall appetite and energy consumption in a proportion of the cohort,” they said.

Public health implications

“[Taken together, the findings imply that] increasing MedDiet adherence is an actionable public health message and aligns with many principles of healthy eating,” the researchers said.

“[T]he MedDiet pattern should be encouraged in older adults to potentially reduce the risk of frailty, while the impact of UPF intake should be further explored given the convenience these foods provide to a population whose access to unprocessed food may be limited due to socioeconomic, health, and lifestyle factors,” they added.