Intensive Weight-Loss Lifestyle Intervention Using Mediterranean Diet and COVID-19 Risk in Older Adults: Secondary Analysis of PREDIMED-Plus Trial

OBJECTIVES

We tested the effects of a weight-loss intervention encouraging energy-reduced MedDiet and physical activity (PA) in comparison to ad libitum MedDiet on COVID-19 incidence in older adults.

DESIGN

Secondary analysis of PREDIMED-Plus, a prospective, ongoing, multicentre randomized controlled trial.

SETTING

Community-dwelling, free-living participants in PREDIMED-Plus trial.

PARTICIPANTS

6,874 Spanish older adults (55-75 years, 49% women) with overweight/obesity and metabolic syndrome.

INTERVENTION

Participants were randomised to Intervention (IG) or Control (CG) Group. IG received intensive behavioural intervention for weight loss with an energy-reduced MedDiet intervention and PA promotion. CG was encouraged to consume ad libitum MedDiet without PA recommendations.

MEASUREMENTS

COVID-19 was ascertained by an independent Event Committee until December 31, 2021. COX regression models compared the effect of PREDIMED-Plus interventions on COVID-19 risk.

RESULTS

Overall, 653 COVID-19 incident cases were documented (IG:317; CG:336) over a median (IQR) follow-up of 5.8 (1.3) years (inclusive of 4.0 (1.2) years before community transmission of COVID-19) in both groups. A significantly lowered risk of COVID-19 incidence was not evident in IG, compared to CG (fully-adjusted HR (95% CI): 0.96 (0.81,1.12)).

CONCLUSIONS

There was no evidence to show that an intensive weight-loss intervention encouraging energy-reduced MedDiet and PA significantly lowered COVID-19 risk in older adults with overweight/obesity and metabolic syndrome in comparison to ad libitum MedDiet. Recommendations to improve adherence to MedDiet provided with or without lifestyle modification suggestions for weight loss may have similar effects in protecting against COVID-19 risk in older adults with high cardiovascular risks.

Potential prebiotic activity of oligosaccharides obtained by enzymatic conversion of durum wheat insoluble dietary fibre into soluble dietary fibre

BACKGROUND AND AIMS

Epidemiological evidence indicates that cereal dietary fibre (DF) may have several cardiovascular health benefits. The underlying mechanisms have not yet been elucidated. Here, the potential nutritional effects of physico-chemical properties modifications of durum wheat dietary fibre (DWF) induced by enzyme treatment have been investigated.

METHODS AND RESULTS

The conversion of the highly polymerised insoluble dietary fibre into soluble feruloyl oligosaccharides of DWF was achieved by a tailored enzymatic treatment. The in vitro fermentation and release of ferulic acid by intestinal microbiota from DWF before and after the enzymatic treatment were assessed using a gut model validated to mimic the human colonic microbial environment. Results demonstrated that, compared to DWF, the enzyme-treated DWF (ET-DWF) stimulated the growth of bifidobacteria and lactobacilli. Concurrently, the release of free ferulic acid by ET-DWF was almost three times higher respect to the control. No effect on the formation of short chain fatty acids was observed.

CONCLUSIONS

The conversion of insoluble dietary fibre from cereals into soluble dietary fibre generated a gut microbial fermentation that supported bifidobacteria and lactobacilli. The concurrent increase in free ferulic acid from the enzyme-treated DWF might result in a higher plasma ferulic acid concentration which could be one of the reasons for the health benefits reported for dietary fibre in cardiovascular diseases.