Longer-term soya nut consumption improves cerebrovascular function

Alpro Foundation Supported Research

Prof. Ronald Mensink and Dr Peter Joris, Department of Nutrition and Movement Sciences, Maastricht University

Age related health conditions such as impaired cognitive function and cardiovascular disease (CVD) are amongst the most prevalent conditions globally. Effective interventions are therefore needed to reduce the disease burden.

Plant-based diets have been shown to reduce risk of CVD and may also have the potential to prevent age related cognitive decline. Soya foods have gained particular attention due to their beneficial nutrition profile often associated with improved cognitive performance. Soya foods are the main dietary source of the phytoestrogens - isoflavones as well as providing cis-poly-unsaturated fatty acids (PUFA), and high-quality plant proteins.

This Alpro Foundation grant aimed to measure the effect of longer-term soya nut consumption on cerebral blood flow (CBF), a marker of cerebrovascular function as well as cognitive performance in older adults.

Study overview

This was a randomized, controlled, single blinded crossover study involving 23 healthy men and women between the ages of 60 and 70 years. Participants took part in a 16-week dietary intervention where they consumed 67g of soya nuts daily (equivalent to 25g protein and 174mg isoflavones) and a 16-week control diet. During the study, participants were encouraged to eat according to the 2015 Dutch food-based dietary guidelines.

At baseline and follow up points during the study, researchers measured:

• Serum isoflavones (a marker of compliance)

• CBF via MRI scan

• Cognitive performance (via standardised tests)

Statistical analysis using a linear mixed model was performed to determine the impacts of the dietary intervention on participants’ cognitive function.

Key findings

Serum isoflavone concentrations increased during the soya nut intervention indicating good compliance with the diet. Overall, soya nuts were well tolerated by participants and no adverse effects were reported.

There were several key observations following the intervention:

• Global and gray matter CBF, and CBF in the left and right hemispheres did not differ between the control and soya nut diets

• Regional blood flow significantly increased following the soya nut dietary intervention in four regional brain clusters

• Movement reaction time in the cognitive tests was significantly reduced during the soya nut intervention by 20 milliseconds which suggests an improvement in psychomotor speed performance

• Executive function and memory did not change during the study

The research demonstrates the potential for soya nuts to improve cognitive function in older adults, although it is unknown whether this is a result of soya isoflavones, plant-based protein or cis-PUFA.

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Conclusion

In summary, longer-term soya nut consumption has been shown to improve cerebral blood flow and therefore may improve cerebrovascular function of older adults, specifically in the area of psychomotor speed.

Read the original study.

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