The effect of soya foods on cognitive function and menopausal symptoms in post-menopausal women

Abstract

The menopause is a natural transition that occurs at midlife for a woman and is accompanied by a number of symptoms which can significantly affect quality of life, the most commonly reported being hot flushes. Impaired cognitive function has also been observed in menopausal women and natural alternatives to hormone therapy for the alleviation of menopausal symptoms are being sought. The aim of this thesis was to investigate the effects of soya isoflavones on cognitive function and menopausal symptoms in post-menopausal women.
In an observational study, food diaries were completed by post-menopausal women (n=75). Principal component analysis was used to determine dietary patterns and associations with cognitive function, as assessed by CANTAB, were investigated. 5 final dietary patterns were identified. The 'meat and dairy' dietary pattern was associated with greater performance in the spatial working memory cognitive test. 'The social' dietary pattern was associated with negative effects on cognitive performance as was the 'potatoes and poultry' dietary pattern.A randomised controlled trial in post-menopausal women (n=101) was conducted to investigate the effects of soya isoflavones on cognitive function and menopausal symptoms. Participants consumed a volume of soya drink providing a low (10mg; control group), medium (35 mg) or high (60 mg) dose of soya isoflavones daily for a period of 12 weeks and cognitive function was assessed using CANTAB (spatial working memory, spatial span, pattern recognition memory, 5-choice reaction time and match to sample visual search). Menopausal symptoms were also assessed using a validated questionnaire. Isoflavone supplementation had no effect on the primary outcome measure, cognitive function, although consumption of 350ml of soya drink/day (providing 35mg isoflavones) significantly reduced hot flushes in post-menopausal women with more severe symptoms at baseline.An observational study was conducted using focus groups to determine overall perceptions towards soya in post-menopausal women and to partly evaluate the soya intervention. Post-menopausal women reported barriers and enablers of consumption as well as attitudes towards soya products in an Irish and Northern Irish population. The main findings from the focus groups include the awareness of soya in the diet and also the benefits that can be attained from consuming soya. Main barriers to soya consumption include price and lack of knowledge about soya products while enablers of consumption include Alpro® being considered a reliable and good brand.This thesis questions the potential benefits of soya isoflavones on cognitive function in healthy post-menopausal women within 7 years post-menopause. Future studies should investigate effects in earlier post-menopausal women and/or in those with mild cognitive impairment. Soya isoflavone consumption in post-menopausal women had no effect ocognitive function although may alleviate vasomotor symptoms in those with more severe symptoms at baseline. With the potential risks associated with hormone therapy, soya isoflavones may be a natural alternative for the alleviation of vasomotor symptoms.

Date of Award	May 2019
Original language	English
Sponsors	ALPRO Foundation
Supervisor	Pamela Magee (Supervisor)