Participants will be randomly assigned to one of three treatment groups to receive soyafoods (Alpro drinks) providing a low (<10 mg), medium (35mg) or high-dose (60 mg) of isoflavones daily for a period of 12 weeks. The group receiving <10mg isoflavones daily will serve as a low-dose control group. Women will be asked to avoid consuming any additional soya foods during the study.

Dietary intake will be assessed at baseline using the validated food frequency questionnaire a 4 day food diary will be completed at baseline and post-intervention. Weight and height will be measured and a general health & lifestyle questionnaire will also be completed by participants at baseline. Cognitive function will be assessed at baseline and post-intervention using the well validated and widely used computerised test battery system. Menopausal symptoms, quality of life, mood, stress and coping will also be assessed.

Plasma concentrations of the soya isoflavones genistein and daidzein will be measured to assess compliance. Circulating concentrations of equol (a daidzein metabolite), will also be measured to investigate associations between equol and cognition and menopausal symptoms as a potential mechanism for the efficacy of soya.

Inclusion Criteria:

• apparently healthy
• within 7 years postmenpopausal with the absence of vaginal bleeding for at least 1 year
• ≥ 24 in mini mental state examination
• not suffering from psychiatric distress as assessed using GHQ28 questionnaire

Exclusion Criteria:

• surgically induced menopause
• habitual consumers of soys foods (> 2 serves/week)
• currently using hormone therapy
• currently on isoflavone supplements
• antibiotics use within last 3 months
• use of psychoactive medication
• history of CVD, cancer, diabetes, thyroid, renal or kidney disease, alcohol or drug abuse
• red-green colour blindness