Inclusion Criteria:  eGFR ≥ 20 and <60 ml/min/m2/year, and a decline in eGFR of ≥ 3 ml/min/m2/year in the previous 12 months Blood pressure <140/90 mm Hg prior to initiation of sulphoraphane stable anti-hypertensive regimen for at least one month prior to initiation of sulphoraphane or successful run-in period able to provide consent able to swallow capsules  Exclusion Criteria:  significant co-morbid conditions with life expectancy of <1 year uncontrolled hypertension serum potassium of >5.5 mEq/L at screening New York Heart Association Class 3 or 4 heart failure symptoms, known EF ≤30% or hospital admission for heart failure within the past 3 months factors judged to limit adherence to interventions current participation in another study pregnancy or planning to become pregnant or currently breastfeeding history of dementia on anticoagulants or immunosuppression under treatment for cancer