This study evaluates the feasibility of walnuts supplementation among population of high CVD risks over a period of 6 months. 70 participants will be controls receiving non-edible gifts. 70 participants will be given 30 grams of walnuts everyday and 70 participants will be given 60 grams of walnuts a day.

Increased consumption of nuts improves the levels of lipid risk factors associated with cardiovascular disease and consistently relates to lower risk of cardiovascular disease (CVD) in prospective cohort studies. The estimates of health effects and potential population benefits of increased consumption of nuts are based mostly on observational data and there remains considerable uncertainty about whether higher intake of nuts will actually reduce cardiovascular outcomes. To address this uncertainty will require a well-conducted, adequately powered, large-scale, randomised control trial that tests the causal relationship between nut intake and the risk of cardiovascular diseases.

We hereby designed a 6-month walnut supplementation trial in a rural area of China with high rates of CVD, to obtain data to support and help to refine the design of a future long-term large RCT testing the effect of nut supplementation on CVD risk. The main objectives of the current trial are to assess the acceptability and adherence to two different doses of walnut supplementation (30 and 60 grams per day). The exploratory objectives are to determine the effects of walnut supplementation on cardiovascular risk factors including blood lipids, fasting glucose, and body weight.

Inclusion Criteria:

1. A history of CVD, defined on the basis of a prior hospitalisation for a myocardial infarction or stroke, unstable angina, coronary artery bypass graft, percutaneous coronary intervention (with or without stenting), peripheral revascularization (angioplasty or surgery), symptomatic with documented hemodynamically-significant carotid or peripheral vascular disease, or amputation secondary to vascular disease, OR
2. Male aged >60 years, or female aged>65 years, AND

With at least two of the following risk factors:

1. Type 2 diabetes requiring treatment with at least two oral anti-hyperglycaemic agents and/or insulin
2. Systolic blood pressure > 140 mmHg while on one or more antihypertensive agents
3. Current daily smoking
4. Dyslipidaemia defined as HDL-cholesterol<1.0mmol/L or LDL-cholesterol>6.0mmol/L
5. Micro or macro albuminuria

Exclusion Criteria:

1. Allergic to nuts (history of food allergy with hypersensitivity to any of the components of nuts)
2. Other serious medical condition that prevents nut consumption (e.g. digestive disease with fat intolerance)
3. Any medical condition thought to limit survival to less than 1 year
4. Difficulty with consuming nuts (e.g. dental health issues that prevent chewing walnuts)
5. Unwilling to consume nuts

This study is a single-blinded trial where investigators and outcome assessors will be blinded to the groups the participants are randomized to.