Inclusion Criteria:  Fasting blood glucose 6.1-8.4mmol /L; HBA1c 5.7-7.0%; OGTT 2h or postprandial blood glucose 7.8-11.1 mmol/L; Patients with previously diagnosed type 2 diabetes with stable drug hypoglycemic treatment and blood glucose controlled well.  Exclusion Criteria:  Under 30 years old or over 75 years old; Suffering from severe obesity, thyroid disease, or other serious diseases, such as mental illness; Take nutritional supplements, such as fish oil capsules, Perilla seed oil and flaxseed oil capsules, for nearly one month; Intake more than 20g walnuts per day or more than 100g fatty fish per week in the last month; Daily cooking oil is linseed oil or rapeseed oil and other α -linolenic acid rich vegetable oil; Have been diagnosed with type 2 diabetes and are currently receiving insulin injection; Allergic to the content of intervention; Failure to eat the tested sample as prescribed and affect the efficacy or safety judgment.