Researchers said the benefits appeared to come from the nutritional value of nuts.
Study co-author Dagfinn Aune, from Imperial College London, said: “Nuts and peanuts are high in fibre, magnesium, and polyunsaturated fats – nutrients that are beneficial for cutting cardiovascular disease risk and which can reduce cholesterol levels.
“Some nuts, particularly walnuts and pecan nuts are also high in antioxidants, which can fight oxidative stress and possibly reduce cancer risk.”
Although nuts are high in fat, there was also evidence they could reduce the risk of obesity, he suggested.
Dr Aune said that just a handful of nuts seemed to have a “substantial effect” with results found consistently across a number of diseases.
The team, whose findings appear in the journal BMC Medicine, analysed data from 29 studies including more than 800,000 participants.
While there was some variation between the populations that were studied, such as between men and women, people living in different regions, or people with different risk factors, the researchers found that nut consumption was associated with a reduction in disease risk across most of them.
No added benefit was found from eating more than 20g or 0.7 oz of nuts daily.