Eating nuts each day may help to protect against metabolic syndrome, a collection of symptoms, including obesity, high blood pressure, and insulin resistance, which significantly increases a person's risk of developing cardiovascular disease and type 2 diabetes.

Researchers recruited 1224 participants with metabolic syndrome to see if eating nuts would improve their health. Participants were divided into three groups. Participants in the first group, which acted as the control, were given advice about eating a low-fat diet. Participants in the second group received quarterly teaching on the Mediterranean diet – eating plenty of vegetables, cereal crops and fruit, and reducing dairy produce and red meat consumption – and were given 1 liter of virgin olive oil each week to supplement their diet. Whist those in the third group received the same quarterly advice on the Mediterranean Diet, but were given 30 g of mixed (unsalted) nuts to eat each day instead of olive oil. Participants were followed up 12-months later to see if their health had improved.

Results showed that the health of 13.7% of those in the group given nuts had improved to the extent that they were no longer classed as having metabolic syndrome, in comparison to 6.7% in those given olive oil, and just 2% in the control group.

In conclusion, lead author, Dr Jordi Salas-Salvado, said: "The results of the study show that a non-energy restricted traditional Mediterranean diet enriched with nuts, which is high in fat, high in unsaturated fat and palatable, is a useful tool in managing metabolic syndrome."

Salas-Salvadó J, Fernández-Ballart J, Ros E, et al. Effect of a Mediterranean Diet Supplemented With Nuts on Metabolic Syndrome Status. Arch Intern Med. 2008;168:2449-2458.

Daily nuts may help boost health. BBC News. December 9th 2008.