Eating walnuts may help to reduce the risk of developing breast cancer, research suggests.
The nuts contain ingredients such as omega-3 fatty acids, antioxidants and phytosterols that may all reduce the risk of the disease. Mice fed the human equivalent of two ounces (56.7g) of walnuts per day developed fewer and smaller tumours. The US study was presented to the American Association for Cancer Research annual meeting.
Researcher Dr Elaine Hardman, of Marshall University School of Medicine, said although the study was carried out in mice, the beneficial effect of walnuts was likely to apply to humans too. She said: "We know that a healthy diet overall prevents all manner of chronic diseases. It is clear that walnuts contribute to a healthy diet that can reduce breast cancer."
Previous research has suggested eating walnuts at the end of a meal may help cut the damage that fatty food can do to the arteries. It is thought that the nuts are rich in compounds that reduce hardening of the arteries, and keep them flexible. In the latest study mice were either fed a standard diet, or the walnut-based diet.
The animals fed walnuts developed fewer tumours, and those that did arise took longer to develop and were smaller. Molecular analysis showed that omega-3 fatty acids played a key role - but other parts of the walnut contributed as well.