Antioxidants deactivate free radicals – cell-destroying compounds in the body that can cause heart disease, cancer and strokes.

While almonds have long been recognized as an excellent source of magnesium and vitamin E, comprehensive work had yet to be done on the quantity and quality of their antioxidant content.

One of the authors of the study and director of the Antioxidant Research Laboratory at Tufts University, Jeffrey Blumberg, said: “These new findings, coupled with past results, lay the groundwork for future clinical trials that examine a link between whole almond consumption and the reduced risk of heart disease and other chronic conditions.”

The Tufts researchers tested the skins and kernels of the eight most common varieties of California almond - Butte, Carmel, Fritz, Mission, Monterey, Nonpareil, Padre and Price - using HPLC/ECD and UV detection. They aimed to indentify the main flavonoids and phenolic acids contained in the nuts.

Total phenol content was found to range from 127mg GAE/100g in the case of Fritz, to 241 in Padre.

"The principal flavonoids in almonds - catechin, epicatechin and Kaempferol - provide the hihgerst degree of protection against oxidant-induced cell dealth than any other flavonoids," wrote the researchers. On a weight basis, the total flavonol content of almonds was found to be similar to red onions. The kaempferol and quercetin content was on a par with broccoli, and the catechin content between that of brewed black tea and brewed green tea.

The next stage of the research will focus on determining how the human body extracts and absorbs the beneficial compounds.

In addition to their high antioxidant content, many health experts extol the virtues of almonds as an effective means of lowering cholesterol.

Previous research has found that the antioxidants and vitamin E in almonds work in tandem – and are more effective when taken in conjunction with each other – to prevent the oxidization of LDL, ‘bad' cholesterol. According to the Almond Board of California, around a handful of the nut reduces LDL cholesterol by 4.4% from baseline.

A single ounce of almonds contains 160 calories, calcium, potassium and iron as well as being a good source of protein and fibre.

Today's research was partly funded by the Almond Board of California and published in the Journal of Agricultural and Food Chemistry.