The US National Institute of Standards and Technology (NIST) reported this week that it has just certified the exact contents of Popeye's favourite food.
NIST confirmed that spinach is rich in the antioxidants beta-carotene and lutein. Although the actual amounts look small (the antioxidants constitute 0.0019 per cent and 0.0033 per cent of the spinach by mass, respectively), spinach contains far more of the two combined than most other fruits or vegetables.
Beta-carotene converts to vitamin A in the body and is needed for healthy sight, skin and hair. Lutein is a pigment found in the retina and may help guard against eye diseases such as age-related macular degeneration. Among its other attributes, spinach also contains 1.55 per cent dietary fiber by weight.
Antioxidants are believed to fight the formation of free radicals, highly reactive molecules that can damage DNA and are implicated in the development of certain diseases.
NIST reached its conclusions after using the Standard Reference Material (SRM) 2385 that consists of small jars of slurried spinach - pure spinach that has been blanched, pureed and passed through filter screens.
Concentrations of vitamins and other constituents were measured and certified, so that 'the food industry can use the SRM to validate analytical methods and provide accurate nutritional information for its products,' the group said in a statement this week.
'An analytical method is evaluated by using it to measure constituents in the SRM and then comparing the results to the NIST-certified values,' they added.
According to the group, the new SRM was developed at the request of the food industry and with the help of more than 10 food manufacturers.
NIST now supplies 37 different food SRMs to the industry, one or more for each of the nine sectors of the Association of Analytical Communities' food triangle, which categorises food based on its fat, carbohydrate or protein content.
The food triangle helps to assure the availability of validated analytical methods for all types of foods, concluded NIST.
Founded in 1901, NIST is a non-regulatory federal agency within the US Commerce department's technology administration.