Potatoes are a nutritionally complete food.  A medium-sized potato supplies 7.5 grams of protein* and 8 grams of fiber.  In addition, potatoes contain Omega 3 and 6 fatty acids, 28 grams of Vitamin C and significant levels of calcium, magnesium, phosphorus, iron, vitamin B, iodine, vitamin K and vitamin A.  Potatoes are low in sodium and contain no cholesterol.

Two vital nutrients missing in potatoes are vitamins D and E.  Pre-Famine Irish tenants doubtless got sufficient vitamin D from the buttermilk they ate with their potatoes.  Vitamin E was probably obtained from turnips, cabbage and oatmeal – other staples of the working class Irish diet prior to the Famine.

Irish poor also ate herring and other fish when they could, but usually only had meat on the holidays.

* The protein derived from potatoes is considered ‘complete’ since potatoes contain so many amino acids.