Our “daily bread” is not such a good idea for everyone. There is a remarkable epidemiological report on the advantages of potatoes over bread in the work of Adam Smith, an 18th century economist. Grains, mostly wheat and oats, formed the main part of the diet of working class British in his time, while potatoes were the staple food of the Irish. Smith reported that potatoes were a superior food because “the strongest men and the most beautiful women perhaps in the British dominions, are said to be, the greater part of them, from the lowest rank of people in Ireland, who are generally fed with this root. No food can afford a more decisive proof of its nourishing quality, or its being peculiarly suitable to the health of the human constitution."
Today, potatoes are under fire for having a high glycemic index, which is a measure of their ability to raise blood glucose and insulin levels. There are conflicting reports about how significant this is. It didn't seem to be a problem for the low income people who had not much else in their diets.
Wheat has a more complicated history. Dr. John M Duggan of Princeton Medical Center reports that wheat deserves credit for great progress in western civilization, but that progress came at a price. The gluten protein in wheat provokes a complex immunological response in some people.
Celiac disease is the most severe form of gluten sensitivity. The treatment is a gluten-free diet for life, which is difficult and expensive because wheat and other gluten-containing grains are used in so many of our foods. Dr. Duggan reports that celiac disease has replaced syphilis as “the great imitator”. The symptoms may or may not include intestinal disorders. Fatigue and anemia are common complaints that lead to a diagnosis of celiac disease. Other conditions associated with celiac disease include neurological, psychiatric, endocrine, renal, locomotor, skin, dental, and cardiovascular disorders.
Genetic modification of wheat can remove the offending peptide sequences in gluten, but the celiac-safe flours produced so far do not have adequate physical properties to replace ordinary flour in many recipes.