From Rita Bhatia:
Dietary guidance recommends consumption of whole grains to reduce the risk of chronic diseases including cancer and cardiovascular disease. Epidemiologic studies support the belief that whole grains are protective against cancers, especially gastrointestinal cancers such as gastric and colonic, and cardiovascular disease. Components in whole grains that may be protective are diverse and include compounds that affect the gut environment, i.e., dietary fibre, resistant starch, and other undigestible compounds in whole grains, compounds that function as antioxidants such as trace minerals and phenolic compounds, and compounds that are phytoestrogens with potential hormonal effects. Many of the protective compounds in whole grains are also in fruits and vegetables, but some plant compounds are more concentrated in whole grains, such as phenolic compounds including ferulic and caffeic acid. Other potential mechanistic effects of whole grains include binding of carcinogens and modulation of glycemic index.
It is also well known that during milling of grains lot of nutrients are lost.
If the question is for food assistance purposes:
In many current emergencies milled and fortified flour is procured in the region and distributed. E.g - Syria, Turkey, Palestine, Lebanon, Afghanistan.
As you know WFP is using less and less food aid and more cash to ease local and regional procurement. However, if that is not possible, then bulk milling is either done in the country and includes fortification of maize and wheat flour or the losses incurred in milling are compensated, in particular with Maize flour. Shelf Life of flours is limited.
In the Middle East, in particular with the urban population, bread is not made at home but procured. So an option is vouchers for bread and other commodities.