Srimathe Ramanujaya Namaha,
Thats correct as “Adiyen” BhagavAta mentioned which is the Macro Answer as per Poorvacharyars vachanam.
Getting into micro level, specific to Vitamin B12 & D, its already included in our SriVaishanava system.
Vitamin D:
All types of people get Vitamin D from Sun by doing Soorya Namaskaram at Dawn and Dusk when Sun is Orange or close to orange Brahmins who do Sandhya Vandhanam (SV) during this time looking at Sun, get these Vitamin D and their eyesight improves tremendously. One who does SV by not looking at Sun, gets all benefits excluding the full benefits of eyesight. Also, male does kainkaryam in temples without wearing shirt, so the male gets full benefit of Vitamin D from Sun whcih is good for teh body and good for Athma as well due to Service mind. We learn theory of Ahara Niayamam and KAinakryam inside A/C room, but don’t do in actual on-site in these circumstances, doesn’t fully help, since Knowledge is not fully put into action. Same as a farmer who ploughs the agricultural land doesn’t wear shirt in olden days. Now, with full shirt and covered, ploughing in Tractor, then we need to think about how to get Vitamin D and spend extra time, money, hospital bills etc…..But many Materialistic Bhoga lovers unknowingly get Vitamin D by taking sun bath, which is Ok for the body but not good for Athma due to no usage of that body.
Vitamin B12:
It’s obtained from non-GMO (close enough to old style processing method) milk, cheese, ghee and other non-prohibited vegetables. But, Milk added with Coffee has no benefits, since Caffeine drains all your stored calories/energy, which helps to make one tired trrebily in 1~2 hours, due to whcih they drink another coffee and further after 2 hours another coffee, eventually making the healthy body digestive system and metabolism to fail after some time which results in further diseases, plus adding refined sugar with added sweeteners for taste that has no molasses of the cane sugar, elevates the diseases more.
So Ahara Niyamanam says, no coffee and no extracted sugar. So have milk (vitamin B12) with panam kalkandu or Cane sugar, and no coffee/sweetener.
Adiyen (ElayaAlwar) Srinivasa (DhoddayacharyAr) Dasan.