The peoples of Central and Southern Europe and Asia assimilate milk and dairy products well, while the northern peoples lack the ability to assimilate milk (for example, in the Yakuts, drinking milk causes discomfort and indigestion). Why?
1) for the breakdown of milk sugar (lactose), a special enzyme is needed – lactase; this enzyme is produced during the period of breastfeeding, and with age, the production of the enzyme decreases or stops;
2) among peoples who are historically associated with cattle breeding, the production of the enzyme is maintained throughout life, and they digest milk and dairy products well, since these products are present in their diet; among northern peoples, the ability to assimilate milk is absent, since their production of the enzyme lactase stops.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.