If you possibly have the time, try and listen to both part one & part two of ‘Hunting with the Hadza’s’ on BBC radio’s iPlayer – it’s very illuminating, and shows that in the near future ;we’ (western world humans) might be able to introduce good bacteria into our guts to stop many common illnesses. Evidently the number of gut microbiomes has decreased by 40% over the last 50 years because of our narrow diet. To the Hadza tribe (the last of the hunter gatherers) heart disease & bowl cancer are virtually unknown due to their more varied diet.