A similar question has been asked before; u/400-Rabbits gave an answer that may be helpful for you.

The short answer is that people in developed countries today are taller than their ancestors because they tend to have access to better nutrition and healthcare during their growing years than people did in the past. This article(PDF) by Jeorg Baten examines as much data as was available at the time of its writing (2006) to examine trends in height around the world from the early 19th century to the late 20th. Baten found that the increase in height was most closely correlated with increase in per capita GDP. In other words, wealthier countries have taller people. There is more to it than just that, of course, and I encourage you to read the entire article. Height also correlates with protein intake, though high protein foods like meat tend to be expensive, and so are eaten more often by wealthy people than by poor people.

Edit: typo