Set the width of regulartable() when exported in word document
This helps:
#convert your dataframe into datatable
library(data.table)
#save your rownames
tab1 <- data.table(tab, keep.rownames = TRUE)
regulartable(tab1) %>%
align(align = "center", part = "all")%>%
theme_zebra() %>%
fit_to_width(max_width = 7.5)