This text has many of the features of a well-written paragraph discussed above.  

The words in bold are the main characters, which are introduced in the first sentence (the point sentence) and repeated throughout the paragraph. In some cases, the words are direct repetitions (red wine or health), while in others the author uses a pronoun or a hypernym (its and alcohol) or an adjectival form (healthier). Note that the author opts for direct repetition (red wine) in the first two sentences to reinforce the importance of the term in the text before introducing variation.

The word in square brackets ([ ]), the adverb however, is the only transition word in the text, but it signals a key point: the limitations of previous research. It is this word that tells readers that the text is about to take a new direction and the limitations described justify the need for the present study.

The author starts the text with a concept that is familiar to all readers (red wine) and then moves on to say something about it that they may or may not know (it has health benefits). The structure of the second sentence is similar to that of the first. It begins by repeating the familiar concept (red wine), which is now a character in our text, and then extends the idea introduced in the first sentence by specifying exactly what these health benefits are. The third sentence again begins with familiar information, this time because it refers back to the information given in the previous one (the reduction of risk) by using a shell noun (effect), an abstract noun that summarizes a previously stated, more complex idea. The fourth sentence starts with the contrastive adverb however and then uses the concept introduced at the end of the previous sentence (antioxidants) as the subject of the main verb. The subject of the final sentence (study) is neither a character nor a concept introduced previously, but in the context it is easily understandable and the information given in the rest of the sentence repeats the main concepts in the text so far: red wine and health (introduced in the very first sentence) and antioxidants, a concept that will also clearly become a main character.