Vertical table headers (i.e. headers on the left) in Markdown?

As Waylan suggested in the comments, we can use pure HTML in Markdown.

<table>
  <tr>
    <th>Fruit</th>
    <td>Banana</td>
  </tr>
  <tr>
    <th>Vegetable</th>
    <td>Carrot</td>
  </tr>
</table>