Just pass a TempData down from one of your controllers like this:
TempData("CurrentPage") = "Nutrition"
Then, in your View add a conditional like this:
<ul>
@For Each item In Model
Dim currentItem = item
If (Not String.IsNullOrEmpty(TempData("CurrentPage")) And TempData("CurrentPage") = currentItem.NAV_Element) Then
@<li><a class="current" href="@Html.DisplayFor(Function(modelItem) currentItem.NAV_Destination)">@Html.DisplayFor(Function(modelItem) currentItem.NAV_Element)</a></li>
Else
@<li><a href="@Html.DisplayFor(Function(modelItem) currentItem.NAV_Destination)">@Html.DisplayFor(Function(modelItem) currentItem.NAV_Element)</a></li>
End If
Next
</ul>