Well some of the stuff on our reecc reading list in MSc was like Michael Colgan stuff, 'Optimum Nutrition' and some physiology books.
But main nutrition books I would recc are....
Dietary Reference Values of Food Energy and Nutrients for the United by Dept.of Health, published by Stationery Office Books 1991
Human Nutrition and Dietetics by James, W.P.T., Ralph, Alan, published by Elsevier Health Sciences 1999
McCance and Widdowson's the Composition of Foods by Food Standards Agency, published by Royal Society of Chemistry 2002
Plus this one which is very useful
but slightly off topic.
Textbook of Endocrine Physiology
Edited by James E. Griffin and Sergio R. Ojeda
Think its on its fifth outing that book.
The first three are probably more useful to the course than actually becomming a nutritional guru if you see what I mean.