Beets are an epic source of folate and betaine. Betaine is made in the body and works with the functioning of the liver's cell production. It also aids in the formation of carnitine. Back in the 90's homocysteine was all the rage due to it's negative effects on the heart and the betaine from beets can help counteract the homocysteine.
Folate helps with cancer prevention and cardiovascular health as well, when you combine the two in beets, homocysteine and other inflammatory biological hockey goons are carted off into the penalty box for cardiovascular misconduct.
On the cancer end, the betacyanins which give beets that deep red wine color are being studied and have properties as potential cancer fighters in laboratory animals.
University of Maryland Medical Center:
Office of Dietary Supplements: http://ods.od.nih.gov/factsheets/Folate-HealthProfessional/#h7
Gina Lesako RD, LD is the SCAN blog coordinator (those interested in writing for SCAN can email her directly at email@example.com, resolve to increase your online exposure).
She can also be found blogging at http://dietitianseatchocolatetoo.blogspot.com/).
Find her on SCAN: http://www.scandpg.org/dietitians/15720/