The nutritional value of beets lies in their concentration of folate, vitamin C, and the minerals potassium and manganese. They are low in calories and contain a small amount of protein. Most of the calories in beet roots comes from carbohydrates. Fresh beets can sometimes be purchased with the greens attached, or the greens can be purchased separately. While the nutritional value of beets is somewhat low, beet greens contain significant amounts of a variety of vitamins and minerals.
One half a cup of cooked beets contains about a quarter of the recommended daily allowance (RDA) of folate, which is one of the B vitamins. One half cup is about 3 ounces (85 g). This same serving can also contribute to the daily need for vitamin C, as it provides about 5 percent of the RDA for this vitamin. A serving of cooked beets also contains traces of other B vitamins and a small amount of vitamin A.
The nutritional value of beets also includes a fair amount of certain minerals, although within a limited range. They are a very good source of manganese and a good source of potassium. Beets also contain the minerals iron and magnesium in fair amounts. Cutting beets into slices and steaming rather than boiling them whole shortens cooking time and may help them retain more nutrients.
As they are made mostly of water, the nutritional value of beets doesn't include many calories. A half-cup serving has only about 40 calories. This serving has no fat, and about 1g of protein, with nearly all of the calories coming from carbohydrates. A serving of this size provides close to 10 percent of the RDA for fiber.
If they are purchased fresh, the nutritional value of beets can be complemented by cooking the greens or using them fresh in salads. Beet greens are a very good source of the vitamins A, C, and K. They also contain some vitamin E and B vitamins, especially B2. Beet greens are high in minerals, especially potassium, and are a good vegetable source of calcium; 2.5 ounces (72 g) of cooked greens provides about 20 percent of the RDA for potassium and 10 percent of calcium.
Beets are thought to be related to spinach and are in fact the same plant, botanically, as Swiss chard. Unlike chard, beets have been cultivated for their roots. The greens have nutritional value similar to spinach and chard and can be prepared similarly.