Sunchokes

These can be trouble to gardener - they multiply - as a tuber - they come back each year  - so they should be planted in spots they are not going to be used for something else.  They flower like a small sunflower.

Sunchokes are good to eat - tasting like a potato and an artichoke.  I prefer them sauteed or as chips - pureed - used in soups - roasted whole - any way you like a potato.  Leave the skin on when grown in organic soils for greater nutrients.

"Jerusalem artichokes are about 80% water, 15% protein, 1% fat, 60% inulin, 4% fiber and 5% ash, 0.099% phosphorus, 0.023%, 3.4 mg iron with traces of aluminum, chlorine, iodine, magnesium, potassium, sulphur, zinc, vitamins B and C." ... from eattheweeds.com

Inulin
Inulin is a root starch and is a non-digestible soluble fiber; it works as a pre-biotic, working in the large intestines as a useful “food” for the healthy gut bacteria.  It is used in the production of fructose - better tolerated by people with diabetes.  Colder regions produce a tuber lower in inulin than tropical regions.

Jerusalem artichokes are a good source of hair health promoting nutrients such as iron, copper and vitamin C
Jerusalem artichokes provide even more potassium than bananas. 
Jerusalem artichokes are packed with B vitamins, particularly thiamine, or B1

Source: http://healwithfood.org/health-benefits/jerusalem-artichokes.php#ixzz3GJOq4PcQ