Rhubarb crumble season is upon us again and this is one of my absolute favourite dishes! Whilst the stems can be prepared and eaten in a variety of ways, the leaves are reputed to be poisonous due to their high levels of oxalates. However even the stems of the vegetable contain a significant amount of oxalic acid and it may not be advisable to eat rhubarb too regularly if you are prone to conditions such as gout or kidney stones as it may exacerbate these conditions.
Herbalists also employ the root as a medicine for digestive complaints such as diarrhoea because of its astringent action, but in larger doses it has a laxative effect. Rhubarb can also be applied directly to the skin to treat burns and cold sores as it contains several chemicals which can aid healing.
Rhubarb is one of the least calorific of vegetables and it is an excellent source of dietary fibre. The stalks are rich in B-complex vitamins such as folates, riboflavin, niacin, vitamin B-6 (pyridoxine), thiamin, and pantothenic acid. It is also a good source of vitamin A and the red colour stalks contain more of this vitamin than the green stems.
Like other dark green vegetables, rhubarb contains goodly amounts of vitamin K and minerals such as iron, copper, calcium, potassium, and phosphorus. However some of these minerals are not absorbed very well as they are converted into insoluble complexes by oxalic acid, which are then excreted from the body.
Rhubarb can be harvested from late winter/early spring through to June and July. Some later varieties can be harvested right through until September or October.