Wednesday, 29 February 2012

Why Everyone Should Eat Broccoli For Health and Nutrition

Broccoli is sometimes called a “super food”, with good reason. It’s rich in vitamins and minerals and also contains important phytonutrients. Phytonutrients, sometimes known as phytochemicals, are plant substances that aren’t essential in our diet but are thought to fight disease.

Broccoli is an excellent source of vitamins C and K. It’s also a good source of vitamin A (as beta-carotene, which our bodies convert into the form of vitamin A that we need), folate and vitamin B6, and contains a smaller amount of other vitamins in the B family. Broccoli also supplies us with a range of minerals and is a particularly good source of manganese. It’s important to cook broccoli without much water, such as by steaming, so that water soluble nutrients like vitamins B and C don’t leach into the water.

The phytonutrients in broccoli are especially intriguing. Two of these phytonutrients are lutein and zeaxanthin, yellow pigments that belong to the carotenoid family. They are located in the retina, the light-sensitive layer at the back of the eyeball, and are most concentrated in an oval, yellow spot in the center of the retina called the macula. The macula is responsible for our sharpest vision.
 
Lutein and zeaxanthin absorb high energy blue and ultraviolet light, preventing the radiation from damaging the retina.  Zeaxanthin in particular is highly concentrated in the macula and is thought to help prevent age-related macula degeneration (AMD), which is the most common cause of vision loss in elderly people.
 
Our bodies collect lutein and zeaxanthin from our diet. Eggs and green vegetables like broccoli, Brussels sprouts, kale and spinach are good sources of the pigments.
 
Broccoli: a public domain image by Jon Sullivan

Broccoli also contains phytonutrients that are strongly suspected of lowering the risk of cancer.  Cruciferous vegetables, which include broccoli, Brussels sprouts, cauliflower, cabbage, bok choy and kale, contain chemicals called glucosinolates. Under certain conditions these chemicals are converted into other substances which are believed to have health benefits.

One of the glucosinolates in broccoli is glucoraphanin. When the plant is injured - such as by being chopped or chewed - the gluoraphanin is changed into sulforaphane. Sulforaphane inhibits cancer cells in lab dishes and mice, and population surveys have shown that people who have a high intake of broccoli and other cruciferous vegetables have a lower risk of developing cancer. These observations don’t prove that sulforaphane helps prevent cancer in humans, but they do suggest that this is true.

Researchers at Oregon State University have discovered two ways by which sulforaphane may reduce the risk of cancer - by inhibiting enzymes called histone deacetylases, or HDACs, and also by inhibiting the process of DNA methylation. HDACs and DNA methylation inactivate certain genes. Normally the activation and deactivation of genes occurs as necessary in our bodies and is a balanced process, but sometimes this balance is altered in a harmful way. For example, HDAC can interfere with the action of tumor suppressor genes, so the production of too much HDAC in our bodies can have serious consequences. Sulforaphane can help correct the imbalance.

Children (and some adults) may not appreciate the somewhat pungent and bitter taste of broccoli, but it really is a food that should be included in the diet if at all possible. Adding a sauce, such as one containing cheese, can help improve the taste for people who don’t like to eat broccoli on its own. A healthy dressing containing some fat is useful to promote the absorption of fat-soluble nutrients such as beta-carotene and vitamin K from the broccoli.