Green vegetables to heart rescue

LEAFY greens have bounty of benefits. Packed with nutrients and fiber, it is low in calories. BEN UKWUOMA reports that researchers have uncovered a possible reason why green vegetables are good for the heart.

RESEARCHERS have discovered a possible reason why green vegetables such as broccoli, cabbage and cauliflower are good for the heart. Their work suggests that a chemical found in vegetables can boost natural Defence mechanism to protect arteries from diseases.

The Imperial College London team hopes their work could lead to new dietary treatments to prevent heart problems.

Details that appear in Arteriosclerosis Thrombosis and Vascular Biology shows that many heart diseases are caused by build up of fatty plaques in the arteries, known as atherosclerosis.

However, arteries do not get clogged up with these plaques in a uniform way. Bends and branches of blood vessels - where blood flow is disrupted and can be sluggish - are much more prone to the build-up.

The latest study has shown that a protein that usually protects against plaque build up, called Nrf2, is inactive in areas of arteries that are prone to diseases.

However, it also found that treatment with a chemical found in green "brassica" vegetables such as broccoli can activate Nrf2 in these disease-prone regions.

Lead researcher, Dr Paul Evans said: "We found that the innermost layer of cells at branches and bends of arteries lack the active form of Nrf2, which may explain why they are prone to inflammation and disease.

"Treatment with the natural compound sulforaphane reduced inflammation at the high-risk areas by 'switching on' Nrf2.

"Sulforaphane is found naturally in broccoli, so our next steps include testing whether simply eating broccoli, or other vegetables in their 'family', has the same protective effect.

"We also need to see if the compound can reduce the progression of disease in affected arteries."

Professor Peter Weissberg, medical director of the British Heart Foundation, which funded the research, said: "These fascinating findings provide a possible mechanism by which eating vegetables protects against heart disease, as well as adding evidence to support the importance of eating 'five-a-day'. The biochemistry revealed in this research could lead to more targeted dietary or medical approaches to prevent or lessen disease that leads to heart attacks and strokes."

Using normal mice, and mice engineered to lack the Nrf2 protein, the research found that in straight sections of arteries Nrf2 was present in the endothelial 'lining' cells.

Through its action on other proteins, it prevented the cells from becoming inflamed, an early stage in the development of atherosclerosis.

In the lining cells of disease-prone sites - such as bended or branched arteries - Nrf2 was attached to a protein that made it inactive. This stifled its protective properties.

But the addition of sulforaphane re-activated Nrf2 in the disease-prone regions of the artery, restoring the cells' ability to protect themselves from becoming inflamed.

The researchers believe that this will enable these artery regions to remain healthy for longer or even reduce the progression of existing disease. Dark green leafy vegetables are warehouses for calories, perhaps the most concentrated source of nutrition of any food. They are rich sources of minerals (including iron, calcium, potassium, and magnesium) and vitamins, including vitamins K, C, E, and many of the B vitamins. They also provide a variety of phytonutrients including beta-carotene, lutein, and zeaxanthin, which protect our cells from damage and our eyes from age-related problems, among many other effects. Dark green leaves even contain small amounts of Omega-3 fats.

Perhaps the star of these nutrients is Vitamin K. A cup of most cooked greens provides at least nine times the minimum recommended intake of Vitamin K, and even a couple of cups of dark salad greens usually provide the minimum all on their own. Recent research has provided evidence that this vitamin may be even more important than we once thought (the current minimum may not be optimal), and many people do not get enough of it.

Dark green leafy vegetables are calorie for calorie, perhaps the most concentrated source of nutrition of any food. They are a rich source of minerals like iron, calcium, potassium, and magnesium and vitamins, including vitamins K, C, E, and many of the B vitamins. They also provide variety of phytonutrients, including beta-carotene, lutein, and zeaxanthin, which protect our cells from damaging and our eyes from age-related problems, among many other effects. Dark green leaves even contain small amounts of Omega-3 fats.

Perhaps the star of these nutrients is Vitamin K. A cup of most cooked greens provides at least nine times the minimum recommended intake of Vitamin K, and even a couple of cups of dark salad greens usually provide the minimum all on their own. Recent research has provided evidence that this vitamin may be even more important than we once thought -the current minimum may not be optimal. And many people do not get enough of it.

Dr. Albert Osaretin Egbuhi, an associate professor of Biochemistry, College of Medicine University of Lagos, said: "Greens have very little carbohydrate in them, and the carbohydrate that are there are packed in layers of fiber, which make them very slow to digest. That is why, in general, greens have very little impact on blood glucose."

Broccoli for instance is said to be highly nutritious, containing over 20 vitamins and minerals. A cup is bursting with 2280 IU of vitamin A and 123 mg of vitamin C.

"It is an excellent source of folate and dietary fiber and a good source of potassium, calcium, the B vitamins and other essential nutrients. In addition to its sulforaphane content which aids in increasing the levels of enzymes that block cancer, its indole-3 carbinol content has captured the attention of those looking to prevent hormone-related cancers, including breast and prostate cancer." Egbuhi stated.

Aside from being a very good source of vitamin C, cucumber is also packed with molebdenum, a mineral that reduces the symptoms of allergy and helps prevent anemia by enabling the body to use iron. In addition to its vitamin A, D and E contents, this watermelon relative also contains vitamin K, a nutrient required to make at least three proteins essential for bone formation. A cup of cucumber contains 149 mg of potassium

Essentially, most vegetables are nutrient dense and loaded with good-for-you vitamins and phytonutrients, but green vegetables and leafy greens pack a pile of health benefits into two important factors: flavonoids and folate.

"Flavonoids are anti-oxidant compounds that give some of the colour to foods like dark chocolate, grapes, strawberries, blueberries, and peppers."

Flavonoids, according to experts, also help keep arteries flexible, acting almost like a non-stick coating preventing cholesterol buildup. Two of the richest sources of flavonoids are green beans and broccoli.

Green beans have high concentration of Vitamins A and C, two other potent anti-oxidants which do everything from protecting us against cancer causing free radicals to promoting collagen and elastin production in the skin, to help fight signs of aging.

Broccoli, while high in flavonoids, also contains important phytonutrients that aid in cancer prevention. In some studies it has been shown to reduce the size of cancerous tumors that already exist. In addition, broccoli is high in calcium as well as vitamin C, having nearly twice the amount of vitamin C of that of orange. The significance of that combination is that vitamin C aids in the absorption of calcium.

Folate is a B vitamin that helps cells regenerate, or renew themselves. While it assists in the production of healthy blood cells and the treatment of anemia, it is also a needed component in the making of DNA, the building blocks of cells. By preventing changes to DNA, it also aids in the prevention of many types of cancers.

Clinical studies have also shown that a lack of folate increases the risk for alzheimers, depression, and other forms of mental fatigue. Because of the connection with the production of red blood cells, folate, or the manufactured form, folic acid, has long been recommended to pregnant women as it aids in the development of a healthy nervous system in the fetus. What are our best green food sources of folate? Spinach, kale and asparagus.

Green vegetables also contain many phyto-chemicals and beta-carotene. These nutrients help protect cells from damaging, improve immune functions and help protect our eyes from age-related diseases. Some studies suggest that lutein and zeaxanthin may reduce the risk of certain types of cancers such as breast and lung cancers. They are useful in reducing the risk of cancer and heart disease since they are low in fat, high in dietary fiber, and rich in folic acid, vitamin C, potassium and magnesium as well as containing a host of phytochemicals, such as lutein, beta-cryptoxanthin, zeaxanthin, and beta-carotene.

One study showed that an increment of one daily serving of green leafy vegetables lowered the risk of cardiovascular disease by 11 per cent.

In the Adventist health study, the frequent consumptions of green salads by African-Americans were associated with a substantially lower risk of mortality.

Because of their high magnesium content and low glycemic index, green leafy vegetables are also valuable for persons with type 2 diabetes.

Green vegetables are also major sources of iron and calcium for any diet. Swiss chard and spinach are not considered good sources of calcium, due to their high content of oxalic acid. Green leafy vegetables are rich in beta-carotene, which can also be converted into vitamin A, and also improve immune functions. Millions of children around the world have increased risk of blindness, and other illnesses because of inadequate dietary vitamin A from green leafy vegetables.

Lutein and zeaxanthin, carotenoids found in dark-green leafy vegetables, are concentrated in the eye lens and macular region of the retina. They play a protective role in the eye. They protect against both cataract and age-related macular degeneration, the major cause of blindness in the elderly. Some studies suggest that lutein and zeaxanthin may help reduce the risk of certain types of cancers, such as breast and lung cancer, and may contribute to the prevention of heart disease and stroke.

In a Swedish study, it was reported that eating three or more servings a week of green leafy vegetables significantly reduced the risk of stomach cancer, the fourth most frequent cancer in the world. Cabbage, cauliflower, brussels sprouts, and broccoli are rich in indoles and isothiocyanates, which protect us against colon and other cancers.

Broccoli sprouts have been reported to contain 10 or more times as much sulforaphane, a cancer-protective substance than does mature broccoli. A higher consumption of green leafy vegetables has been shown to significantly decrease the risk of breast cancer and skin cancer.

Studies have identified a gene, connexin 43, whose expression is upregulated by chemopreventive carotenoids and which allows direct intercellular gap junctional communication. In many human tumors, gap junctional communication is deficient and its upregulation is associated with decreased proliferation. Hence, the cancer-preventive properties of carotenoids are partly explained by their impact on gene regulation.

Quercetin is a bioflavonoid found in leafy green vegetables. Quercetin has an antioxidant and anti-inflammatory activity and displays unique anticancer properties. Quercetin is a natural compound that blocks substances involved in allergies and acts as an inhibitor of mast cell secretion, and causes a decrease in the release of interleukin-6.

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