November 24, 2010

Orange And Dark Vegetables Tied To Less Disease

A new study suggests that eating lots of orange and dark green veggies like carrots, sweet potatoes and green beans may be tied to less disease and longer life.

Scientists believe carotenoid antioxidants promote health by counteracting oxygen-related damage to DNA.

Dr. Chaoyang Li of the U.S. Centers for Disease Control and Prevention (CDC), told Reuters Health that consumption of fruits and vegetables has long been associated with lower risks of health problems like cancer and heart diseases.

However, he also said it is not clear which elements contribute to the health effects or how they do so.  He pointed to recent studies that have found no apparent benefit for beta-carotene supplements as an example.

The researchers analyzed information on over 15,000 people who were participating in the Third National Health and Nutrition Examination Survey Follow-up Study.  All of the participants provided blood samples at the start of the study, along with other medical and lifestyle information.

Nearly 4,000 participants had died by the end of the 14-year study.  Li and his colleagues found that the more alpha-carotene participants had in their blood at the start of the study, the lower their risks of disease and lifestyle information.

The researchers reported in the Archives of Internal Medicine that the individuals with the highest levels of alpha carotene in their blood had up to a 39 percent lower risk of dying. 

The findings held after accounting for risk factors like age and smoking. 

The researchers caution that the link does not prove that alpha-carotene deserves the credit though.

"Alpha-carotene may be at least partially responsible for the risk reduction," Li said. "However, we are unable to rule out the possible links of other antioxidants or other elements in vegetables and fruits to lower mortality risk."

"Alpha-carotene has a lot of overlapping chemical properties with beta-carotene, as well as the same perceived mechanisms of effect," added Howard Sesso of the Harvard School of Public Health, in Boston, who reviewed the findings for Reuters Health. "In fact, it's hard to disentangle the two from each other. They tend to travel together."

Laboratory studies have hinted that alpha-carotene is about 10 times more effective at inhibiting some forms of brain, liver and skin cancer than beta-carotene.

"We don't know how this is going to translate into practice yet, but it is encouraging," said Sesso. "If nothing else, these results reinforce the point that there is likely little downside to increasing your fruit and veggie intake."


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