A long time coming
Heart disease doesn't just happen overnight; it's the result of many complex processes that are typically at work over many years. Some of the better-known risk factors for cardiovascular disease include:
- High blood pressure
- Family history of heart disease
- Sedentary lifestyle
- Excess weight
- Metabolic syndrome
- Elevated blood markers, such as total and LDL ("bad") cholesterol, and C-reactive protein (CRP) levels
The effects of CRP were addressed in a study conducted at the University of Palermo, Italy. CRP is a measure of inflammation in the body. Anything that causes inflammation can cause a rise in CRP levels, like a flare-up of certain types of arthritis. But high CRP levels in a person without another disease that could explain the elevation could indicate an increased risk of heart disease.
A juicy way to keep inflammation at bay
Fruits and vegetables seem to protect against heart disease by providing blood pressure-lowering minerals, blood sugar-stabilizing fiber, and anti-inflammatory and antioxidant compounds. Red oranges, also known as blood oranges, are rich in antioxidants and anti-inflammatory substances, so the researchers wanted to see if drinking red orange juice might improve blood flow through the arteries and help decrease inflammation.
Nineteen people (average age 48 years) at risk for heart disease took part in the study. Twelve people who were not at increased risk served as a control group.
The study took place in two parts. In the first, half of the people were given 500 ml of red orange juice to drink each day for seven days; the rest of the people were given a placebo drink. After a three-day break, the groups were switched.
The researchers measured blood fats and markers of inflammation and oxidative stress (caused by free radicals), as well as blood flow through a major artery.
After the red orange juice period, people at high risk for heart disease had significantly better blood flow through their arteries. Compared with the control group, the high-risk group had significantly higher markers of inflammation at the start of the study. But after one week of drinking the red orange juice, these markers decreased significantly.
Free-radical damage markers (which measure the amount of oxidation damage that is occurring) were elevated at the beginning of the study in the high-risk group compared with the control group. Red orange juice didn't appear to significantly change these levels.
Other studies have looked at blonde (regular) orange juice on blood vessel function, as well. The results weren't as impressive, with improvements only lasting for a short period after the juice was drunk. "Red orange juice tested in our study seemed to induce a more sustained and stable improvement of [blood vessel] function than that of similar fruit beverages," said the researchers.
Putting it in perspective
While it appears that drinking red orange juice could decrease inflammation and improve blood flow, the study didn't show that there was any direct effect on the people's heart disease risk. Reduced inflammation and improved blood flow does not necessarily imply a reduced risk of developing heart disease. This was a small study whose results need to be confirmed in larger trials.
(Am J Clin Nutr 2012;95:1089-95)