Coffee surpasses fruit and veg as dietary antioxidant source
their diet and are gleaning the majority of their antioxidants from
coffee, according to new research from the University of Scranton,
Pennsylvania.
The research, presented yesterday at the national meeting of the American Chemical Society, involved analyzing the antioxidant power of 100 foods and beverages common in the American diet and comparing this to a USDA database on estimated per capita consumption of each item.
In terms of antioxidant content per serving, dates came out as a clear winner with an antioxdiant value of 1744.
Coffee - both caffeinated and decaffeinated - was lower down on the list, at 936, but since most Americans consume considerably more coffee than the higher-ranking items, it makes it the biggest overall antioxidant contribution to the average American's diet, offering 936mg of antioxidants per day on average.
According to the latest annual report from the National Coffee Association of the USA, 49 percent of adults are coffee-drinkers, averaging 3.4 cups a day.
"Unfortunately, consumers are still not eating enough fruits and vegetables, which are better for you from an overall nutritional point of view due to their higher content of vitamins, minerals and fiber," said lead researcher Joe Vinson of the University of Scranton, Pennsylvania.
The USDA's dietary guidelines for Americans recommend between five and 13 portions of fruit and vegetables per day, depending on calorie intake. But the average American eats just three portions (excluding potatoes, which are a starch).
Antioxidants are believed to play a role in warding off a number of serious health conditions, including heart disease and stroke, high blood pressure and some types of cancer. Nutrients found in certain fruits and vegetables have also been linked to a reduced risk of other health conditions, such as beta-carotene (from sources including carrots and cantaloupe) and cataracts, and folic acid (from spinach, asparagus, oranges and others) and Alzheimer's disease.
Some studies have also attributed health benefits to coffee; in this month's issue of International Journal of Cancer (vol 116, issue 1, pp 150 - 154) researchers reported further evidence for coffee's role in preventing liver disease, and the International Journal of Obesity also investigated the putative connection with diabetes.
But since other studies have implicated coffee as leading to high blood pressure and increased heart rate - not to mention the jitters and stomach pains that can be caused by excessive consumption - Vinson said that more human studies are needed to clarify its role in health.
In the meantime, he said: "One or two cups a day appear to be beneficial." ,p>Black tea was ranked as the second highest source of antioxidants in the American diet, contributing 269mg on average per day. A recent report from market researcher Packaged Facts showed that black tea is still the most popular type of tea drunk in the US, but media attention on green tea and its health benefits has meant that the market for this is growing apace.
This is despite the fact that Vinson's team has found little difference in the antioxidant value of the different teas.
The US market for tea and ready-to-drink tea is estimated to be worth $6.8 billion in 2005, a 9.4 percent increase over last year. By 2010 Packaged Facts projects that it will reach $10 billion.
Vinson issued another important caveat. Despite focusing his research on antioxidant levels in food, he said that these do not necessarily translate to high levels in the body.
Different foods are absorbed and utilized by the body in different ways, and this has an impact on the antioxidants made available to the body. According to Vinson, this process is not fully understood.
