Preliminary Study Proves Centuries Of Herbalists Right About Echinacea

March 3, 1999

GAINESVILLE—Echinacea, an herbal cold remedy used for centuries, does, in fact, stimulate the immune system, a University of Florida researcher has found.

In the first clinical study of the popular herb’s effects on healthy men, UF nutritional scientist Susan Percival found that echinacea stimulated white blood cells, which fight infection.

“I expected to find what I found,” said Percival, a researcher in UF’s Institute of Food and Agricultural Sciences. “The literature is scarce, mostly German or Chinese, but cell culture and animal studies indicated this would happen.

“So that’s good. If for years we’ve been saying echinacea does this, it’s nice to know that it does.”

Percival now will expand and repeat her preliminary study with the goal of one day submitting a full-scale study proposal to the National Institutes of Health.

For centuries, echinacea, commonly known as purple coneflower, has been used by cold sufferers who believed it would reduce the severity and duration of colds because it boosts the immune system. But until now there has been little scientific evidence of whether it worked in people, said Percival, whose research focuses on immune function.

With the recent surge in interest in herbal and botanical remedies in the United States, the NIH formed the Office of Dietary Supplements to foster better research into the popular, but largely unproved, remedies.

In her preliminary study, Percival gave 10 healthy, college-age men an echinacea supplement for four days, taking measurements of immunity on day one and day four. In just four days, she found a stimulation of the immune system in the form of a threefold increase in the ability of white blood cells to kill bacteria.

She cautions that her findings do not support the practice of taking echinacea regularly, in the absence of cold symptoms.

“When people are told it boosts the immune system, that’s something they believe should be consumed at all times,” Percival said. “But a stimulated immune system produces a lot of free radicals, and we know from other research that free radicals are not a good thing. We want the free radicals to kill microorganisms, but we don’t want free radicals being produced all the time because they will damage healthy tissues.

“Because we don’t have the scientific studies, we don’t understand yet the mechanism of how echinacea works,” Percival said. “So it’s important that consumers understand echinacea should not be taken chronically. It would do more harm than good, taken regularly. Echinacea is only really going to be helpful at the first sign of symptoms of illness.”

The boom in the popularity of herbal and botanical remedies began in 1994, when Congress passed the Dietary Supplement Health and Education Act in response to consumer demand. The law allowed dietary supplements, vitamins, minerals, amino acids, herbs and botanicals to be marketed without federal premarket safety and efficacy evaluations. The labels cannot make claims about a disease, but they can claim to “enhance” or “boost” a bodily function.

With the market flooded with herbs and botanicals making claims, the NIH has emphasized research to determine if the substances do what they claim to do.

“Echinacea has been alleged to help cure the common cold. People have felt that it shortens the duration of colds, makes them have fewer, milder symptoms of illness, so it’s a natural herb for me to study,” Percival said. “But echinacea is only one of thousands of botanicals that should be studied.”

Consumers wanted the 1994 law because they wanted unrestricted access to herbs and botanicals. The supplements have become popular because they give consumers the option of maintaining their own health, without the need of a doctor visit or prescription.

The manufacturers, when asked, must supply studies to back their claims. But so many manufacturers use anecdotal or case studies, some from overseas, that the NIH decided to support controlled U.S. experiments, Percival said.

“Our studies so far have shown only that we could enhance certain functions of the immune system,” Percival said. “It’s very important that we find out exactly what the active compounds are and how they work.

“Echinacea is a plant, an herb. It is very complex. It has all kinds of chemicals, proteins, carbohydrates, vitamins, minerals and phytochemicals. There are thousands of things in this one herb that could be enhancing immune function.

“That’s the important thing to find out, the mechanism by which these changes occur,” Percival said. “We don’t know yet. We just know that it happens.”