A compound in coffee, which has long been in use in India, has been found to be estrogenic, according to Texas AgriLife Research scientists.
Trigonelline or "Trig"-a natural compound used in traditional Indian culture for post-menopausal women may be a factor in estrogen-dependent breast cancer but beneficial against colon cancer development, they said.
"The important thing to get from this is that 'trig' has the ability to act like a hormone. So there is a tie to cancer in the sense that we are looking at estrogen-dependent cancer cells. But that doesn't suggest that it would actually cause the disease. I don't believe there should be any concern about drinking coffee at this point," said Dr. Clinton Allred, AgriLife Research nutrition scientist.
He studies dietary compounds that can mimic the hormone estradiol - the primary hormone in women.
His main focus has been to look at how estrogen protects against the development of colon cancer. Estradiol is one of three estrogen hormones.
Allred said a former colleague mentioned an interest in finding the properties of "trig", but as the chemical structure of this compound was so unlike estradiol, he didn't think the compound would be estrogenic.
"Estrogen-dependent tumors in the presence of estradiol will grow faster. If you use those cells in a laboratory setting, you can determine whether something is estrogenic because they will literally make a tumor grow faster," said Allred.
He said that a series of experiences and different approaches showed that "trig," a vitamin derivative, was fairly estrogenic at very low concentrations.
"We haven't gotten as far as to suggest that if a woman had the disease that it would necessarily be a problem. But what we've proven is that the compound is estrogenic or can be at certain concentrations and doses," said Allred.
He added that "trig" is in coffee beans, though in different amounts depending on the variety of coffee bean.
"The more you roast a coffee bean, the less there is. But the most critical aspect is that when you do a water extract of ground coffee, which is basically how you make a cup of coffee. It does in fact come out in the water, so we know it is in a cup of coffee," said Allred.
Nevertheless, the researchers have no idea what the exposure level would be or whether a particularly exposure - say from one cup of coffee - would be in the range seen in the laboratory tests.
"It is way too early to say that drinking a cup of coffee is exposing you to something that is definitely going to be estrogenic. All we know is that there is a compound in there that can be estrogenic in our systems. That is really the take-home message," Allred said.
He also cautioned that people often narrow one compound in a food without considering the total mix of compounds and how they interact with each other or in a human body.
"There is never a single compound when you're looking at food, and a cup of coffee is a food. There's a whole bunch of other things in it. There's caffeine. There's actually a little bit of fat. There are all sorts of others things in a cup of coffee that could interact with this," said Allred.
He explained that the numerous compounds in each food product means there are complex interactions, which is why nutritionists advise people that the whole food is better than any individual compound.
"That's why you can't take supplements to make up for food. You can never take all the things that are in a carrot and replace a carrot. In the end, you need to eat the carrot. We're a long way from understanding what this compound could do in the context of a food," he said.
The study was published in the Journal of Nutrition.