More than 40 million women are estimated to experience hot flashes each year. Everybody knows that prescribing hormones can reduce these symptoms in menopausal and perimenopausal women. Yet how much is really known about how hot flashes work, or why certain things, like alcohol consumption, trigger them? One recent paper, published in the journal Fertility and Sterility, looked at the influence of alcohol consumption on hot flashes in midlife women.
The research was aimed at explaining an earlier finding, that moderate alcohol consumption of up to three drinks per month, actually reduced the severity of hot flashes by 25 percent. This effect disappeared in women who drank more than three drinks per month.
Since it is known that alcohol consumption can affect metabolism in some animals, the team believed that light drinking may be altering sex steroid hormone levels in midlife women. But their analysis turned up no significant hormonal differences between the alcohol users and the women who never used alcohol.
“We dont know why (moderate alcohol consumption) is reducing the risk of hot flashes, other than it doesnt seem to be doing so by changing hormone levels,” professor Jodi Flaws, University of Maryland, said.
Estrogen at Fault
The precise reason for hot flashes is not totally understood, but do they result from decreases in the hormone estrogen. It is thought that estrogen production may affect the area of the brain which controls the body’s temperature. But its not as simple as that. And whats the deal with alcohol?
One possible theory goes like this: alcohol increases blood levels of estrogen; when these levels suddenly drop after the alcohol is processed by the body and removed from the blood stream, then there is a severe drop in estrogen and it’s this drop which causes the hot flashes. An analogy of this mechanism would be what happens when you consume too much sugar…..a short sugar buzz, followed a few hours later by an big energy crash.
Another theory is that hot flashes may be triggered by increased blood flow in the heat regulating center of the brain. Your brain, detecting an increased body
temperature, then releases chemicals which cause your skins blood vessels to dilate, so that the surplus heat can be radiated into the surrounding air.
Hormones like estrogens apparently permit the body to have greater tolerance for changes in core body temperatures. So, normally a body may tolerate a change of 1.4 degrees Celsius before dilating the blood vessels, but with lowered levels of these hormones, the blood vessels are triggered to dilate at a change of only 0.75 degrees Celsius, for example.
If true, this would mean that anything raising core body heat or possibly even just the heat of an increased blood flow at the brain’s heat regulatory center can cause a hot flash. The hot flash will stay in effect as long as needed to in order release the surplus heat.
It may or may not be related to the typical hot flash, but symptoms of flushing and rapid heart rate are many times due to having an abnormal version of the enzyme which breaks down alcohol into acetaldehyde. This enzyme is called Alcohol Dehydrogenase or ADH.
About 50% of Japanese people have this abnormal enzyme, known as ALDH2, and they get what is called Asian Flush when drinking. Their ADH enzyme works around 5 times faster than the regular version and so build-ups of acetaldehyde accumulate faster than the liver can clear them.
The enzyme does occur among people of all races however. The after effects of the Asian Flush are so uncomfortable, that the enzyme was used to develop an anti-alcholism treatment medication known as Antibuse.
So, why does drinking alcohol cause hot flashes? It could be any one of the above reasons, or a combination of two or more, or some other reason. Like I said before, nobody really knows. It seems like someone would have done more research on this, given the 40 million a year figure, (that’s women, not $) but I guess there are more important things to worry about.
Photo by Guudmorning!, Creative Commons Attribution License