23 March 2007

Let's Have Coffee?

Coffee sets the blood in motion and stimulates the muscles; it accelerates the digestive processes, chases away sleep, and gives us the capacity to engage a little longer in the exercise of our intellects.
~ Honore de Balzac

I never drink coffee at lunch. I find it keeps me awake for the afternoon.
~ Ronald Reagan

A Reuters report said that heavy coffee drinkers had little to worry about concerning the development of high blood pressure, or hypertension.
In the new study, published in the American Journal of Clinical Nutrition, researchers found that healthy women who drank upwards of six cups of coffee per day were no more likely than abstainers to develop high blood pressure over the next decade.

On the other hand, women who drank coffee occasionally or in moderation --- reporting anywhere from zero to three cups a day --- had a higher risk of developing high blood pressure than the heavy coffee drinkers or the abstainers.

For men, the risk of high blood pressure did not significantly increase or decrease, regardless of how much coffee they drank each day. However, men who abstained did have a lower risk than any coffee drinkers.

[Reuters, 21 March 2007]

What does this study tell us?

It tells us that the blood pressure effects of coffee drinking vary based on gender and consumption. The study should not be interpreted as an excuse to drink more coffee, because if you read the abstract of the study, the results and conclusion still emphasize that people who did not drink coffee had a lower risk of developing hypertension than coffee drinkers.

The study focused on healthy subjects. It might be prudent for those with existing cardiovascular and hypertensive conditions to be more cautious with their coffee consumption.

Also, the study noted that older coffee drinkers (39 years old and older) had significantly lower blood pressure readings than those who were younger (38 years old and younger).

Why did the study show that older and heavy coffee drinkers had a lower risk of developing hypertension?

The answer is probably due to tolerance.

According to the study, if you are 39 years old or older, and drink 6 or more cups of coffee everyday, your chances of having spike readings in your systolic and diastolic values are minimal (maybe even none) compared to a younger person who drinks coffee lightly at 1 to 3 cups daily. The young light coffee drinker is more sensitive.

That is simply the beauty of this human body. If you subject it to constant stress like caffeine overdose, it develops tolerance over time, and hypertensive risk decreases.

Does this mean we can now binge on our coffee consumption?

Let me present you with available medical and scientific data on the pros and cons of coffee drinking, and from there, let you decide whether to have a cup of coffee or not:


  • Randomized control trials have shown that boiled, unfiltered coffee contains significant amounts of cafestol and kahweol, which are diterpenes, a class of hydrocarbons that has a significant cholesterol-raising effect, and may contribute to an increased coronary heart disease risk.

  • Three studies (here, here, and here) have shown that caffeine in coffee has a short-term pressor effect, or the ability to acutely increase blood pressure, and can trigger cardiovascular disease events.

  • Another short-term caffeine effect is decreased glucose tolerance and decreased insulin sensitivity (from the same three studies mentioned above), and researchers have speculated that this might increase the risk for neuropathy and diabetic retinopathy.

  • In animal studies, high concentrations of caffeine were shown to be teratogenic.

  • One study has shown that caffeine can potentiate the teratogenic effect of other substances, such as tobacco and alcohol.

  • Two medical articles mentioned that among pregnant mothers, drinking 3 cups of coffee daily can decrease the birth weights of their babies.

  • Among the elderly, caffeine has been shown to increase the risk of having kidney stones and osteoporosis.

  • Caffeine dependency is characterized by the development of tolerance, as reflected by increases in dose size with time, persistent desire, and a study has described its withdrawal symptoms like headaches, irritability, anxiety, depression, drowsiness, and fatigue.

7 reactions:

Ross said...

Hi Doc Emer,

Nice article. I always drink coffee. This article is very helpful.



Anonymous said...

great post, i'll use this info in my practice. thank you.

I'd like to ask a quick favor. I deleted my old blog, and somehow a sleazy company set up a new one immediately using my now defunct URL. They are selling a potentially dangerous drug called phentermine from my old site. If you'd be so kind please change your blogroll to http://scienceblogs.com/drcharles or just delete me. Thank you very much. I'll be contacting Blogger about this as well.

bayi said...

I love drinking coffee but gave up this habit for a while. When I started drinking it again recently, I found that I could not sleep at night! I could have downed a couple of cups close to midnight previously without any side effect but it looks like my days of indulgence in this wonderful habit is over. :(

But I guess sleep is even more enjoyable! Previously I thought sleep was a waste of time but now I would like to sleep more if I could! :)

I still take an occasional cup, black and no sugar. This is the best for maximum pleasure as the aroma in undiluted.

Dr. Emer said...

ROSS: Thank you and welcome to this blog.

Dr. CHARLES: Sleazy companies are like cockroaches indeed. Difficult to kill. Acknowledged your new URL. It's in my bookmarks.

BAYI: We could always enjoy tea, my friend....though Dr Charles up there might say it stains the teeth too much. *LOL*

Ipanema said...

I average 2-3 cups of coffee per day, I have hypertension and I'm in my early 40s. As much as possible, I try to avoid it if I can. But i can't work without drinking one. I tried weaning myself from coffee and yes, I experienced those caffeine dependence symptoms. When I started drinking again, I'm always alert.

Dr. Emer said...

Ipanema: Have you tried green tea?

Stephen said...

In addition to osteoporosis, caffeine can give some people arthritis. I had to give it up. Fortunately, ten months of abstinence allowed full reversal of symptoms. At least two doctors told me that there is no correlation. My evidence is solid.