Coffee drinking linked to high blood pressure

Many drink coffee for different reasons; some because of the aroma and some, for stimulating them. These are all good reasons that, however, need to be weighed against the possibility of coffee putting them at risk of hypertension, reports Sade Oguntola.

IF you are a coffee lover and are accustomed to pumping up your body’s caffeine level in order to accomplish your daily tasks, you ought to think of the consequences of this to your health, especially if you are predisposed to high blood pressure problems.

Whether it is just a cup or more a day, coffee increases your likelihood of having to start using drugs to control high blood pressure, or hypertension. This has been observed among coffee drinkers and researchers also found no relationship between how much coffee one drinks and increased risk of hypertension. So, whether you drink one or more cups per day, you are still at risk.

Although there have been debates on how healthy coffee and cola are, but the latest finding by Dr. Gang Hu, of the National Public Health Institute, Helsinki, Finland, and his colleagues, reported in the American Journal of Clinical Nutrition further points to the need for caution.

The researchers followed 24,710 Finnish subjects between the ages of 25 and 64 years with no history of drug treatment for hypertension, coronary heart disease, or stroke. Self-administered questionnaires were used to assess daily coffee consumption for an average of 13.2 years. During that time, 2,505 individuals started anti-hypertensive drug treatment.

They found that the risk of having to start using anti-hypertensive drugs was higher in coffee drinkers than in non-coffee drinkers, with the highest increased risk of 29 per cent, being associated with drinking two to three cups daily. Also, drinking more than eight cups per day only increased the risk by 14 per cent.

According to Hu and colleagues, “Even though the risk of hypertension associated with coffee consumption was relatively small, it may have some public health importance because coffee is the most consumed drink, other than water, and hypertension is a major health problem in the world.”

Even among the Dutch, the case was similar. In a large 11-year cohort study, this is where a group of subjects are studied from a baseline point for a number of years, people that take between one and three cups of coffee in a day were found to have a higher rate of hypertension than abstainers. In women, that drink 6 cups a day or more, the risk is also higher.

Two thousand,nini hundred and eighty-five men and 3,383 women were enrolled in Dutch city of Doetichem between 1987 and 1991 and had their first follow-up done between 1993 and 1997, and a second between 1998 and 2002. They completed food-frequency questionnaire, which provided information about tea intake as well as other health and demographic data.

Even after allowances were made for those factors known to affect the development of high blood pressure such as age, sex, body height and weight, smoking, alcohol intake, tea intake, educational level, occupational status, and total calorie intake, the study found that low-consumption coffee intake is an independent risk factor for high blood pressure both in men and women.

If that is not enough, another study authored by Charalambos Vlachopoulos of the Athens Medical School in Greece found out that caffeine caused stiffness of the arteries. The study showed that caffeine quickly increases the stiffness of the large arteries in people with high blood pressure. The researchers observed an 11-point jump in systolic blood pressure and an eight-point jump in diastolic blood pressure after thirty minutes of taking caffeine. The effect is said to have peaked after 60 minutes and remained significant for at least three hours.

Aside that caffeine has also been associated with heart rhythm irregularities or the incidence of heart palpitations, it was similarly linked to heart problems (coronary disease). In people who took more caffeine the risk increased significantly. The same study showed that coffee drinking increases the risk of succumbing to an acute myocardial infarction in people with diabetes. Two cups per day increases the risk by 32 per cent, while four cups increases the risk by 64 per cent. This effect is even more pronounced in individuals younger than 59. For younger adults, heart attack risk is increased by 24 per cent with one cup of coffee daily, 67 per cent by two to three cups of coffee or 133 per cent by four or more cups.

Among kids, the same principle holds true. This was the conclusion of another study at Harding University in Searcy, Arkansas. It showed that caffeine elevates children’s blood pressure, lowers the heart rate but does not affect metabolism. Kids who participated in the study took caffeinated drinks twice a day for four days. After drinking, they were told to exercise on a stationary bicycle while blood pressure rate and oxygen consumption were measured. It turned out that most of the kids were found to have increased blood pressures.

According to Dr. Ada Asinobi, a consultant pediatrician at the University College Hospital (UCH), Ibadan, children with blood pressure problems must abstain from coffee. This remains one way of reducing their chances of developing hypertension.

She stated that the caffeine in coffee could cause a temporary increase in blood pressure. Though this may not be harmful in people with normal blood pressure, she said several studies however suggest that regular, heavy coffee drinking (an average of five cups per day) can boost blood pressure, thus making it harmful in people with hypertension.

Considering that many people are not aware of their being hypertensive and even those that know do not ensure that their blood pressures are well controlled, she said indulging in the habit of taking coffee may not be too good after all.

Drinking coffee also increases excretion of calcium and the fact that many people are not too mindful of their health and so do not take balanced diet to ensure that their body has enough supplements such as calcium, calcium depletion from coffee drinking may thus affect blood pressure too.

A nutritionist at UCH, Mr. Tunde Ajobo said that because the caffeine in coffee drinks (and other caffeinated beverages) is a stimulant, it could cause jitters, nervousness, and high blood pressure for some.

He explained that one common way this occurs is that caffeine narrows the blood vessels by blocking the hormone that normally keeps them open - adenosine.

Caffeine also causes cortisol and adrenaline, both stress hormones to be released, thereby causing a direct increase in blood pressure. This can be harmful to the heart if elevated over a long period. It can also weaken the immune system, and damage blood vessels.

Going by what James Lane, associate research professor of psychiatry at Duke University Medical Centre said after a study she did on 72 habitual drinkers, “Moderate caffeine consumption makes a person react like he or she is having a very stressful day. If you combine the effects of real stress with the artificial boost in stress hormones that come from caffeine, then you have compounded the effects considerably.”

Caffeine, no doubt, is among the many addictions that individuals need to do away with for a healthier lifestyle. For those who try boosting their alertness or ability to focus with coffee drinks, what should be done is to weigh all the risks and the benefits side by side and decide what steps to take.