Whether coffee can be good or bad for your heart depends on your genes
For some people, consuming lots of coffee each day can be bad for their hearts, for others 3 cups a day may be good for their hearts, it depends on their genetic make-up.
According to a study published in the Journal of the American Medical Association (JAMA), 4,000 people were monitored in Costa Rica by researchers from the University of Toronto, Canada. 2,014 of them had had a heart attack (non-fatal) during the period 1994-2004. The others had not had a heart attack during that period.
If your genetic profile means your body breaks down caffeine slowly, your chances of suffering a heart attack are 64% higher.
The researchers wanted to find out whether caffeine alone may be associated with cardiovascular disease risks, as opposed to other chemicals present in coffee.
Depending on your genetic profile, controlling the action of cytochrome (CYP1A2), an enzyme which metabolises caffeine, can vary. CYP1A2 must be activated in order to break down (metabolise) the caffeine. People with a slow variation of a gene are slower at activating CYP1A2.
The volunteers were asked about their coffee consumption. They also underwent genetic tests to determine which variation of the gene they had, slow or fast.
They found that those carrying the slow form of the gene had:
– 36% higher risk of heart attack if they drank 2-3 cups of coffee a day (compared to people who only drank up to one cup and had the slow form of the gene)
– 64% higher risk of heart attack if they drank 4 or more cups of coffee a day
The risk was clearer for people under 50.
Surprisingly, those who had the fast gene actually lowered their heart attack risk if they consumed up to 3 cups of coffee a day.
If you just drink one cup of coffee a day your risk of heart attack is not altered, whether you have the slow or fast gene, according to this study. The researchers stressed that other lifestyle factors influence your risk of heart attack much more than coffee, such as smoking, what you eat and how much exercise you do.
So, if this study is anything to go by, it is perhaps better to stick to one cup a day until you know what your genetic profile is.
Tags: coffee, gene, heart attack
March 3rd, 2009 at 7:21 am
* Miscarriage
There may be as much as a 30 percent increase in early miscarriage of normal pregnancies for women who drink one to two cups of coffee a day. One study has shown this goes up to 40 percent with four cups. There’s also concern about caffeine consumption while trying to conceive. Some studies have shown infertility rates double for women who drink more than two and a half cups of coffee a day.
* Cancer, coffee and smoking
No cancer correlation to caffeine has been found, except that women who smoke often do so at the same time that they drink their coffee. There is no increase in breast cancer from caffeine, although some women find breast tenderness is worsened with increased caffeine consumption.
* Osteoporosis
There is no conclusive link between caffeine and osteoporosis, but if caffeinated beverages (without milk) preclude milk or calcium-containing fluid consumption, the lack of calcium intake will correlate with osteoporosis risk.
* Hypertension
Caffeine can raise blood pressure for a few minutes, and in some cases hours. However coffee consumption does not seem to cause ongoing hypertensive disorder. If you already have hypertension, however, a cup of coffee may temporarily raise your blood pressure and this could ultimately increase your more immediate risk of stroke.
* Heart disease
Caffeine can cause palpitations, irregular or fast heartbeat, and if you have an existing abnormal heart rate or heart disease, this could be a problem. One study found an increased risk of cardiac arrest in nonsmokers who consumed six or more cups of coffee a day. But in general we can’t blame heart disease or heart attacks on reasonable caffeine consumption.
* Headaches
Caffeine can increase the effectiveness of headache medications (and many of the over-the-counter headache medications in fact combine caffeine with either aspirin or a Tylenol-like component). But these combined products can actually cause rebound headaches. To avoid this “take a pill feel better, then worse” cycle, over-the-counter medications with caffeine shouldn’t be used for more than two days at a time.
* PMS
Caffeine acts as a diuretic and should decrease discomfort and bloat. But it can also cause a fall in blood sugar, which increases symptoms of PMS. There can be a three-fold increase in PMS if we drink more than three to four cups of coffee a day.
* Bladder conditions
Caffeine speeds the kidneys’ processing of fluid, so we have to go more frequently. It can also irritate the bladder, leading to certain forms of incontinence.
* Caffeine and sleep
Caffeine stimulates the brain and also affects levels of melatonin, which promotes sleep. It takes four to seven hours to metabolize caffeine. The older we are, the longer it takes. And if you are on birth control pills or estrogen, the half life of caffeine may be doubled. So an afternoon cup of coffee can cause late night insomnia.
* Caffeine and anxiety
High doses increase the level of brain chemicals associated with anxiety.
* Caffeine and heartburn
Even decaffeinated coffee can increase stomach acid production and affect the closing of the valve between the stomach and esophagus, leading to reflux and heartburn. If you do have this problem, you not only need to decaffeinate, but you need to de-decaffeinate, i.e. no types of coffee at all.
The bottom line
In summary, caffeine does make us feel better, more alert; we sometimes exercise better, even think better. But we should not be consuming it, especially more than one to two cups per day, if we have:
* Irregular heartbeats or palpitations
* Severe PMS
* Sleep problems
* Bladder problems
* Anxiety and/or panic attacks