You might not be surprised to hear that more than 80% of American adults consume caffeine regularly, through coffee, energy drinks, sodas, and even pills. Caffeine is often harmless and in most cases can even provide significant benefits. Here is a rundown of when caffeine helps, hurts, and doesn’t matter, from the Nutrition Action newsletter:
When it May Help:
- Sleep Deprivation: Caffeine works by temporarily binding to adenosine (a natural sedative) receptors in the brain, which prevents it from making us feel drowsy. Adenosine levels build during waking hours and drop as we sleep. If you stay up late and don’t get a full night’s sleep, your adenosine levels are higher in the morning and caffeine helps neutralize them.
- Mental Stimulation: People who don’t use caffeine regularly tend to become significantly more alert and better able to perform cognitive tasks if they’re given the right dose of caffeine. However, regular users don’t get as much of a benefit.
- Physical Performance: Caffeine can improve physical performance in endurance exercises like running, and this benefit is true for both regular users and occasional ones. It prompts the body to use more stores of fat when the carbohydrates in our muscles run out.
- Headaches: Caffeine constricts blood vessels which are dilated when we have headaches. Many headache medicines contain caffeine for this reason.
- Parkinson’s Disease: Several studies have concluded that a higher caffeine intake is associated with a reduced chance of developing Parkinson’s Disease. In a study of 600,000 adults, those who consumed the most caffeine were about 20% less likely to be diagnosed with Parkinson’s in 10 years, compared to those who drank the least amount.
- Gallstones: Women in the Nurses’ Health Study who drank 2-3 cups of coffee per day were 20% less likely to develop gallstones over a 20-year period than those who drank no coffee.
- Dementia: In mice bred to develop Alzheimer’s, caffeine protects against inevitable memory impairment but also decreases the amount of beta-amyloid, a “bad”protein thought to cause the disease.
When it May Hurt:
- Pregnancy: The March of Dimes recommends that women who are pregnant consume no more than 200 mg of caffeine per day because harmful effects “cannot be ruled out.”
- Disrupted Sleep: People who rely too much on caffeine to counteract too little sleep can end up in a vicious cycle, since disturbed sleep leads to sleepiness and then to increased caffeine consumption, then more disturbed sleep.
When it Doesn’t Matter:
- Heart: In a study of morei than 130,000 Kaiser Permanente members in California over 30 years, drinking coffee didn’t increase the risk of cardiac arrhythmias, even among people with existing heart conditions.
- Weight: There is little evidence that caffeine leads to significant weight loss or helps people keep it off long-term, although many weight loss supplements contain caffeine because it speeds up metabolic rate for a short period of time.
- High Blood Pressure: While caffeine users experience a mild increase in blood pressure, there isn’t an established link between the development of hypertension and long-term caffeine consumption.