The harmful effects of caffeine are sometimes harder to find information on than all of the reported positives .
Here are a few of the studies that said that caffeine could be dangerous to one's health.
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Research Showing Harmful Effects of Caffeine
- More than 4 cups of coffee linked to early death. A Mayo Clinic partnered study found that men who drank more than four 8 fl.oz. cups of coffee had a 21% increase in all-cause mortality. However, those who reported that they were very likely to smoke and have poor fitness. Dr. Nancy Snyderman from NBC said there were a few discrepancies with the study, but stresses that moderation is still key. See Her Interview Here .
- Caffeine can raise blood pressure. Especially in those already suffering from hypertension and those who do not normally consume caffeine . People with hypertension were given 250 mg of caffeine (about 2 coffees) and the data revealed that their blood pressure was elevated for about 2-3 hours after the caffeine. Src . A second study performed by The Mayo Clinic found similar results from a 160 mg dose. All participants experienced a marked rise in blood pressure and it was the most pronounced in those that did not normally consume caffeine. Src .
- Increased risk of heart attacks among young adults . A study conducted by Dr. Lucio Mos found that young adults who were diagnosed with mild hypertension had 4 times the risk of having a heart attack if they consumed the amount of caffeine equivalent to 4 cups of coffee. More moderate weather showed 3 times the risk. Src .
- Caffeine linked to gout attacks . This study showed that people who caffeinated beverages increased their risk for a gout flare-up. Src .
- Breast tissue cysts in women . One study showed that "Women who consumed 31-250 mg of caffeine / day had a 1.5-fold increase in the odds of developing fibrocystic breast cancer and women who drank over 500 mg / day had a 2.3-fold increase in the odds of developing cysts Src .
- Caffeine could cause incontinence . A study out of the University of Alabama showed that women who consume a lot of caffeine are 70% more likely to develop incontinence. Src .
- Caffeine may cause insomnia . Caffeine in a person's system at bedtime can mimic the symptoms of insomnia. Src .
- Caffeine can cause indigestion . People who consume caffeinated beverages often report an upset stomach or indigestion. This usually occurs when the beverages are consumed on an empty stomach. Src .
- Caffeine can cause headaches . While occasional dosages of caffeine can relief headache symptoms, the overuse of caffeine can cause headaches and lead to migraines. Src .
- Caffeine could reduce fertility in women . A study from the University of Nevada School of Medicine showed that caffeine can reduce a woman's chances of becoming pregnant by about 27%. Src .
- Caffeine and miscarriage risk : In a recent study, both men and women who consumed at least two caffeinated beverages a day during the week prior to conception increased the risk of a miscarriage. Src .
- Caffeine may not be healthy for type 2 diabetics . A study conducted by the American Diabetes Association showed that caffeine impaired glucose metabolism in those with type 2 diabetes. Src .
- Caffeine overdose . While overdose is rare, it can lead to many adverse symptoms including death, especially in those with underlying medical conditions. Some have a lower tolerance for caffeine than others. Src .
- Caffeine allergies . Some people have over-sensitivity to the caffeine molecule, which causes allergic-like reactions in the body such as hives and pain. Although not a true allergy, many report very negative symptoms after consuming even the smallest amounts. Src .
- Caffeine causes more forceful heart contractions . A recent study showed that immediately after energy drink the heart produced more forceful contractions. It is unclear if this has any long-term health implications except for those with known health conditions. Src .
- Worse menopause symptoms . A recent study published in The Journal of The North American Menopause Society showed that menopausal women who consumed caffeine had a greater degree of vasomotor symptoms. Src .
- Caffeine can lead to increased anxiety, depression and the need for anxiety medication . Src and Src . See also our article as to why caffeine causes anxiety and panic attacks .
- Caffeine increases the number of sugary drinks consumed by people , which contributes to obesity and diabetes. Src .
- Caffeine inhibits collagen production in the skin . This effect is dose-dependent but really heavy caffeine consumers should be aware. The study
- Caffeine interferes with ossification and could also lead to a greater risk of bone fractures . This is dose dependent, but heavy caffeine consumers should take note. Study 1 (pdf) Study 2 .
- Caffeine does not help with prolonged sleep deprivation: This can lead to a false sense of security for those who have been depressed for several days in a row and choose to get behind the wheel or some other focus required task, thinking that as long as they have caffeine, they'll be able to perform. Researchers from the American Academy of Sleep Medicine came to this conclusion after studying caffeine's effects on their sleep-deprived test subjects. Here's the study in detail .
- Caffeine may impair hearing loss: For guinea pigs exposed to excessive levels of noise, caffeine was shown to delay the rate at which the guinea pigs recovered from noise-induced hearing loss. Here are the results of a recent study that investigated the problem. A correlation to humans is believed to exist but more research will be needed.
When not managed caffeine can quickly become an out of control problem.
If you are experiencing any tell-tale signs of the risks above, then it's time to start cutting back. Otherwise, it's just a matter of time.
Other Claims Against Caffeine
You may have heard or read about other negative health effects from caffeine, but as of now, there is not enough evidence to fully endorse those as legitimate health concerns.
Some of those negatives include:
- Adrenal fatigue
- Irregular heartbeat
- Hallucinations
- Accelerates bone loss. Src .
- Tremors
Caffeine is a drug and can affect people differently just like any other substance. It's important that consumers understand how to interact with their bodies in regards to their personal health histories.
The food and beverage industry spends millions, if not billions, of dollars worldwide to fund studies and promote caffeinated products as safe or even healthy.
Fortunately, caffeine is one of the most researched substances on the planet and there is some unbiased data in which to glean some reliable information from.
While much of the research is published, it is possible to see the safety and potential benefits of caffeine (in moderation), there are a handful of research studies that highlight the potentially harmful effects of caffeine.
The risks of suffering from any of the harmful effects of caffeine are diminished by being aware of how much is personally being consumed daily .
It is also important to be aware of any pre-existing medical conditions that may contribute to caffeine's negative effects.