“Many companies add caffeine to weight-loss pills because it speeds up the metabolic rate, at least for a short period of time. Yet “there’s little evidence that consuming caffeine leads to significant weight loss or helps people keep weight off”
These days, consumers might notice caffeine in some unexpected places. People can purchase caffeine-infused bottled water, jelly beans, breath mints, peanut butter and chewing gum.
There are even caffeinated bath soaps that supposedly help wake people up in the morning. Although caffeine can be absorbed through the skin, it’s doubtful this soap will improve alertness during the day, Lane said.
Caffeine has also been added to shampoos to purportedly thicken hair and stop hair loss, but there’s no good evidence that these pricey products can truly deliver results.
“Caffeine is a natural stimulant most commonly found in tea, coffee and cacao plants.
It works by stimulating the brain and central nervous system, helping you to stay alert and preventing the onset of tiredness.
Historians track the first brewed tea to as far back as 2737 BC (1).
Coffee was reportedly discovered many years later by an Ethiopian shepherd who noticed the extra energy it gave his goats.
Caffeinated soft drinks hit the market in the late 1800s and energy drinks soon followed.
Nowadays, 80% of the world’s population consumes a caffeinated product each day, and this number goes up to 90% for adults in North America (1)”
Caffeine is a powerful stimulant, and it can be used to improve physical strength and endurance. It is classified as a nootropic because it sensitizes neurons and provides mental stimulation.
Habitual caffeine use is also associated with a reduced risk of Alzheimer’s, cirrhosis, and liver cancer.
Drinking a cup of coffee can help you lose weight by stimulating “brown fat”, which burns calories to generate body heat, experts have found.
“Brown fat works in a different way to other fat in your body and produces heat by burning sugar and fat, often in response to cold,” said Professor Michael Symonds, from the School of Medicine at the University of Nottingham, who co-directed the research. He added that it was this was the first research to show how coffee has an impact on brown fat in humans.
The US National Library of Medicine – www.ncbi.nlm.nih.gov
Probably the most cited source for weight loss science online.
“The effects of caffeine intake on weight loss: a systematic review and dose-response meta analysis of randomized controlled trials.
This systematic review and meta-analysis of randomized controlled trials (RCTs) was performed to summarize the effect of caffeine intake on weight loss. We searched the following databases until November 2017: MEDLINE, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials.
Overall, the current meta-analysis demonstrated that caffeine intake might promote weight, BMI and body fat reduction”
“Once consumed, caffeine is quickly absorbed from the gut into the bloodstream. From there, it travels to the liver and is broken down into compounds that can affect the function of various organs. That being said, caffeine’s main effect is on the brain. It functions by blocking the effects of adenosine, which is a neurotransmitter that relaxes the brain and makes you feel tired.
Normally, adenosine levels build up over the day, making you increasingly more tired and causing you to want to go to sleep. Caffeine helps you stay awake by connecting to adenosine receptors in the brain without activating them. This blocks the effects of adenosine, leading to reduced tiredness.
It may also increase blood adrenaline levels and increase brain activity of the neurotransmitters dopamine and norepinephrine”
As well as its stimulating effects, caffeine has been heralded for providing an array of health benefits.
Last year, Medical News Today reported on a study suggesting that consuming three cups of coffee a day may reduce the risk of liver cancer by 50%, while another study suggests that drinking four cups a day could halve the risk of mouth and throat cancer.
Caffeine consumption has also been associated with positive effects on the brain.
Last year, a study from the Harvard School of Public Health suggested that drinking between two and four cups of coffee a day may reduce suicide risk in adults, while more recent research found that ingesting 200 mg of caffeine each day may boost long-term memory.
Other studies have also suggested that caffeine intake may protect against type 2 diabetes, Parkinson’s disease, cardiovascular disease and stroke.
“Caffeine can improve memory, decrease fatigue, improve your mental functioning, study after study suggests. It can improve your short-term memory and speed up your reaction times, according to a study presented in 2005 at the Radiological Society of North America.
Coffee drinking, the researchers say, may help prevent type 2 diabetes, Parkinson’s disease, and liver disease, including liver cancer. And it doesn’t appear to significantly increase heart disease risk or cancer. But, they warn, those with high blood pressure, as well as children, teens, and the elderly, may be more vulnerable to caffeine’s adverse effects”
“Most adults don’t experience the effects of caffeine intoxication while drinking less than 250 milligrams of caffeine (about 2.5 cups of coffee) per day. You are more likely to experience negative side effects if you drink more than the recommended 400 milligrams per day.
The stimulant properties of caffeine increase your blood pressure and heart rate. Consuming too much may give you the “caffeine jitters,” which is that jumpy and slightly alarmed feeling. Larger amounts of caffeine may make you irritable, sleepless, and may even trigger anxiety and cause diarrhea. Other side effects include:
- Anxiety and nervousness
- Frequent urination
- Upset stomach
- Heart palpitations or fast heartbeat
- Muscle spasms
Caffeine can act as a diuretic, so it was once assumed that drinking too much coffee or other caffeinated beverages would cause dehydration. However, researchers found that your body adjusts to your caffeine intake, so drinking caffeinated beverages won’t increase your need for water”
“There’s no clear link between caffeine intake and depression. However, caffeine intake and depression may be linked indirectly for people who are particularly sensitive to the effects of caffeine or who have too much caffeine.
- Caffeine can cause sleep problems that affect mood.
Caffeine can make it harder to fall asleep and stay asleep. Lack of sleep can worsen depression. If you have trouble sleeping, don’t drink caffeinated beverages late in the day. Some people need to limit caffeine to the morning or quit drinking caffeinated beverages completely to avoid sleep problems. Also, anxiety and depression often occur together, and caffeine can worsen anxiety.
- Stopping abruptly can worsen depression.
If you regularly drink caffeinated beverages, quitting can cause a depressed mood until your body adjusts. It can also cause other signs and symptoms, such as headaches, fatigue and irritability2
For healthy adults
“The FDA recommends that healthy adults limit their caffeine intake to a maximum of 400 milligrams (mg) a day, about 4 or 5 cups of coffee. This amount is not associated with negative effects.
There is no set limit for children, but the American Academy of Pediatrics (AAP) discourages the consumption of caffeine and other stimulants by children and adolescents”
“For breastfeeding or pregnant women
A review by the EFSA recommends that women who are breastfeeding, pregnant, or planning to become pregnant limit their intake to 200 mg of caffeine per day. Other reviews have concluded that 300 mg/day is safe,but you may be cutting it close, since taking more increases the risk of nausea and, worse, of miscarriage.
For children and adolescents
The EFSA notes that the “information available is insufficient to derive a safe caffeine intake” for children and adolescents, but it recommends using the adult population’s upper limit for single doses (3 milligrams per kilogram of bodyweight) as the younger population’s upper limit for daily intake.Health Canada and non-governmental reviews, however, have called for a lower upper limit: 2.5 mg/kg/day.According to Health Canada, 2.5 mg/kg/day translates to the following approximate limits:
- 4–6 years: 45 mg/day
- 7–9 years: 62.5 mg/day
- 10–12 years: 85 mg/day”