At the 11-year follow-up, the investigators found that compared with light coffee drinkers (one to two daily cups), heavy coffee drinkers (more than six cups per day) tended to have smaller amounts of total brain volume, especially in the hippocampus, the region responsible for short- and long-term memory.
Negative effects of caffeine on long-term memory
The conclusion was that long-term consumption of caffeine could inhibit hippocampus-dependent learning and memory partially through inhibition of hippocampal neurogenesis.
There is limited evidence that caffeine affects performance in memory tasks beyond improved reaction times. For drug factors, a dose-response relationship may exist but findings are inconsistent. Moreover, there is evidence that the source of caffeine can modulate its effects on memory.
Feeling Jittery? Got Brain Fog and Fatigue? Bad Coffee Can Be Toxic… Low quality coffee beans are almost always contaminated with impurities and mycotoxins: a damaging compound created by moulds growing on the beans, which can lead to sickness, jitters, headaches, brain fog or a general bad feeling.
What are the long-term effects? Most healthy adults that use low to moderate amounts of caffeine (up to 3 cups of coffee) every day don't seem to have any long lasting effects. Some women who drink (more than 3 cups a day) may be at risk of bone fractures (especially in the hips) as they get older.
Drinking coffee in moderate amounts (about 4 cups daily) is likely safe for most people. Drinking more than 4 cups of coffee daily is possibly unsafe. Drinking large amounts might cause side effects due to the caffeine content.
When people consume too much caffeine, they can go into what is known as caffeine intoxication, where they become confused and disoriented. This is when a caffeine coma can occur, as well as seizures.
“Overconsumption of caffeine can cause anxiety, jitters and nervousness,” notes Harris. “It can also cause an inability to focus, digestive discomfort, insomnia and irritability.”
After you have drunk a cup of coffee your body's excretion mechanism slowly starts to flush out the caffeine [5]. In regular coffee drinkers, this excretion mechanism leads to feelings of lethargy and concentration loss which can be felt after a couple of hours or a day after your last intake of caffeine.
Caffeine intakes (derived from regular coffee and tea) up to 400 mg/day were significantly associated with a lower risk of dementia compared to ≤100 mg/day according to all statistical models tested (Table 3; Table S4). A similar but slightly lower risk pattern was observed for Alzheimer's dementia.
There have also been other suggestions as to how coffee can help against dementia. Research has shown that caffeinated coffee increases production of granulocyte-colony stimulating factor, which helps the brain in several ways.
Low to moderate doses of caffeine (50–300 mg) may cause increased alertness, energy, and ability to concentrate, while higher doses may have negative effects such as anxiety, restlessness, insomnia, and increased heart rate.
You may want to cut back if you're drinking more than 4 cups of caffeinated coffee a day (or the equivalent) and you have side effects such as: Headache. Insomnia. Nervousness.
Eating small snacks packed with certain nutrients and good fats is a great way to get the benefits of a natural buzz. One study found that a high-fiber breakfast provided the greatest boost in alertness, and high-quality proteins — like those found in eggs — are also important.
The severity of symptoms vary from individual to individual, and most commonly include a headache, fatigue, decreased energy/activeness, decreased alertness, drowsiness, decreased contentedness, depressed mood, difficulty concentrating, irritability, and feeling foggy/not clearheaded.
This can be caused by overworking, lack of sleep, stress, and spending too much time on the computer. On a cellular level, brain fog is believed to be caused by high levels inflammation and changes to hormones that determine your mood, energy and focus.
Caffeine can disrupt your sleep up to six hours after consuming it, leading to an hour or more lost in rest, one study found. So if you want to start winding down and going to bed at 9 p.m., drinking coffee after 3 p.m. is a bad idea. Some health experts recommend people stop drinking coffee as early as 2 p.m.
Con: Increased Risk
Drinking coffee also causes the body to lose calcium, which is carried out excessively by the urine. Over time, excessive coffee drinkers could be putting themselves at risk of conditions such as osteoporosis, where the bones become less dense and more fragile.
4. How much caffeine is too much? For healthy adults, the FDA has cited 400 milligrams a day—that's about four or five cups of coffee—as an amount not generally associated with dangerous, negative effects.
Researchers followed 957 older adults, average age 65, who were part of the Singapore Longitudinal Aging Study. Of these, 69% drank tea on a frequent basis. After a five-year period, the researchers found that the tea drinkers had a 50% lower risk of dementia.