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Caffeine

The effect of caffeine on memory

Higher coffee consumption linked to lower dementia risk in women

Data from the Women's Health Initiative Memory Study, involving 6,467 postmenopausal women (65+) who reported some level of caffeine consumption, has found that those who consumed above average amounts of coffee had a lower risk of developing dementia.

Caffeine intake was estimated from a questionnaire. The median intake was 172 mg per day (an 8-ounce cup of brewed coffee contains 95mg of caffeine, 8-ounces of brewed black tea contains 47mg, so slightly less than 2 cups of coffee or less than 4 cups of tea). The women were cognitively assessed annually.

Why dark chocolate is good for your heart

Submitted by Fiona McPherson on

A study involving 44 middle-aged overweight men who consumed 70 grams of dark chocolate per day over two periods of four weeks, has found that dark chocolate helps restore flexibility to arteries while also preventing white blood cells from sticking to the walls of blood vessels. Both arterial stiffness and white blood cell adhesion are known factors that play a significant role in atherosclerosis.

http://www.eurekalert.org/pub_releases/2014-02/foas-wdc022714.php

Green tea plus exercise may speed up weight loss

Submitted by Fiona McPherson on

Mice given decaffeinated green tea and regular exercise lost weight and improved their health after 16 weeks. Specifically, they reduced body mass by 27% (on average), reduced abdominal fat by 37%; reduced blood glucose level by 17%, plasma insulin level by 65%, and insulin resistance by 65%..

Neither green tea alone, nor exercise alone, produced such significant changes. The amount of green tea was a lot: the equivalent of 8-10 cups a day. Decaffeination may not be important; it was done to keep the effects of caffeine out of the study.

Caffeine gives honeybees memory boost

Submitted by Fiona McPherson on

Caffeine occurs naturally in the nectar of coffee and citrus flowers. A study of honeybees has revealed that those fed on caffeinated nectar were three times more likely to remember a flower's scent than bees fed sugar alone, after 24 hours. After three days, they were still twice as likely to remember the flower than those fed sugar alone.

How green tea helps fight cognitive decline & dementia

Green tea is thought to have wide-ranging health benefits, especially in the prevention of cardiovascular disease, inflammatory diseases, and diabetes. These are all implicated in the development of age-related cognitive impairment, so it’s no surprise that regular drinking of green tea has been suggested as one way to help protect against age-related cognitive decline and dementia. A new mouse study adds to that evidence by showing how a particular compound in green tea promotes neurogenesis.

Scent of rosemary may help cognition

A small study involving 20 people has found that those who were exposed to 1,8-cineole, one of the main chemical components of rosemary essential oil, performed better on mental arithmetic tasks. Moreover, there was a dose-dependent relationship — higher blood concentrations of the chemical were associated with greater speed and accuracy.

Coffee and a healthy diet reduce the risk of Alzheimer’s

Dietary changes affect levels of biomarkers associated with Alzheimer's

In a study involving 20 healthy older adults (mean age 69.3) and 29 older adults who had amnestic mild cognitive impairment (mean age 67.6), half the participants were randomly assigned to a high–saturated fat/high–simple carbohydrate diet (HIGH) and half to a low–saturated fat/low–simple carbohydrate diet (LOW) for four weeks, in order to investigate the effects on biomarkers associated with Alzheimer’s.

Caffeine

  • Caffeine has both good and bad effects, both of which may impact on cognitive performance.
  • Coffee contains active ingredients other than caffeine which may, directly or indirectly, impact on cognitive performance.
  • Caffeine appears to be of greater potential significance to older adults.
  • However, those with hypertension, diabetes, impaired glucose tolerance, or high homocysteine levels, would be wiser to avoid coffee, even if decaffeinated.
  • Caffeine's main impact is on attention.

It seems clear that caffeine improves alertness and reaction time, but evidence is inconclusive for its effect on higher memory and reasoning processes. It is possible that caffeine may in fact impede memory, where the information is complex or ambiguous.

Caffeine can be helpful in ameliorating the effects of time of day and sleep deprivation on cognitive performance. In normal circumstances (i.e., not prolonged sleep deprivation, or extreme stress), caffeine seems to be more helpful to older adults, in helping them overcome time-of-day effects.

Recent research has demonstrated that caffeine affects blood flow in the brain. It is not yet clear what the implications of this may be.

Caffeine has been implicated in raising blood pressure. High blood pressure is undoubtedly a risk factor for cognitive decline and dementia for those over 60. However, recent studies suggest that, while it is clear that coffee raises blood pressure, it is not clear that caffeine is the culprit.

Brewed coffee raises homocysteine levels. High homocysteine levels in older adults increase the risk of cognitive decline and dementia. Recent research suggests however that caffeine is not the sole ingredient in coffee responsible for the homocysteine-raising effect.

Evidence for the effect of caffeine on glucose regulation is inconclusive as yet, but there is some suggestion that caffeine may be a risk factor for impaired glucose tolerance. Impaired glucose tolerance is a risk factor for cardiovascular disease (and thus, by implication, cognitive decline, since research now indicates that “what is good for the heart is good for the brain”). More direct evidence also suggests that impaired glucose tolerance in older adults is associated with memory problems.

While people clearly build up a tolerance to some of the effects of caffeine, it is not yet clear what the long-term effects of regular caffeine use are. Nor can we say, as yet, what factors are important in determining those long-term effects, although we can speculate that gender, metabolic factors, cardiovascular health, alcohol and tobacco use are all possible influences.

Conclusion: Clearly, caffeine has both good and bad effects, both of which may impact on cognitive performance. Moreover, the main vehicle for caffeine — coffee — contains active ingredients other than caffeine which may, directly or indirectly, impact on cognitive performance. Caffeine does appear to be of greater potential significance to older adults. Overall, the evidence suggests that, while caffeine may help older adults in the later part of the day, those with hypertension, diabetes, impaired glucose tolerance, or high homocysteine levels, would be wiser to avoid coffee, even if decaffeinated. In general, while caffeine may help you overcome factors that lower your cognitive performance, it does not seem that caffeine has any significant direct effect on memory, although it may well help you pay attention.

This is a summary of research into the effects of caffeine on memory. You can download the full report (in pdf format).

Older news items (pre-2010) brought over from the old website

Caffeine reverses memory impairment in Alzheimer's mice

Consistent with earlier indications that moderate caffeine consumption may protect against memory decline, a study of genetically engineered mice has found that when the old mice began to show memory impairment, those given caffeine for 2 months performed as well as normal aged mice on cognitive tests, while those given plain drinking water continued to do poorly. The Alzheimer's mice received the equivalent of five 8-oz. cups of regular coffee a day (or two cups of Starbucks coffee, or 14 cups of tea). Moreover, the brains of the caffeinated mice showed nearly a 50% reduction in levels of beta amyloid. The effect appears to be through suppression of both β-secretase and presenilin 1 /g-secretase expression. Caffeine had this effect only on those with Alzheimer’s; normal mice given caffeine through adulthood showed no cognitive benefit.

Arendash, G.W. et al. 2009. Caffeine Reverses Cognitive Impairment and Decreases Brain Amyloid-β Levels in Aged Alzheimer's Disease Mice. Journal of Alzheimer's Disease, 17 (3), 661-680.

Cao, C. et al. 2009. Caffeine Suppresses Amyloid-β Levels in Plasma and Brain of Alzheimer's Disease Transgenic Mice. Journal of Alzheimer's Disease, 17 (3), 681-697.

http://www.eurekalert.org/pub_releases/2009-07/uosf-crm070109.php

Midlife coffee drinking reduces risk of dementia

A large, long-running Finnish study has found that those who were coffee drinkers at midlife had lower risk for dementia and Alzheimer’s later in life compared to those drinking no or only little coffee midlife. The lowest risk was found among moderate coffee drinkers (drinking 3-5 cups of coffee/day). Tea drinking was relatively uncommon and was not associated with dementia.

Eskelinen, M.H. et al. 2009. Midlife Coffee and Tea Drinking and the Risk of Late-Life Dementia: A Population-based CAIDE Study. Journal of Alzheimer's Disease, 16(1).

http://www.physorg.com/news151225794.html

Chocolate, wine and tea improve brain performance

A study of over 2000 older Norwegians (aged 70-74) has found that those who consumed chocolate, wine, or tea had significantly better cognitive performance and lower risk of poor cognitive performance than those who did not. Those who consumed all 3 studied items had the best performance and the lowest risks for poor test performance. The associations between intake of these foodstuffs and cognition were dose dependent, with maximum effect at intakes of around 10 grams a day for chocolate and around 75–100 ml a day for wine, but approximately linear for tea. The effect was most pronounced for wine and modestly weaker for chocolate intake. The finding is consistent with research indicating that those who consume lots of flavonoids have a lower incidence of dementia.

Nurk, E., Refsum, H., Drevon, C. A., Tell, G. S., Nygaard, H. A., Engedal, K., & Smith, D. (2009). Intake of flavonoid-rich wine, tea, and chocolate by elderly men and women is associated with better cognitive test performance. The Journal of Nutrition, 139(1), 120-127. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/19056649

http://www.physorg.com/news149185135.html

Coffee helps you retain mental sharpness later in the day

A recent study of 40 older adults (over 65) confirmed the popular belief in the value of caffeine in helping overcome a decline in mental sharpness later in the afternoon. All the participants (like three-quarters of all people in that age group, studies suggest) described themselves as "morning people". Testing confirmed that they were less alert later in the day. Given coffee, but not told whether it was "real" coffee or decaffeinated, those who drank the regular coffee did not experience mental declines in the afternoon tests. Note that participants were already regular coffee drinkers (and were asked to abstain before arriving for the test).

Ryan, L., Hatfield, C., & Hofstetter, M. (2002). Caffeine reduces time-of-day effects on memory performance in older adults. Psychological Science: A Journal of the American Psychological Society APS, 13(1), 68-71. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/11892781

http://www.nytimes.com/2002/01/01/health/psychology/01AGIN.html?rd=hcmcp?p=041sRh041sTt436WO012000mo9$ho9mk

Helping memory with "natural" supplements

Do caffeine and glucose help concentration? A recent study found that volunteers who drank a mixture containing caffeine and glucose (as well as trace levels of guarana, ginkgo and ginseng) showed clear improvements in memory and attention. Those who consumed the individual ingredients, or a placebo, did not show such improvements.

Scholey, A. & Kennedy, D. 2003. Report at the British Psychological Society Annual Conference in Bournemouth 13-15 March.

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