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Koffie en diabetes en een langer leven*
Uit twee studies blijken de voordelen van het drinken van koffie zowel tegen hart- en vaatziektes en tegen diabetes type-2. Uit een Amerikaanse studie onder ruim 143.000 mannen en vrouwen die 30 jaar gevolgd werden blijkt dat het regelmatig drinken van koffie de kans op hart- en vaatziektes en andere ziektes doet afnemen waardoor men langer leeft. Uit de tweede Deense studie, in het laboratorium en met ratten blijkt dat een paar van de wel duizend bioactieve stoffen in koffie belangrijk zijn om de kans op diabetes te verkleinen. Eerdere studies lieten nl. zien dat het drinken van koffie de kans op diabetes doet verkleinen. De stoffen waren cafestol en cafeïnezuur die in zeer kleine hoeveelheden in koffie zitten. Filterpapier laat echter weinig cafestol door.
De studie ¹ ².  (Januari 2016)

Moderate coffee drinking may be linked to reduced risk of death
Drinking a second or third cup of coffee may do more than get you through a long day -- it may also reduce your risk of death from heart disease and other illnesses.
In a study reported in the American Heart Association journal Circulation, people who regularly drank moderate amounts of coffee daily --less than 5 cups per day -- experienced a lower risk of deaths from cardiovascular disease, neurological diseases, Type 2 diabetes and suicide.
The benefit held true for drinking caffeinated and decaffeinated coffee, suggesting it's not just the caffeine providing health perks but possibly the naturally occurring chemical compounds in the coffee beans.
"Bioactive compounds in coffee reduce insulin resistance and systematic inflammation," said Ming Ding, M.D., the study's first author and doctoral student at the Harvard T.H. Chan School of Public Health in Boston, Massachusetts. "They might be responsible for the inverse association between coffee and mortality. However, more studies are needed to investigate the biological mechanisms producing these effects."
The findings are based on data from three large ongoing studies: 74,890 women in the Nurses' Health Study; 93,054 women in the Nurses' Health Study 2; and 40,557 men in the Health Professionals Follow-up Study.
Researchers assessed coffee drinking every four years using validated food questionnaires and followed participants for up to 30 years. During the follow-up period, 19,524 women and 12,432 men died from a range of causes.
In general, people who frequently drank coffee were more likely to smoke and drink alcohol. To separate the effects of coffee from smoking, researchers repeated their analysis among never-smokers, and found that the protective benefits of coffee on deaths became even more evident.
"Regular consumption of coffee can be included as part of a healthy, balanced diet," said senior author Frank Hu, M.D., Ph.D., a Professor of Nutrition and Epidemiology at Harvard. "However, certain populations such as pregnant women and children should be cautious about high caffeine intake from coffee or other beverages."
The study was not designed to show a direct cause and effect relationship between coffee consumption and dying from illness. So the findings should be interpreted with caution, researchers said. One potential drawback of the study design was that participants were asked to report how much coffee they drank, however researchers found the assessment to be reliable.
Previous studies found inconsistent associations between coffee drinking and risk of total and cause-specific death. This study adds to the literature that moderate coffee consumption may confer health benefits. However, more research is needed to determine how coffee affects the body and whether different types of coffee may play a role.
Other co-authors are Ambika Satija, B.A.; Shilpa N. Bhupathiraju, M.D.; Yang Hu, M.S.; Qi Sun, M.D., D.Sc.; Jiali Han, D.Sc. ; Esther Lopez-Garcia, Ph.D. ; Walter Willett, M.D., Dr.PH.; and Rob van Dam, Ph.D.
The National Institutes of Health funded the study.
Reference:
1. Ming Ding et al. Association of Coffee Consumption with Total and Cause-Specific Mortality in Three Large Prospective Cohorts. Circulation, 2015 DOI: 10.1161/CIRCULATIONAHA.115.017341 

Specific coffee chemicals may ward off type 2 diabetes
Coffee and diabetes are two of the most commonly covered topics in current medical news. The latest research looks in detail at some of coffee's ingredients and their potential effects on diabetes. 
A new study finds interesting links between specific chemicals in coffee and type 2 diabetes.
The prevalence of coffee and diabetes in modern media makes a great deal of sense: almost 1 in 10 Americans are diabetic, and more than half of American adults drink coffee daily. 
The US spends roughly $40 billion on coffee per year, and in 2012, the total estimated cost of diagnosed diabetes in America was $245 billion. 
Any links between these two unlikely bedfellows are likely to be chased down with vigor. 
Recent research published in the American Chemical Society's Journal of Natural Products gives us a glimpse into the potential benefits of some of coffee's natural compounds in the management of type 2 diabetes. 
Type 2 diabetes
Individuals with type 2 diabetes have a resistance to insulin. Insulin normally helps control the amount of glucose in the blood. If levels are high, it instructs the liver and muscles to absorb more. 
Diabetes causes the body to stop reacting to insulin as it should. Insulin is released, but the liver and muscle cells no longer absorb the excess glucose. In the early phases of the disease, an increased amount of insulin is produced in an effort to convince the body to take on more glucose. 
As the disease progresses, insulin-producing cells in the pancreas slowly die off through overuse. 
The health implications of diabetes can be dire: damage to large blood vessels in the heart, brain and legs. Also, damage to smaller blood vessels can cause problems in the kidneys, eyes, feet and nerves. 
The chemistry of coffee
All in all, there are more than 1,000 distinct chemical compounds in coffee. This impressive recipe includes quinic acid, 3,5-dicaffeoylquinic acid, acetylmethylcarbinol, dimethyl disulfide, putrescine, niacin, trigonelline, theophylline and our old friend and foe, caffeine. 
Each of coffee's ingredients has the potential to affect human biology. More than likely, the majority of compounds, in the tiny amounts they are present in coffee, will not have a great effect on the body. 
Having said that, there is no reason not to study each of these molecules in an effort to get to grips with the myriad of effects that coffee appears to exert on us. 
Coffee and diabetes
Research into coffee and its ability to prevent or slow the onset of type 2 diabetes has garnered a fair amount of attention. A recent review of the literature concluded that habitual coffee drinking does seem to lower the risk of type 2 diabetes. 
The next challenge is to tease apart the many components of coffee to pinpoint the active ingredients. As the bewildering list of chemicals above infers, this may be a gargantuan task. 
Recent research conducted by Søren Gregersen and colleagues at the Department of Endocrinology and Internal Medicine at Aarhus University Hospital in Denmark may have narrowed the search. 
Gregersen and his team looked at the effect of a number of coffee's constituents on rat cells in vitro. Most of the compounds did not have significant effects, but cafestol and caffeic acid threw out some intriguing results. 
Cafestol and caffeic acid
Cafestol makes up around 0.5% of the dry weight of coffee beans. It has been found to have anti-carcinogenic effects in rats and neuroprotective roles in the fruit fly model of Parkinson's disease. 
Caffeic acid plays a major role in the building of lignin and is therefore found in all plants. It occurs in coffee but only in tiny amounts - around 0.03 mg per 100 g. Some studies have shown it to have anti-cancer and anti-inflammatory effects. 
The present study found that cafestol and caffeic acid increased insulin production in the presence of glucose. Cafestol was also found to increase glucose uptake into muscle cells at a similar rate to current diabetes drugs. 
According to Gregersen: 
"This newly demonstrated dual action of cafestol suggests that cafestol may contribute to the preventive effects on type 2 diabetes in coffee drinkers."
The study will add another welcome avenue of research into potential treatments for diabetes. 
However, to re-muddy the water, coffee filters eliminate most of the cafestol from the resulting cup. So, cafestol is unlikely to be the only useful additive for type 2 diabetics. The search is still very much on. 
Cafestol, a bioactive substance in coffee, stimulates insulin secretion and increases glucose uptake in muscle cells: studies in vitro, Mellbye FB et al., Journal of Natural Products, doi: 10.1021/acs.jnatprod.5b00481.