Three cups of tea a day ‘protects against heart problems and diabetes’
This appears to be a rather casual look at existing epidemiological findings, and the authors themselves note the limitations in drawing inferences from such data. And the blather about antioxidants is just fashionable crap that goes against the evidence. A not very impressive job of work on behalf of the tea industry but it's probably the best they could do
Drinking just three cups of tea a day may protect against heart attacks and type 2 diabetes, claim researchers. A review shows regular drinking of black tea, with or without milk, can reduce the risk of heart problems by cutting levels of bad cholesterol and blood sugar.
Experts say the benefits of tea are largely due to the flavonoid content – antioxidant ingredients that counteract cardiovascular disease.
One cup of tea provides 150-200mg of flavonoids and it is the best source of antioxidants in the nation’s diet. In terms of the delivery of antioxidants, two cups of tea is equivalent to five portions of vegetables.
A review in the journal Nutrition Bulletin found drinking three or more cups of black tea a day protects against heart disease and two or more cups a day may protect against type 2 diabetes.
In addition, a 12-week study in 87 volunteers found that drinking three cups of tea a day produced a significant improvement in various cardiovascular risk factors.
Almost 80 per cent of Britons are tea drinkers and 165million cups are drunk every day.
Overall, flavonoids found in tea are thought to control inflammation, reduce excess blood clotting, promote blood vessel function and limit furring up of the arteries.
Nutritionist Dr Carrie Ruxton, co-author of the latest review and a member of the industry-backed Tea Advisory Panel (TAP), said: 'There is far more to the nation's favourite drink than we realise. 'With its antioxidant flavonoids, black tea packs a powerful punch with many health benefits particularly for the heart. And recent studies show that the flavonoids work their magic whether or not we choose to add milk.'
Dr Tim Bond also from TAP, added: 'Black tea flavonoids are thought to be the compounds responsible for the protective effects of black tea on health. 'Chronic conditions such as heart disease, stroke and diabetes are associated with inflammatory processes and the presence of excessive pro-oxidant free radicals in the body. 'The proven antioxidant and anti-inflammatory effects of black tea flavonoids may therefore be responsible for the positive health effects of black tea.'
Is black tea consumption associated with a lower risk of cardiovascular disease and type 2 diabetes?
C. H. S. Ruxton & P. Mason
Type 2 diabetes mellitus and cardiovascular disease represent major causes of morbidity, which impact greatly on healthcare expenditure. Clinical studies suggest that ingestion of black tea, which contains a range of bioactive compounds, can inhibit oxidative damage and improve endothelial function. The objectives of this review are to: (1) evaluate observational evidence linking black tea consumption with the prevalence of cardiovascular diseases and type 2 diabetes; (2) consider the mechanisms by which black tea may have a protective effect; and (3) examine the potential role of tea drinking in relation to public health.
The findings from epidemiological studies suggested a significant association between regular black tea consumption and a reduced risk of coronary heart disease at around three or more cups per day. For diabetes risk, the data are restricted to a few large cohort studies that suggested a beneficial association at one to four cups daily. These findings need to be confirmed by intervention trials. While some studies suggest that drinking black tea may reduce the risk of stroke, likely mechanisms remain unclear, highlighting the need for more human intervention studies. Disparities found involving studies may have been influenced by variations in reported tea intakes, limited sample sizes in intervention trials and inadequate control of confounders. In conclusion, drinking black tea may have a role in lowering the risk of coronary heart disease and type 2 diabetes. Future research should focus on controlled trials and studies to elucidate likely mechanisms of action.
Pesky! But it's just working class habits being picked up again
Diet soda may benefit the waistline, but a new study suggests that people who drink it every day have a heightened risk of heart attack and stroke.
The study, which followed almost 2,600 older adults for a decade, found that those who drank diet soda every day were 44 percent more likely than non-drinkers to suffer a heart attack or stroke.
The findings, reported in the Journal of General Internal Medicine, don’t prove that the sugar-free drinks are actually to blame. There may be other things about diet-soda lovers that explain the connection, researchers say.
“What we saw was an association,” said lead researcher Hannah Gardener, of the University of Miami Miller School of Medicine. “These people may tend to have more unhealthy habits.”
She and her colleagues tried to account for that, Gardener told Reuters Health. Daily diet-soda drinkers did tend to be heavier and more often have heart risk factors like high blood pressure, diabetes and unhealthy cholesterol levels.
That all suggests that people who were trying to shed pounds or manage existing health problems often opted for a diet soda over the sugar-laden variety.
But even after the researchers factored in those differences — along with people’s reported diet and exercise habits — they found that daily diet soda was linked to a 44-percent higher chance of heart attack or stroke.
Nevertheless, Gardener said, it’s impossible for a study to capture all the variables that could be at work.
The findings do build on a few recent studies that also found diet-soda drinkers are more likely to have certain cardiovascular risk factors, like high blood pressure or high blood sugar.
This is the first study, Gardener said, to look at actual “vascular events” — that is, heart attacks, strokes and deaths from cardiovascular causes.
The findings are based on 2,564 New York City adults who were 69 years old, on average, at the outset. Over the next decade, 591 men and women had a heart attack, stroke or died of cardiovascular causes.
That included 31 percent of the 163 people who were daily diet-soda drinkers at the study’s start. In contrast, 22 percent of people who rarely or never drank diet soda went on to have a heart attack or stroke.
There was no increased risk linked to less-than-daily consumption. Nor was regular soda tied to heart attacks and strokes.
If diet soda, itself, somehow contributes to health risks, it’s not clear how, Gardener said.
There’s research in rats suggesting that artificial sweeteners can end up boosting food intake and weight. But whether results in rodents translate to humans is unknown.
“I don’t think people should change their behavior based on this study,” Gardener said. “And I wouldn’t advocate drinking regular soda instead.”
Regular soda is high in calories, and for people who need to shed pounds, experts often suggest swapping regular soda for the diet version.
A study out this month found that the advice may be sound. Obese people who were randomly assigned to drink water or diet drinks in place of sugary ones lost about five pounds over six months.
Gardener said that further studies such as hers are still needed to confirm a connection between diet soda and cardiovascular trouble.
Ultimately, she noted, clinical trials are considered the “gold standard” for proving cause-and-effect. That would mean randomly assigning people to drink diet soda or not, and then following them over time to see if there were differences in their rates of heart problems or stroke.
A study like that, Gardener said, would be “difficult and costly” — since it would have to follow large groups of people over many years, and rely on people to stick with their assigned beverages.
SEE: http://bit.ly/widyUV Journal of General Internal Medicine, online January 27, 2012.