Tea is a great passion of mine. I prefer it to coffee because of how many flavors and how much life there is to tea. I find that a cup of tea can be either a soothing or exhilarating experience. I have enjoyed trying many different types of tea and ...continue reading]]> By Erik Todd, Chemist

Tea is a great passion of mine. I prefer it to coffee because of how many flavors and how much life there is to tea. I find that a cup of tea can be either a soothing or exhilarating experience. I have enjoyed trying many different types of tea and noting the subtleties of each of them. However, there is another great reason for drinking tea. Tea could help reverse or even prevent some of the damages of Alzheimer’s disease.

Alzheimer’s disease (AD) is a serious affliction that impacts a great deal of the world’s population. As reported by Buckingham et al (1) in 2000 there were 4.5 million individuals with AD with the prediction that in 2050 there will be approximately 13 million sufferers. The disease is physiologically characterized by amyloid beta (Aβ) plaques forming in the regions outside of the neurons of the brain. AD is also sometimes associated with an increase in adenosine levels in the brain as well as an increase in oxidative damage. Symptoms are most generally memory and cognitive function loss.

Scientists are studying the mechanisms that cause the plaques and the loss of mental function.  There have been many theories and they tend to make sense. One of the theories that I most agree with indicates that a certain protein, Amyloid Precursor Protein (APP), is cleaved by several enzymes, most notably β‐site Amyloid Protein Precursor Cleaving Enzyme (BACE). BACE cleaves APP into two pieces:  A soluble piece, which basically floats through the extracellular fluid; and an insoluble form which remains bound to a cellular wall. The soluble pieces are brought together, most likely complexed by copper or zinc in the fluids (2), to form oligomers which are shown to be associated with cognitive decline.

Research indicates that caffeine may be able to slow the progression of Alzheimer’s disease as well as reverse the cognitive loss associated with the disease (3,4). Caffeine competes very strongly for adenosine receptors which prevents the adenosine from binding. This inhibition may promote a decrease in inflammation. Though the mechanism is still being investigated, the results do indicate that an increase in caffeine consumption may in fact help to reverse the damages of Alzheimer’s disease.

Other researchers have indicated that patients with AD exhibit an elevated amount of oxidative stress. In other words, there are radical oxygen species which are damaging the brain, which is highly susceptible to oxidative damage. Siegel et al. have suggested that the oxidative damage is a cause for AD (5). Tea contains polyphenols such as tannin and flavonoids. Tannin is associated with the astringency of certain teas and wines. Flavonoids are multifaceted in their many roles, but are great antioxidants (6).

It is because of the caffeine and the oxidative damage that tea has great potential in relieving the symptoms of Alzheimer’s disease. Though there is, to my knowledge, little or no experimentation taking place on the topic, from the information gathered in the references above, one could definitely see the benefits of drinking tea.

A more complete paper regarding caffeine and Alzheimer's disease can be found at the following web site.  It also contains more references on the topic.
http://science.csustan.edu/stone/chem4400/SJBR/ErikTodd.pdf

Erik can be contacted at:  Erik.M.Todd@Vanderbilt.edu

References:

1) Buckingham, S. D.; Jones, A. K.; Brown, L. A.; Sattelle, D. B.; Nicotinic Acetylcholine Receptor
Signalling: Roles in Alzheimer’s Disease and Amyloid Neuroprotection. Pharmacol Rev.
2009, 61, 39‐61.

2) Danielsson, J.; Pierattelli, R.; Banci, L.; Gräslund, A.; High‐resolution NMR studies of the zincbinding
site of the Alzheimer’s amyloid β‐peptide. FEBS Journal. 2007, 274, 46‐59.

3) Chen, J.; Sonsalla, P.; Pedata, F.; Melani, A.; Domenici, M. R.; Popoli, P.; Geiger, J.; Lopes, L.
V.; de Mendonça, A.; Adenosine A2A receptors and brain injury: Broad spectrum of
neuroprotection, multifaceted actions and ‘‘fine tuning’’ modulation. Prog Neurobiol.
2007, 83, 310‐331.

4) Arendash, G; Mori, T.; Cao, C.; Mamcarz, M.; Runfeldt, M.; Dickson, A.; Rexai‐Zadeh, K.; Tan,
Jun.; Citron, B. A.; Lin, X.; Echeverria, V.; Potter, H.; Caffeine Reverses Cognitive
Impairment and Decreases Brain Amyloid‐β Levels in Aged Alzheimer’s Disease Mice. J.
Alzheimer’s Dis. 2009, 17, 661‐680.

5) Siegel, S. J.; Bieschke, J.; Powers, E. T.; Kelly, J. W.; The Oxidative Stress Metabolite 4‐
Hydroxynonenal Promotes Alzheimer Protofibril Formation. Biochemistry, 2007, 46,
1503‐1510.

6) Heim, K.E.; Tagliaferro, A. R.; Bobilya, D. J.; Flavonoid Antioxidants: chemistry, metabolism
and structure‐activity relationships. J. Nutr. Biochem. 2002, 13, 10, 572‐584.

A flurry of tea articles appeared in the press recently, so I thought I'd give you the highlights:

A Cup of Coffee OK During Pregnancy

The American College of Obstetricians and Gynecologists has changed their recommendation regarding caffeine consumption during pregnancy.  Formerly, caffeine was considered off-limits since it ...continue reading]]> By Lori Bricker, MS, RD

A flurry of tea articles appeared in the press recently, so I thought I'd give you the highlights:

A Cup of Coffee OK During Pregnancy

The American College of Obstetricians and Gynecologists has changed their recommendation regarding caffeine consumption during pregnancy.  Formerly, caffeine was considered off-limits since it can cross the placenta, but now the group says up to 200 mg of caffeine per day is unlikely to cause an increased risk of miscarriage or premature delivery.  Two recent studies each followed 1000 pregnant women.  One study found no increased risk of miscarriage with any amount of caffeine; the other found no increased risk at intakes up to 200 mg per day. Two other studies showed no risk of premature delivery with moderate caffeine intake.  So how much is 200 mg?  Approximately 12 oz. of coffee, 24-32 oz. of tea, or 6 or 7 dark chocolate bars (please don't eat that many at once!).

Black Tea Compounds Show Anti-Allergy Potential

A new study that used mice shows that theaflavins, the flavanoid found in black tea, reduce a certain type of allergic reaction.  The researchers gave mice large doses of theaflavin extract and then subjected them to various allergens (allergy-causing substances).  Compared to control mice who were not given the theaflavin, the mice had much lower responses to the allergens. Responses were measured by looking at blood levels of certain markers of inflammation.  Keep in mind that a) this study was on mice, not humans; and b) the dose given the mice was rather large (50 mg theaflavins per kg body weight).  If a human were to get a comparable dose of theaflavin from tea, it would take between 20-25 cups.

Greater Concentrations of Fluoride in Tea than Once Thought

Researchers at the Medical College of Georgia have come up with a new way to test how much fluoride is in tea, and it's more than we thought.  The researchers bought seven brands of black tea from grocery stores and brewed each for 5 minutes in water that did not contain fluoride.  While previous methods showed amounts of 1-5 mg fluoride per liter, the new method showed fluoride levels as high as 9 mg per liter (a liter is about a quart, or 4 cups).  Although this is not a concern for most tea drinkers, those who drink the most tea, say a gallon or more a day, should be concerned.  Too much fluoride over a very long period of time (such as 20 mg per day for at least 10 years) can result in skeletal fluorosis, a condition that can lead to damaged and painful joints.  The lead researcher, Dr. Gary Whitford, had seen 4 patients with skeletal fluorosis, and they all drank 1-2 gallons per day of  tea for 10-30 years.  Dr, Whitford said,  “The additional fluoride from drinking two to four cups of tea a day won’t harm anyone; it’s the very heavy tea drinkers who could get in trouble.”

This research specifically discusses black tea.  Someone asked me if the same is true for green, oolong, and white tea.  I haven't seen any data regarding re-testing the amount of fluoride in other kinds of tea, so I just don't know.  It makes sense to me that higher levels would be found there as well, as compared to previous measurements.  Green tea has roughly the same amount of fluoride as black tea.

If you are concerned about the fluoride in your tea

• Find out how much fluoride is in your local water supply.
• Use bottled water (or other non-fluoridated water) to brew your tea. 
• Don't drink gallons. 
• Discuss fluoride with your doctor and dentist and let them know how much tea you drink.

I hate giving people answers they don't want to hear.  As a tea shop owner, I get a lot of questions about the health effects of tea.  Since I have a background in nutrition, I have some insight into how complicated the question really is, so my answers are ...continue reading]]> By Lori Bricker, MS, RD

I hate giving people answers they don't want to hear.  As a tea shop owner, I get a lot of questions about the health effects of tea.  Since I have a background in nutrition, I have some insight into how complicated the question really is, so my answers are never what people expect.  People ask pretty specific questions, but sadly, the specific answers they want are not available yet.

Here are some really good questions that have no known answers:

    •    Which tea is the most healthful?
    •    Which tea has the least caffeine?
    •    Which tea will cure my [fill in the blank]?
    •    How much tea should I drink in a day?

The science of tea (Camellia sinensis)  is too young to offer definitive answers to these and other popular questions. But there are a lot of studies being done, and many get written up in the popular press.  So many, in fact, that it's easy to get the impression that tea is a real cure-all.  I'd like to talk about why you should be cautious when you read these articles.  For this post, I'll just talk about cohort studies, and another post will discuss research studies.

Here's what you need to know about cohort studies:

• Cohort studies involve large numbers of people (not rats!) who have something in common and following them for several years, then studying data collected during that time and to look for trends in the various outcomes.  For example, you might look at everyone born before 1950 in a particular town, and follow them for 15 years to determine the rates of a certain disease.  You compare the disease trends with the information the participants give you about their diet, health history, medications, etc.

• Their major strength is that because cohort studies last so long, you can see real outcomes, like death and disease, that you just don't get with shorter experiments.

• The downside is that lots and lots of things happen to the people in your cohort, and you have less control over it than you would in an experiment.

• Cohort studies usually use questionnaires to gather data from the participants.  For food and beverage intake data, researchers use a tool called a food frequency questionnaire, which will ask you potentially hundreds of questions such as, "How often do you eat broccoli in a month and what is the serving size?"  By the time you get to the end, your mind is mush.  Even in a well-designed food frequency tool, self-reported data is only as good as the participants' memories, patience, and honesty.

• Cohort studies usually do not show cause and effect.  They show correlations, but they don't tell if one thing caused the other. To illustrate the point, you might notice a correlation between the occurrence of rain the the appearance of umbrellas.  Of course, you would be wrong to conclude that umbrellas caused the rain.

Another confounding factor for ANY tea research is that tea preparation methods can affect how concentrated a brew you are consuming, which in theory should affect the results.  I might brew an 8 oz. cup of tea for 8 minutes in boiling water using 3 tsp of leaves.  You might drag a tea bag through 8 oz. of tepid water and be done.  There could be a huge difference in the amount of tea catechins and other active compounds in these two beverages.

Now, of course, the scientists doing this research know all these things, but sometimes these concerns don't get addressed in media stories about the research. 

When reading an article in the popular press about a research article involving a cohort:

•  Read carefully to see if they use the word, "correlation," and if so, don't misread causation into that.

• Notice details about the cohort itself– is it all women, all men, all people from one country or another, do they have any diseases, what kind of tea do they drink?

• What do they say about the kind of questionnaire used?  Was it filled out just once at the beginning or multiple times?  Do they tell you what they asked regarding tea consumption?

• Read more than one article about the same research to see if you get a consistent message.

Be aware that it takes mounds of research before you can really say something with confidence. In this online article reporting on a heart disease study that involved tea and coffee, Dr. Frank Hu, professor of nutrition and epidemiology at the Harvard School of Public Health, is quoted as saying,

"Based on current evidence, it is very difficult to come up with an optimum amount of coffee or tea for the general population." 

After years of research on tea (and coffee), this is where we are?  Yes, and we are likely to be here for a while.
 

Someone I follow on Twitter asked whether having afternoon tea with a sweet treat would harm her attempts at weight loss.  She referenced an article called, Tea Time Calls For Sweet Treat, by Ginna Parsons, who mentions a book she read whose author says she finds that having a ...continue reading]]> By Lori Bricker, MS, RD

Someone I follow on Twitter asked whether having afternoon tea with a sweet treat would harm her attempts at weight loss.  She referenced an article called, Tea Time Calls For Sweet Treat, by Ginna Parsons, who mentions a book she read whose author says she finds that having a 150 calorie treat mid-afternoon helps her not eat too much later on.  As a dietitian, I thought I should offer my opinion. 

This can be a fine strategy for a number of reasons:

1.  Having a reasonable portion of a perceived "treat" each day can help you cope with the otherwise hard facts of dieting.  If you continually deny yourself every treat for the sake of your diet, you will set yourself up for a binge episode, which can easily get out of hand.  But knowing that you can have a treat everyday is very soothing when you're feeling a bit deprived, and it gives you something to really look forward to.

2.  A tea break in the afternoon (with or without food) can provide relief from the mental stress of your day.  We all tend to eat more when we feel overwhelmed, so by preventing your stress level from climbing, you can avoid stress-eating later..

3.  I have found that when you prevent yourself from getting overly hungry, it can help you eat less at the next meal.  This doesn't always work for everyone, however, so you need to see how you do with it.  The suggestion in the article of a 150 calorie treat seems reasonable — just enough to make you feel like you had something without blowing it.  Make sure to help yourself control portion sizes by only taking to the table what you are allowing yourself to have, otherwise you may be too tempted to have a second helping.

If you're worried that having a treat will make you go over on your allowed calories, burn some extra by taking a brisk walk.  A walk of 45 minutes should burn off that treat.

So what should you have?  It seems to me that afternoon tea is very suggestive of the proper kind of treat to allow yourself.  Typical treats at a casual afternoon tea would be a small scone, a couple of small cookies, or finger sandwiches.  Just enough to go with a couple of cups of tea.  Here is a list of snacks for roughly 150 calories, in case you'd like some ideas: Sweet, Creamy, and Crunchy Snacks for 150 Calories or Less.  Oh, if you put milk or sugar in your tea, don't forget that counts, too.

My preference is for a small slice of homemade banana bread or some similar item.  I like to make them myself so I can use whole wheat flour and less sugar and fat to keep it more nutritious.

Do you take afternoon tea?  Anyone have any recipes or suggestions they'd like to share?

Although not as popular in the United States, it is quite common in Britain to add milk to black tea. Some research has shown that this practice may interfere with the antioxidants in black tea, but the results have been inconsistent. In a study just published in the British ...continue reading]]> By Lori Bricker, MS, RD

Although not as popular in the United States, it is quite common in Britain to add milk to black tea. Some research has shown that this practice may interfere with the antioxidants in black tea, but the results have been inconsistent. In a study just published in the British journal Nutrition Research, researchers examined five brands of British black tea with the addition of 10, 15, and 20 mL (for reference, one fluid ounce is roughly 28 mL) of whole, low-fat, and skim cow’s milk to 200-mL of brewed tea (about 7 oz.). They found that skim milk decreased the antioxidant capacity of the tea significantly more than either whole milk or low-fat milk. The authors conclude that “black tea is a valuable source of antioxidants and that the effect of milk on the total antioxidant capacity may be related to the fat content of the milk.”

Source:  Nutrition Research Volume 30, Issue 1, January 2010, Pages 14-20.

doi: 10.1016/j.nutres.2009.11.005

There has been so much media hype over green tea and weight loss in the last couple of years that a lot of consumers are becoming very annoyed with what they perceive as slick marketing or outright lies.  It is extremely common, especially on the Internet, to find all ...continue reading]]> By Lori Bricker, MS, RD

There has been so much media hype over green tea and weight loss in the last couple of years that a lot of consumers are becoming very annoyed with what they perceive as slick marketing or outright lies.  It is extremely common, especially on the Internet, to find all kinds of “too good to be true” health claims for tea, particularly as it pertains to weight control, a topic of interest to so many.   As is frequently the case with exaggerated nutrition claims, there may be some truth behind the hype.  So how much can you really depend on green tea to help you slim down?  A new review published in The American Journal of Clinical Nutrition demonstrates how complicated this issue is and suggests that green tea is no magic bullet.

The authors of the paper searched for recent studies that had evaluated the effects of green tea catechins, both with caffeine and without, on body weight, BMI (body mass index), waist circumference, and waist-to-hip ratio.  To be included in the review, the studies had to be randomized and had to meet validity criteria as determined by use of the American Dietetic Association Research Design and Implementation Checklist.  This means that the research was, for example, bias-free, provided a clear statement of the research question, and used appropriate statistical analysis, among other things.

Fifteen research studies met these criteria and were evaluated in this paper.  The studies fell into three groups:   In seven studies, green tea catechins with caffeine were compared to caffeine-matched controls (we’ll call these Group 1); in six studies, green tea catechins with caffeine were compared to caffeine-free controls (Group 2); and in two studies, caffeine-free green tea catechins were compared to caffeine-free controls (Group 3).

They found the following:

• For Group 1, doses of green tea catechins of 583-714 mg/day over a median of 12 weeks had a statistically significant benefit on BMI, body weight, and waist circumference, but no effect on waist-to-hip ratio.
• For Group 2, green tea catechin intake of 141-1207 mg/day significantly reduced body weight, but had no effect on the other parameters.
• For Group 3, (green tea catechin intake of 282-548 mg/day) there were no significant changes in any of the parameters.

So, off-hand, it looks promising with 2 groups showing “statistically significant” changes in the observed parameters.  But here are some things to note:

• Just because a result is statistically significant doesn’t mean it is a big difference; it just means it is unlikely to be caused by chance.  For the statistically significant weight loss results observed for Group 1, the amount of weight lost averaged just 3 pounds over 12 weeks for the tea group compared to the control group.  That’s something, but it is not like these people lost 10 or 20 pounds in a two weeks by ingesting green tea catechins.  For Group 2, the results were even less impressive at an average of <1 pound.
• On a similar note, the authors pointed out that the waist circumference measurements, although reduced by statistically significant amounts for Group 1 (an average of <2cm), practically speaking could have occurred as part of normal measurement error.
• How much green tea catechin were the subjects consuming?  The studies evaluated here used varying amounts of green tea catechin, the equivalent of roughly 1-8 cups of tea per day.  This makes it very difficult to generalize, and the authors noted they were unable to determine if the effects of green tea catechin were dose-dependent.
• There are also several different green tea catechins, and their specific effects are not fully understood.  Some studies reviewed here specified which catechins were given, but others did not.
• The authors also noted that the ingestion of green tea catechins with or without food can affect its absorption (it is increased on an empty stomach), and these studies were inconsistent with respect to when catechins were given to the subjects.
• The populations studied in these trials also varied and included children, men only, postmenopausal women, healthy adults, and adults with various conditions (such as obesity, diabetes, high cholesterol).   The authors pointed out that they were unable to say which of these populations might benefit the most from the green tea catechins.
• Group 3 only contains 2 studies, so perhaps we shouldn’t generalize too much about decaffeinated green tea catechins.
• Something to keep in mind in general when looking at tea studies is that how the tea is brewed can effect the quantities of catechin present in the final beverage, so that is often an unknown factor.  I also wonder if green tea catechin in capsule form has the same effects as that in brewed tea?  This question is not typically addressed.

The authors concluded that the observed reductions in weight loss and other parameters, although statistically significant in some cases, practically speaking are not all that important.  As a registered dietitian, if I were counseling someone on a weight loss plan, I would suggest drinking green tea if they like it (why not?), but I certainly would not make it a requirement and would explain that, while it appears to aid in weight loss a bit, it won’t have a dramatic effect.  Changing your overall diet to include more vegetables, fruits, whole grains, and fiber while getting plenty of exercise will do far more than green tea.

Source:  Phung, O.J., et. al. Effect of green tea catechins with or without caffeine on anthropometric measures:  a systematic review and meta-analysis.  Am J Clin Nutr 2010;91:73-81.

The other day I received the following questions in my email from a student doing a project on tea and health.  I thought these sounded like fine questions, so I’m posting them with my answers here.

What is the main benefit of drinking tea? It’s really difficult to pick ...continue reading]]> By Lori Bricker, MS, RD

The other day I received the following questions in my email from a student doing a project on tea and health.  I thought these sounded like fine questions, so I’m posting them with my answers here.

What is the main benefit of drinking tea? It’s really difficult to pick one thing.  The research being done these days covers so many interesting topics, including heart disease, cancer, Parkinson’s disease, cognitive function, blood vessel function, mood, stress, weight loss, dental health — the list goes on and on.  But not all of these studies have found definitive answers to our questions about tea and health, and sometimes even conflicting results are found.  Much more research needs to be done to pin down the intricacies of how tea affects our bodies. So rather than focus on one benefit, I usually think of tea as a way to improve overall health and well-being.  There are few people who can’t benefit in one way or another from drinking reasonable amounts of tea on a regular basis.  Even one cup has been shown to offer some benefits.  The other question that people always ask is whether green tea is better for you than black tea.  It is becoming apparent that all kinds of tea are good for you:  black, green, oolong, and white.  (Herbal teas are not true “teas” in that they are not made from the Camellia sinensis plant – so those are really completely different topic.)  I encourage people to drink all kinds if they like them, and if they only like one kind, then just drink that one.  Drinking tea should not be a chore.  It is a very pleasant activity, and that in itself may contribute to some of its effects on our mood and stress level.

Could you say that tea helps increase longevity? How so? Perhaps.  There was a study published this year that found that  Chinese men who drink more than 3 cups a day of tea have longer telomeres.  Telomeres are part of our chromosomes.  They are a repetitive piece of DNA located at the ends of our chromosomes, and each time a cell divides, a bit of this telomere gets sheared off and shortened.  Telomeres protect our DNA from being damaged during cell division, much like the end of a shoelace protects the shoelace from unraveling.  Once the telomeres are gone, our DNA is subject to degradation during cell division, and animal studies suggest this plays an important role in aging at the cellular level.  (See this Wikipedia article for more detail about telomeres.) The mechanism by which tea might protect telomeres is not known at this time.  Another recent study found a correlation between green tea intake and reduced death rate from all causes – there could be many different things at work here.  If tea consumption can reduce the incidence or death rate of certain diseases, then that alone may increase longevity.

Are the downsides of caffeine enough to outweigh the positives of tea? It is generally agreed that, for most people, moderate caffeine consumption (up to 300 mg. per day) is harmless.  Many people find that caffeine boosts mental clarity and alertness in a pleasing way.  Tea contains, roughly, only 40 mg caffeine per 6 oz. cup, compared to brewed coffee at 100-150 mg., so you’d have to drink quite a bit more tea to get “too much” caffeine.   Also, tea is unique in that it contains the amino acid L-theanine, which “significantly increases activity in the alpha frequency band which indicates that it relaxes the mind without inducing drowsiness” (Ref: http://highwire.stanford.edu/cgi/medline/pmid;18296328).  This may explain why some people report tea calms them in spite of the caffeine content.  Since caffeine is a cardiac stimulant, however, people with certain heart conditions should avoid caffeine, and excessive caffeine intake can cause restlessness, insomnia, and anxiety. Women should avoid caffeine throughout pregnancy and while nursing.

Are there any other negatives to drinking tea? There really aren’t any.  The only possible downside is that it is hard to get a decent cup of tea at most restaurants, and you’re kind of left out when people are enjoying their coffee drinks.  But it is delicious, inexpensive, enjoyable, and healthful.  What more could you possibly want?

In an effort to examine the possible effects of flavonoid-rich foods on age-related cognitive decline, researchers in Norway performed cognitive testing on participants of a large public health study.  The Hordaland Health Study (HUSK) was conducted from 1997-1999 and included participants born between 1925-1927.  A total of 2031 participants ...continue reading]]> By Lori Bricker, MS, RD

In an effort to examine the possible effects of flavonoid-rich foods on age-related cognitive decline, researchers in Norway performed cognitive testing on participants of a large public health study.  The Hordaland Health Study (HUSK) was conducted from 1997-1999 and included participants born between 1925-1927.  A total of 2031 participants received the cognitive testing and filled out the required food-frequency questionnaire for the current study, published this year.  The purpose of the questionnaire was to obtain information on intake of 169 different food items during the last year.  Portion sizes of wine, tea, and chocolate were obtained as follows:  chocolate (type not specified), 60 g or about 2 oz.; wine (type not specified), 120 mL or 4 oz.; and tea (Camelia sinensis), 200 mL or about 6.5 oz.  Most Norwegians at that time drank black tea, so it was presumed most tea drinkers were consuming black tea; likewise, most chocolate in Norway is milk chocolate.

Cognitive testing included 6 tests administered by trained nurses at the study location.  Consumers of chocolate, wine, and tea performed better on all 6 tests than non-consumers.  For consumers, the mean intake of chocolate was 7.5 g/day (about 1/4 of an oz.); of wine, 51 mL/day (about 1.7 oz.); and of tea, 417 mL/day (about 14 oz.), so these are not particularly high intakes.

Statistical analyses were done to help omit confounding factors and to separate each of the three foods’ effects.  After these adjustments, the wine drinkers’ scores remained significantly better than non-consumers’ scores on all 6 tests.  The chocolate-consumers’ scores were significantly better on 5 of the 6 tests, and the tea-drinkers’ scores were significantly better on 4 of the 6 tests, in comparison to non-consumers.

The researchers noted that the cognitive test scores improved with the number of these three foods consumed.  So those who consumed wine, tea, and chocolate outperformed those who only consumed one or two of those foods.  When looking at individual food items, improvements in test scores were dose-dependent up to a plateau at which no further improvement was found:  for wine, this plateau was about 1/2 glass per day; for chocolate, about 10 g/day (about 1/3 of an ounce); but there was not a plateau for tea.

Strengths of this study include the large number of participants, the large number of cognitive tests performed on each subject, and that the food frequency questionnaire had been previously validated for accuracy.  It is difficult, however, for dietary intake studies to be completely accurate, and in this study, for example, they did not give participants the opportunity to specify type of wine (red or white), tea (green or black), or chocolate (milk or dark).  Nor could subjects  specify weak or strong tea.  (Also, alcohol intake is known to be frequently under-reported.)  But given the overwhelming popularity of black tea and milk chocolate in Norway, these two variables may not be that important for this population.  Also keep in mind that an elderly person’s lifetime exposure to foods appears to be related to mental performance, but this study only looked at the previous year’s food intake (obviously for good practical reasons).  The researchers were also careful t0 mention that just because these foods are correlated with better cognitive testing does not mean for certain that the flavonoids in these foods are responsible for this result, and they recommend further studies be performed that directly address this question.

I’ve already had my tea today . . . On to a small glass of wine and a half-square of chocolate.  I can do this!

Reference:  J Nutr 139: 120-127, 2009.