Health Professionals Newsletter

Welcome to the ninth newsletter from the United Kingdom Tea Council. This service will keep you up to date with current tea4health activities and events and inform you of the latest published research. We'll keep you updated on a quarterly basis with news and views from across the tea industry.

Research Update

One step closer to understanding tea's positive effect on cognition and mood
A combination of caffeine and L-theanine, naturally present in tea, has positive effects on cognition and mood in young adults according to researchers from Northumbria University.

Studies that have considered effects of tea on cognition and mood have found that, although the majority of effects can be explained by caffeine, some differences exist between tea and coffee, even when the caffeine level is matched. The current researchers are proposing L-theanine may hold the key to teas enhanced effects.

The current randomised, placebo controlled, double-blind, balanced crossover study investigated the cognitive and mood effects of the two compounds both alone [L-theanine (250 mg), caffeine (150 mg)] and in combination (250 mg/150 mg). The tasks selected to measure mood and cognition included attention tasks as well as specific memory and reasoning tasks, which are known to be sensitive to caffeine. Mood ratings were also assessed.

Twenty four undergraduate students (mean age 21.3 years) took part in the study and were asked to abstain from caffeine and alcohol 12 hours prior to the study. Participants were randomised to a treatment group and received 4 different beverages (250ml drinks as previously described) plus a placebo on separate occasions 7 days apart. On each occasion the tests were carried out before taking the drink, 30 minutes after the drink and 90 minutes post-drink. Each testing session lasted approximately 30 minutes.

Compared to the isolated effects of caffeine and L-theanine, the combined action resulted in improvements in visual tasks and 'mental fatigue' ratings. In addition the combination of caffeine and L-theanine also speeded up the completion of a number of cognitive tasks. Participants also reported fewer headache symptoms and felt more alert.

As the levels of L-theanine and caffeine used in this study are higher than those found in tea beverages, which are typically in the region of 40 mg caffeine and 20 mg L-theanine, the researchers suggest that further studies should be conducted looking at different doses of L-theanine, as well as researching L-theanine-caffeine combinations that examines the effects of everyday doses both in isolation and in combination at levels and ratios found in real tea beverages.

In the mean time, the results from this initial study suggest that beverages, like tea, containing L-theanine and caffeine may have a positive effect on cognition and mood.
Crystal F. Haskell, David O. Kennedy, Anthea L. Milne, Keith A. Wesnes and Andrew B. Scholey (2008) The effects of L-theanine, caffeine and their combination on cognition and mood. Biological Psychology 77: 113-122

Black tea is not related to iron status in a black, adult, African population
A recent study has found no evidence that black tea increases the risk of iron deficiency or iron deficiency anaemia in a black adult population in South Africa.

Iron deficiency anaemia is highly prevalent in developing countries where dietary iron intake is low and does not meet requirements. Iron status is also affected by other dietary factors, such as polyphenols from tea. The assessment of the compounds in the diet that affect the bioavailability of iron could in theory help in providing dietary advice that may reduce the risk of iron deficiency. As black tea is a drink frequently consumed by children and adults in South Africa, this might place the population at risk for iron deficiency. For this reason a collaborative study between researchers in the Netherlands and South Africa investigated the association between black tea consumption and iron status in a sample of black African adults.

The THUSA (Transition and Health during Urbanization of South Africans) study was conducted from 1996 to 1998. For this cross-sectional study, 'apparently healthy' adults aged 15 to 65 years were recruited from thirty seven randomly selected sites in the North West Province of South Africa. Subjects with known diseases (including HIV), pregnant and lactating women and subjects using chronic medication were excluded. In total, data were analysed by food frequency questionnaire, anthropometric measurements and biochemical analyses from 1605 apparently healthy adults. Furthermore the iron status of populations at risk of iron deficiency was further examined - women 40 years of age or younger; men and women who had a dietary intake of iron ≤ 5.8mg/ day; men and women with a serum ferritin level of ≤ 26.6µg/l.

No associations were found between black tea consumption and concentrations of serum ferritin or haemoglobin in men or women. Furthermore tea consumption did not significantly increase the risk of iron deficiency or iron deficiency anaemia in men or women. The prevalence of iron deficiency and iron deficiency anaemia was especially high in women, 21.6 and 14.6 %, respectively. However tea consumption was not associated with iron deficiency and iron deficiency anaemia even in sub-populations which were assumed to be at risk of iron deficiency.

The researchers concluded that black tea consumption as part of a complete diet was not a significant predictor of iron status, iron deficiency or iron deficiency anaemia. Tea intake was also not shown to be related to iron status in sub-populations at risk of iron deficiency. Instead other strategies are needed to address the high prevalence of iron deficiency in this group.
P. S. Hogenkamp, J. C. Jerling, T. Hoekstra, A. Melse-Boonstra, and U. E. MacIntyre (2008). Association between consumption of black tea and iron status in adult Africans in the North West Province: the THUSA study. British Journal of Nutrition Feb 14:1-8.

Other News

New Advisory Panel has been created
The Tea Advisory Panel is a new, expert panel which can:

Provide independent and objective information about the latest health benefits regarding black tea
Answer all of your nutrition and hydration questions about black tea
Set the record straight on 'science' myths associated with black tea

Members of the Tea Advisory Panel include nutritionists; dieticians and doctors. For further information please call 020 70528989 or visit the Tea Advisory Panel (TAP) on the website.







Health Professionals Newsletter Welcome to the ninth newsletter from the United Kingdom Tea Council. This service will keep you up to date with current tea4health activities and events and inform you of the latest published research. We'll keep you updated on a quarterly basis with news and views from across the tea industry. Research Update One step closer to understanding tea's positive effect on cognition and mood A combination of caffeine and L-theanine, naturally present in tea, has positive effects on cognition and mood in young adults according to researchers from Northumbria University. Studies that have considered effects of tea on cognition and mood have found that, although the majority of effects can be explained by caffeine, some differences exist between tea and coffee, even when the caffeine level is matched. The current researchers are proposing L-theanine may hold the key to teas enhanced effects. The current randomised, placebo controlled, double-blind, balanced crossover study investigated the cognitive and mood effects of the two compounds both alone [L-theanine (250 mg), caffeine (150 mg)] and in combination (250 mg/150 mg). The tasks selected to measure mood and cognition included attention tasks as well as specific memory and reasoning tasks, which are known to be sensitive to caffeine. Mood ratings were also assessed. Twenty four undergraduate students (mean age 21.3 years) took part in the study and were asked to abstain from caffeine and alcohol 12 hours prior to the study. Participants were randomised to a treatment group and received 4 different beverages (250ml drinks as previously described) plus a placebo on separate occasions 7 days apart. On each occasion the tests were carried out before taking the drink, 30 minutes after the drink and 90 minutes post-drink. Each testing session lasted approximately 30 minutes. Compared to the isolated effects of caffeine and L-theanine, the combined action resulted in improvements in visual tasks and 'mental fatigue' ratings. In addition the combination of caffeine and L-theanine also speeded up the completion of a number of cognitive tasks. Participants also reported fewer headache symptoms and felt more alert. As the levels of L-theanine and caffeine used in this study are higher than those found in tea beverages, which are typically in the region of 40 mg caffeine and 20 mg L-theanine, the researchers suggest that further studies should be conducted looking at different doses of L-theanine, as well as researching L-theanine-caffeine combinations that examines the effects of everyday doses both in isolation and in combination at levels and ratios found in real tea beverages. In the mean time, the results from this initial study suggest that beverages, like tea, containing L-theanine and caffeine may have a positive effect on cognition and mood. Crystal F. Haskell, David O. Kennedy, Anthea L. Milne, Keith A. Wesnes and Andrew B. Scholey (2008) The effects of L-theanine, caffeine and their combination on cognition and mood. Biological Psychology 77: 113-122 Black tea is not related to iron status in a black, adult, African population A recent study has found no evidence that black tea increases the risk of iron deficiency or iron deficiency anaemia in a black adult population in South Africa. Iron deficiency anaemia is highly prevalent in developing countries where dietary iron intake is low and does not meet requirements. Iron status is also affected by other dietary factors, such as polyphenols from tea. The assessment of the compounds in the diet that affect the bioavailability of iron could in theory help in providing dietary advice that may reduce the risk of iron deficiency. As black tea is a drink frequently consumed by children and adults in South Africa, this might place the population at risk for iron deficiency. For this reason a collaborative study between researchers in the Netherlands and South Africa investigated the association between black tea consumption and iron status in a sample of black African adults. The THUSA (Transition and Health during Urbanization of South Africans) study was conducted from 1996 to 1998. For this cross-sectional study, 'apparently healthy' adults aged 15 to 65 years were recruited from thirty seven randomly selected sites in the North West Province of South Africa. Subjects with known diseases (including HIV), pregnant and lactating women and subjects using chronic medication were excluded. In total, data were analysed by food frequency questionnaire, anthropometric measurements and biochemical analyses from 1605 apparently healthy adults. Furthermore the iron status of populations at risk of iron deficiency was further examined - women 40 years of age or younger; men and women who had a dietary intake of iron ≤ 5.8mg/ day; men and women with a serum ferritin level of ≤ 26.6µg/l. No associations were found between black tea consumption and concentrations of serum ferritin or haemoglobin in men or women. Furthermore tea consumption did not significantly increase the risk of iron deficiency or iron deficiency anaemia in men or women. The prevalence of iron deficiency and iron deficiency anaemia was especially high in women, 21.6 and 14.6 %, respectively. However tea consumption was not associated with iron deficiency and iron deficiency anaemia even in sub-populations which were assumed to be at risk of iron deficiency. The researchers concluded that black tea consumption as part of a complete diet was not a significant predictor of iron status, iron deficiency or iron deficiency anaemia. Tea intake was also not shown to be related to iron status in sub-populations at risk of iron deficiency. Instead other strategies are needed to address the high prevalence of iron deficiency in this group. P. S. Hogenkamp, J. C. Jerling, T. Hoekstra, A. Melse-Boonstra, and U. E. MacIntyre (2008). Association between consumption of black tea and iron status in adult Africans in the North West Province: the THUSA study. British Journal of Nutrition Feb 14:1-8. Other News New Advisory Panel has been created The Tea Advisory Panel is a new, expert panel which can: Provide independent and objective information about the latest health benefits regarding black tea Answer all of your nutrition and hydration questions about black tea Set the record straight on 'science' myths associated with black tea Members of the Tea Advisory Panel include nutritionists; dieticians and doctors. For further information please call 020 70528989 or visit the Tea Advisory Panel (TAP) on the website.
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