Health Professional Newsletter

7/27/2019 Health Professional Newsletter

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tea was made up using 3 grams of tea and infused for 7 minutes in 300mls of water (to allow the maximum

release of flavonoids). This infusion was filtered before either 100mls of cold water or semi-skimmed milk

was added. Blood samples were taken 10 minutes before the volunteers drank one of the test beverages,

then 50, 80 and 180 minutes afterwards. Volunteers did not eat anything, nor drink more than 100mls of

water, until after the last blood sample was taken.

Within 50 minutes of drinking black tea, the level of flavonoids in the volunteers’ blood rose by up to 45%.

Within 80 minutes the antioxidant potential of the blood rose by 10%. The findings were unchanged when

milk was added to the drink. No significant changes in plasma flavonoid concentrations were seen after

drinking the control beverage.

As well as demonstrating that longer brewed tea has higher concentrations of flavonoids, this study provides

further support that flavonoids from tea do have antioxidant properties in the blood once they have been

consumed and that these effects are not altered when milk is added.

Kyle JA, at al (2007) Effects of Infusion Time and Addition of Milk on Content and Absorption of Polyphenols

from Black Tea. J Agr Food Chem; May 10 (epub ahead of print)

Tea is the number one provider of flavonoids for the US population

A study that has sought to determine the average intake of flavonoids among the US population has found

that, out of a range of fruit, vegetables and beverages, tea was the major flavonoid source in the US diet.

High consumption of fruit and vegetables has been associated with a reduced risk of diseases such as

cancer, heart disease, and various other degenerative conditions. In addition to the vitamins and minerals

present in fruit and vegetables, plant compounds, known as phytochemicals, may also contribute to these

beneficial effects. One group of phytochemicals that have been the subject of much research are flavonoids.

As well as fruit and vegetables, flavonoids are also present in certain beverages such as tea, wine and beer.

Data from the recently released United States Department of Agriculture (USDA) flavonoid database was

expanded to include similar foods that had different processing techniques e.g. frozen, tinned, baked,

steamed, etc. In this way a more complete flavonoid database was established. Twenty four hour dietary

recalls from 8809 adults, which participated in the National Health and Nutrition Examination Survey

(NHANES) during the period 1999-2002, were then analysed using this expanded database.

Results from this study established that the total daily flavonoid intake in subjects over 19 years old was

approximately 190mg/ day. Flavon-3-ols were the major contributors (82.5%) to flavonoid intake, followed

by flavanones (7.6%), flavonols (6.8%), anthocyanidins (1.6%), flavones (0.8%) and isoflavones (0.6%).



Tea was identified as the most important source of flavonoids contributing 157mg a day. Other important

sources included fruit juices (8mg), wine (4mg) and citrus fruits (3mg).

This study is the first step towards gaining baseline data of flavonoid intake among US adults. From this

information further investigations are required to determine the relationship between flavonoid intake and

the prevention of chronic disease.

OK Chun, et al (2007) Estimated Dietary Flavonoid Intake and Major Food Sources of US Adults. J. Nutr

137:1244-1252

Other News

New flavonoid database published

The United States Department of Agriculture (USDA) has recently updated their flavonoid database. The new

release provides analytical values for 26 selected flavonoid compounds in 393 foods, including tea.

For the update, scientists with the Agricultural Research Service analyzed the flavonoids in nearly 60

representative fruits, nuts and vegetables taken from a nationwide sampling. In addition, data from nearly

100 new scientific papers on the flavonoid content of various foods were evaluated for inclusion.

The new release includes the quantities of the 26 selected flavonoids found in 168 new foods that have been

added to the original database. Data for many of the food items included in the first release were also

updated.

Research studies have consistently provided evidence suggesting an association between consumption of

diets high in flavonoids and reduced risk of cancer and heart disease. Documenting the flavonoid content of

foods is essential to researchers who strive to evaluate associations between dietary flavonoid intake and

risk factors for various chronic diseases.

This supplemental flavonoid database complements the National Nutrient Database for Standard Reference,

SR19, which is the major authoritative source of food composition information in the United States.

Supplemental databases for other phytochemicals found on the Nutrient Data Laboratory website include

those for proanthocyanidins and isoflavones.

The new database can be accessed by visiting www.ars.usda.gov/Services/docs.htm?docid=6231

An Update on Theanine and Tea

Drinking tea has traditionally been associated with stress relief with many people believing that having a

http://www.ars.usda.gov/Services/docs.htm?docid=6231






‘cuppa’ helps them relax after facing the stresses of everyday life. Despite limited scientific evidence for the

relaxing properties of tea, one recent human study found that people who drank tea 4 times a day, for 6

weeks, were able to recover quicker after a stressful event and also had lower blood levels of the stress

hormone cortisol, compared to a placebo drink.1

Although the exact mechanisms are not known, it has been proposed that the many ingredients in tea may

somehow affect neurotransmitters in the brain.

One compound in tea that is receiving attention for its relaxing and calming properties is theanine.

Theanine is a unique amino acid present almost exclusively in the tea plant (Camellia sinensis). It appears

to only occur in three other species; one mushroom species and two other species of the Camellia genus.

Since tea is the second most consumed beverage in the world, a considerable amount of theanine is

consumed daily throughout the world.

Theanine comprises 1-2 percent of the dry weight of tea leaves, makes up approximately 50% of the amino

acids in tea, and is present as the free amino acid only – it does not occur in proteins. Theanine is

synthesized in the root of the plant and concentrates in the leaves, where sunlight converts theanine to

polyphenols. Because of this, some tea cultivators grow their plants out of direct sunlight to preserve the

theanine content.

In rats theanine has been shown to cross the blood-brain barrier and on reaching the brain it has been

shown to increase alpha-brain wave activity, a sign of induced relaxation.

A small Japanese study of university students showed oral theanine administration of 200 mg led to

increased alpha-brain waves and a subjective sense of relaxation. This relaxed, yet alert, state of mind,

began approximately 40 minutes after theanine was consumed.2

Another study subjected 12 participants to four separate trials: one in which they took theanine at the start

of a stressful task, one in which they took theanine midway, and two control trials in which they either took

a placebo or nothing. The results showed that theanine intake resulted in a reduction in the heart rate (HR)

and salivary immunoglobulin A (s-IgA) after the stress induced task compared to the placebo control

condition. Moreover, analyses of heart rate variability indicated that the reductions in HR and s-IgA were

likely to be due to an effect on the sympathetic nervous activation. It was concluded that the oral intake of

theanine could cause anti-stress effects via the inhibition of cortical neuron excitation.3





20 mg of L-theanine, whereas effective dosage for most studies is 200 mg. Once absorbed in the

small intestine, the kidneys hydrolyze (use water to split the molecule) L-theanine into

glutamate. Free L-theanine in the bloodstream not yet processed by the kidney can cross the

blood brain barrier via a leucine-preferred transporter system[1]. The effects of L-theanine

parallel the role of GABA neurotransmission, regulating a delicate interplay between excitation

and inhibition. These inhibitory signals are essential for the regulation of mood, memory,

attention and relaxation in our cognitive framework.

Significant Findings

L-theanine affects alpha-band oscillatory brain activity

Electroencephalographic (EEG) recordings measure the brain’s spontaneous activity from

electrodes placed on the scalp. These recordings are particularly useful for detecting different

phases of consciousness and brain activity. Alpha-band oscillations (8-14 Hz) indicate a relaxed,

but attentive state. Using EEGs, researchers examined differences in alpha-band activity during a

demanding attention task where individuals were given either 250 mg L-theanine or a placebo. A

robust increase in attention related alpha-band signal was recorded in those administered L-

theanine[2]. Furthermore, topographic analysis showed increased activity localized to right

hemispheric posterior parietal cortex. These findings support a strong psychoactive effect of L-

theanine, specifically on visual attention.

Researchers also aimed to compare the effects of L-theanine with GABA supplementation.

Using EEG recordings, they quantified alpha wave frequencies, detecting relaxation, and higher

frequency beta waves, indicative of stressed mental states. GABA and L-theanine

supplementation provided similar results, elevating alpha-wave and depressing beta-wave

frequencies when compared to the control supplement [3](Fig 2).



L-theanine improves memory, attention, and is synergistic with caffeine.

A double blind, placebo controlled study of LGNC-07, a green tea extract containing L-theanine,

or placebo examined cognitive skills in adults with mild attention deficits disorders in response

to treatment for 16 weeks. Neuropsychological tests and EEG evaluated memory, attention, and

brain activity. LGNC-07 treatment led to improvements in each parameter, concluding that long

term, high dose (1600 mg/day). L-theanine supplementation can enhance cognition in individuals

who find it difficult to focus[4].

Current research shows that combination of L-theanine and caffeine produces a synergistic effect

and mediates cognitive benefits. A study of healthy adults given either L-theanine (100mg), L-

theanine(100 mg) + caffeine(50 mg), or placebo, reported that only the L-theanine combination produces significant results in response time and correct answer frequency during a memory and

attention-switching task[5] (Fig 3).





L-theanine increases the inhibitory neurotransmitter, glycine

Glycine is an inhibitory neurotransmitter with analogous properties to GABA. Glycine and

GABA receptors are structurally similar and often co-localize in the same subset of cells to

regulate inhibition[11]. An L-theanine supplement can directly elevate glycine concentration in

the brain [12](Fig 6). Furthermore, while glycine mediates glutamate inhibition, it promotes the

release of dopamine within the striatum, a part of the forebrain receiving input from the cortex to

modulate behavior. L-theanine’s mood regulating properties and balance of neurotransmission

are hypothesized to directly result from elevated glycine.

L-theanine enhances immunity through priming T-lymphocytesThe body’s defense against foreign particles is regulated through a number of immune cell types.

A special subset of T-lymphocytes know as gamma-delta T-cells recognize foreign particles

based on a different mechanism than other T-cells. The chemical structure of L-theanine primes

gamma-delta T-cells and enhances their capacity to proliferate and secrete cytokines, helping the

body to decrease the incidence of immune challenges[13].



Conclusion

The anecdotal evidence from centuries of tea drinkers has led to the investigation of its active

constituents. The health benefits and effects on cognition of L-theanine are well studied and

include relaxation, alertness, memory improvements, increased attention, increased immunity,

and long-term neuroprotection. The biological link between L-theanine and these benefits is alsowell characterized. The chemical similarity to GABA permits L-theanine to cross the blood-brain

barrier and mediate inhibitory neurotransmission. This inhibition produces profound cognitive

effects by moderating glutamate excitation, increasing glycine levels, and elevating dopamine

release. Ultimately L-theanine promotes a balancing of excitation in important brain regions. In

addition, L-theanine can stimulate the production of neurotrophic factors, such as BDNF, to

decrease anxiety and elevate mood, and prime a subset of T-lymphocyte immune cells to help

keep the immune system strong.

The only negative results that have been published regarding L-theanine show no net benefit to

supplementation during a particular cognitive task. However, there are a significant number of

studies that conclude the maximal benefit occurs when L-theanine and caffeine are combined.

Caffeine is a known neurostimulator and enhancer of cognition. Although it may be contrary to

the philosophy of Alpha BRAIN, a low dose of caffeine in combination with L-theanine will

provide the maximum cognitive benefits.

Replacing the GABA component with L-theanine should not alter the effectiveness of Alpha

BRAIN. Both mediate inhibition and have proven to reduce anxiety when taken as a supplement.

Furthermore, the L-theanine provides an array of benefits that can outlast the acute effects of

relaxation, such neuroprotection and immune support. Overall, including L-theanine into theAlpha BRAIN formula is well advised.

Dosage and Warnings

The typical dose of L-theanine used in most studies was between 200-250 mg. Toxicity can

occur at dose of 5000 mg.Ingredient Summary

L-theanine is an amino acid isolated from tea leaves and the major contributor to the health

benefits of green tea. Chemically similar to our own inhibitory neurotransmitters, GABA, L-

theanine promotes a healthy balance of excitation and inhibition in our brain. The health benefits

include assisting the body with relaxation, increased attention, decreased stress, immune support,

and long-term neuroprotective effects.

References1. Wakabayashi C, Numakawa T, Ninomiya M, Chiba S, Kunugi H: Behavioral and molecular evidence

for psychotropic effects in L-theanine. Psychopharmacology (Berl).

2. Gomez-Ramirez M, Kelly SP, Montesi JL, Foxe JJ: The effects of L-theanine on alpha-band

oscillatory brain activity during a visuo-spatial attention task. Brain Topogr 2009, 22:44-51.



3. Abdou AM, Higashiguchi S, Horie K, Kim M, Hatta H, Yokogoshi H: Relaxation and immunity

enhancement effects of gamma-aminobutyric acid (GABA) administration in

humans. Biofactors 2006, 26:201-208.

4. Park SK, Jung IC, Lee WK, Lee YS, Park HK, Go HJ, Kim K, Lim NK, Hong JT, Ly SY, Rho SS: A

combination of green tea extract and l-theanine improves memory and attention in subjects with

mild cognitive impairment: a double-blind placebo-controlled study. J Med Food , 14:334-343.

5. Owen GN, Parnell H, De Bruin EA, Rycroft JA: The combined effects of L-theanine and caffeine on

cognitive performance and mood. Nutr Neurosci 2008, 11:193- 198.

6. Takeda A, Sakamoto K, Tamano H, Fukura K, Inui N, Suh SW, Won SJ, Yokogoshi H: Facilitated

neurogenesis in the developing hippocampus after intake of theanine, an amino Acid in tea leaves,

and object recognition memory. Cell Mol Neurobiol , 31:1079-1088.

7. Kakuda T: Neuroprotective effects of theanine and its preventive effects on cognitive

dysfunction. Pharmacol Res,64:162-168.

8. Ritsner MS, Miodownik C, Ratner Y, Shleifer T, Mar M, Pintov L, Lerner V: L-theanine relieves

positive, activation, and anxiety symptoms in patients with schizophrenia and schizoaffective

disorder: an 8-week, randomized, double-blind, placebo-controlled, 2-center study. J Clin Psychiatry, 72:34-42.

9. Rogers PJ, Smith JE, Heatherley SV, Pleydell-Pearce CW: Time for tea: mood, blood pressure and

cognitive performance effects of caffeine and theanine administered alone and

together. Psychopharmacology (Berl) 2008, 195:569-577.

10. Shimmyo Y, Kihara T, Akaike A, Niidome T, Sugimoto H: Three distinct neuroprotective functions

of myricetin against glutamate-induced neuronal cell death: involvement of direct inhibition of

caspase-3. J Neurosci Res 2008, 86:1836-1845.

11. Ross ST, Soltesz I: Long-term plasticity in interneurons of the dentate gyrus. Proc Natl Acad Sci U S

A 2001, 98:8874-8879.

12. Yamada T, Terashima T, Kawano S, Furuno R, Okubo T, Juneja LR, Yokogoshi H: Theanine, gamma-glutamylethylamide, a unique amino acid in tea leaves, modulates neurotransmitter concentrations

in the brain striatum interstitium in conscious rats. Amino Acids 2009, 36:21-27.

13. Bukowski JF, Percival SS: L-theanine intervention enhances human gammadelta-lymphocyte

function. Nutr Rev 2008,66:96-102.

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