Have you ever noticed that it becomes harder to choose gifts for friends as they get older? That is if you plan on giving a thoughtful gift and not just a generic pair of socks at Christmas or an impersonal bottle of wine.
My good friends know that I am a fan of minimalism which makes it hard to buy me gadgets, gizmos and 'stuff' in general. Most people who have met me know that I am into health and wellness.
Recently, one of my dear friends bought me a gift of white tea figuring that it was expensive and had lots of health benefits (or at least that's what the man in the shop told her as he mentally spent the healthy commission he would make on the tea).
I was very touched by the gift but to be honest I had no idea if white tea does anything for health. I have just made myself a pot of fragrant white tea and off to PubMed I go, to read about this beverage.
In this article, we will only look at white tea research. After all, if my friend wanted to give me green tea, she could have gone to the corner shop and saved herself a fortune.
What Is White Tea?
Tea has been enjoyed as a drink and used as a medicine for the past 5000 years. White tea originates from the Fujian Province of China and comes from the same plant (Cammelia sinesis) as black tea and green tea (1).
The main difference between these three teas relates to the degree of processing that the Camellia undergoes. White tea is the least processed of all the teas. It is neither fermented nor roasted. The leaves are harvested and then quickly dried.
The processing of tea leaves activates the polyphenol oxidases in the tea. The assumption is that white tea might contain a higher content of health-promoting goodies as compared to the green or black teas.
While white tea may undergo less processing, it is actually more expensive than black or green teas and generally harder to source. That being said it can be re-steeped which can reduce the cost per cup of this luxury item.
I was curious to see why white tea was more expensive if it involved less processing? It seems that there are also differences during the growth and harvesting of the Cammelia sinesis for white tea.
Only very young leaves or buds are used for white tea and these young leaves and buds can only be harvested in early spring (2). The buds used for white tea are typically protected from sunlight which reduces chlorophyll production which in turn gives the leaves a white color (3). I guess I can see why white tea would be more expensive.
That leaves us with the obvious question of whether white tea is worth the extra cost?
White tea is naturally rich in polyphenols, flavanols, proteins, polysaccharides, minerals, trace elements, amino acids, lignans, and methylxanthines (caffeine, theophylline, and theobromine (4). Overall, white tea contains less caffeine than green or black tea (5).
There are a number of popular brands of white tea including Exotica China White and Dragonwell Special Grade. Certainly, none of my local stores stock the tea.
I was temporarily excited when (on a whim) I ordered a white tea in Starbucks yesterday. I expected a steaming pot of fragrant tea in an infuser (I must have been delusional to expect a tea ceremony in a fast food franchise). Instead, I got a super sweet, cold tea instead. Not exactly what I had in mind!
I can officially attest to the fact that a cup of hot white tea tastes so much better than the Starbucks version.
There are almost 777 white tea-related products for sale on Amazon including loose tea, tea bags, and cosmetics.
An ounce of the best selling brand of white tea costs in the region of $8 while an equivalent amount of the same brand black tea costs $2 and green tea costs $3.
Is There Any Research?
There are 805 publications including 3 clinical trials on white tea. Doing some additional manual searching, I found 2 more studies. Why did these studies not show up while doing a regular search? These studies were published in dental journals and were not indexed in the medical scientific literature.
To put all this into context, there are over 30,000 publications and over 1000 clinical trials on green tea.
Does it Kill Cancer Cells?
Researchers in New Mexico and UCLA studied the effects of white tea on cell death in cells taken from patients with a particular type of lung cancer (non-small cell lung cancer) (6). They found that the extract from white tea could kill the cells.
To add further weight to these scientific findings, they also elucidated the mechanism of action of the white tea in these cancer cells. Convincing as this may seem, we cannot generalize to all cancers nor can we generalize what effect (if any) would be seen in humans with lung cancer.
A very detailed study in 344 rats showed that white tea could inhibit PhIP (2-amino-1-methyll-6-phenylimidazol (4,5-b) pyridine (Santana Rios (7). You may well be thinking what on earth does this mean in the real world? Good question.
PhIP can cause cancer in the colon in experimental animal models. This study showed that white tea blocked PhIP and blocked the development of abnormal colonic cells.
A laboratory-based study from Kuala Lumpur showed that white tea prevented the growth of colorectal cancer cells but had no effect on normal cells (8).
Cocoa tea is a naturally decaffeinated drink that contains theobromine instead of caffeine (9). As mentioned above, it is different from white tea. Studies have shown beneficial effects of white cocoa tea on prostate cancer but that is not what we are interested in here.
While there are some limited data on the effects of white tea on cancer cells in laboratory experiments, there is no information from human clinical studies and as such we have to say that there is no proof that white tea kills cancer cells.
Does It Improve Cognitive Function?
Researchers in chemical engineering in Spain showed that pre-treatment of specialized striatal brain cells in a laboratory model prevented oxidative damage to the cells but not cell damage caused by other toxic insults (10). This is definitely interesting but we have to stick to the bottom line here.
There is no proof that white tea improves cognitive function.
Does White Tea Have Anti-Oxidant Properties?
A 2010 study compared the polyphenol and antioxidant activity of 8 commercially available white teas versus green tea (11) The study found variations in the levels of these compounds among the different brands of white tea tested.
They concluded that it is too simplistic to have a hierarchy of 'green tea is better or worse than white tea' when there is such variability among the teas depending on the cultivar and processing techniques used.
The mechanism by which white tea might exert anti-oxidant effects was studied in healthy rats who were given a chemotherapy agent, adriamycin. (12). It was found that white tea had effects on Nrf2, Gst, Nqo1, Ho1, Cat, Sod, and Gr. While this may seem very confusing, it at least shows that white tea has anti-oxidant properties.
Finally, sea bream fed on either a standard diet, a standard diet plus methionine or a standard diet plus methionine plus white tea were studied in a 2012 publication (13). It was found that dietary white tea increased superoxide dismutase levels and activity which would generally be considered to be a good thing from an anti-oxidant perspective.
A really nice article from 2011 piqued my interest for several reasons (14). I was interested in the results as they related to white tea. However, I was even more interested in the thought processes of the researchers. The researchers explained that white tea is a rich source of flavan-3-ol and as such could be assumed to have antioxidant benefits in humans.
The researchers established that there are no intervention trials proving this fact and they were uncomfortable with mere supposition. As readers of Healthy But Smart will know, many bloggers and researchers would stop right there, and turn their assumptions into dogma. Not these researchers. They tested the theory in 70 healthy non-smokers.
These study participants were randomized to either green tea, white tea or water. As expected the white and green tea increased blood levels of flavan-3-ols. However, contrary to expectation, this increase in flavan-3-ol did not result in increases in antioxidant activity. It just goes to show that it is best not to make assumptions in science.
A 2016 study from Malaysia showed that prolonged steeping of white tea in hot or cold water gave the highest anti-oxidant activity while prolonged steeping of green tea in cold water gave the best results for anti-oxidant activity (15).
This pattern was also seen in a study from Italy which additionally showed that milled leaves had greater antioxidant effects (16).
White tea does have anti-oxidant properties but as of now, this has not been shown to translate into health benefits in humans.
Does It Help Male Fertility?
Sertoli cells support spermatogenesis. A 2014 study showed that white tea increased lactate production which is believed to support Sertoli cell function (17).
Building the case even further, there is another study that showed that white tea extract was shown to increase sperm number and activity in diabetic rats (18).
Interestingly, white tea was shown to be an excellent transport media for sperm in a Portuguese study (19). As an aside, this group of Portuguese researchers based in Covilhã are the most prolific researchers on white tea.
White tea has been shown to promote sperm health in laboratory studies but has not yet been studied in humans.
Does It Reduce Cholesterol Levels?
Possibly. Let me explain some more.
Ingredients in white tea are poorly absorbed in the gut but this means that white tea may have positive downstream effects (if you can please excuse the pun) (20). This allows key ingredients such as polyphenols and anti-oxidants reach the lower gut and colon where they can exert a local anti-inflammatory effect.
This theory was supported in this 2015 study which compared the polyphenol content of white, green and black tea and declared white tea to be the overall winner. Additionally, it was found that most of the polyphenol catechins were not absorbed but accumulated in the gut lumen where they were found to bind glucose and lipids in model simulations of gut activity.
This led to the additional hypothesis that not only are polyphenols in white tea a good source of anti-oxidants but they also may play a role in the regulation of blood glucose and lipid levels.
It is theoretically possible but unproven that white tea could help with lipid levels.
Does White Tea Help Reduce Weight?
That was fun to write.
There are no studies looking at white tea and weight loss.
Does It Improve Oral Health?
White tea is believed to contain a triad of ingredients which are beneficial for dental health:
- flouride (34%) which is well documented to promote oro-dental health
- tanins which inhibit salivary amylase and can reduce the ability of starch to cause caries and
- catechins which have been shown to inhibit plaque (21).
This theory was road tested in 45 healthy volunteers who were randomized to either: white tea, placebo distilled water or chlorhexidine for 4 days (22).
The study subjects were not allowed to brush during the study days. There were some not so nice close ups of the teeth in the journal article which I definitely did not enjoy. Plaque significantly increased in all 3 arms of the study.
Chlorhexidine was the overall winner but the white tea was better than the placebo. Additionally, white tea inhibited the growth of three key bacterial species which are linked to dental disease (Porphyromonas gingivalis, Porphyromonas intermedia, and Aggregatibacter actinomycetemcomitans).
There are very limited but positive data to suggest that white tea can help with oro-dental health.
Does It Help Skin?
Dermatologists in Cleveland, Ohio studied skin in both in vivo and ex vivo samples (23). In vivo refers to living skin cells in a living, breathing human while ex vivo means skin cells that have been removed from a living human.
Hannibal Lecter took ex vivo to a whole new level but gives a clear idea of what ex vivo means. The dermatologists showed that white tea offered protection against sun damage.
What is particularly interesting here is the fact that white tea has a sun protection factor of just 1 which means that the skin benefits came from something other than sun factor protection but it is not clear what that mechanism might be.
White tea may offer some skin protection from sun damage.
Is It Safe?
In a near first for HealthyButSmart, I could not find any publications relating to toxicity or side effects of white tea.
In other words, proceed with caution.
There is too little data to decide if white tea offers any major health benefits. The best data relates to male fertility but as I don't have any Sertoli cells, I can hardly justify spending money on white tea for that reason.
I wonder if the type of tea is really the critical factor here? Even if white tea had a superior track record to black tea, I can't imagine that a sugary white tea in a to-go cardboard cup could out-perform black tea made in a traditional tea ceremony style and slowly savored with friends.
For me, I will re-steep this tea and enjoy it but I will not buy a replacement when this box of white tea is finished.