Health & Nutrition
Miscellaneous diet and health topics
In recent years there has been an ongoing effort to promote the use of tea with birds, primarily by an individual who has a business selling tea products aimed at birds. This article will take a look at whether there is a good basis for the claims that are being made, using quotes from sources that include the In Your Flock tea article, the Bird Channel tea article, and the In Your Flock raw foods article. The raw foods article suffers from a variety of defects that go beyond tea claims, but I will not discuss them here except to say that there is a general lack of evidence for effectiveness and a disregard for potential risks with the tea claims, and the same statement could be made about the oil claims. I have a separate article on coconut oil and why it doesn't seem like an appropriate thing to feed to a bird.
When it comes to herbal tea, the evidence for the claimed benefits for humans is generally shaky and much of it smacks of exaggeration and hype. Miracle claims usually turn out to be mostly wishful thinking but still, it's important to remember that these teas are being touted for their purported drug effects, not as sources of nutrients. If these teas do what they're said to do, you need to consider whether it's desirable to medicate your bird in this way.
A website for the tea line says that it was developed in part by a veterinarian with a certificate in homeopathy. This is an unproven 'alternative' treatment method whose operating principles fly in the face of the known laws of the universe (see homeopathy article). At least one of the product's creators doesn't seem to believe that medical recommendations need to have scientific rigor or objective evidence behind them.
There is some reasonably substantial evidence for the benefits of green and black tea for humans, but there is also evidence of risks. All foods contain some negative compounds and teas are no exception. There are also many unknowns, and research on using tea with birds is virtually nonexistent. The teas that are being promoted were all produced for human consumption and have been repurposed for birds; there is nothing bird-specific about them. All vertebrates have many similarities in their physical functioning but there are also many differences, and we can't be certain that tea will affect birds the same way it affects humans. So it would be prudent to limit the use of tea to the occasional sip for birds who like to share their owner's beverage, and to situations where a specific tea is being used in conjunction with careful research to help solve a specific problem.
Many birds who like sharing their person's tea seem to mostly enjoy the warmth rather than the taste of the tea. As a safe, healthy alternative to tea, your bird might enjoy having its own cup or bowl of warm water, perhaps with something floating in it like a lemon slice or piece of broccoli. Be aware that warm foods can trigger breeding urges in some birds; regurgitation is part of the courtship ritual in many species and it's served warm.
Claim: "What birds drink in the wild is far from sterile. Many species of birds visit water sources like tree hollows into which these plant components leach tannins, other compounds and minerals. We have all seen wild birds drinking from what appears to be "dirty” puddles and other water sources. However, many contain a type of "tea” from the leaves that have fallen into the water."
It is certainly true that birds drink impure water in the wild, but it's nonsensical to equate this with tea drinking. It's as logical as saying we should dip our birds' drinking water out of a fish tank because wild birds drink from ponds and streams containing fish, or that it's desirable for humans to gather up any random leaves that they find outside and make tea out of them for their own consumption. The mix of chemical compounds in the water is expected to vary considerably from place to place depending on local vegetation and other factors like weather conditions, and we shouldn't assume that the compounds in the water are beneficial or that the chemical content of natural puddles is similar to the teas that are being sold. These teas are apparently considered to be pretty dissimilar to each other since at least 15 different types are being promoted, which is very inconsistent with the premise that basically any kind of human tea is similar to wild water.
It's inappropriate to assume that drinking impure water in the wild is beneficial. Humans evolved drinking impure water too, and our experience was that it's risky and potentially deadly. That's why we go to so much trouble and expense to purify our water and make sure it's safe. The lack of pure water is still a major cause of death in the third world.
I couldn't locate any research on the factors that affect a bird's decision on where to get a drink, but it's likely that in many cases safety, convenience, and availability are more important to the bird than the content of the water. Birds need to drink, but they also need to avoid predators and aggressive rivals, and some birds need to stay in their own territory to guard it against competitors. Any water that isn't acutely toxic will meet the bird's physical needs, and we can't tell why they chose to drink from a specific source.
There is no evidence that birds intentionally seek out tannin-laced "tea" water, but there is evidence that some birds might avoid such water when they can. A study on cockatiels found that they preferred pure water over water containing plant tannins, and they were much more sensitive to the taste of tannins than the taste of salt and sugar (Matson et al). This sensitivity to tannins is probably protective; according to Cornell University, small quantities of tannins in the diet can cause adverse effects in poultry. Levels from 0.5% to 2% can cause depression in growth and egg production, and levels from 3-7% can be fatal.
In many cases, birds that desire specific plant compounds wouldn't need to look for water that contains them. The plant itself will usually be standing near the tannin-laced water, and if the bird wants the plant's compounds it can chew on the plant to get them.
Tannins/polyphenols are a large class of natural plant compounds that on the whole are considered to be antinutrients or toxins. They vary in their chemical properties, but in general they help protect the plant from being eaten and also play a role in regulating the growth of the plant. Some of these compounds may have health benefits for humans, particularly as antioxidants, but there are concerns about toxicity even with the "good" polyphenols (Galati & O'Brien).
Claim: "Blended teas offer countless benefits for parrots"
The purported benefits of most of these teas haven't been studied well in humans, let alone birds. There have been a considerable number of human studies on widely used black and green teas, with findings of potential benefits. But the evidence isn't strong enough for the FDA to allow sellers to make marketing claims about health benefits (CBS News, FDA), and there is also evidence of potential harm from habitually drinking these same teas (for example BBC News, Molinari et al, Fluoride Alert). In fact all the teas being promoted for birds are associated with warnings about human health risks, but this is never mentioned in the bird-magazine articles. The risks associated with specific teas will be discussed at the end of this article.
I was able to find only one scientific paper on the use of tea with birds. It involved starlings and black tea, and found that the use of tea reduced the amount of iron stored in the liver (Seibels et al). This is an example of the antinutrient properties of the tannins in black tea; they interfere with the absorption of iron. Some bird species like toucans and lories are highly susceptible to hemochromatosis (iron storage disease), and it is desirable to inhibit iron absorption in these species. Most pet bird species are much less sensitive to iron, and inhibiting iron absorption in these species could potentially result in iron deficiency.
There isn't enough information on how tea affects birds to make a fully informed decision on whether it's safe or desirable to offer it. When complete information isn't available it's still possible to make a rational decision based on the circumstances and the limited information that is available. For example the Riverbanks Zoo Toucan Manual and their separate article on toucan diet explain the reasons for their decision to feed black tea to their toucans in an effort to prevent iron storage disease. Both documents are outdated now and the originals were removed from the Riverbanks website; these copies are from alternate sources. Private communication with the zoo indicates that they stopped using tea because a low-iron pellet became available (reducing the need for preventive measures), and the zoo veterinarian did not feel that the data demonstrated a benefit from the tea.
It does not appear that the tea promoter has constructed a similar science-based rationale as the basis for his recommendations. In a direct conversation with him online, he said his rationale for offering tea to birds was "why not" (in addition to the dubious contention that birds "exploit tea resources" in the wild). His response to a question about potential risks was "I haven't seen any problems". It's unlikely that he's monitoring the health of all his customers or that it would be easy to identify tea as the culprit in a situation where it did cause a problem, so I wouldn't consider his personal observations to be serious evidence that there aren't any risks.
A bird isn't likely to be harmed by an occasional sip of tea just for fun, and there may be circumstances where a specific tea might provide relief for a specific health problem. But it is irresponsible and potentially dangerous to use teas indiscriminately without carefully considering the available evidence about the benefits and risks. The bird magazine articles don't talk about restraint, moderation or risks:
Recommendations: "The use of tea is yet another way to incorporate items into the diet thereby increasing vitamins and minerals in your bird’s daily regimen. They also serve as a great enrichment tool; use a different kind each day to keep tea stimulating and engaging. ... When cooking for your bird, it is quite easy to substitute water for tea when preparing egg foods, beans, rice, pasta and other items that are prepared in hot water. Baking is another opportunity to incorporate tea by replacing water with tea in the recipe for bird bread, crumble, muffins or another concoction your birds prefer. Offering certain teas without steeping them is another option, as small birds love to eat flowers, for example, within their dry food mix. For our softbills, we also roll items like chamomile or calendula flowers into our daily fresh fruit mixture for our birds to increase and diversify the nutritional content of every bite. ... Many herbal teas may be fed dry or mixed with dry and fresh food mixtures, but we do recommend steeping for the full benefits."
The Bird Channel article says "Check with your avian veterinarian for guidance in regard to the frequency, amount and types of tea you might offer your bird before incorporating giving tea to your pet bird." This is good advice, but most vets aren't expected to be knowledgeable about teas and you need to do your own homework as well. The other two articles have no such warning, and the general impression created by all three articles is that tea is a marvelously healthy, risk-free food that will cure or prevent a long list of ailments and can be used without restraint or moderation.
The recommendation to feed tea leaves to birds is particularly disturbing. With brewed tea we have centuries of human experience to help us predict the possible results, although there is no guarantee that birds will respond to tea chemicals the same way humans do. But humans do not normally eat tea leaves, and these leaves are expected to contain insoluble compounds that are not present in liquid tea because they are not released by the brewing process. The leaves haven't been studied to see what compounds remain in them, so we don't know what these compounds are and can't predict the long term consequences of habitually eating them. Many plants are toxic.
The tea producing nations generally have a long history of poverty and hunger, and the fact that they do NOT normally eat tea leaves suggests that there is a good reason not to do it. Toxicity issues are one possible reason, but there's also a very good chance that it's simply because because tea leaves are pretty much indigestible. Most leaves are so high in fiber that an animal needs special digestive adaptations to use them as a food source. Humans don't have this special equipment and neither do most birds, including parrots. That's why they gather seeds, fruit, and insects in trees and bushes instead of eating the leaves.
The pro-tea articles recommend a few specific teas to mix directly into a bird's food, but there's also a nonspecific statement that "Dried tea leaves can be mixed in your bird's regular food", with no mention at all of whether there are any teas that should NOT be added to the food. I can't find any evidence that wild birds eat tea leaves, so it can't be argued that this is a normal part of their diet. Insects and fungi are the crop pests for black and green tea. The only mention of birds I could find in connection with tea pests was a site saying that birds were beneficial because they ate insects, so birds are obviously not devouring the tea crop. The two specific teas that were recommended for mixing in food were chamomile and calendula. The crop pests for both are insects not birds, and calendula actually has some insect repellent properties which raises questions about its desirability as pet food. Feeding tea leaves to birds is a venture into the unknown, conducting a food safety experiment using your bird as the test animal.
One of the articles includes a recommendation to bathe birds in aromatic teas. Birds have very sensitive respiratory systems so the safety of this is questionable.
The Bird Channel article says "Your bird should always have fresh water, with tea as a supplement to the other foods she gets." This is very wise advice that everyone should follow (the part about fresh water anyway - tea is certainly not required). The In Your Flock tea article isn't as cautious; it says "It is not recommended to completely replace water with tea, however, so as to avoid dehydration if the bird chooses not to accept the tea readily". This is not the same as making sure your bird always has fresh pure water, and this recommendation is part of the instructions for introducing tea to a reluctant bird. The article says nothing about making sure pure water is available after the bird has accepted the tea. You should always provide fresh pure water for the sake of your bird's health and safety, and not try to force it to drink something non-essential. Water is what birds really drink in the wild, and anything else that happens to be mixed in with that water is incidental.
It appears that tea is generally a poor source of vitamins and minerals. It's difficult to even find sources talking about the vitamin and mineral content of tea, although it's said that black tea contains some vitamin C, E, and K (Livestrong) and green tea apparently contains at least C and K. It appears that the only noteworthy mineral in green and black teas is fluoride, which is beloved by the dental community but generally damned by the "health food" community as toxic (which is true if you ingest enough of it). Tea plants take up fluoride much more readily than most other plants, and green and black teas contain the highest fluoride level of any food source (FluorideAlert, FoodInfo). If you drink tea made with fluoridated water you get a double dose of fluoride.
It's known that tannins in black tea (including decaffeinated) interact with thiamine (vitamin B1), converting it into a form that's more difficult to absorb. Drinking black tea and chewing tea leaves can cause thiamine deficiency in humans, although it generally isn't considered to be a major risk unless the diet is low in thiamine or vitamin C (which apparently prevents the undesirable interaction) (Medline Plus, Medical News Today) Birds make their own vitamin C so tea-induced thiamine deficiency is probably not a risk for them. But this is a good demonstration of the unexpected ways that plant tannins can interfere with the absorption of nutrients, and there may be other undesirable interactions that we don't know about.
The abstract for a paper titled Risks associated with consumption of herbal teas (Manteiga et al) says that little is known about the chemical composition of herbal teas and it's unwise to drink too much of them until we learn more, because they could contain some seriously dangerous chemicals including carcinogens/mutagens and substances that cause alkaloid poisoning.
There's also the question of whether the plant material in the box is even the same as what it says on the label. Herbal products including teas are poorly regulated and there are widespread problems with contamination, plant substitution, and adulteration. A study by Stoeckle et al found that 1/3 of the herbal teas they tested included plants that were not identified on the label. A study by Newmaster et al detected that alfalfa was used as a filler in 16% of the teas they tested. Most of the herbal products tested were deemed to be of poor quality, with considerable product substitution, contamination and use of fillers, and 59% of the products contained plant species not listed on the label. (CBC News, Science Daily).
Abouleish and Abdo cited papers finding problems in herbal tea products including microorganisms and heavy metals such as arsenic and mercury. Their paper studied nitrate and nitrite contamination, and found that 20% of the samples had levels that exceeded EPA guidelines. Consumer Lab found lead in green tea leaves, but reported that the lead remained in the leaves and did not leach out into the liquid part of the tea. THIS IS AN EXCELLENT EXAMPLE OF WHY YOU SHOULDN'T FEED TEA LEAVES TO YOUR BIRD. There have been multiple recalls of herbal tea due to salmonella or botulism contamination (Tega, Teavana, RemedyTeas, Harmony Chai). The heat of brewing is not protective because salmonella can survive the process and flourish in the tea (Keller et al). Some herbal teas and remedies have even been contaminated with prescription drugs (Norcross et al, Ernst).
Claim: "Teas: Another Raw, Whole Foodstuff"
Tea isn't a whole raw food unless you're eating fresh raw tea leaves. Otherwise it's more accurately described as a cooked processed food. Tea leaves are dried in a multistage process that often includes the use of heat (Wikipedia). Decaffeination involves more heat and a chemical process to remove the caffeine (Wikipedia). Despite the claims about "Select teas that are decaffeinated via a natural process using CO2 and/or water", soaking tea leaves in carbon dioxide under pressure to make the CO2 act as a solvent is a manmade process that does not occur in nature. The more common process of "natural decaffeination" using ethyl acetate isn't a natural process either (Arbor Teas, Amazing Green Teas).
In the hands of the consumer, the tea is processed again in water (usually hot water) to extract the water soluble compounds in it, then this water is drunk and the actual tea leaves are thrown away. Imagine doing all this with broccoli and trying to convince someone that it's a serving of whole raw food.
Claim: "Brewing releases beneficial compounds that may not otherwise be readily available to our birds."
Brewing releases water soluble compounds in the leaves without regard to whether these compounds are beneficial or not, and it fails to release compounds that aren't water soluble whether they are beneficial or not. The hydrochloric acid in the digestive tract and other aspects of the digestive process are very efficient at releasing water soluble compounds from foods without any assistance from brewing, and it also extracts a good many of the insoluble compounds including important vitamins and minerals.
Credentials claim: "[Name of promoter] is a degreed biologist."
The internet indicates that he's a full time high school biology teacher and part time instructor at a small college. It's customary to describe people in this line of work as a teacher or instructor, since they were hired to teach concepts to students, not to conduct biological research or do hands-on biological management. The term 'biologist' is usually applied to people like professional researchers (including full-fledged university professors; their primary job is conducting research and teaching is a secondary activity) and people who are actively engaged in wildlife monitoring and environmental management.
Credentials claim: Statement by the promoter on this Avian Answers Facebook thread: "I have done years of peer-reviewed medical research on these teas so I'm well versed in the research."
The link is an open, public Facebook group, so anyone who is logged into Facebook can view the thread without being a member of the group. I have a screen capture of this comment in case access to the original becomes difficult.
For those unfamiliar with the research world, the term "peer review" doesn't apply to the actual research process. Research is conducted and scientific papers are written reporting the results of the research. These papers are submitted for publication to a high-quality scientific journal or a scientific conference. The papers are then evaluated by other researchers in the same field to determine whether they are worthy of publication, and papers that are approved and published are called peer-reviewed. Publication in a peer-reviewed journal is the highest, most prestigious level of publication for a scientific paper, and the majority of scientific papers are published at a lesser level (mostly scientific conferences).
So a claim that one has "done years of peer-reviewed medical
research" carries serious weight - if it's true. It's easy to look up scientific papers and their authors on science-oriented venues like Google Scholar. A search for the promoter's name on Google Scholar turns up NO publications in peer-reviewed journals, scientific conferences, or any other science-related publication, and he doesn't appear to be qualified to publish in such a venue. Since there is virtually no scientific research on the use of tea with birds, it's obvious that the information presented in the bird magazine articles is based primarily on personal opinion, anecdote, and assumptions based on limited human data. This does not meet scientific standards of evidence and is not an acceptable basis for a peer-reviewed paper.
As mentioned earlier, peer-reviewed papers about some teas do exist. But reading peer-reviewed papers written by other people is NOT "doing peer-reviewed research". That description applies to people who actually write and publish peer-reviewed papers based on their research.
An Australian researcher with the same name as the tea promoter published a small number of papers related to topics like weather forecasting and water flow in Australian agriculture, but this is clearly not the same person.
The health risks of specific teas
The bird magazine articles cited at the top of the article go into detail about the claimed benefits of a wide variety of teas, with no mention of possible health risks. This section of the article will fill that gap.
Many of the risks listed below relate to exacerbating an existing condition, but some refer to tea consumption potentially causing a health problem that didn't previously exist. In the case of green and black tea, some but not all of the listed risks are related to caffeine and can be reduced or eliminated by using decaffeinated tea. Many of the herbal teas are reputed to have estrogenic/hormonal effects which is not something to play around with lightly, some are considered to be too dangerous to use in pregnancy, and others are not recommended for use in pregnancy because too little is known about them. It is wise to carefully research a specific tea prior to use to determine whether the potential benefits appear to outweigh the potential risks.
Green tea: anemia, anxiety disorders, bleeding disorders, heart disorders, diabetes, diarrhea, irritable bowel syndrome, glaucoma, high blood pressure, liver damage, osteoporosis, skeletal fluorosis (WebMD, Tea Talk)
Black tea: anemia, anxiety disorders, bleeding disorders, heart disorders, diabetes, diarrhea, seizures, glaucoma, hormone-sensitive cancers, high blood pressure, irritable bowel syndrome, osteoporosis, overactive bladder, skeletal fluorosis (WebMD, Tea Talk). The Cleveland Clinic says "Although many foods contain oxalate, only nine foods are known to increase oxalate in the urine and kidney stone formation" and they recommend that people with kidney stone issues avoid these foods. Tea is one of them. (Massey et al). The article doesn't specify what kind of tea, but black tea was probably meant since it's the kind that's most commonly consumed in the US.
White tea: there's little in the way of individual reporting on this type, but it comes from the same plant as green tea and black tea, so it's likely that it would have similar properties.
Calendula tea: Likely unsafe for pregnancy and breastfeeding, with possible increase for risk of miscarriage. Allergic reactions, drug interactions, sedative effects, fertility and menstrual cycle disruption (WebMD, Herbal Resource)
Rose hip tea: not recommended for pregnancy and breastfeeding. Bleeding conditions, diabetes, glucose-6PD deficiency, kidney stones, iron-related disorders, sickle cell disease, anticoagulant, nausea, headache, dizziness (WebMD, Rosehips Tea)
Hibiscus tea: possibly unsafe in pregnancy with some evidence that it can cause miscarriage. Estrogenic effects, drug interactions, diabetes, low blood pressure, intoxication/hallucenogenic (WebMD, Tea Lovers, SFGate)
Jasmine tea: little is known about this tea. Not recommended for pregnancy and breastfeeding. Green tea is the primary ingredient, so see green tea warnings. Contains caffeine which can trigger insomnia, irritability, dizziness, heart palpitations, and numerous other problems. (WebMD, Livestrong, SFGate)
Copyright 2014 Carolyn Tielfan all rights reserved