With the emergence of social media, especially Instagram and TikTok, myths, legends and even falsehoods related to food have multiplied. Proof of this is the proliferation of so-called superfoods, a heterogeneous group of foods with supposed almost miraculous properties and benefits where we can find chia, goji berries or red tea, among others.
It is said that this infusion helps you lose weight, affects your sleep, increases blood pressure, helps you concentrate, causes constipation, takes care of your cardiovascular system, reduces stress… Irene Fernández-Espada, dietician-nutritionist and member of the Spanish Academy of Nutrition and Dietetics, analyses how much truth there is in these claims.
Origin of red tea or pu-erh
Red tea or Pu-erh is named after its geographical origin, the city of Pu’er, located in the Yunnan region (China), where the fresh leaves of the tea are collected. Camellia sinensisAfter harvesting, the leaves are dried in the sun, rolled and left to ferment and post-ferment. This process generates physical, biochemical and microbial changes in the tea. Not only does it change its green hue to reddish hues, it also acquires other organoleptic characteristics, such as its characteristic aroma and bitter taste.
Differences between red tea and green tea
Among the main differences between red tea and green tea, Irene Fernández-Espada highlights that “fully fermented and post-fermented teas, such as pu-erh, have more antioxidants, such as theaflavins and thearubigins, than green tea. On the contrary, green tea has higher levels of catechins and flavins, also antioxidants.”
The following table prepared by the expert shows other differences:
| Red tea | Green Tea | |
| Level of fermentation | Post-fermented Heap fermentation (non-enzymatic auto-oxidation and enzymatic oxidation) | Not fermented |
| Microbiota | 88% of the total are mushrooms. This gives it a mild, slightly bitter taste and its brownish red color. | No |
| Properties of tea | Rough and ashy appearance Bitter taste Slightly astringent |
Raw, bitter and herbaceous smell |
| Compounds responsible for aroma | β-Damascenone, Trimethoxybenzene, (E,E )-2,4-nonadienal, Linalool, Hexanal, Phenyl, Ethanol, γ-Terpinene, Linalool, 4-Ethylveratrol | Hydrocarbons, alcohols, acyclic monoterpenoids (linalool), aldehydes, ketones, esters and phenols |
| Compounds responsible for flavor | Methyl alycylate, caffeine, catechin, epigallocatechin gallate, benzaldehyde and amino acids | Aspartic and glutamic acids |
| Compounds responsible for color | Theaflavins, thearubigins | Chlorophyll a and b |
Composition and assumptions of properties of red tea
Although it has been consumed in China for over a millennium, red tea has only been consumed in the West for a couple of decades. Part of its popularity is due to its flavour and intense colour, but also to the fact that It is credited with healing or protective properties against various pathologies, although none of these have scientific evidence in humans. As we will see later
Red tea has vitamins B, C and D, as well as minerals such as fluoride, zinc, potassium, magnesium and iodine. It is also a powerful source of fiber, theophylline, caffeine and polyphenols. Now, all of these Nutrients and micronutrients refer to the plant itself, not the infusion, where all these components are very diluted. Furthermore, there are no conclusive studies in humans with tea infusions.
The usual dose to infuse is usually 3-4 grams of dried leaves of this tea per cup. It would take a huge amount of cups of tea to consider the possible beneficial effects of these components on human health.
Best time for pu-erh, morning or night?
Many people recommend drinking it in the morning because of its supposed energizing power, which helps you face the day with energy. Others, however, prefer to drink it at night because they believe it helps reduce bloating, aid digestion and, therefore, help you sleep better. On the other hand, there are those who advise against it because its ability to increase energy could cause insomnia.
With scientific evidence in hand, Irene Fernández-Espada refutes all claims. Drinking red tea before going to sleep or as soon as the alarm clock rings is not going to change our health in a decisive way.
The benefits of red tea, under the microscope
Since so many benefits are attributed to the consumption of red tea, the expert analyzes whether any of them can be justified in light of the evidence.
Does red tea really help you lose weight?
As obesity levels rise in Western societies, there is a paradox that studies are also increasing in search of a chimera: ‘slimming superfoods’. Red tea is not exempt from this trend. United Nations Chinese study conducted on mice with post-fermented pu-erh rich in polyphenols and caffeine concludes that the extract of ripe pu-erh tea It could prevent obesity by rebalancing the intestinal microbiota.
The expert stresses that these studies should be taken with a grain of salt, since They have only been tested in mice with obesity and induced metabolic syndrome.but not in humans. And he explains the conclusions as follows: “The polyphenols and caffeine in red tea would have contributed to reducing weight gain, fat accumulation and adipose inflammation.” The study also points to a regulation in the intestinal bacterial microbiota of rodents, previously altered by scientists. This bacterial homeostasis in the intestine would ultimately be responsible for better behavior with fats and the consequent weight loss.
The conclusions of this study, therefore, They cannot in any case conclude that red tea helps you lose weight.. It is not even useful for controlling weight in humans.
There is another Japanese study of 36 people that did show noticeable reductions in weight and abdominal fat. The study subjects consumed 33 milligrams of pu-erh tea extract three times a day for 12 weeks. And that’s the catch: the results are positive, but they weren’t drinking cups of tea, but rather a powdered concentrate.
Strengthens the immune system
Another of the chimeras that accompanies red tea are its supposed anti-inflammatory, anti-tumor, antibacterial, anti-inflammatory and antiviral effects. In short, supposed medicinal powers that do not even come close to being supported by sufficient evidence.
Theories that gloss over the supposed ‘pharmacological effects’ of red tea are nourished by studies such as East of China School of Materia Medica. “The study is based on the fact that pu-erh tea is rich in multiple active compounds such as flavonoids, catechins, phenolic acids, flavonol polymers, purine alkaloids and hydrolysable tannins. These qualities are due to the fact that it is a tea fermented with microbes,” says the expert. Based on this observation, the authors of the study suggest possible pharmacological effects associated with red tea (as they call it in the title of the study).
This is actually a generic analysis. It does not specify how it should be taken, in what quantity and how many times a day to benefit from these possible effects. In fact, the authors assume that larger studies would be needed to corroborate these hypotheses. In other words, It is not possible, in light of the evidence, to claim that red tea has any healing properties of any kind.nor preventive in any case. And in any case, there would be effects associated with one or more of its components, and not with the food itself.
Regulates cholesterol
Others mouse studies They also noted improvements in blood cholesterol levels after ingesting concentrates of this tea for 30 weeks. Again, The results cannot be extrapolated to hypercholesterolemia in humans.because we are not talking about cups of tea. And, of course, a rodent’s organism is not the same as that of a person.
Protects the nervous system and improves concentration
No properties of any kind can be attributed to red tea as an infusion on the nervous system of people.
Digestive properties
Once again, attempts are being made to extrapolate the results of studies with mice to humans. These studies show that the intake of red tea could reduce the expression of the Inflammatory bowel protein and other possible ones digestive pathologies. As interesting as these results may seem, they should always be considered as limited experiments with mice. In summary: No benefits of any kind can be concluded from tea drunk as an infusion for humans.
Improves the cardiovascular system
This same study refers to improvements in cardiovascular parametersis, such as blood lipid levels or blood pressure. But, once again, the The model is limited to mice and cannot in any way be extrapolated to humans..
Diuretic properties, increased energy and reduced stress
These three benefits are very popular on social media. However, the expert from the Spanish Academy of Nutrition and Dietetics emphasizes that There is not enough scientific evidence to be able to say that this is the case for red tea..
Contraindications of red tea
He The caffeine content of this tea would make its consumption inadvisable. in patients with pressure
high blood pressure, although without scientific evidence, and in pregnant women. The content is Caffeine can range from 30 to 100 milligrams. depending on the amount left to infuse in each cup and the infusion time
The expert recalls that “high doses of caffeine during pregnancy have been associated with an increased risk of congenital pathologies, intrauterine growth restriction, premature birth, abortion and low birth weight.” During pregnancy, caffeine intake should not exceed 200 milligrams per day.equivalent to 6 cups of tea,” concludes the expert.
For the general healthy population, Recommendations suggest not exceeding 200 to 400 milligrams of caffeine Up to date. This Equivalent to 950 milliliters maximum (about 4 cups of red tea), always keeping in mind that the caffeine content directly depends on the infusion time. Not forgetting that the total caffeine count also takes into account the intake of other caffeinated foods, such as coffee, cocoa, cola soft drinks and energy drinks.
The ALDI Council
The tannins in tea affect tooth enamel and can even darken teeth if we drink too much of this beverage. Proper tooth brushing after drinking tea helps to keep our smile free of stains.
Irene Fernandez-Sword. Graduated in Human Nutrition and Dietetics from the Pablo de Olavide University, Seville. Expert in psychonutrition and specialized in maternal-child and diabetes mellitus. Registered in CODINAN with number 01123. Lives in Seville, where she practices telemedicine and face-to-face consultations in Seville and Conil de la Frontera (Cádiz). Part of her working time is dedicated to teaching children’s nutrition, giving courses on complementary and infant feeding to interested families. WEB: https://ireneespada.com. LINKEDIN: www.linkedin.com/in/irene-f-espada; INSTAGRAM: @Ireneespada_nutricion
