Matcha — myths & realities

A single-blind, randomised, crossover controlled trial in 30 healthy young women. Each participant received 3 g of matcha and then a placebo (and vice versa), with brown adipose tissue (BAT) activity measured by thermography under cold exposure. BAT is the fat tissue involved in thermogenesis — the body's production of heat from fat.

Primary result: no significant difference between matcha and placebo across the group as a whole. Analysis stratified by BAT-activity tertiles revealed a localised effect: in the subgroup with low baseline BAT activity, the increase was significantly greater than placebo. The medium- and high-activity groups showed no difference.

What it refines: the modest thermogenic effects documented for green tea (Q82, roughly +4 to 5% thermogenesis according to meta-analyses) may apply to matcha in a targeted way — in people with low baseline thermogenesis. Limitations: acute effect of a single intake (no data on chronic consumption), small sample (n=30), young women only. It does not change the book's general conclusion on Q82.

An experimental study comparing 16 growing treatments that combined foliar nano-selenium fertilisation, cultivar, altitude and shading level, followed by an in vivo component in an animal model. The best analytical quality was observed in the group combining selenium, high altitude and prolonged shading on the Fuyun No. 6 cultivar: the highest L-theanine content, the lowest polyphenol-to-amino-acid ratio, and the best sensory score.

The in vivo component documents, for selenium-enriched matcha: increased glutathione peroxidase activity, lower malondialdehyde in the liver and kidneys, higher expression of intestinal-barrier proteins (Claudin-1, Occludin), and modulation of the gut microbiota — notably an increase in bacteria of the genus Ligilactobacillus.

Important limitations: the study used a Chinese cultivar (Fuyun No. 6) under experimental growing conditions with nano-selenium fertilisation — not a standard practice in Japanese tencha production. The in vivo results are from an animal model. What it opens up: it confirms the documented importance of altitude, shading and cultivar for quality (Q15, Q18–19, Q45); on selenium biofortification, no direct transposition to market matcha — Japanese or otherwise — is possible without a dedicated regulatory framework.

A study published in npj Science of Food (Nature group) shows that matcha reduces the sneezing reflex in mice presenting allergic-rhinitis symptoms. The mechanism is neurological rather than immune: matcha suppresses activation of the ventral trigeminal nucleus in the brainstem — the area involved in the sneezing reflex — without altering the classic immune markers (IgE, mast cells, T cells).

Important limitation: a mouse-model study only. No human clinical study of this effect exists to date. Prof. Kaminuma (Hiroshima University) notes that the aim is “an evidence-based dietary option, complementary to standard treatments”.

What it opens up: if confirmed in humans, this would be a third documented mode of action of matcha on the nervous system — distinct from the L-theanine/alpha-wave effect (Q79) and the anti-inflammatory effect of catechins (Q78). Not included in the print edition: the study was published after the book went to press.

A double-blind, randomised controlled trial in 99 older adults with mild cognitive decline, over 12 months, with 2 g of matcha per day. A significant result on the perception of facial emotions (social acuity, p = 0.028). Overall cognitive indicators (MoCA) showed no significant change — which clarifies that the effects are targeted rather than general. A trend toward improved sleep quality (p = 0.088, not statistically significant).

A meta-analysis of 178,000 participants confirming a 37% reduction in the risk of cognitive decline among regular green-tea drinkers (≥ 2 cups/day). No equivalent meta-analysis specific to matcha yet exists — the distinction between infused green tea and matcha is maintained in the book.

Japanese green-tea exports reached 13,125 tonnes in fiscal year 2025 (April 2025 – March 2026), up 42% by volume. Their value more than doubled, to 84.7 billion yen (about US$580 million), driven by soaring prices on international markets. Green-tea powder, matcha included, accounts for roughly 70% of the total volume exported — the other varieties (sencha chief among them) are in decline.

On a calendar-year basis, 2025 exports (January–December) reached 72.1 billion yen (about US$460 million), according to MAFF. The two figures reflect different time windows but point the same way: 2025 is the year Japanese tea exports crossed an unprecedented threshold.

Two documented side effects: tencha production (matcha's raw material) rose for four consecutive years through 2024; meanwhile, thirteen Japanese tea producers ceased operations in 2025, against eight the year before — the shift in production from sencha to tencha is not neutral for farms in mountainous areas, which account for about 40% of plantations.

The global matcha market reached US$5 billion in 2024 (MAFF, via Forbes and Radio-Canada). Japanese tea exports grew by 115% over five years. The shortage of certified-organic tencha is the leading documented limiting factor for producers targeting European markets.

In May 2026, an association bringing together producers, exporters and other players in the Japanese tea sector filed an application to register the name nihon cha (“Japanese tea”) under Japan's geographical-indication (GI) system, managed by MAFF. The system, in force since 2015, already protects certain regional appellations — Kobe beef, Echizen crab, and, for matcha, Uji matcha and Nishio matcha.

The stated reason for the move: according to industry players, green teas produced in China or elsewhere are being marketed on foreign markets using Japanese place names on their packaging. A national GI covering Japanese tea as a whole would, if granted, make it possible to bring legal action against misleading labelling and to support exports.

What it refines relative to the book (Q97): three levels of protection would eventually stack up — Japanese regional GIs (Uji, Nishio), a broad national GI (Nihon cha, under review), and European recognition via the EU–Japan EPA (2019, which already includes Uji matcha and Nishio matcha). The logic echoes the case of nihonshu (Japanese sake), registered as a GI in 2015. Status: application filed, review under way — recognition and the exact scope remain to be confirmed.