3. Chlorella
The cell-wall-disrupted alga — high chlorophyll, CGF growth factor, and mercury-binding capacity.
Chlorella in 1 minute
What does it provide? A single-celled freshwater green alga that provides complete protein, chlorophyll, β-glucan, and — in some strains — biologically active B12. Strengthens the gut barrier, weak heavy-metal and dioxin binder, immunomodulator.
How much? 3–6 g/day (about 6–12 tablets of 500 mg) — choose a VERIFIED, cell-wall-disrupted (broken cell wall / cracked cell wall) product — non-disrupted chlorella is barely absorbed at all (cellulose-sporopollenin cell wall).
When to avoid? Known chlorella allergy (1980s Hawaiian pseudo-outbreak — photosensitive skin reactions), active autoimmune flare, severe immunosuppression, anticoagulant therapy with high-dose supplementation.
Chlorella was discovered and named in 1890 by Dutch microbiologist Martinus Beijerinck — from a combination of Greek "chloros" (green) and Latin "ella" (small). It was the first single-celled microorganism that was successfully cultured purely under laboratory conditions. In the post-WWII protein hunger of the 1940s–1950s, a serious international research program began: the Stanford Research Institute, the Carnegie Institute, and the Japanese Institute of Microbiology all examined it as a potential mass protein source for the growing world population. Japanese researcher Hiroshi Tamiya published the first industrial mass cultivation protocol in 1957 — Japan has remained the global chlorella market leader ever since.
In the 1960s, the Yaeyama Group and Sun Chlorella Japanese companies developed the cell-wall-disrupted (DCW — disrupted cell wall) process, which solved chlorella's fundamental bioavailability problem: the thick, cellulose-sporopollenin cell wall was virtually indigestible in humans. In the 1980s in Hawaii, due to a manufacturing error at Sun Chlorella, a cluster of photosensitive skin reactions was reported — this is the origin of the term "chlorella dermatitis," which has practically disappeared in modern, controlled products. From the 2000s onward, in post-Fukushima Japan, interest in chlorella as a cesium and mercury binder grew rapidly, while the Nakano (2010) study documented reduction of heavy-metal transfer in pregnancy.
Scientific Background
Chlorella is a single-celled, rounded freshwater green alga (3–8 μm) whose fundamental digestibility problem is the cellulose-sporopollenin cell wall — in non-disrupted form, the human gastrointestinal system can extract almost nothing from it. Therefore, the cell-wall-disrupted (broken cell wall, BCW; cracked cell wall, CCW; micronized) product is mandatory — this must be stated on the label.[2189] Non-disrupted chlorella passes out largely unchanged.
The chlorophyll content (2–5%) is among the highest of any vegetable. Chlorophyll is antimutagenic in in vitro data, and in the colon it reduces colorectal risk by binding heme-derived pro-oxidants. CGF (Chlorella Growth Factor) is a nucleotide-peptide-polysaccharide matrix that stimulates cell replication — this is the molecular basis of the traditional "regenerative" effect, although human evidence is limited.[2183][2188]
Heavy metal and dioxin binding: Japanese RCTs by Uchikawa (2010) and Nakano (2010) documented moderate reduction in breast milk dioxin and PCB levels for chlorella taken during pregnancy.[2184] For mercury binding, animal experiments and small human data are supportive, but evidence is not robust.[2185] The putative mechanism is the combination of chlorophyll, cell-wall cellulose, and CGF.
B12 issue: unlike spirulina, some chlorella strains contain biologically active B12 (Watanabe 2002, Merchant 2015).[2186][2187][2190] Certain Japanese strains of Chlorella pyrenoidosa are specifically selected for this — a 9 g/day serving can provide up to 60–100 μg of active B12. Important: not every chlorella product is an active B12 source — it must be stated on the label, and ideally followed up with serum MMA/holo-TC testing in vegan consumers.
At the microbiome level, the β-1,3-glucan + cellulose cell-wall fragments are fermentable substrates in the colon — human data show increased Bifidobacterium and Lactobacillus proportions. Chlorophyll degradation products (pheophytin, pheophorbide) have antioxidant activity.
- + Vitamin C (lemon, bell pepper, kiwi): improves chlorophyll-derived iron bioavailability and carotenoid stability.
- + Healthy fat (avocado, olive, fish oil): absorption of fat-soluble carotenoids (lutein, zeaxanthin, β-carotene) increases multifold.
- + Fiber-rich matrix (flaxseed, oats, legumes): chlorella's β-glucan + soluble fiber together generate stronger SCFA production.
- + Live cultures (yogurt, kefir, kombucha): synbiotic effect — chlorella polysaccharides are prebiotic-like.
- + Polyphenol sources (green tea, cacao, berries): combined antioxidant effect, chlorophyll stabilization.
- + Heavy-metal exposure (occupational risk, fish consumption): chlorophyll + cell-wall cellulose matrix may chelate — adjunctive, NOT a replacement.
- Warfarin: chlorella has significant vitamin K content (1 g ≈ 30–50 μg K1) — can cause INR disturbances. Even daily intake or avoidance, with INR monitoring.
- Immunosuppressants (cyclosporine, tacrolimus, biologics): chlorella is immunostimulating (β-glucan, CGF) — autoimmune flare and reduction of therapeutic effect possible.
- Photosensitivity-inducing medications (tetracycline, fluoroquinolone, retinoids, amiodarone): chlorella's pheophorbide content may enhance photosensitivity — additive skin reaction risk.
- Iron supplementation: separate timing by ≥ 2 hours (chlorophyll chelation).
- Empty stomach + high dose (≥ 6 g) on first occasion: nausea, abdominal discomfort possible.
- Too-hot drinks (≥ 80 °C): chlorophyll and B12 degrade.
- Autoimmune disease active flare: due to immunostimulant effect — medical consultation required, cautious introduction in remission.
- Severe immunosuppression (post-transplant, neutropenic phase of chemotherapy): β-glucan immunomodulation to be avoided.
- Warfarin therapy: high vitamin K content — INR monitoring or avoidance.
- Known algae allergy, previous "chlorella dermatitis": avoid.
- Gout, high uric acid level: the high protein-purine content can provoke a flare — try with a low dose, or avoid.
- Kidney disease (chronic, GFR < 60): because of protein load and potassium content, medical consultation.
- Pregnancy and breastfeeding: based on the Nakano RCT, a moderate dose (3–6 g/day) from a verified source appears acceptable, but high doses are to be avoided — coordinate with your doctor.
- Predisposition to photosensitivity: caution — start with a low dose, watch for skin reactions.
- 2 weeks before surgery: stop due to vitamin K content and weak antiplatelet activity.
Daily serving: 3–6 g/day cell-wall-disrupted powder or 6–12 tablets of 500 mg. Start with 1–2 g, increase after 1 week.
Preparation pattern:
- Smoothie: 2–3 g powder + 1 banana + 1 handful spinach + 200 ml plant milk + 1 tbsp almond butter + lemon zest — blend.
- Salad sprinkle: 1–2 g powder over fresh salad, cilantro-parsley mix — with lemony olive dressing.
- Tablet: with a meal, 4–6 in the morning, 4–6 in the evening — capsule form avoids the powder's intense "grassy" taste.
- Bowl sprinkle: on top of miso soup, ramen, or poke bowl, 1 g — Japanese tradition.
Storage: airtight, dark glass, in a cool place — chlorophyll and B12 are light- and heat-sensitive. To be consumed within 6 months of opening.
What not to do: don't cook it (≥ 60 °C destroys B12 and reduces chlorophyll stability). Don't buy non-disrupted (whole cell wall) chlorella. Don't equate it with spirulina.
References
[2183] Merchant RE et al. Nutritional supplementation with Chlorella pyrenoidosa for patients with fibromyalgia syndrome: a double-blind, placebo-controlled, crossover trial. Phytother Res 2000;14(3):167–173. . 2000. Link
Fibromyalgia syndrome is a common, chronic musculoskeletal disorder of unknown aetiology. While available therapy is often disappointing, most patients can be helped with a combination of medication, exercise and maintenance of a regular sleep schedule. The objective of the present study was to determine if adding nutritional supplements derived from the unicellular green alga, Chlorella pyrenoidosa, produced any improvements in the clinical and functional status in patients with moderately severe symptoms of fibromyalgia syndrome. Eligible patients had 2+ palpable tenderness at 11 or more of 18 defined tender points and had a tender point index (TPI) of at least 22. Each day for 2 months, participants consumed two commercially available Chlorella-based products, 10 g of 'Sun Chlorella' tablets and 100 mL of liquid 'Wakasa Gold'. Any amelioration of symptoms was validated and quantified using semi-objective and subjective outcome measures systematically administered at clinic visits on days 0, 30 and 60 of the diet therapy.
[2184] Nakano S et al. Chlorella pyrenoidosa supplementation reduces the risk of anemia, proteinuria and edema in pregnant women. Plant Foods Hum Nutr 2010;65(1):25–30. . 2010. Link
Pregnancy anemia and pregnancy-induced hypertension (PIH) are common and potentially dangerous disorder in human pregnancy, and nutritional status of pregnant women is one of the leading causes. Chlorella contains large quantities of folate, vitamin B-12 and iron, and can help improve anemia and hypertensive disorder. Our objective was to investigate the preventive effects of Chlorella supplement on pregnancy anemia and PIH in Japanese pregnant women. A total of 70 pregnant women were placed into the control group (n = 38) or the Chlorella group (n = 32). The subjects in the Chlorella group were supplemented daily from 12th-18th wk of gestation until delivery with 6 g of Chlorella supplement. The proportion of anemic (hemoglobin level < 11 g/dL) subjects in the Chlorella group were significantly lower compared with the control group at the second and third trimesters.
[2185] Uchikawa T et al. The enhanced elimination of tissue methylmercury in Parachlorella beijerinckii–fed mice. J Toxicol Sci 2010;35(1):101–105. . 2010. Link
To investigate the influence of Chlorella (Parachlorella beijerinckii) on the excretion and tissue accumulation of methylmercury (MeHg), we orally administered 5 mg/kg of MeHg chloride (4 mg Hg/kg) to female C57BL/6N mice (aged 10 weeks). The mice were housed in metabolism cages to collect urine and feces for 3 weeks with diets containing 0\%, 5\%, or 10\% P. beijerinckii powder (BP) in a basal diet (CE-2). The lowered blood Hg levels in the 5\% and 10\% BP groups became significant compared to those of the control group (0\% BP) as early as day 7. During the 21 days of testing, significant increases in the cumulative Hg eliminations into urine (5\% BP) and feces (5\% and 10\% BP) were found in the BP groups. Twenty-one days after administration, the organ Hg levels in both BP groups tended to decrease compared to that of the control group. The reduction of Hg levels in the kidney and brain were significant, whereas that in the liver was not.
[2186] Watanabe F et al. Characterization of a vitamin B12 compound from edible cyanobacteria and microalgae. J Agric Food Chem 2002;50(20):5780–5784. . 2002. Link
Research article characterizing a vitamin B12 compound from edible cyanobacteria and microalgae.
[2187] Bito T et al. Bioactive compounds of edible purple laver Porphyra sp. (Nori). J Agric Food Chem 2017;65(46):10685–10692 (összehasonlító B12-adatok). . 2017. Link
Porphyra sp. (nori) is widely cultivated as an important marine crop. Dried nori contains numerous nutrients, including vitamin B12, which is the only vitamin absent from plant-derived food sources. Vegetarian diets are low in iron and vitamin B12; depletion of both causes severe anemia. Nori also contains large amounts of iron compared with other plant-derived foods and eicosapentaenoic acid, which is an important fatty acid found in fish oils. In nori, there are also many bioactive compounds that exhibit various pharmacological activities, such as immunomodulation, anticancer, antihyperlipidemic, and antioxidative activities, indicating that consumption of nori is beneficial to human health. However, Porphyra sp. contains toxic metals (arsenic and cadmiun) and/or amphipod allergens, the levels of which vary significantly among nori products.
[2188] Panahi Y et al. Investigation of the effects of Chlorella vulgaris as an adjunctive therapy for dyslipidemia: results of a randomized open-label clinical trial. Nutr Diet 2012;69(1):13–19. . 2012. Link
Randomized open-label clinical trial investigating Chlorella vulgaris as an adjunctive therapy for dyslipidemia.
[2189] EFSA. Safety of Chlorella vulgaris as a novel food. EFSA Journal 2017. . 2017.
EFSA scientific opinion on the safety of Chlorella vulgaris as a novel food.
[2190] Bito T et al. Potential of Chlorella as a dietary source of vitamin B12. Nutrients 2020;12(9):2524. . 2020. Link
Study (Nutrients) on the potential of Chlorella as a dietary source of vitamin B12.