Spirulina - unwanted side effects and contraindications. Suitable dosage of spirulina

Systematic scientific investigations have confirmed that regular consumption of the cyanobacterium *Arthrospira platensis*—commonly referred to as spirulina—exerts a beneficial effect on the organism’s lipid profile while reducing the risk of atherosclerotic vascular disease development. In controlled experiments published in esteemed journals such as *The Journal of Nutritional Science* and *Vitaminology*, laboratory rabbits were administered a high-cholesterol diet (HCD) containing 0.5% pure cholesterol for four weeks, followed by an eight-week supplementation period with a 5% spirulina additive. Upon completion of the full research cycle, a statistically significant 41% reduction in LDL fraction was observed, alongside decreased circulating serum triglyceride levels and total cholesterol content. Additionally, researchers documented that consistent intake of the supplement reduced the surface area of atherosclerotic lesions in the abdominal aorta by 33–48%, suggesting a potential preventive effect against the progression of coronary artery disease and cerebrovascular incidents.

Currently, there is insufficient scientific evidence regarding the safety of blue-green algae supplementation, including spirulina, during pregnancy and lactation. Consequently, healthcare professionals strongly advise exercising caution and refraining from consumption during these critical life stages. Furthermore, spirulina has the potential to overstimulate immune system activity, which may exacerbate clinical symptoms in individuals diagnosed with autoimmune disorders. Patients suffering from multiple sclerosis (MS), systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), or other autoimmune conditions should categorically avoid this supplement. An additional concern arises from potential drug interactions—spirulina may diminish the therapeutic efficacy of immunosuppressive medications, risking severe complications. Particular attention must be given to individuals with phenylketonuria (PKU), a rare genetic metabolic disorder characterized by phenylalanine hydroxylase deficiency. In these patients, spirulina consumption—given its high phenylalanine content—may intensify neurological manifestations such as psychomotor developmental delays, seizure episodes, hyperactivity, and cognitive impairments.

Algal preparations contaminated with toxins or heavy metals may induce severe health complications, including but not limited to hepatic injury, abdominal discomfort, recurrent episodes of vomiting, persistent nausea, generalized fatigue, excessive thirst (polydipsia), accelerated heart rate (tachycardia), circulatory shock, and—in extreme cases—fatal outcomes. For this reason, consumption of algae-based supplements from unverified or untested sources must be strictly avoided to prevent exposure to potential contaminants. Furthermore, the metabolic breakdown of spirulina’s high-protein content results in elevated ammonia synthesis within the body, which is subsequently converted into urea. This biochemical conversion places an augmented demand on renal function, as the kidneys must efficiently clear excessive nitrogenous waste from the bloodstream—a prolonged strain that may contribute to progressive renal impairment over time. In susceptible individuals, elevated urea concentrations within the urinary system may additionally predispose to nephrolithiasis (kidney stone formation), underscoring the necessity for cautious dosing and avoidance of excessive intake of this dietary supplement.

The optimal dosage of spirulina is contingent upon multiple variables, including the consumer’s age and current physiological condition. At present, there remains an insufficient body of scientific evidence to establish universally applicable dosing standards for this type of algae. It is critical to recognize that, contrary to common perception, natural supplements are not inherently risk-free and may induce adverse effects; therefore, strict adherence to manufacturer guidelines provided on product packaging is essential. Additionally, consultation with a qualified healthcare professional—such as a physician, pharmacist, or clinical nutritionist—is strongly advised prior to commencing supplementation. Clinical studies conducted to date have employed highly variable dosages of spirulina, yet even daily intake ranging from 1 gram to 8 grams has demonstrated measurable health benefits. This microalga is distinguished by an exceptionally nutrient-dense composition, rendering it a valuable addition to a balanced diet. However, caution must be exercised when selecting a source: spirulina harvested from unverified natural water bodies—such as lakes, ponds, or marine environments—may contain hazardous contaminants, including toxins. For this reason, procurement should be limited to reputable suppliers who ensure rigorous quality control and microbiological safety standards.