Spinach

Spinach (Spinacia oleracea L.): A Comprehensive Reference

1. Identity and Botanical Description

Botanical name: Spinacia oleracea L. Spinach (Spinacia oleracea L.) is widely regarded as a functional food due to its diverse nutritional composition, which includes vitamins and minerals, and to its phytochemicals and bioactives that promote health beyond basic nutrition.

Spinach (Spinacia oleracea) is a leafy green vegetable that originated in Persia. It belongs to the amaranth family and is related to beets and quinoa. Botanically, spinach has its stem as a vertical, round, delicate, succulent structure that may reach a height of 30 cm. It can grow up to 30 cm in height and its leaves can have a width of up to 15 cm and length of 30 cm. Its seed comes from very small fruits (10 mm in radius), which in turn come from equally small flowers (5 mm).

Research studies reveal that spinach is a cool-season crop that mainly grows during winter and early spring. The leaves should be cut about one inch above the soil surface before forming seed stalks. These leaves are eaten either fresh or cooked.

Common Forms and Preparations

• Fresh whole leaf: Consumed raw in salads or cooked (sautéed, steamed, boiled).
• Frozen spinach: A widely available processed form.
• Canned spinach: Heat-processed for shelf stability.
• Spinach powder (dehydrated): Spinach powder has been reported to contain 8.2% crude fiber, 19.2% protein, 1,304 mg/100g calcium, and 40.4 mg/100g iron.
• Spinach extract (thylakoid extract): Used in clinical supplementation studies, typically standardized to thylakoid membrane content.
• Spinach juice: Used historically in folk medicine and studied in some acute clinical trials.

Spinach's nutritional composition can vary based on factors like maturity stage, cultivation method, and processing techniques. For instance, spinach harvested between the 4th and 6th weeks shows increased levels of crude fiber, protein, and minerals like iron and calcium, while fermentation can enhance mineral bioaccessibility and reduce antinutrients like oxalates. Hydroponically grown spinach tends to have slightly lower vitamin C content compared to non-hydroponic spinach.

2. Historical and Traditional Use

Origins in Persia

Spinach was first cultivated in Persia around 2,000 years ago, though its origin is in southwest Asia. Spinach's place of origin is ancient Persia (today's Iran and surrounding countries). From there it crossed into India, though it is not known who brought it there. Iran is the early center of spinach diversity, and its wild species grow as wild vegetables in many of Iran's mountains, including the northern slopes of the Alborz and Zagros.

Spread to China

Ancient Chinese received it from India and gave it the name "Persian vegetable." The first written mention of spinach states that it came to China via Nepal somewhere around the year 647. In traditional Chinese medicine, spinach was recognized for its health benefits, attributed to its rich content of vitamins and minerals, and its incorporation into medical prescriptions emphasized its role in promoting overall well-being. Spinach was believed to aid digestion, improve skin health, and possess invigorating properties.

Arab World and Medieval Europe

Saracens brought spinach to Sicily in the year 827. The first texts to mention spinach in the Mediterranean were written in the 10th century. By the 10th century, it was referenced in works by prominent scholars such as al-Rāzī (Rhazes), Ibn Waḥshīyah, and Qusṭus al-Rūmī. Spinach gained significant popularity in the Arab Mediterranean, earning the title raʼīs al-buqūl, or "chieftain of leafy greens."

In Arab culture, spinach was used for its medicinal properties against stomach and liver pain. Arabs introduced it to Spain in about the 11th century, and it had spread throughout Europe by the 14th century. The vegetable was first mentioned in the English cookbook The Forme of Cury (1390), where it appeared as "spinnedge" and "spynoches."

Historically recognized as a medicinal herb, spinach gained popularity in Europe by the Middle Ages and became associated with health due to its iron content, although early claims about its iron richness were exaggerated due to a miscalculation. In 1870, the German chemist Erich von Wolf was researching the iron content of various green vegetables and misplaced a decimal point when recording the amount in spinach.

By the fifteenth century, spinach was common in the Mediterranean region, where it was popular among royalty. It was particularly desirable because it matured so early in spring, when few fresh vegetables were available and winter stores were depleted.

Folk and Wartime Use

During World War I, spinach juice was blended into wine and given to hemorrhaging French soldiers to thicken the blood, hoping to slow the bleeding. Throughout history, spinach has been used in medicinal remedies and was valued for its anti-inflammatory properties and antioxidants to protect the cells against the damage caused by free radicals. The Iranian wild spinach (Blitum virgatum L.) is an important traditional medicinal plant used for antiviral diseases such as pneumonia and other respiratory tract infections.

3. Key Constituents and Active Compounds

Vitamins

The nutritional composition of spinach is characterized by a rich vitamin profile, particularly folate, vitamin K, and ascorbic acid (vitamin C). According to the U.S. Department of Agriculture, one cup of raw spinach has only 7 calories, but it provides 121% of the vitamin K a man should consume each day and 161% of the amount recommended for women. Cooked spinach, per cup, provides 129% of the recommended daily vitamin A for women and 105% of the suggested amount for men.

Minerals

Spinach (Spinacia oleracea) is a nutrient-rich leafy vegetable known for its low-calorie content and high levels of essential nutrients such as zinc, folic acid, iron, calcium, magnesium, retinol, and ascorbic acid. Spinach is also a notable source of minerals, including iron (Fe), calcium (Ca), zinc (Zn), potassium (K), magnesium (Mg), sodium (Na), and phosphorus (P).

Carotenoids

The content of lutein and zeaxanthin in vegetables varies greatly; the highest content is found in kale (~39 mg/100 g) and spinach (~11.9 mg/100 g). The protective effects of carotenoids are mainly related to their defense against oxidative stress and their ability to scavenge free radicals. Lutein and zeaxanthin are the only dietary carotenoids that accumulate in the retina, specifically the macula, and are called macular pigments. Spinach also contains beta-carotene (a provitamin A carotenoid), neoxanthin, and violaxanthin.

Total carotenoids in spinach have been measured at approximately 0.346 ± 0.042 mg/g dry weight.

Flavonoids and Phenolic Compounds

Phytochemical constituents of spinach include flavonoids, carotenoids, and phenolic compounds, which serve as the primary bioactive agents responsible for health-promoting effects. Notable flavonoids identified in spinach include kaempferol, quercetin, and various glycosylated derivatives. Flavonoids and other bioactive compounds in spinach could help resist oxidative stress, control blood sugar levels, improve bone health, and may even lower the risks of some cancers.

Dietary Nitrates

Spinach is an excellent source of nitrates, compounds that have been shown to enhance the health of blood vessels and improve circulation. Once ingested, nitrates are converted to nitric oxide, a molecule that dilates blood vessels, leading to improved blood flow and reduced blood pressure.

Thylakoids

Thylakoids are membrane proteins extracted from green leaves such as spinach, and some studies suggest they can reduce weight in humans by inducing satiety, decreasing appetite, and possibly reducing food intake through homeostatic and non-homeostatic pathways. The observed positive effects of thylakoid extracts on anthropometric indices, glucose homeostasis, and lipid profile could be explained by probable mechanisms such as lipase/colipase inhibition, which stimulates the compensatory release of lipase/colipase and acts as a mechanism to increase enterostatin, an appetite suppressant peptide.

Oxalic Acid (Antinutrient)

Consumption of a normal portion of spinach (50–100 g) will result in a load of approximately 500–1,000 mg of dietary oxalate and can significantly increase urinary oxalate excretion. Oxalic acid binds to minerals such as iron and calcium, forming insoluble salts and reducing their bioavailability from spinach relative to what the total mineral content might suggest.

Fatty Acids

The fat content in spinach is generally low, but it contains beneficial fatty acids such as α-linolenic and linoleic acids.

Phylloquinone (Vitamin K1)

Phylloquinone (vitamin K1) is a dietary form of vitamin K created by plants and green vegetables like spinach and kale. The amount of vitamin K in spinach is about four times more than lettuce, about five times more than broccoli, and eight times more than cabbage.

4. Scientific Evidence by Health Area

4.1 Cardiovascular Health and Blood Pressure

As a nitrate-rich vegetable, spinach shows cardioprotective effects through inducing an increase in postprandial plasma nitrate and nitrite concentrations and lowering blood pressure.

A key mechanism involves the nitrate–nitrite–nitric oxide (NO) pathway. The primary mechanism through which dietary nitrate may impact cardiovascular health is via augmentation of nitric oxide. Endothelium-derived NO maintains vascular tone, influencing blood flow and blood pressure.

Randomized controlled trial (Bondonno et al., 2012): Compared to control, all treatments (apple and/or spinach) resulted in higher flow-mediated dilatation (p < 0.05) and lower pulse pressure (p < 0.05), and apple and spinach resulted in lower systolic blood pressure (p < 0.05). No significant effect was observed on diastolic blood pressure. The combination of apple and spinach did not result in additive effects on nitric oxide status, endothelial function, or blood pressure.

Randomized controlled crossover trial (Bondonno et al., 2013, n=26): Twenty-six participants aged 38–69 years were recruited to a randomized controlled crossover trial. The acute effects of two energy-matched meals, administered in random order, were compared. The meals were either high nitrate (220 mg of nitrate derived from spinach) or low nitrate (control). Spinach resulted in an eightfold increase in salivary nitrite and a sevenfold increase in salivary nitrate concentrations from pre-meal (p < 0.001) to 120 minutes post-meal. Spinach compared with control resulted in higher large artery elasticity index (p < 0.001), and lower pulse pressure (p < 0.001) and systolic blood pressure (p < 0.001). Post-meal carotid-femoral pulse wave velocity, augmentation index, small artery elasticity index, and diastolic blood pressure were not significantly altered by spinach relative to control.

Evidence strength: The evidence for acute blood-pressure-lowering effects via dietary nitrate is moderate, supported by multiple small randomized crossover trials in healthy adults. Results support findings from short-term clinical trials and meta-analyses of these trials demonstrating a benefit of nitrate intake on blood pressure; however, not all clinical trials have observed a reduction in blood pressure with nitrate intake. Long-term cardiovascular outcome data attributable specifically to spinach consumption are limited.

4.2 Eye Health — Age-Related Macular Degeneration (AMD) and Visual Function

Lutein and zeaxanthin are the only dietary carotenoids that accumulate in the retina, specifically the macula, and are called macular pigments. Lutein and zeaxanthin form macular pigments that may protect against AMD by reducing oxidative stress, absorbing blue light, and stabilizing cell membranes.

Regular consumption of foods such as spinach, kale, and cabbage has been shown in many studies to provide significant protection against the onset of late AMD.

Prospective cohort studies: Prospective cohort study cohorts from the Nurses' Health Study and the Health Professionals Follow-up Study in the United States followed a total of 63,443 women and 38,603 men from 1984 and 1986, respectively, until 2010. Despite strong biological plausibility, evidence from epidemiologic studies and clinical trials on the relations between intakes of lutein and zeaxanthin and AMD has been inconsistent. The roles of other carotenoids are less thoroughly investigated.

Intervention study: An eight-week intervention using spinach powder as a lutein/zeaxanthin-rich food found improvements in macular pigment levels (MPL) in the highest serum responders and in those with initially low MPL, supporting observational evidence to date.

AREDS2 trial evidence (supplement-based): The AREDS2 study group found that individuals with low dietary lutein and zeaxanthin were about 25% less likely to develop advanced AMD if they supplemented. The removal of beta-carotene did not affect the formulation's protective effect, and formulations containing lutein and zeaxanthin and no beta-carotene had an 18% reduction in developing advanced AMD compared to participants who took the AREDS2 formula with beta-carotene and no lutein or zeaxanthin.

Clinical trial outcomes (lutein/zeaxanthin supplements): Observational studies have reported that increased dietary intake and higher serum levels of lutein and zeaxanthin are associated with lower risk of AMD, especially late AMD. Randomized, placebo-controlled clinical trials have demonstrated that xanthophyll supplementation increases macular pigment levels, improves visual function, and decreases the risk of progression to late AMD, especially neovascular AMD.

Evidence strength: Moderate-to-good for dietary lutein/zeaxanthin from sources including spinach reducing risk of AMD progression, based on large cohort data and supporting clinical trials. Evidence from spinach-specific (rather than supplement) interventions is more limited.

4.3 Obesity, Satiety, and Metabolic Health (Thylakoids)

Spinacia plants have also been used as a food that confers anti-obesity effects. These effects mostly derive from its ability to induce satiety hormones secretion and to reduce postprandial glucose response. Thylakoids, the green-plant membranes, have an influence on these effects.

Double-blind, placebo-controlled crossover trial: A double-blind, placebo-controlled, randomized crossover-designed study conducted among sixty overweight or obese males and females indicated that supplementation with 5 g of thylakoids could increase satiety as well as a greater increase in the postprandial plasma glucose response compared to the placebo group.

Randomized controlled trial in women (Stenblom et al.): Stenblom et al. concluded that the dietary addition of thylakoids to a carbohydrate-rich breakfast resulted in a significant increase in CCK (cholecystokinin) levels postprandially and prevented postprandial hypoglycemia in 20 healthy women.

12-week RCT in obese men: Sixty-eight obese male subjects were randomly divided into four groups: control, supplement, training, and combined training and supplement. The training groups commenced a twelve-week HIFT program (3 sessions/week, 30 min each). Eligible candidates were randomly assigned to either receive thylakoid-rich spinach extract (5 g per day) or a matching placebo (5 g per day of corn starch, 30 min before lunch) for 12 weeks. While no significant differences were observed between training-only and training-plus-thylakoid groups for systemic metabolic markers, preliminary data suggested that thylakoid supplementation might provide modest complementary modulations in specific myokines. However, these observed trends did not reach clinical superiority over exercise alone in the broader metabolic profile.

RCT in obese women with PCOS: Forty-four obese women with PCOS participated in a randomized, double-blind, placebo-controlled clinical trial for 12 weeks and were allocated to receive 5 g of thylakoid membranes of spinach extract combined with a hypo-caloric diet or 5 g placebo along with a hypo-caloric diet. Novel atherogenic and anthropometric indices including atherogenic index of plasma, Castelli risk indices, TyG-BMI, and insulin resistance markers were assessed. Thylakoid membranes of spinach supplementation along with a calorie restriction diet showed a significant decrease in the atherogenic index of plasma, Castelli risk index I and II, TyG-BMI, and metabolic score for insulin resistance (p < 0.05).

Evidence strength: Early-to-moderate; multiple small RCTs support short-term effects of spinach thylakoids on satiety and select metabolic markers, but larger, longer-term trials are needed to establish clinical relevance for weight management.

4.4 Cognitive Health

A prospective study of 960 older adults (average age 81) from the Rush Memory and Aging Project found that higher consumption of green leafy vegetables, including spinach, kale, collard greens, and lettuce, was associated with a significantly slower rate of cognitive decline over roughly 4.7 years. Those in the highest quintile of green leafy vegetable intake (about 1.3 servings/day) showed decline rates in global cognition scores equivalent to being 11 years younger compared with those in the lowest intake quintile (about 0.09 servings/day).

Nutrients abundant in green leafy vegetables, such as folate, lutein, vitamin K (phylloquinone), and nitrate, were each individually associated with slower cognitive decline, suggesting mechanisms by which spinach-rich diets may protect brain health.

In vitro and animal studies have highlighted vitamin K involvement in brain cell development and survival. In particular, vitamin K seems to have an antiapoptotic and anti-inflammatory effect mediated by the activation of Growth Arrest Specific Gene 6 and Protein S. Moreover, this vitamin is involved in sphingolipids metabolism, a class of lipids that participates in the proliferation, differentiation, and survival of brain cells. Evidence shows interesting, even though not definitive, correlation between vitamin K levels and cognitive performance.

Evidence strength: Observational (cohort study) for green leafy vegetable intake and cognitive decline. Spinach-specific intervention data for cognition are lacking. Mechanistic evidence for individual constituents (folate, lutein, vitamin K, nitrate) is biologically plausible but requires dedicated clinical trials.

4.5 Bone Health

Vitamin K (VK) is a lipid-soluble vitamin that contributes to blood coagulation and maintenance of bone health. Most studies state that the essential role of vitamin K in osteoblastic function is mediated through the classical protein γ-carboxylation pathway, which is well established. Other studies have explored different mechanisms of vitamin K action on bone and showed evidence that the osteoprotective action of vitamin K2 is mediated through the upregulation of bone marker genes.

The overall evidence highlights the potential of vitamin K, especially K2, in supporting bone and cardiovascular health, though effects may vary by form, dose, and target outcome. Spinach provides vitamin K1 (phylloquinone), and while it contributes significantly to daily vitamin K intake, most of the bone-specific RCT evidence is based on vitamin K2 (menaquinone) supplementation, not dietary K1 from spinach. Spinach also contains calcium, although its bioavailability is reduced by concurrent oxalic acid content.

Evidence strength: Preliminary for direct spinach consumption on bone endpoints. Vitamin K1 from spinach plausibly supports coagulation-related bone protein activation, but human clinical trials focused on dietary spinach and bone mineral density are not established in the reviewed literature.

4.6 Antioxidant Activity and Cancer (Preclinical and Epidemiological)

Spinach has strong antioxidant properties, triggered by carotenoids such as lutein and zeaxanthin, that are important in maintaining vision and fighting age-related macular degeneration. The introduction of flavonoids, carotenoids, omega-3 fatty acids, vitamins, minerals, and antioxidants through fruits and vegetables appears to have positive effects in reducing some types of cancer and chronic diseases, thanks to the ability of these molecules to reduce the damage caused by reactive oxygen species (ROS).

Carotenoids and lipophilic active compounds present in Spinacia spp. — i.e., lutein, neoxanthin, zeaxanthin — may be considered as beneficial and contributive sources to observed antineoplastic effects.

In vitro evidence: Among the antiproliferative phytochemicals, DNA damage reduction up to 40% was recorded with the highest dose of 20-hydroxyecdysone (1.5 and 15 µM) and, among the carotenoids, up to 50% with lutein at 2 µM. β-carotene (1.5 and 15 µM) reduces DNA damage by about 15–20%.

Evidence strength: Largely preclinical (in vitro and animal models). Overwhelming evidence indicates that diets rich in fruits and vegetables are protective against common chronic diseases such as cancer, obesity, and cardiovascular disease. Leafy green vegetables, in particular, are recognized as having substantial health-promoting activities attributed to the functional properties of their nutrients and non-essential chemical compounds. However, direct spinach-specific human cancer intervention data are absent in the reviewed literature; findings are primarily extrapolated from broader dietary pattern research.

4.7 Folate and Hematological / Prenatal Health

Folate (vitamin B9) functions as a cofactor or co-substrate in many one-carbon transfer reactions important for amino acid metabolism and for the synthesis of nucleic acids. When DNA synthesis is impaired, the production of red blood cells is disrupted, and deficiency in folate can lead to megaloblastic anemia. Spinach is one of the most concentrated dietary sources of natural food folate.

Folic acid — also known as folate or vitamin B9 — is vital for pregnant women and essential for normal cellular function and tissue growth. Natural food folates from spinach contribute to meeting folate requirements that are especially critical during early pregnancy for neural tube development.

Evidence strength: Well established at the nutrient level (folate's role in preventing neural tube defects and megaloblastic anemia is consensus science); spinach as a dietary folate source is recognized but is rarely singled out in clinical trials versus total dietary folate intake.

5. Body Systems and Health Areas Associated with Spinach

• Cardiovascular system: Blood pressure modulation via dietary nitrate → nitric oxide pathway; endothelial function; arterial elasticity.
• Visual system: Macular pigment optical density maintenance via lutein and zeaxanthin; AMD risk reduction.
• Musculoskeletal system: Bone health via vitamin K1 (γ-carboxylation of bone proteins); calcium and magnesium content.
• Nervous system / Cognition: Folate-mediated neurotransmitter synthesis; vitamin K involvement in sphingolipid metabolism; lutein accumulation in neural tissue.
• Hematological system: Folate for red blood cell synthesis; iron for hemoglobin production; vitamin K for coagulation factor activation.
• Metabolic / Endocrine system: Thylakoid-mediated satiety signaling; postprandial glucose and insulin response modulation; potential effects on lipid profiles.
• Antioxidant / Cellular protection: Scavenging of reactive oxygen species via carotenoids, flavonoids, and ascorbic acid; protection against lipid peroxidation.

Research studies have revealed that the leaves of spinach contain a significant amount of magnesium, which supports energy metabolism, muscle and neuron function, heart rhythm, immune health, and blood pressure regulation.

6. Dosage Forms and Doses Reported in Clinical Studies

There is no established standardized therapeutic dose for spinach as a dietary supplement. The following represent doses reported in published research:

• Whole spinach (nitrate/cardiovascular trials): 220 mg of nitrate derived from spinach, administered as a single high-nitrate meal in a randomized controlled crossover trial.
• Spinach thylakoid extract (satiety/obesity trials): 5 g per day of thylakoid-rich spinach extract, administered 30 minutes before lunch for a total duration of 12 weeks in RCTs.
• Spinach thylakoid extract (PCOS/metabolic trial): 5 g of thylakoid membranes of spinach extract combined with a hypo-caloric diet over 12 weeks in a randomized, double-blind, placebo-controlled trial.
• Spinach powder (lutein/zeaxanthin/macular pigment): An eight-week intervention used spinach powder as a lutein/zeaxanthin-rich food to assess macular pigment levels. Specific powder dosage was not extractable from available abstracts.
• Dietary lutein targets: The recommended daily intake of lutein is approximately 10.0 mg and that of zeaxanthin is 2 mg; lutein intake in adults varies, with average intakes being 1–2 mg/day. Dietary models describe suggested effective levels of lutein and zeaxanthin achievable through diet at values of 5 mg and 10 mg per day.

7. Safety Considerations and Drug–Nutrient Interactions

Oxalate Content and Kidney Stones

Despite infrequent consumption, cooked and raw spinach was listed as the major source of dietary oxalate in long-term cohort studies. Consumption of a normal portion of spinach (50–100 g) will result in a load of approximately 500–1,000 mg of dietary oxalate and can significantly increase urinary oxalate excretion. These studies showed a minor risk associated with dietary oxalate intake and stone disease (relative risk 1.21 in men and 1.22 in older women). People who are prone to kidney stones are sometimes put on a low-oxalate diet. Boiling spinach can decrease the amount of oxalates consumed.

Vitamin K and Anticoagulant Therapy (Warfarin)

Vitamin K, which plays an important role in blood clotting, can interfere with the blood thinner warfarin. That is less of an issue with newer blood thinners, but people on warfarin should be consistent in their consumption. Vitamin K, which plays an important role in blood clotting, can interfere with the blood thinner warfarin. People on warfarin should be consistent in their consumption of vitamin K, which will help stabilize warfarin levels.

Potassium and Chronic Kidney Disease

Spinach is high in potassium; individuals with chronic kidney disease or those advised to limit potassium should discuss appropriate amounts and alternatives with their medical team.

Gout

Spinach contains purines, which are converted to uric acid in the body. In people who have gout, uric acid can trigger an attack; however, studies have shown that consumption of spinach has little to no effect on the risk of a gout attack.

Iron Bioavailability

While spinach is a good source of iron, its absorption is inhibited by oxalates present in the leaves. The presence of oxalate forms insoluble iron complexes in the gut, substantially reducing the bioavailability of the non-heme iron that spinach provides, despite its relatively high total iron content.

Microbial and Contaminant Risks

Research has identified potential risks including pesticide residues, microbial contamination, heavy metals, and nitrate accumulation that warrant attention from both consumers and food safety professionals. Spinach is a highly perishable leafy green vegetable that requires proper handling, storage, and processing for safety and quality maintenance.

Nitrate Accumulation

Spinach can accumulate high levels of nitrate from soil, which is the basis for its cardiovascular benefits via the nitrate–nitric oxide pathway. However, in the context of food safety, particularly for infants, very high nitrate intake from certain prepared foods has been monitored by food safety authorities. In adults consuming spinach within normal dietary ranges, adverse effects from nitrate have not been established in the reviewed literature.

References

• Balasubramaniam AK et al. (2025). Nutritional and health beneficial properties of spinach (Spinacia oleracea L): A comprehensive review. ScienceDirect.
• Roberts JL, Moreau R. (2016). Functional properties of spinach (Spinacia oleracea L.) phytochemicals and bioactives. Food & Function, RSC Publishing.
• Roberts JL, Moreau R. (2016). Functional properties of spinach (Spinacia oleracea L.) phytochemicals and bioactives. PubMed.
• Yadav SK et al. (2021). Nutritional characterization and food value addition properties of dehydrated spinach powder. PMC/NIH.
• Ammarellou A, Mozaffarian V. (2021). The first report of iron-rich population of adapted medicinal spinach (Blitum virgatum L.) compared with cultivated spinach (Spinacia oleracea L.). PMC/NIH.
• Extraction and Natural Bioactive Molecules Characterization in Spinach, Kale and Purslane: A Comparative Study. PMC/NIH.
• Biological Effect of Different Spinach Extracts in Comparison with the Individual Components of the Phytocomplex. PMC/NIH.
• Plants of the genus Spinacia: From bioactive molecules to food and phytopharmacological applications. ScienceDirect.
• Bondonno CP et al. (2012). Flavonoid-rich apples and nitrate-rich spinach augment nitric oxide status and improve endothelial function in healthy men and women: a randomized controlled trial. PubMed.
• Bondonno CP et al. (2013). Effects of a nitrate-rich meal on arterial stiffness and blood pressure in healthy volunteers. PubMed.
• Vegetable nitrate intake, blood pressure and incident cardiovascular disease: Danish Diet, Cancer, and Health Study. PMC/NIH.
• Eisenhauer B et al. (2017). Lutein and Zeaxanthin—Food Sources, Bioavailability and Dietary Variety in Age-Related Macular Degeneration Protection. PMC/NIH.
• Lutein and Zeaxanthin and Their Roles in Age-Related Macular Degeneration—Neurodegenerative Disease. PMC/NIH.
• Intakes of Lutein, Zeaxanthin, and Other Carotenoids and Age-Related Macular Degeneration During 2 Decades of Prospective Follow-up. PMC/NIH.
• Nolan JM et al. (2016). Lutein, Zeaxanthin, and meso-Zeaxanthin in the Clinical Management of Eye Disease. PMC/NIH.
• Supplementation with spinach-derived thylakoid augments the benefits of high intensity training on adipokines, insulin resistance and lipid profiles in males with obesity. PMC/NIH.
• Razi O et al. (2026). Adipo-Myokine Modulation in Obesity: Integrative Effects of Spinach Thylakoids and Functional Training in Men with Obesity. PMC/NIH.
• Nikrad et al. (2023). The Effect of Thylakoid Membranes of Spinach Extract Supplementation on Atherogenic, Glycemic, and Anthropometric Indices and Renal Function in Obese PCOS Women. Journal of Food Biochemistry.
• Dietary oxalate and kidney stone formation. PMC/NIH.
• Influence of Vitamin K on Bone Mineral Density and Osteoporosis. PMC/NIH.
• The Relationships Between Vitamin K and Cognition: A Review of Current Evidence. PMC/NIH.
• Vitamins and Minerals for Energy, Fatigue and Cognition: A Narrative Review of the Biochemical and Clinical Evidence. PMC/NIH.
• American Heart Association. (2024). Among leafy green powerhouses, spinach packs a wallop.
• EBSCO Research Starters. Spinach (Spinacia oleracea). Nutrition and Dietetics.
• Improved Effect of Spinach Extract on Physical Performance: A Systematic Review of Randomized Controlled Trials. PMC/NIH.