Complete Protein, Squalene, and Cardiovascular Support

How amaranth's exceptional amino acid profile, cholesterol-lowering squalene, and anti-inflammatory phytochemicals set it apart from common grains

Amaranth is an ancient pseudo-grain — botanically a seed, not a grass — that has been cultivated for over 8,000 years in Mesoamerica and South Asia. Unlike wheat, rice, or corn, it contains a complete amino acid profile with an unusually high lysine content, making it one of the few plant foods that fully meets the protein reference standard humans require [3]. A 100g cooked serving delivers roughly 4 grams of protein, 65 mg of magnesium, 2 mg of iron, and meaningful amounts of manganese and phosphorus — alongside dietary fiber and a unique fatty compound called squalene [7]. The squalene in amaranth oil has been studied in human trials for cardiovascular support, with measurable reductions in total cholesterol and blood pressure [1]. For anyone eating a plant-forward diet, amaranth is one of the most nutritionally complete grains available, and one of the few that pulls its weight on protein quality.

Why Protein Quality Matters — and Why Amaranth Wins

Most plant proteins are limited by one or more essential amino acids. Wheat is low in lysine. Corn is low in lysine and tryptophan. Rice is low in lysine and threonine. This is why populations relying heavily on a single cereal grain historically showed signs of protein deficiency despite adequate calorie intake — they were missing the amino acids their bodies could not synthesize.

Amaranth is a rare exception. Its lysine score — the ratio of lysine content to the FAO/WHO reference pattern — reaches 107%, meaning it fully exceeds the international reference for this typically limiting amino acid [3]. Its protein digestibility is also high relative to other grains, owing to the fact that its protein fractions are predominantly albumins and globulins (the same protein classes dominant in eggs and legumes), with minimal prolamins — the poorly digestible storage proteins that dominate wheat and corn. By one analysis, amaranth's biological protein value (NPU coefficient) is nearly 47% higher than wheat semolina [3].

Practical implication: Amaranth can serve as a lysine bridge in plant-based diets. Combining it with rice or corn — both lysine-deficient — produces a combined protein profile that approaches completeness, without requiring animal products.

Squalene: Amaranth's Standout Lipid Compound

Squalene is a naturally occurring hydrocarbon found in small amounts in olive oil, shark liver oil, and various plant sources. Amaranth seed oil contains by far the highest plant-based concentration of squalene: approximately 7.6 grams per 100 grams of oil — more than three times the concentration found in buckwheat oil [6]. Shark liver oil has historically been the dominant commercial source, making amaranth's squalene content a meaningful alternative for plant-based or sustainability-conscious applications.

Squalene functions as an antioxidant lipid, acting as a quencher of singlet oxygen in cell membranes and a precursor to cholesterol synthesis — which, paradoxically, also gives it a role in down-regulating endogenous cholesterol production. In a systematic review of 33 studies on amaranth's cardiovascular effects, squalene was identified alongside phytosterols, unsaturated fatty acids, and fiber as the key bioactive compounds driving the lipid-lowering signals seen across animal models [2].

Cardiovascular Evidence: What the Human Data Shows

The most cited human study on amaranth and cardiovascular outcomes is a randomized controlled trial published in Lipids in Health and Disease, in which 125 patients with diagnosed coronary heart disease or hypertension received amaranth oil (providing 100–600 mg/day of squalene) alongside a standard antiatherogenic diet for three weeks [1]. Results across dosage groups:

Total cholesterol decreased by 14–20%
LDL cholesterol decreased by 19–25%
Systolic blood pressure decreased by 18–21%
Triglycerides/VLDL decreased by 13–36%
No adverse effects reported in any participant

The 12 ml/day group (providing approximately 400 mg squalene) showed the most favorable lipid outcomes. These are substantial reductions for a three-week dietary intervention, though it should be noted that the oil was administered as an adjunct to standard care — not as a standalone treatment — and the squalene concentrations achieved through amaranth oil are much higher than those obtainable through whole amaranth grain alone.

A 2019 systematic review of all available human and animal evidence concluded that amaranth shows consistent lipid-lowering effects in animal models, with preliminary antidiabetic, antihypertensive, and antioxidant signals in human pilot studies, but called for larger, well-powered human RCTs before definitive clinical recommendations can be made [2].

Honest framing: The cardiovascular evidence is more compelling for amaranth oil (concentrated squalene) than for whole-grain amaranth itself. Eating amaranth grain regularly is nutritionally valuable but should not be expected to produce the dramatic cholesterol reductions seen in the oil trials.

Glycemic Impact: Preparation Method Matters Enormously

Amaranth's glycemic index varies widely depending on preparation. A human study in patients with type 2 diabetes found that whole-grain amaranth blended with wheat at a 25:75 ratio had a glycemic index of approximately 66 — comparable to whole wheat bread and classified as low GI [4]. However, popped amaranth with milk produced a GI of approximately 97 — in the high GI range, comparable to white bread.

The key variable is the integrity of the grain structure. When amaranth is cooked whole, digestion is slowed by the intact cell matrix and the higher amylose fraction of its starch. Popping or extruding amaranth gelatinizes and disrupts the starch, making it rapidly digestible. This has direct practical implications:

Cooked whole grain (simmered with water like porridge): low to moderate GI, recommended for blood sugar management
Popped amaranth (used as a snack or cereal): high GI, best combined with fiber and fat to blunt the glucose response
Amaranth flour in baked goods: moderate GI depending on overall recipe composition

Antioxidant Phytochemicals

Beyond squalene, amaranth contains a profile of polyphenol antioxidants including rutin, quercetin, kaempferol, isoquercetin, myricetin, and hyperoside — with rutin and quercetin in the highest concentrations [5]. Betacyanins and betalains — the same pigment compounds that make beets red — are present in red-leafed amaranth varieties and have their own documented antioxidant and anti-inflammatory activities.

These compounds contribute to amaranth's measured antioxidant capacity against free radicals (DPPH and ABTS assays), and quercetin in particular has well-documented anti-inflammatory mechanisms through NF-κB inhibition — see our Quercetin page for more on this.

How to Use Amaranth

As a porridge: The most nutrient-preserving preparation. Simmer 1 cup amaranth in 2.5 cups water for 20–25 minutes. The grain becomes slightly sticky, similar to polenta. Add cinnamon, coconut milk, and fruit for a complete breakfast.
As a grain base: Cooked amaranth can replace rice or quinoa under vegetables, stews, or curries. Its earthy, slightly nutty flavor pairs well with bold seasonings.
Combined with legumes: Pair with black beans, lentils, or chickpeas for a complete protein meal with complementary flavors and textures.
Amaranth flour in baking: Can replace up to 25% of wheat flour in most baked goods for added protein and mineral density. Higher substitution ratios affect texture due to the absence of gluten.
Avoid popped amaranth as a primary carbohydrate source if managing blood sugar — the glycemic index rises dramatically with this preparation method.

See our Resistant Starch page for more on how grain preparation affects glycemic impact, and our Quinoa and Protein Quality overview for comparison across plant protein sources.

Evidence Review

Randomized Controlled Trial: Amaranth Oil and Cardiovascular Risk Factors (Martirosyan et al., 2007)

This human RCT, published in Lipids in Health and Disease, enrolled 125 patients aged 32–68 with clinically diagnosed coronary heart disease or hypertension across four dosage arms [1]. Patients received amaranth oil at 6 ml, 12 ml, or 18 ml per day (delivering 200, 400, or 600 mg squalene/day respectively) alongside a standard hyposodium antiatherogenic diet, compared to the diet alone. Duration was three weeks.

Across all three dosage groups, significant reductions were observed in total cholesterol (14–20%), LDL (19–25%), systolic blood pressure (18–21%), and triglycerides/VLDL (13–36%). The 12 ml/day group showed the most consistent lipid-lowering effect, with gains at 18 ml/day not proportionally larger — suggesting a dose-response plateau around 400 mg squalene. No adverse effects, lipid abnormalities, or supplement intolerance were recorded in any participant.

Limitations: the study used amaranth oil rather than whole grain, so findings cannot be directly extrapolated to dietary amaranth consumption. The concurrent use of a structured antiatherogenic diet makes it impossible to isolate amaranth oil's independent contribution. Three weeks is a short intervention period for a condition that typically requires longer-term dietary management. The study originated from a single Russian research group and has not been independently replicated in a similarly powered RCT.

Systematic Review: Cardiovascular Effects Across 33 Studies (Chmelík et al., 2019)

Published in Nutrition Research, this systematic review synthesized evidence from 33 studies including human observational data, clinical pilot studies, and animal experiments [2]. Animal studies uniformly showed amaranth reduced total cholesterol and LDL in models of diet-induced dyslipidemia, with effects attributed to squalene, phytosterols, unsaturated fatty acids, soluble fiber, and protein. Human data were more limited: a small human crossover trial (n=20 adults with elevated cardiovascular risk) found that amaranth oil increased LDL compared to rapeseed oil — a counterintuitive finding the authors attributed to differences in baseline lipid profiles and study population (overweight/obese adults vs. the cardiovascular patients in Martirosyan 2007).

Antidiabetic signals were supported by multiple in vitro and animal studies showing improved insulin sensitivity and glucose uptake. Antioxidant effects were consistently documented across model systems. The authors concluded that the evidence justifies further well-designed human RCTs but is insufficient to make firm clinical recommendations for cardiovascular prevention.

Strengths: systematic search, broad scope. Limitations: heterogeneity across included studies makes meta-analysis inappropriate; human evidence is sparse and sometimes contradictory.

Protein Quality Analysis (Zharkov et al., 2014)

This Russian-language study published in Voprosy Pitaniia conducted a comparative biochemical analysis of amaranth flour against wheat semolina across multiple batches and preparations [3]. Protein content of amaranth flour ranged from 14.9% to 16.2% by weight — 10.8–24.3% higher than wheat semolina on a dry-weight basis. The net protein utilization (NPU) coefficient was 46.51% higher for amaranth than semolina.

The lysine amino acid score — which compares actual lysine content to the WHO/FAO adult reference pattern for essential amino acid requirements — reached 107.54% for amaranth versus only 40.95% for wheat semolina. This is the defining nutritional asymmetry: wheat protein is lysine-deficient, meaning that even if sufficient calories are consumed, protein synthesis may be limited. Amaranth exceeds the lysine reference pattern entirely, fulfilling all essential amino acid requirements without combination. Fiber content was 15.5–30-fold higher than semolina. The study also confirmed low prolamin content and absence of alpha-gliadin, making amaranth naturally suitable for gluten-free diets.

Limitations: laboratory analysis of flour characteristics, not a human feeding trial; clinical effects of the protein quality difference were not measured in vivo.

Glycemic Index Study in Type 2 Diabetics (Chaturvedi et al., 1997)

This human glycemic index study enrolled adults with non-insulin-dependent diabetes mellitus (NIDDM) and measured blood glucose response to 50-gram carbohydrate portions of amaranth-based foods versus white bread as reference [4]. Testing conditions followed standard glycemic index methodology: overnight fasting, timed post-meal glucose at 15, 30, 45, 60, 90, and 120 minutes.

Results by preparation:

Amaranth-wheat blend (25:75): GI = 65.6 (low, comparable to whole wheat)
Amaranth-wheat blend (50:50): GI = 75.5 (medium)
Popped amaranth with milk: GI = 97.3 (high)

The sharp difference between whole-grain blends and popped amaranth highlights the importance of preparation method in determining glycemic response. Intact grain structure and ungelatinized starch are the dominant determinants of slow digestion; processing destroys these physical barriers. The study population (established diabetics) may show greater glycemic variability than healthy controls, and sample sizes were not reported for individual GI measurements. The study remains the primary direct measurement of amaranth GI in humans.

Phytochemical Characterization (Sarker et al., 2020)

This open-access study in Frontiers in Nutrition characterized the antioxidant phytochemical profiles of multiple vegetable amaranth genotypes grown under field conditions [5]. Using HPLC and spectrophotometric assays, the researchers quantified rutin, quercetin, kaempferol, isoquercetin, myricetin, and hyperoside in leaf and stem tissue. Rutin and quercetin were consistently the most abundant polyphenols across genotypes, with the highest-performing lines (LS7 and LS9) showing the greatest radical scavenging activity by DPPH and ABTS assays.

The study also quantified betacyanins, betalains, betaxanthins, and chlorophyll in red and green varieties. Betacyanin-rich lines (typically red-pigmented) showed the strongest antioxidant capacity. These findings support the use of amaranth leaf (in addition to grain) as a source of anti-inflammatory phytochemicals, particularly in cuisines — including South Asian and African traditions — where amaranth leaves are consumed as vegetables.

Limitations: characterization of vegetable amaranth (leaf types) rather than grain amaranth; in vitro antioxidant assays do not directly predict bioavailability or in vivo anti-inflammatory effects in humans.

Evidence Strength Summary

Amaranth's nutritional case is strong and well-supported: its amino acid profile, lysine content, and protein quality are documented by established analytical methods. The glycemic impact data from the human GI study is methodologically sound within its limitations. The cardiovascular/squalene evidence is promising but rests primarily on one human RCT using concentrated oil and a body of animal model research; the systematic review identifies mixed signals and calls for larger trials. Antioxidant phytochemical data is solid but in vitro. Overall, amaranth warrants its reputation as an unusually complete plant food, while the stronger cardiovascular claims should be understood as pertaining specifically to amaranth oil rather than whole grain.

References

Amaranth oil application for coronary heart disease and hypertensionMartirosyan DM, Miroshnichenko LA, Kulakova SN, Pogojeva AV, Zoloedov VI. Lipids in Health and Disease, 2007. PubMed 17207282 →
Amaranth as a potential dietary adjunct of lifestyle modification to improve cardiovascular risk profileChmelík Z, Šnejdrlová M, Vrablík M. Nutrition Research, 2019. PubMed 31757630 →
Amaranth flour: characteristics, comparative analysis, application possibilitiesZharkov IM, Miroshnichenko LA, Zviagin AA, Bavykina IA. Voprosy Pitaniia, 2014. PubMed 25059059 →
Glycemic index of grain amaranth, wheat and rice in NIDDM subjectsChaturvedi A, Sarojini G, Nirmala G, Nirmalamma N, Satyanarayana D. Plant Foods for Human Nutrition, 1997. PubMed 9201751 →
Bioactive Components and Radical Scavenging Activity in Selected Advance Lines of Salt-Tolerant Vegetable AmaranthSarker U, Hossain MN, Iqbal MA, Oba S. Frontiers in Nutrition, 2020. PubMed 33330589 →
Pseudocereal Oils, Authenticated by Fourier Transform Infrared Spectroscopy, and their Chemopreventive PropertiesPaśko P, Galanty A, et al.. Plant Foods for Human Nutrition, 2024. PubMed 38231454 →
Amaranth grain, cooked — FoodData CentralUSDA Agricultural Research Service. USDA FoodData Central, 2019. Source →