Avena (Avena sativa)

Description

Avena sativa is an annual cereal of the Poaceae family, cultivated mainly in temperate and cool regions. The plant has erect culms, linear leaves and a loose panicle-type inflorescence, quite different from the compact ears of wheat and barley, with drooping spikelets that contain the caryopses. The grains are elongated, straw-coloured and originally covered by tough hulls; dehulling yields groats (naked kernels), which are further processed into flakes, flours or bran. Oats are known for their high soluble fibre content (especially β-glucans), a lipid fraction rich in unsaturated fatty acids and antioxidant components, and for bioactive compounds such as avenanthramides, appreciated in cosmetics for their soothing and protective properties.

Botanical classification

• Common name: oat, common oat

• Scientific name: Avena sativa

• Family: Poaceae (Gramineae)

• Genus: Avena

• Origin: temperate regions of Europe and Western Asia; now grown in many temperate areas worldwide

• Growth habit: annual cereal with erect culms (60–120 cm), loose panicle and often hulled, elongated caryopses

Cultivation and growing conditions

Climate

• Suited to temperate and cool–temperate climates, with cool springs and summers that are not excessively dry.

• More tolerant of humidity and spring rains than wheat and barley, but less resistant to severe cold.

• Prefers hilly and mid-altitude environments with good water availability during the crop cycle.

Exposure

• Requires full sun for good tillering and grain filling.

• In shaded positions it tends to grow tall and weak, lodge more easily and yield less.

Soil

• Grows well on medium-textured, well-drained soils, including slightly acidic soils where other cereals may struggle.

• Tolerates cool, moist soils better than wheat and barley, but still suffers under prolonged waterlogging.

• Prefers soils rich in organic matter and well-structured.

Irrigation

• Generally grown under rainfed conditions, relying on autumn–spring or spring rainfall.

• In areas with dry springs it may benefit from supplementary irrigation during stem elongation and booting/anthesis.

• Sensitive to drought during stem elongation, flowering and grain filling, with yield reductions if stress is prolonged.

Temperature

• Optimal germination between 5 and 15 °C.

• Autumn-sown (winter) types tolerate cold, but less so than wheat or barley; they are susceptible to severe frosts without snow cover.

• Spring oats prefer cool springs and summers that are not too hot.

Fertilization

• Has intermediate nutrient requirements compared with other cereals.

• Needs a balanced supply of nitrogen, phosphorus and potassium.

• Excess nitrogen increases the risk of lodging and can favour some fungal diseases.

• In low-input systems it benefits from good rotations with legumes that enrich soil nitrogen.

Crop management

• Requires a well-prepared seedbed, fine and level.

• Can be sown in autumn (winter oat) or in spring (spring oat), depending on variety and region.

• Usually fairly competitive against weeds thanks to its tillering; in early stages, where necessary, mechanical weeding or selective herbicides are used.

• Susceptible to some fungal diseases (rusts, powdery mildew, helminthosporium) and to lodging under conditions of strong vegetative growth.

Harvest

• Typically harvested between late June and August, depending on sowing time and climate.

• Combine harvesting is carried out when the grain has reached physiological maturity and moisture content suitable for storage.

• The product is used for human nutrition, animal feed, flakes, flours and sometimes technical uses.

Propagation

• Propagated exclusively by seed.

• Use healthy, certified seed to reduce seed-borne diseases.

• Sowing rate and density depend on soil fertility, sowing date and intended use (for forage or grain).

Indicative nutritional values per 100 g (whole dry oats)

(Values for uncooked whole/rolled oats; actual composition varies with cultivar and process.)

• Energy: ~370–390 kcal

• Water: ~8–10 g

• Total carbohydrates: ~60–65 g

  • starch (predominant fraction)

  • simple sugars: ~1 g

• Total dietary fibre: ~8–12 g

  • β-glucans: ~3–5 g

• Protein: ~11–15 g

• Total fat: ~5–7 g

  • SFA: minor fraction

  • MUFA: moderate fraction

  • PUFA: relevant fraction (mainly linoleic acid, n-6)

  • TFA: negligible

• Vitamins: B-group vitamins, vitamin E

• Minerals: manganese, phosphorus, magnesium, zinc, iron, copper, selenium

Key constituents

• Carbohydrates and fibre

  • slowly digestible starch

  • soluble fibre (β-glucans) with strong viscosity-forming capacity

  • insoluble fibre (cellulose, hemicelluloses, lignin)

• Proteins

  • avenins and other storage proteins, with a relatively favourable amino-acid profile for a cereal

• Lipid fraction

  • unsaturated fatty acids (oleic, linoleic, traces of α-linolenic)

  • phytosterols and tocopherols (vitamin E)

• Micronutrients

  • B-group vitamins and vitamin E

  • essential minerals (manganese, phosphorus, magnesium, iron, zinc, copper, selenium)

• Phytocompounds

  • avenanthramides (oat-specific polyphenols with antioxidant and anti-irritant activity)

  • phenolic acids (ferulic, caffeic, p-coumaric)

  • saponins and other minor constituents

Production process

• Cultivation

  • autumn or spring sowing in temperate, relatively cool climates

  • good tolerance to acidic soils and moderate input levels

  • important agronomic role in crop rotations with other cereals and legumes

• Harvesting

  • mechanical combining at full maturity, when grain moisture is suitable for safe storage

• Post-harvest

  • drying, if needed, to about 12–14% moisture

  • cleaning and removal of foreign matter

  • dehulling to remove the inedible hulls and obtain oat groats

• Processing

  • cutting of groats (steel-cut oats), rolling/steaming (rolled oats), instant flakes

  • separation of fractions such as oat bran (β-glucan-rich) and oat flour

  • enzyme-stabilising heat treatments to reduce lipid rancidity

• Storage

  • grain and flakes stored in cool, dry, well-ventilated conditions

  • flours in protective packaging, with rapid stock rotation to limit oxidation

Physical properties

• Groats: elongated kernels, straw-yellow, hard texture

• Flakes: thin or thick lamellae with cream–straw colour and high water-absorption capacity

• Oat flour: variable particle size, off-white to light greyish colour

• Moderate bulk density and high capacity to absorb water and aqueous liquids (milk, plant drinks, etc.)

Sensory and technological properties

• Aroma: mild cereal character with sweet, slightly toasted and nutty notes, more pronounced after roasting or prolonged cooking.

• Taste: gentle natural sweetness, soft and “comforting” flavour, particularly appreciated in porridge and baked goods.

• Technological functionality:

  • β-glucans increase viscosity and gelling capacity, useful in porridges, beverages and dairy/plant-based products,

  • strong water-binding capacity, useful for structuring breakfast cereals, bars and plant-based burgers,

  • flour and flakes contribute soft, moist crumb in bakery (biscuits, muffins, sandwich bread).

Food applications

• Rolled oats

  • traditional porridge, muesli, granola, overnight oats,

  • toppings for yoghurt, desserts, dairy and plant-based fermented products.

• Oat flour

  • biscuits, pancakes, muffins, bars, bread and bakery products (often in blends),

  • thickener for soups, creams and sauces.

• Oat bran

  • ingredient in high-fibre products, breakfast cereals, breads and bars.

• Industrial preparations

  • oat-based beverages (“oat drinks”),

  • extruded snacks, breakfast cereals, baby foods and instant porridges.

Nutrition and health

• Oats are a significant source of β-glucans; at appropriate intakes, this soluble fibre contributes to maintaining normal blood LDL-cholesterol levels as part of a varied, balanced diet.

• Total fibre (soluble and insoluble) supports normal bowel function and promotes satiety, with potential benefits for weight management and post-prandial glycaemic response.

• The lipid fraction, though moderate in quantity, is rich in unsaturated fatty acids and vitamin E, contributing to protection from oxidative stress.

• Proteins, B-group vitamins and minerals support energy metabolism and normal function of the nervous system.

• Polyphenols, particularly avenanthramides, are being studied for antioxidant and inflammation-modulating properties.

Portion note

• Dry rolled oats: about 40–60 g per adult portion of porridge or muesli.

• Oat bran: typical daily intakes of 10–30 g in foods or as an ingredient.

• Oat drinks: 150–250 mL per serving, depending on the overall dietary context.

Allergens and intolerances

• Oats contain avenins, structurally different from wheat gluten, but:

  • conventional oats are often contaminated with wheat/barley/rye and therefore not suitable for coeliac individuals,

  • only certified gluten-free oats are potentially appropriate for coeliac patients, under medical guidance and according to current regulations.

• Specific oat allergies are possible, though less common.

• Industrial products may contain other allergens due to cross-contamination; label checks are always necessary.

Storage and shelf-life

• Whole grain and rolled oats:

  • store in a cool, dry place away from light and strong odours;

  • typical shelf-life 6–12 months; wholegrain products are more prone to lipid rancidity.

• Oat flours:

  • more perishable than grain, with indicative shelf-life of 3–6 months,

  • require good protection from oxygen and heat.

• Processed products (bars, biscuits, ready-to-eat cereals):

  • shelf-life depends on water activity, fat content and packaging.

Safety and regulatory

• All cultivation and processing stages must follow GMP and HACCP principles, with particular attention to:

  • mycotoxins typical of cereals,

  • integrity and traceability in gluten-free supply chains.

• Oat-based products bearing nutritional or health claims on β-glucans (cholesterol, glycaemia) must comply with quantitative requirements and conditions defined by legislation, including minimum daily intakes for specific claims.

Labelling

• Clear sales name (e.g. “whole rolled oats”, “oat bran”, “oat flour”, “oat drink”).

• Ingredient list in descending order by weight.

• Allergen declaration for gluten-containing cereals, or “gluten-free” indication only if legal thresholds and process controls are respected.

• Complete nutrition declaration.

• Any fibre-, β-glucan-, cholesterol- or glycaemia-related claims only if fully compliant with applicable regulations.

Troubleshooting

• Porridge too thick or “gluey”

  • Causes: too low water:oat ratio, prolonged cooking, very fine flakes.

  • Solutions: increase liquid, reduce cooking time, use thicker flakes or blends with other cereals.

• Crumbly or dense baked goods

  • Causes: excessive replacement of gluten-rich flours with oats.

  • Solutions: blend with wheat or other strong flours, adjust hydration, use binders (egg, soluble fibres, hydrocolloids).

• Rancid flavour

  • Causes: oxidation of the lipid fraction due to prolonged storage or exposure to heat/light.

  • Solutions: shorten storage time, use oxygen- and light-barrier packaging, store in cool conditions.

Sustainability and supply chain

• Oats adapt well to acidic soils and moderate input systems, and are widely used in low-impact and organic farming.

• Inclusion in crop rotations improves soil structure and helps reduce weed and disease pressure.

• By-products (bran, screening residues, processing fines) can be valorised in feed, as fibre-rich ingredients or as biomass for energy/compost.

• In milling and flaking plants, sustainable water and effluent management, with monitoring of BOD and COD, is important to minimise environmental impact.

Main INCI functions (cosmetics)

(Especially for “Avena sativa (Oat) Kernel Extract”, “Avena sativa (Oat) Kernel Flour”, “Colloidal Oatmeal”.)

• skin conditioning – improves skin softness and comfort thanks to polysaccharides, lipids and colloidal components.

• soothing – calming effect on sensitive or irritated skin, supported by β-glucans and avenanthramides.

• emollient – helps maintain stratum corneum hydration and suppleness.

• antioxidant – polyphenols and vitamin E help counteract oxidative stress and protect the formulation.

• mild abrasive – in some scrubs using finely milled oats for very gentle exfoliation.

• film forming / protective – colloidal oatmeal forms a thin protective film on the skin surface, useful in products for dry or irritated skin.

Conclusion

Oats (Avena sativa) are a cereal with particularly interesting nutritional, functional and cosmetic profiles. Their β-glucans, unsaturated fatty acids, avenanthramides and micronutrients make them a key ingredient in health-oriented foods and a valuable soothing active in dermocosmetic formulations. Versatile, relatively sustainable and rich in bioactive components, oats represent a high-value resource in modern food and cosmetic supply chains when cultivated, processed and labelled in full compliance with current regulations, including those relating to gluten.

Studies

The active components are hypolysaccharides of mucilosis (β-glucan), proteins (glutelin and avenin) and flavonoids.  Consuming oatmeal regularly can help lower cholesterol levels and reduce the risk of heart disease (1) due to its soluble fiber content.

Blood Sugar Control: The beta-glucan in oatmeal helps slow the absorption of carbohydrates into the bloodstream, aiding in blood sugar control (2) and making it a good dietary choice for people with diabetes.

Digestive Health: The fiber in oatmeal supports digestive health, helping to prevent constipation, promote regular bowel movements and has an effect on gut microbial functions (3).

Versatile Ingredient: Oatmeal can be used in various culinary applications, from breakfast cereals to baking. It can be made into porridge, added to baked goods like cookies and bread, or used as a thickener in soups and stews.

Weight Management: The high fiber content in oatmeal can help you feel fuller longer, potentially aiding in weight management by reducing overall calorie intake.

Skin Health: Colloidal oatmeal (finely ground oatmeal) has properties that can soothe skin irritation and itching, making it a beneficial ingredient in skincare products for conditions like eczema and rashes (4).

More recent studies have shown the antioxidant (5) capacity of this cereal .  

Oatmeal studies

References________________________________________________________________________

(1) Kwok CS, Gulati M, Michos ED, Potts J, Wu P, Watson L, Loke YK, Mallen C, Mamas MA. Dietary components and risk of cardiovascular disease and all-cause mortality: a review of evidence from meta-analyses. Eur J Prev Cardiol. 2019 Sep;26(13):1415-1429. doi: 10.1177/2047487319843667. Epub 2019 Apr 11. PMID: 30971126.

Abstract. Aims: The optimal diet for cardiovascular health is controversial. The aim of this review is to summarize the highest level of evidence and rank the risk associated with each individual component of diet within its food group. Methods and results: A systematic search of PudMed was performed to identify the highest level of evidence available from systematic reviews or meta-analyses that evaluated different dietary components and their associated risk of all-cause mortality and cardiovascular disease. A total of 16 reviews were included for dietary food item and all-cause mortality and 17 reviews for cardiovascular disease. Carbohydrates were associated with a reduced risk of all-cause mortality (whole grain bread: relative risk (RR) 0.85, 95% confidence interval (CI) 0.82-0.89; breakfast cereal: RR 0.88, 95% CI 0.83-0.92; oats/oatmeal: RR 0.88, 95% CI 0.83-0.92). Fish consumption was associated with a small benefit (RR 0.98, 95% CI 0.97-1.00) and processed meat appeared to be harmful (RR 1.25, 95% CI 1.07-1.45). Root vegetables (RR 0.76, 95% CI 0.66-0.88), green leafy vegetables/salad (RR 0.78, 95% CI 0.71-0.86), cooked vegetables (RR 0.89, 95% CI 0.80-0.99) and cruciferous vegetables (RR 0.90, 95% CI 0.85-0.95) were associated with reductions in all-cause mortality. Increased mortality was associated with the consumption of tinned fruit (RR 1.14, 95% CI 1.07-1.21). Nuts were associated with a reduced risk of mortality in a dose-response relationship (all nuts: RR 0.78, 95% CI 0.72-0.84; tree nuts: RR 0.82, 95% CI 0.75-0.90; and peanuts: RR 0.77, 95% CI 0.69-0.86). For cardiovascular disease, similar associations for benefit were observed for carbohydrates, nuts and fish, but red meat and processed meat were associated with harm. Conclusions: Many dietary components appear to be beneficial for cardiovascular disease and mortality, including grains, fish, nuts and vegetables, but processed meat and tinned fruit appear to be harmful.

(2) Missimer A, DiMarco DM, Andersen CJ, Murillo AG, Vergara-Jimenez M, Fernandez ML. Consuming Two Eggs per Day, as Compared to an Oatmeal Breakfast, Decreases Plasma Ghrelin while Maintaining the LDL/HDL Ratio. Nutrients. 2017 Jan 29;9(2):89. doi: 10.3390/nu9020089. 

Abstract. Eggs contain high quality protein, vitamins, minerals and antioxidants, yet regular consumption is still met with uncertainty. Therefore, the purpose of this study was to compare the effects of consuming two eggs per day or a heart-healthy oatmeal breakfast on biomarkers of cardiovascular disease (CVD) risk and satiety measures in a young, healthy population. Fifty subjects participated in a randomized crossover clinical intervention; subjects were randomly allocated to consume either two eggs or one packet of oatmeal per day for breakfast for four weeks. After a three-week washout period, participants were allocated to the alternative breakfast. Fasting blood samples were collected at the end of each intervention period to assess plasma lipids and plasma ghrelin. Subjects completed visual analog scales (VAS) concurrent to dietary records to assess satiety and hunger. Along with an increase in cholesterol intake, there were significant increases in both low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol following the egg consumption period (p < 0.01). However, there was no difference in the LDL/HDL ratio, a recognized biomarker of CVD risk, nor in the plasma glucose, triglycerides or liver enzymes, between diet periods. Several self-reported satiety measures were increased following the consumption of eggs, which were associated with lower plasma ghrelin concentrations (p < 0.05). These results demonstrate that compared to an oatmeal breakfast, two eggs per day do not adversely affect the biomarkers associated with CVD risk, but increase satiety throughout the day in a young healthy population.

(3) Valeur J, Puaschitz NG, Midtvedt T, Berstad A. Oatmeal porridge: impact on microflora-associated characteristics in healthy subjects. Br J Nutr. 2016 Jan 14;115(1):62-7. doi: 10.1017/S0007114515004213.

Abstract. Oatmeal porridge has been consumed for centuries and has several health benefits. We aimed to investigate the effect of oatmeal porridge on gut microflora functions. A total of ten healthy subjects ingested 60 g oatmeal porridge daily for 1 week. The following microflora-associated characteristics were assessed before and after the intervention: intestinal gas production following lactulose ingestion, faecal excretion of SCFA and faecal levels of urease and β-galactosidase. In addition, rectal levels of PGE2 were measured. Microbial fermentation as evaluated by intestinal gas production and excretion of SCFA did not change significantly following the dietary intervention. However, faecal levels of β-galactosidase and urease decreased after eating oatmeal porridge (P=0·049 and 0·031, respectively). Host inflammatory state, as measured by rectal levels of PGE2, also decreased, but the change was not significant (P=0·168). The results suggest that oatmeal porridge has an effect on gut microbial functions and may possess potential prebiotic properties that deserve to be investigated further.

(4) Capone K, Kirchner F, Klein SL, Tierney NK. Effects of Colloidal Oatmeal Topical Atopic Dermatitis Cream on Skin Microbiome and Skin Barrier Properties. J Drugs Dermatol. 2020 May 1;19(5):524-531. 

Abstract. Atopic dermatitis is characterized by dry, itchy, inflamed skin with a dysbiotic microbiome. In this clinical study (NCT03673059), we compared the effects of an eczema cream containing 1% colloidal oat and a standard moisturizer on the skin microbiome and skin barrier function of patients with mild to moderate eczema. Patients were randomly assigned to treatment with 1% colloidal oat eczema cream or a standard, non-fragranced daily moisturizer. Treatment lasted 14 days, followed by a 7-day regression period. Of 61 patients who completed the study, 30 received the 1% colloidal oat eczema cream and 31 received the standard moisturizer. At 14 days, the 1% colloidal oat eczema cream reduced mean Eczema Area Severity Index and Atopic Dermatitis Severity Index scores by 51% and 54%, respectively. Unlike treatment with the standard moisturizer, treatment with the 1% colloidal oat eczema cream was associated with trends towards lower prevalence of Staphylococcus species and higher microbiome diversity at lesion sites. The 1% colloidal oat eczema cream significantly improved skin pH, skin barrier function, and skin hydration from baseline to day 14, whereas the standard moisturizer improved hydration. Overall, the results demonstrate that topical products can have differing effects on the skin barrier properties and the microbiome. Importantly, we show that the use of a 1% colloidal oat eczema cream improves microbiome composition and significantly repairs skin barrier defects. J Drugs Dermatol. 2020;19(5):   doi:10.36849/JDD.2020.4924.

(5) Esfandi R, Willmore WG, Tsopmo A. Antioxidant and Anti-Apoptotic Properties of Oat Bran Protein Hydrolysates in Stressed Hepatic Cells.   Foods. 2019 May 11;8(5). pii: E160. doi: 10.3390/foods8050160.

Abstract. The objective of this work was to find out how the method to extract proteins and subsequent enzymatic hydrolysis affect the ability of hepatic cells to resist oxidative stress. Proteins were isolated from oat brans in the presence of Cellulase (CPI) or Viscozyme (VPI). Four protein hydrolysates were produced from CPI and four others from VPI when they treated with Alcalase, Flavourzyme, Papain, or Protamex. Apart from CPI-Papain that reduced the viability of cell by 20%, no other hydrolysate was cytotoxic in the hepatic HepG2 cells. In the cytoprotection test, VPI-Papain and VPI-Flavourzyme fully prevented the damage due to peroxyl radical while CPI-Papain and CPI-Alcalase enhanced the cellular damage. Cells treated with VPI-hydrolysates reduced intracellular reactive oxygen species (ROS) by 20-40% and, also increased the intracellular concentration of glutathione, compared to CPI-hydrolysates. In antioxidant enzyme assays, although all hydrolysates enhanced the activity of both superoxide dismutase and catalase by up to 2- and 3.4-fold, respectively relative the control cells, the largest increase was due to VPI-Papain and VPI-Flavourzyme hydrolysates. In caspase-3 assays, hydrolysates with reduced ROS or enhanced antioxidant enzyme activities were able to reduce the activity of the pro-apoptotic enzyme, caspase-3 indicating that they prevented oxidative stress-induced cell death.