Potential health benefits of oat grain and oat-based products

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Potential health benefits of oat grain and oat-based products

Anthony Fardet

To cite this version:

Anthony Fardet. Potential health benefits of oat grain and oat-based products. XXXVII Brazilian Meeting of Oat Research, Mar 2017, Passo Fundo, Brazil. �hal-01594988�

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Potential health benefits of oat grain

and oat-based products

Anthony FARDET

Senior Researcher in Preventive Nutrition

INRA - Unit of Human Nutrition

Clermont-Ferrand, France

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Part 1 :

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Oat world production (tons)

2011 2013 Russian federation 4 027 274 19 % 4 931 822 21 % Canada 2 811 900 13 % 3 888 000 16 % Poland 1 467 900 7 % 1 190 039 5 % Australia 1 262 032 6 % 1 121 135 5 % Finland 1 073 100 5 % 1 196 800 5 % USA 987 415 5 % 1 016 024 4 % Spain 683 500 3 % 964 700 4 % UK 627 000 3 % 964 000 4 % Sweden 731 200 3 % 851 500 4 % Germany 756 500 4 % 627 700 3 % China 600 000 3 % 614 000 3 % Chile 450 798 2 % 680 382 3 % Ukraine 629 700 3 % 467 270 2% Brazil 431 024 2 % 520 397 2 % Argentina 495 940 2 % 444 820 2 % Other countries 4 278 770 20 % 4 402 408 18 % World 21 314 053 100 % 23 880 997 100 %

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Brazilian oat production (tons)

Source: FAO-ONU, February, 2017

2014 1) Maize: 79 877 714 tons 2) Wheat: 6 261 895 tons 3) Oat: 432 136 tons 4) Barley: 251 539 tons 5) Rice: < 12 000 tons

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Agronomic advantages

• Relatively strong fasciculated root system that allows it to grow on moderately compacted soil and improve its structure when used in catch crop (nitrate traps).

• Produce a consistent biomass and provide excellent soil cover. This cover decomposes slowly (high C/N ratio) and consequently holds on the ground for a long time.

• Thus benefit the crops that succeed it, in particular for the legumes, since it allows a good control of the weeds.

• Excellent cleaning plant.

• Very marked allelopathic faculties, whether in vegetation or in its decomposition. As a result, crops grown on oat residues can generally be conducted without the use of herbicides.

• Oats are often used as nematicides. It is considered a bio pesticide, especially in direct seeding. • Has allelopathic and biocidal effects, either during its growth or during the decomposition of

its straws.

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Oat grain among cereals

(USDA database)

g/100 g Water Carbohydrates Proteins Lipids Fiber Ash

Oat 8.2 66.3 16.9 6.9 10.6 1.7 Wheat 12.8 68.0 15.4 1.9 12.2 1.9 Maize 10.4 74.3 9.4 4.7 7.3 1.2 Barley 9.4 73.5 12.5 2.3 17.3 2.3 Rice (brown) 10.4 77.2 7.9 2.9 3.5 1.5

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Oat grain mineral and oligo-element composition

(USDA database)

Calcium (mg/100 g) Iron (mg/100 g) Magnesium (mg/100 g) Phosphorus (mg/100 g)

54

Wheat

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5 (4)

177 (138)

523 (300)

Potassium (mg/100 g) Sodium (mg/100 g) Zinc (mg/100 g) Copper (mg/100 g)

429 (450)

2 (12)

4 (5.5)

0.6 (0.4)

Manganese (mg/100 g) Selenium (mg/100 g)

5 (3)

10 (71)

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Thiamin (B1) (mg/100 g) Riboflavin (B2) (mg/100 g) Niacin (B3) (mg/100 g) Pantothenic acid (B5) (mg/100 g) Vitamin B6 (mg/100 g)

0.8 Wheat (0.4)

0.1 (0.2)

1.0 (6.4)

1.3 (1.0)

0.1 (0.3)

Total folates (B9) (mg/100 g) Vitamin A (mg/100 g) Vitamin D (mg/100 g) Vitamin E (mg/100 g) Vitamin K (mg/100 g)

56 (44)

0 (0)

15 (0.8)

3.2 (1.9)

Oat grain vitamin composition

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Oat grain lipid composition

(USDA database)

Fatty acids, total saturated (g/100 g)

Fatty acids, total

monounsaturated (g/100 g)

Fatty acids, total polyunsaturated (g/100 g)



1.2 Wheat (0.3)



2.2 (0.2)



2.5 (0.8)

Palmitic acid (mg/100 g) Stearic acid (mg/100 g) Palmitoleic acid (mg/100 g)

1.0 Wheat (0.3)

0.07 (0.02)

0.05 (0.01)

Oleic acid (mg/100 g) Linoleic acid (mg/100 g) Alpha-linolenic acid (mg/100 g)

2.2 Wheat (0.2)

2.4 (0.7)

0.1 (0.04)

Oat SFA/MUFA/PUFA ratio = 20/37/42% Wheat SFA/MUFA/PUFA ratio = 23/15/62%

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Other compounds of oat grain

Shewry PR, Piironen V, Lampi A-M, Nystrom L, Li L, Rakszegi M, et al. Phytochemical and fiber components in oat varieties in the HEALTHGRAIN diversity screen. J Agric Food Chem. 2008;56:9777-84. Free sugars (g/100 g) Lignin (g/100 g) b-glucans (g/100 g) Total sterols (mg/100 g) Total phenolics (mg/100 g) Total avenanthra mides (mg/100 g) 1.5 4.4 5.2 653 531 62 a -tocotrienol (mg/100 g) Sitosterol (mg/100 g) Total bound phenolics (mg/100 g) Total free phenolics (mg/100 g) Total soluble phenolics (mg/100 g) Bound ferulic acid (mg/100 g) 16 408 273 82 176 118 N = 5 cultivars

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Oat grain composition

Summary

Sources of: - Proteins - PUFA - Selenium - Pantothenic acid (B5) Rich in: - Fiber - Phosphorus - Magnesium - Iron - Zinc - Copper - Manganese - Thiamin (B1) - Folates (B9) Low in: - Saturated fat Very low in: - Sodium - Sugars

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Part 2 :

Important (new) nutritional

concepts & paradigms

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Fr

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ma

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to

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cts

Food matrix (Depends on botanical/animal origin and/or processing)

I. Bioaccessibility

(Depends on physical and physico-chemical properties of food matrix)

Macro-, micro- and phyto-nutrients

III. Metabolic effects

(Depends on site of action and metabolization degree)

II. Absorption

(depends on absorption site and physiological parameters such as

transit time)

IV. Health effects

(Depends on initial health status of the subject)

In vitro digestion

Animal & Humans

In vitro coupled

with cells (dialysability)

Animal & Humans

B io av ail ab le f ra cti o n

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One has gradually moved from a technology that was adapted to the food to the food that has adapted to technology

For example, bread has gradually adapted to the technological requirements: - Selection of wheat on protein content for baking process

- Adding vital gluten and enzymes to improve the bread and the structural integrity of industrial products

- Kneading conditions: long and intensive → airy bread with high GI

- Yeast: short fermentation → loss of the benefit of the leavened enzymes - Adding salt to tasteless food

Save time, price, and conservation

time

A bread of poor nutritional quality and

unnatural taste

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A new food classification based on degree of processing: the

international NOVA classification

Carlos Monteiro Sao Paulo University

Group 1

Un- or minimally-processed foods

Group 2 Culinary ingredients Group 4 Ultra-processed foods Group 3 Processed foods

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A new classification of foods on the basis of their degree of processing:

International NOVA classification

1) Monteiro CA, Cannon G, Moubarac JC, Martins AP, Martins CA, Garzillo J, Canella DS, Baraldi LG, Barciotte M, et al. Dietary guidelines to nourish humanity and the planet in the twenty-first century. A blueprint from Brazil.

Public Health Nutr 2015;18:2311-22.

2) Fardet A, Rock E, Bassama J, Bohuon P, Prabhasankar P, Monteiro C, Moubarac J-C, Achir N. Current food classifications in epidemiological studies

do not enable solid nutritional recommendations to prevent diet-related chronic diseases: the impact of food processing. Advances in Nutrition

2015;6:629-38.

3) Moubarac J-C, Parra DC, Cannon G, Monteiro CA. Food Classification Systems Based on Food Processing: Significance and Implications for Policies and Actions: A Systematic Literature Review and Assessment.

Current Obesity Reports 2014;3:256-72. .

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Chambers, L., 2016. Food texture and the satiety cascade. Nutrition Bulletin 41, 277-282.

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Cereal processing: The Satiety Cascade

Chambers (2016) wrote:

“Foods with a hard or viscous texture tend to be consumed more slowly than liquid foods because they require processing in the mouth”

“The need to masticate hard or viscous foods increases ‘oro-sensory exposure time’ (time spent in the oral cavity) and this sensory stimulation is thought to nform the body that nutrients have been consumed, which triggers satiety responses; when sensory stimulation is weak (e.g. when liquids are consumed), monitoring of ingested nutrients may be compromised and satiety responses minimal”

« Longer oro-sensory exposure times, presumably leading to increased sensory signaling, have been consistently related to reduced intake within a meal (i.e. increased satiation)”

“Experimentally increasing chewing activity increased concentrations of peptides associated with satiety”

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Cereal processing: The Satiety Cascade

Chambers (2016) :

“As a final thought, the findings described in this paper hint that the

textural complexity of a healthy, varied diet (plenty of fruit and

vegetables and wholegrains, some dairy or dairy alternatives, and

some beans, pulses, fish, eggs, lean meat and other proteins) could

mean that, in additional to all the other health benefits, it is more

satiating (and therefore more protective against overconsumption) than

diets based on processed foods and energy-containing beverages”

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Food structure and bioavailability: bread crumb density

Burton P, Lightowler HJ. Influence of bread volume on glycaemic response and satiety. Brit J Nutr 2006;96:877-82.

Saulnier L, Micard V. Impact de la structure de l’aliment sur les propriétés nutritionnelles et l’acceptabilité du pain et des pâtes. Innovations Agronomiques 2012;19:63-74.

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Food structure and bioavailability: particle size

Holt SH, Miller JB. Particle size, satiety and the glycaemic response. Eur J Clin Nutr 1994;48:496-502.

Diet based on cereal products with different

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Physical structure and satiety potential

Holt SH, Miller JC, Petocz P, Farmakalidis E. A satiety index of common foods. Eur J Clin Nutr 1995;49:675-90.

Moorhead SA, Welch RW, Barbara M, Livingstone E, McCourt M, Burns AA, Dunne A. The effects of the fibre content and physical structure of carrots on satiety and subsequent intakes when eaten as part of a mixed meal. Brit J Nutr 2006;96:587-95.

Reconstituted carrot from powder nutrients

Whole boiled carrot

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Haber GB, Heaton KW, Murphy D, Burroughs LF. Depletion and disruption of dietary fibre. Effects on satiety, plasma-glucose, and serum-insulin. Lancet 1977;2:679-82.

Physical structure and satiety potential

Apple  Purée  Juice

Satiety Insulin

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Physical structure and satiety (The fullness factor



)

http://nutritiondata.self.com/topics/fullness-factor Human data

Potatoes

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Foods

(cereals)

Processing

degree

Glycemic

impact

Satiety

potential

+

-

+

-

Cereal processing: Satiety and glycemic potential versus degree

of processing (n = 378 foods)

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How are we to get there?

Cereal fractionation and refining: the reductionist

drift

Descartes held that non-human animals could be reductively explained as automata - De homine,

1662.

“In the sciences, application of methodological reductionism attempts explanation of entire systems in terms of their individual, constituent parts and their

interactions”

Linear cause-effect relationship

2 = 1+1

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What is holism?

Holism (from Greek holos "all, whole, entire") is the idea that natural systems and their properties should be viewed as wholes, not as

collections of parts. This often includes the view that systems function as wholes and that

their functioning cannot be fully understood solely in terms of their component parts

Non linear multicausal relationship

2 > 1+1

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Holism vs Reductionism

in the cereal sector

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The concept of grain package and multi-functionality:

a multicausal non linear relationalship

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Cereals as a source of lipotropes

Compounds that act on lipid metabolism by

preventing fat

accumulation within the liver

through:

– hastening fat removal (e.g. via increased phospholipid synthesis for lipoproteins → VLDL secretion, a TG-rich lipoprotein)

– preventing excessive fat deposits/decreasing rate of deposition: • Increased lipid b-oxidation

• Decreased triglyceride synthesis

The term “lipotropic” was first used in 1935 by Best et al. who showed that choline is able to prevent and cure fatty livers in rats and that increased liver fat infiltration and accumulation was primarily due to deficiency in some essentials factors whose the principal role is to assure lipid transport and turnover

(Best et al. The Lipotropic effect of protein. Nature. 1935;135:821-822)

Fat export +

Fat deposits

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• Main lipotropes: choline, betaine, myo-inositol, méthionine and carnitine

• Minerals and vitamins:

– B vitamins (niacin, pantothenic acid and folates) – Magnesium

– Tocotrienols (mainly a and g)?

• Fiber compounds:

– Phytic acid

– Soluble and insoluble fiber – oligofructose • Polyphenolic compounds: – Phenolic acids – Flavonoids – Lignans – Stilbenes – Saponins – g-oryzanol – Curcumin – Phytosterols? – Alkylresorcinols? • Others: – Organosulfur compounds – MUFA/PUFA – SCFA – Mélatonine – Policosanol? – 1-Deoxynojirimycin – …unknown?

• Those only found in animal products:

– Cobalamine: B12 (can be found in PBF, e.g. supplied by yeast in some cereal products) – Taurine

Different and/or common physiological mechanisms

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Cereals as a source of lipotropes

mg/100 g fresh product Choline Betaine Whole cereals 40 183 Leguminous seeds 80 1 Vegetables 17 23 Nuts and seeds 49 4 Fruits 8 0.2 Beverages 12 1.4 mg/100 g fresh product Methionine Myo-inositol Whole cereals 197 37 Leguminous seeds 285 65 Vegetables 35 22 Nuts and seeds 356 20 Fruits 10 61 Beverages 8 38

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The lipotropic vs antioxidant package

Physiological mechanism involved Bioactive compounds

Antioxidant protection (n  34)

(numerous diseases associated with increased oxidative stress: obesity, diabetes, CVD,

cancers,…)

Lipotropic protection (n  23)

(fatty liver associated with alcohol excess,

obesity/overweight, diabetes/insulin resistance, steatohepatitis/fibrosis/cirrhosis)

Reduced glutathione, methionine, cystine, lignins, phytic acid, magnesium, iron, zinc, manganese, copper, selenium, thiamine, riboflavin, tocopherols, tocotrienols, carotene, lutein, zeaxanthin,

b-cryptoxanthin, phenolic acids, flavonoids, lignans, alkylresorcinols, betaine, choline, policosanol, melatonin, g-oryzanol, avenanthramides, saponins

Betaine, choline, methionine, myo-inositol, carnitine, magnesium, niacin, pantothenic acid, folates,

flavonoids, phenolic acids, lignans, saponins, fibre, lignins, phytic acid, phytosterols, alkylresorcinols, oligosaccharides, poly-unsaturated fatty acids (e.g. CLA), short-chain fatty acids (e.g. acetic acid and propionic acid), melatonin, PUFA

Different but complementary physiological modes of action Harmful or side-effects of one compound at high dose

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The concept of fiber co-passengers

Vitaglione, P., Napolitano, A., Fogliano, V., 2008. Cereal dietary fibre: a natural

functional ingredient to deliver phenolic compounds into the gut. Trends in Food Science and Technology 19, 451-463.

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Natural versus added fiber

Monro, J., Mishra, S., Redman, C., Somerfield, S., Ng, J., 2016. Vegetable dietary

fibres made with minimal processing improve health-related faecal parameters in a valid rat model. Food Funct 7, 2645-54.

● Different physico-chemical properties:

- Water-holding capacity

- Porosity

- Consequences on fermentative behaviour

Jones, J.M., 2013. Dietary fiber future directions: integrating new definitions and

findings to inform nutrition research and communication. Advances in Nutrition 4, 8-15.

● Different

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• Germination :

• Germination is the resumption of development and metabolism - water absorption (wicking),

respiration, enzyme activity, etc. – of a spermatophyte embryo until it becomes a mature plant; this germination is naturally inhibited as the seed is in the fruit, and often for some time

• Pre-fermentation :

• Fermentation is a biochemical reaction of the conversion of the chemical energy contained in a

carbon source (often glucose) into another form of energy directly usable by the cell in the absence of oxygen (anaerobic conditions)

• Little used in the West for grains products

Poutanen et al. Sourdough and cereal fermentation in a nutritional perspective. Food Microbiology 2009;26:693-9 :

sourdough bread…

• Widely used in the traditional diet of the developing countries on the grains and seeds, mainly Africa, Asia and South America

Nout MJR. Rich nutrition from the poorest - Cereal fermentations in Africa and Asia. Food Microbiology 2009;26:685-92. • Maize: mawé (Bénin and Togo), kenkey (Ghana)…

• Sorghum: tchoukoutou (beer in Bénin and Togo), uji (porridge)… • Millet: ben-saalga (Burkinabe gruel), jnard (Himalayan beer)… • Rice: idli (India), mifen (Chinese rice noodles)…

• Legumes: wadi, dhokla…

Pre-fermentation, germination and soaking

kenkey tchoukoutou

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Pre-fermentation, germination and soaking

• Increasing protein digestibility

• Increasing levels of macro-, micro- and bioactive phyto-nutrients:

• B vitamins: riboflavins, thiamine, folate ...

• Exo-polysaccharides (prebiotics): e.g., gluco- and fructo-oligosaccharides • Resistant starch

• Free polyphenols

• Small bioactive peptides and free amino acids • Solubilization of fiber: Arabinoxylans

• Degrading phytic acid: increased mineral bioavailability • Increasing energy density

• Improving texture, flavor and palatability

• Changing the properties of the fibrous complex • Reducing glycemic and insulinemic responses • Allergen reduction

• Increasing antioxidant potential • ...

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Fermented oat

Bei Q, Liu Y, Wang L et al. (2017) Improving free, conjugated, and bound phenolic fractions in fermented oats (Avena sativa L.) with Monascus anka and their antioxidant activity. Journal of Functional Foods 32, 185-194.

• Oats soaked in water for 6 h before being used for fermentation

• Fermentation substrate was prepared with oats (20 g), glycerinum (1.6 g), yeast extract (0.4 g), and water added to a 60% moisture content and then sterilized by autoclaving at 115 °C for 30 min and cooled for inoculation.

• The sterilized fermentation substrate was inoculated with a spore solution (105 spores/g of oat) in a 250-mL Erlenmeyer flask containing 20 g of oats and was incubated at 30 °C for 14 day.

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{

Unfermented

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Cereal products & fermentation

(« minimal processing ») :

- Can supply taste : « taste » function - Allow protecting: « safety » function

- Increase health potential: « nutritional » function

Two issues:

New technological challenges

- Acting on composition: Less salt, sugar and salt

- Acting on food structure: Less fractionation and refining

Need to re-learn the taste of less processed products: the most

sustainable solution in the long term

:

- More wholemeal products

- Products with less salt, sugars and fat - More structured products

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Other important issues:

To increase satiety potential via texture

To reduce glycemic potential

To keep fiber co-passengers

To favour natural fiber instead of added fiber

To valorize better lipotropic and antioxidant potentials and

packages

To combine with legumes (as in pasta)

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Part 3 :

Oat-based foods &

Ingredients

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Minimally-processed oat products

• Oat flakes with cold milk

• Oat flour in vegetable soups

• Oat porridge

• Oat muesli

• Oat-bran pasta

• Fermented oat yogurt

• Yumienwowo (Chinese/Mongolian traditional

food): cooked oat purée

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Processed oat products

• Oatmeal breads

• Oat-bran bread

• Honey oat bread

• Oat milk

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Ultra-processed oat products

• Toasted whole grain oat cereal (e.g., Cheerios)

• Instant oatmeal breakfast

• Oat cookies

• Oat muffin

• Oat nutritional bar

• b

-glucan enriched oat-based product

• Oat bran-enriched beverages

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Milling oat ingredients & compounds

• Whole-grain oat

• Wholegrain rolled oat • Whole oat flour

• Husked oat • Naked oat • Oat flour

• Oat groats (hulled kernels of oat grains) • Pearling fractions of oat groats

• Oat bran

• Oat bran concentrate • Oat gum

• (Soluble) oat extracts • Oat fibre

• Oat b-glucans (native, (partially) hydrolysed, oxidized…)

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Part 4 :

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A brief history of Nutrition Transitions

 The discovery of fire (from -400 000 BC to -1,7 Millions years)

 The Neolithic (-9000 BC): sedentarisation and huge increase of grain

consumption including cereals

 The invention of the steam engine (1769) and the industrial era

(1800-1970)

 The onset of ultra-processed foods (1980-today)

 A new nutritional transition: from ultra-processed foods to sustainable

diets

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Chronic diseases

and their multi-causal trigger

Nutritional transition:

- From mostly vegetable foods and little processed to ultra-processed, fractionated, recombined, refined and high-energy foods

- More or less rapid according to countries

Increased physical inactivity and sedentariness:

- Consumed energy > spent energy - Weight gain

A lack of nutritional education :

- Preventive nutrition research is recent - Ignorance causes bad choices

- Ignorance makes us more vulnerable to advertising pressure

The reductionist approach pushed to the extreme: - Application to nutritional research (preventive)

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Grain products vs obesity/overweigth

0 10 20 30 40 50 60 70 80 90 100 Tea Coffee Milk Wine Sweetened beverages

Fruits & Vegetables

Vegetables

Fruits Whole-grain cereals

Legumes Nuts & Seeds

Dairy products Eggs Red/processed meat Poultry Fish Deleterious Neutral Protective

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Grain products vs type 2 diabetes

0 10 20 30 40 50 60 70 80 90 100 Tea Coffee Milk Wine Sweetened beverages

Vegetables

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Grain products vs cardiovascular diseases

0 10 20 30 40 50 60 70 80 90 Tea Coffee Milk Wine Sweetened beverages

Vegetables

Dairy products Eggs Red/processed meat Poultry Fish _Deleterious Neutral Protective

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Grain products vs cancers

0 10 20 30 40 50 60 70 80 90 Tea Coffee Milk Wine Sweetened beverages

Vegetables

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Oat products & health:

A literature review

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Oat products & health: A literature review

Satiety

Rebello CJ, O’Neil CE, Greenway FL. Dietary fiber and satiety: the effects of oats on satiety. Nutr Rev. 2016;74:131-47.

• β-glucan viscosity

:

- interferes with the peristaltic mixing process in the small intestine to

impede digestion and absorption of nutrients

- precipitates satiety signals through increased interaction with the

cells that release satiety hormones stimulating the release of

peptides involved in appetite regulation.

• However:

inconsistent results of the effects of oats on satiety

.

• Whether delivered in a whole food or an extract from the food,

oat

β-glucan appears to have a positive effect on perceptions of satiety

.

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Oat products & health: A literature review

Weight regulation & Satiety

Poutanen, K., M. Lyly, et al. (2010). "Rye, Oats, and Weight Management." Cereal Foods World 55(2): 66-69.

“Thus, it seems that adding oat β-glucan to beverages could boost their satiating capacity compared to

beverages without fiber.”

“In addition, the lowering of a beverage’s viscosity, containing 10 g of β-glucan, by enzymatic treatment reduced the satiating effect, which stayed higher than that of a beverage without β-glucan.”

“ß-glucan increased plasma cholecystokinin (CCK) levels in a dose-responsive manner,

indicating beneficial effects of ß-glucan on postprandial appetite control and GI peptide release.”

The inconsistent results of the short- and long-term studies do, however, suggest that in the longer term, some other factors, such as environmental, social, and psychological factors, are

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Oat products & health: A literature review

Gut microbiota

Rose DJ. Impact of whole grains on the gut microbiota: the next frontier for oats? Br J Nutr. 2014;112:S44-S9.

• Oats are a unique whole grain that may contribute distinctive effects on the gut microbiota.

• These effects could be due to: - the high b-glucan content:

 b-glucan fermentation could contribute to the hypocholesterolaemic properties

b-glucan may slow the rate of starch digestion and help increase the resistant starch content (favors butyrate production, an anti-carcinogenic compound)

- the high lipid content

- the unique antioxidant profile.

• Oat lipids and antioxidants (fibre co-passengers?) have not been studied in relation to gut health, but research in other whole grains suggests that they

influence the types of bacteria that make up the microbiota and impact on

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Oat products & health:

A literature review

2. Human studies

2.1 Cardiovascular diseases and their

risk factors

Oat is anti-atherogenic,

hypolipidemic (TG, LDL-chol

and cholesterol),

hypotensive

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Oat products & health: A literature review

CVD risk markers: hyperlipidemia

Thies F, Masson LF, Boffetta P, Kris-Etherton P. Oats and CVD risk markers: a systematic literature review. Brit J Nutr. 2014;112:S19-S30.

1. Regular consumption of oats or oat bran : beneficial effect on total cholesterol and LDL-cholesterol,

particularly in hypercholesterolaemic subjects.

2. The intervention trials can be divided into 3 groups: oat bran; whole-grain oat cereals; oatmeal.

3. For the studies that showed a significant reduction in total cholesterol and/or LDL-cholesterol, the range of doses used was 25-135 g/d for oat bran, 45–90 g/d for whole-grain oat cereals and 60–150 g/d for oatmeal: the form of oats does not really affect the outcome.

4. Studies using amounts < 50 g/d are scarce.

5. The 3-6% cholesterol reduction (described in the larger studies) would translate to a 6-18% decrease in

CHD risk.

6. It is likely that the benefits of increasing oats intake start very shortly after changing the diet.

7. It is still unclear whether increased oat consumption would significantly affect other risk markers for CVD risk (e.g., blood pressure).

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Oat products & health: A literature review

Hyperlipidemia

Ruxton CHS, Derbyshire E. A systematic review of the association between cardiovascular risk factors and regular consumption of oats. British Food Journal. 2008;110:1119-32.

1. “Regular consumption of oats and oats products can lower plasma levels of total cholesterol and LDL.

2. A dose-dependent response is evident with oat bran having the strongest effect.

3. An approved UK cholesterol reduction claim requires at least 0.75 g oat b -glucan to be delivered per portion.

4. This can be achieved by consuming oat products such as porridge, ready-to-eat breakfast cereals, bread, cereal bars and pasta.

5. The clear evidence on the cardio-vascular benefits represented by oats should encourage the development of more oat-based products.”

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A summary of some of the human studies investigating the

effect of oat-based products on lipemia

Intervention studies

References Process Oat-based products Total cholesterol (%) LDL-cholesterol (%) Triglycerid es (%) Texture Frank et al. (2004)53 Fermenta tion /baking

Yeast-leavened oat bran breads containing β-glucan of low or high average molecular weight

NS NS nd Solid

Kerckhoffs et al. (2003) Oat bran bread NS NS nd Solid

Zhang et al. (1992) Oat bran bread -11 -15 nd Solid

Bremer et al. (1991) Oat bran bread -4 (NS) - 11 (NS) NS Solid

Reyna-Villasmil et al. (2007)

Oat bran bread -16 -28 NS Solid

Bartram et al. (1992)

Breakfast oat cereals

Oat bran cereal muesli -11 -11 nd Solid

Maki et al. (2010) Whole-grain ready-to-eat oat cereal -9 -5 NS Solid

Pins et al. (2002) Oatmeal and ready-to-eat cereals -15 -16 nd Solid

Anderson et al. (1990) Oat-bran cereal (flake, biscuits or ready-to-eat cereals)

-5 -9 nd Solid

Marlett et al. (1994) Oat bran-forms used as hot or cold cereals

 nd nd Solid

Gold et al. (1991) Ready-to-eat oat bran cereals and snack bars

NS NS nd Solid

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A summary of some of the human studies investigating the

effect of oat-based products on lipemia

Intervention studies

References Process Oat-based products Total cholesterol (%) LDL-cholesterol (%) Triglycerid es (%) Texture Romero et al. (1998)64 Ultra-processed (fractiona tion/reco mbinatio n)

Cookies enriched with oat bran nd -26 NS Solid

Amundsen et al. (2003)65 _{Premade diet containing oat bran}

concentrate in 8 products

-6 -9 nd Solid

Bindu & Krishnaveni (2013)66

Oats porridge NS -8 NS Semi-solid

Beer et al. (1995)67 _{Oat gum instant whip} _NS _NS _NS _Semi-solid

Naumann et al. (2006)68

Beverages

β-Glucan incorporated into a fruit drink -3 -5 NS Liquid

Biorklund et al. (2005)52 _{Beverages with beta-glucans from oats} _-7 _-6 _NS _Liquid

Onning et al. (1999)69 _{Oat milk} _-6 _-6 _NS _Liquid

Onning et al. (1998)70 _{Oat milk} _-4 _-9 _nd _Liquid

Martensson et al. (2005)71 _{Fermented, ropy, oat-based products} _-6 _-6 _nd _Liquid

Kerckhoffs et al. (2003)54_???

Oat bran in orange juice -4 -7 nd Liquid

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It is difficult to draw firm conclusions, notably related to the potential matrix effect. Increasing the degree of matrix complexity led to conflicting results concerning its impact on lipemia.

However, study design, status of subject, food matrices, molecular weight of β-glucans appear to greatly differ from study to study making comparison hazardous.

Three hypotheses may be advanced but that request further confirmation:

1) liquid oat-based foods seems to be more consistent in decreasing levels of

cholesterol than semi-solid or solid foods where results are more heterogeneous ; 2) the molecular weight of β-glucans, but also their quantity, probably play a role on

cholesterol reduction ;

3) natural β-glucan-rich oat based foods would have different effect on lipemia than added β-glucans as isolated ingredients.

A summary of some of the human studies investigating the

effect of oat-based products on lipemia

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Oat products & health: A literature review

Hypertension

Maki, K. C., R. Galant, et al. (2007). "Effects of consuming foods containing oat beta-glucan on blood pressure,

carbohydrate metabolism and biomarkers of oxidative stress in men and women with elevated blood pressure." European Journal of Clinical Nutrition 61(6): 786-795.

The results of the present trial suggest beneficial effects of foods containing b-glucan from oats on carbohydrate metabolism, and on

blood pressure in obese subjects.

The oat b-glucan group received (1) a ready-to-eat (RTE) cold cereal made with oat bran, (2) oatmeal and (3) a powdered form of oat b-glucan. Control: maltodextrin.

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Oat products & health: A literature review

Hypertension

Pins, J. J., D. Geleva, et al. (2002). "Do whole-grain oat cereals reduce the need for antihypertensive medications and improve blood pressure control?" Journal of Family Practice 51(4): 353-359.

Men and women (n = 88) being treated for hypertension with a mean baseline BP below 160/100: Quaker Oatmeal and Quaker Oat Squares

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Oat products & health: A literature review

Hypertension

Keenan, J. M., J. J. Pins, et al. (2002). "Oat ingestion reduces systolic and diastolic blood pressure in patients with mild or borderline hypertension: a pilot trial." The Journal of family practice 51(4): 369-369.

A total of 18 hypertensive and hyperinsulinemic ( ≥10 μU/mL) men and women

The addition of oat cereals to the normal diet of persons with hypertension significantly reduces both systolic and diastolic

blood pressure. Soluble fiber-rich whole oats may be an effective dietary therapy in the prevention and adjunct

treatment of hypertension.

Oat cereal group (standardized to 5.52 g/day beta-glucan)

Versus

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Oat products & health: A literature review

Hypertension

Evans CEL, Greenwood DC, Threapleton DE, Cleghorn CL, Nykjaer C, Woodhead CE, et al. Effects of dietary fibre type on blood pressure: a systematic review and meta-analysis of randomized controlled trials of healthy individuals. Journal of Hypertension. 2015;33:897-911.

Diets rich in beta-glucans reduce SBP by 2.7 mmHg and DBP by 1.5 mmHg for a median difference in b-glucans of 4 g.

Higher consumption of b-glucan fibre is associated with lower SBP and DBP.

Diastolic

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Oat products & health: A

literature review

2. Human studies

2.2 Type 2 diabetes and its risk factors

Overweight & Obesity

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Oat products & health: A literature review

Overweight & Obesity

Chang, H.-C., C.-N. Huang, et al. (2013). "Oat Prevents Obesity and Abdominal Fat Distribution, and Improves Liver Function in Humans." Plant Foods for Human Nutrition 68(1): 18-23.

“In conclusion, we found that oat decreased obesity, abdominal fat, serum cholesterol, LDL-C, and liver functions. Taken as a daily supplement, oat could act as an adjuvant therapy for metabolic disorders.”

Subjects with BMI ≧27 and aged 18 –65 Control (n = 18) vs oat-treated (n = 16)

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Oat products & health: A literature review

Overweight & Obesity²

O'Neil CE, Nicklas TA, Fulgoni VL, DiRienzo MA. Cooked oatmeal consumption is associated with better diet quality, better nutrient intakes, and reduced risk for central adiposity and obesity in children 2-18 years: NHANES 2001-2010. Food & Nutrition Research. 2015;59.

Consumption of oatmeal by children was associated with better nutrient intake, diet quality, and reduced risk for central adiposity and obesity and should be encouraged

as part of an overall healthful diet Compared to

non-consumers, oatmeal consumption was associated with a 40%

lower risk of being obese and a 64% lower

risk of having an elevated WC

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Oat products & health: A literature review

Glycaemia and insulinaemia

Tosh, S. M. (2013). "Review of human studies investigating the post-prandial blood-glucose lowering ability of oat and barley food products." European Journal of Clinical Nutrition 67(4): 310-317.

• N = 34 studies.

• Meals (0.3-12.1 g oat b-glucan) reduced glycaemic response by an average of 48 mmol.min/l compared to a suitable control.

• Change in glycaemic response was greater for intact grains than for processed foods.

• For processed foods, glycaemic response was more strongly related to the b -glucan dose alone than to the ratio of b-glucan to the available carbohydrate. • For processed foods containing 4 g of b-glucan, the linear model predicted a

decrease in glycaemic response of 27 mmol.min/l, and 76% of treatments significantly reduced glycaemic response.

• Intact grains as well as a variety of processed oat foods containing at least 4 g of

b-glucan and 30-80 g available carbohydrate can significantly reduce post-prandial blood glucose

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Oat products & health: A literature review

HbA1c, fasting glucose & insulin sensitivity

He LX, Zhao J, Huang YS, Li Y. The difference between oats and beta-glucan extract intake in the

management of HbA1c, fasting glucose and insulin sensitivity: a meta-analysis of randomized controlled trials. Food & Function. 2016;7:1413-28.

Higher consumption of whole oats and oat bran, but not oat beta-glucan extracts, are associated with lower HbA1c, fasting glucose and fasting insulin of T2D, hyperlipidaemic and overweight subjects,

especially people with T2D.

N = 18 studies Oat product dose ranged 20-136 g/d, and b-glucan extract dose ranged 3-10 g/d.

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Oat products & health: A literature review

2. Human studies

2.3 Cancers & overall mortality

Boffetta, P., F. Thies, et al. (2014). "Epidemiological studies of oats consumption and risk of cancer and overall mortality." British Journal of Nutrition 112(SupplementS2): S14-S18.

Seven studies were identified of cancer risk (two each on prostate and

colorectal cancer, and one each on pancreatic, breast and endometrial

cancer), and one study on overall mortality

With the exception of a case-control study of pancreatic cancer, all studies

were of cohort design

The results of most cohort studies suggest a weak protective effect of a

high intake of oats on cancer risk (RR



0.9)

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Oat products & health: A literature review

2. Human studies

2.3 Cancers & overall mortality

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Oat products & health: A literature review

2. Human studies

2.3 Cancers & overall mortality

Crude and adjusted relative risk (RR) of

overall mortality for oatmeal intake of >20 v. ≤20 g/d in (a) men and (b) women.

RR = 0·91 (95% CI 0·81, 1·02) in men RR = 0·97 (95% CI 0·84, 1·11) in women

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Oat products & health: A literature review

2. Human studies

2.3 Bowel disease

Thies F, Masson LF, Boffetta P, Kris-Etherton P. Oats and bowel disease: a systematic literature review. Br J Nutr. 2014;112 Suppl 2:S31-43.

N = 38 articles

Long-term dietary intake of oat or oat bran could present: - Some benefits for patients with IBS and ulcerative colitis

- A plausible but non convincing protective effect on adenoma and cancer

Martínez-Villaluenga C, Peñas E. Health benefits of oat: current evidence and molecular mechanisms. Current Opinion in Food Science. 2017.

Anti-inflammatory effects of oat b-glucans are associated with its ability to reduce the number of lymphocytes T and B and granulocytes, promote leukocyte infiltration in intestinal mucosa, lower the

production of pro-inflammatory enzymes and cytokines and stimulate the release of anti-inflammatory cytokines.

The anti-inflammatory properties of oat b-glucans seem to be related with its molecular weight, but

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Oat products & health: A literature review

3. In vitro studies

• Antioxidant potential

• Viscosity

• Mineral binding

• Fermentation

• Digestibility

• Hepatic steatosis

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Soong, Y. Y., S. P. Tan, et al. (2014). "Total antioxidant capacity and starch digestibility of muffins baked with rice, wheat, oat, corn and barley flour." Food Chemistry 164: 462-469.

Oat products & health: A literature review

Antioxidant potential

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Cai, S., C. Huang, et al. (2011). "In vitro antioxidant activity and inhibitory effect, on oleic acid-induced hepatic steatosis, of fractions and subfractions from oat (Avena sativa L.) ethanol extract." Food Chemistry 124(3): 900-905.

Oat products & health: A literature review

Hepatic steatosis & lipotropic effect

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Oat products & health: Conclusion

Oat-based foods appears to protect more or less from several chronic diseases depending on oat matrices: