When learning the ABCs of nutrition, the focus is on macronutrients (proteins, fats and carbohydrates) and micronutrients (vitamins and minerals) that are essential to human life. However, there is an entire category of nutrients that is often overlooked but that many scientists consider essential, phytonutrients
As the name suggest (phyto = plant), it is about food from plants. For example, it is phytonutrients (also known to scientists as phytochemicals) that gives plants the vibrant color, taste and texture. Phytonutrients are a means of defending plants and are also beneficial to our health. They are known to be powerful antioxidants. They mainly protect against cancer, cardiovascular and neurodegenerative diseases as well as premature aging. They also reduce the inflammatory response and increase our resistance to foreign bodies.
What does food bring us?
Food brings us:
- macronutrients that provide the calories, i.e. energy necessary for the body’s functioning. These are fats, carbohydrates and proteins.
- micronutrients doesn’t play any role in energy but are essential for all chemical reactions. Even if they are present only in very small quantities (micrograms or milligrams) and constitute only about 2% of the diet, they are absolutely necessary to sustain life.
Micronutrients are classified into 4 families:
- minerals and trace elements
- essentials fatty acids
- amino acids
Some micronutrients cannot be synthesized by the body and must be provided by the diet. A deficiency of these, even a slight one, causes health problems; a severe deficiency will lead to illness and in the long term to death.
Phytonutrients are therefore neither vitamins or minerals and are found naturally in plants food. Vegetables and fruits are rich in phytonutrients and micronutrients. Each colors (green, red, yellow, orange, white, brown, blue,mauve) has different levels of these micronutrients and phytonutrients.
Are phytonutrients essential and can they be produced by the body?
Phytonutrients are not essential. The absence of them in our diet will not lead to death. Phytonutrients, like micronutrients, cannot be produced by the body and must be provided by a varied, balanced and good quality diet.
As scientists continue to demonstrate that these natural chemicals have a short-term effect on health (e.g., mood) and a long-term effect on survival, it becomes easier to discuss their essentiality. In other words, lots of studies show that phytonutrients can reduce health risks over a lifetime, it becomes natural to perceive them as “essential”. Since these small molecules act on every system in our body – from the gut to the brain – the health benefits they have are truly countless.
Is there many phytonutrients?
Phytonutrients are a major category. It mainly includes polyphenols and carotenoids. Nutrition enthusiasts will probably like to know that by January 2016, scientists had identified 23,137 unique phytonutrients in plant foods. It is certain that in the coming years, many more will be discovered. Unlike proteins, carbohydrates and fats and even minerals, all of them are good size, each phytonutrient is tiny. They are very small molecules, but when it comes to health protection, their help is very powerful.
Are phytonutrients healthy for us?
Since the discovery of phytonutrients, scientists have focused almost exclusively on their antioxidant activity to explain their benefits. Although this activity is important, it seems that these nutrients promote good health in many ways, including interacting with the immune system and with certain cells that, under their influence, provide optimal performance. Surprisingly, phytonutrients have even been shown to provide a healthy environment throughout the body, improving the health of intestinal microbes. They can also influence blood flow and the expression of genes that help control insulin and blood sugar levels.
Is it difficult to consume enough phytonutrients?
It is becoming increasingly difficult to consume the phytonutrients we used to get from food. Since phytonutrients are very bitter, their content in fresh fruits and vegetables has been selectively reduced to please the delicate North American palate. As a result, the phytonutrients content of some foods has become hundreds of times lower than it was originally. To compensate for the losses caused by selective plant propagation, several leading experts recommend the consumption of phytonutrients from whole plants. Since phytonutrients work together in the same way as musicians in an orchestra, consuming a single phytonutrient isolated from the food does not compensate for these losses.
What are the best known phytonutrients and where are they found?
The most well-known phytonutrients are:
- Phenolic or polyphenol compounds, flavonoids (anthocyanins, proanthocyanins), isoflavonoids, flavonoles, flavones, etc,
Sources: vegetables, fruit, green tea, soya and especially small fruits such as blueberries and cranberries.
- Phenolic acids (ferulic acid, caffeic acid, coumaric acid, ellagic acid, gallic acid)
Sources: whole grains, berries, cherries, grapes, citrus fruits…
- Tannins and catechins
Sources: lentils, beans, tea, grapes, wine…
- Terpenes and Carotenoids (beta carotene, alpha carotene, cryptoxanthin, zeaxanthin, lycopene, lutein…).
Sources: They give an orange color to carrots, peaches, mangoes, but can also be found in green leafy vegetables. Carrot is an important source of carotenoids.
- Limonoids (limonin, nomilin, dlimonin).
Source : citrus fruits
- Sulphur compounds and organosulphur compounds
Allicin in garlic
Sulforaphane in cruciferous plants
What are the potential benefits of the most sought-after phytonutrients? What roles do they play in health and in what foods are they found?
Ellagic acid is found mainly in raspberries, strawberries, wild blueberries, chestnuts, walnuts and pomegranates. Ellagic acid has several interesting properties. It has been shown that among 6 fruits extracts, blackberries and raspberries ranked first and second in the fight against the oxidation of “bad cholesterol” (LDL), an important risk factor for cardiovascular disease. Other studies also show that ellagic acid can reduce plaque deposits in the aorta and blood cholesterol.
As for cancer, numerous studies show that this phytochemical substance prevented the onset of mutations that could pave the way for its appearance. Another mechanism of action attributed to ellagic acid is the ability to inhibit two fundamental proteins (VEGF and PDGF) in the formation of the tumor blood network. Japanese researchers also clinically analyzed the effects of this acid on skin pigmentation and concluded that ellagic acid causes skin to lighten, making it more luminous and radiant because of its inhibitory effect on the process of melanin synthesis, which is responsible for the pigmentation of our skin, eyes and hair. It would also increase the action of a sunscreen by 25% because it enhances the levels of glutathione, a natural antioxidant produced by the body, which protects the DNA of cells. It also helps to reduce age spots.
EPIGALLOCATECHIN 3- GALLATE (EGCG)
Kills human and animal cancer cells in laboratory tests.
In which foods can EGCG be found: Green tea
Protect the colon by promoting the growth of beneficial bacteria and inhibiting the growth of harmful bacteria. May be useful for people treated with antibiotics or chemotherapy.
In which foods can fructo-oligosaccharides be found? Jerusalem artichoke
Seems to reduce the risk of colon, breast and ovarian cancer by limiting the effects of estrogen on these tissues.
In which foods can genistein be found? Legumes, soy milk, tofu
Inhibits certain types of breast cancer by altering the response of cells to estrogen.
In which foods can indole-3-carbinol be found? Broccoli, cauliflower, kale
Promote the production of enzymes that can inhibit the progression of cancer.
In which foods can isothiocynates be found? Watercress
Increases immunity. Used in Japan to treat patients with cancer and HIV infection.
In which foods can lentinane be found? Shiitake mushrooms
Opposes a protein that facilitates the growth of cancer cells. Would be particularly useful in the prevention of breast, liver and lung cancer.
In which foods can limonene be found? Grated citrus peel, mint, kumquats, caraway and celery seeds.
Fights free radicals and seems to inhibit DNA oxidation which can lead to some cancers.
In which foods can lycopene be found? Tomatoes (especially in juice), watermelon, pink grapefruit.
Inhibits the growth of the bacteria that cause most gastric ulcers. Reduces the risk of cataracts.
In which foods can quercetin be found? Apples, berries, tomatoes, red grapes, peas
Help to kill pathogenic protozoa such as Giardia in the digestive tract. Would have cholesterol-lowering effects.
In which foods can saponins be found? Soya beans
Stevia leaf, a calorie-free sweetener that can help you lose weight by reducing the need of sweets. Comes from a sugar molecule in the leaf of the stevia, a South American plant of the Chrysanthemum family.
In which foods can stevioside be found? Supplements sold in health food stores.
Potentializes the activity of Phase II detoxification enzymes that protect healthy cells against disease.
In which foods can sulforaphane be found? Broccoli, cauliflower, kale
Deactivates free radicals that can damage tissues and cause inflammation.
In which foods can zingerone be found? Ginger roots.
Do we eat enough phytonutrient foods?
Studies show that only 31% of the population eats enough vegetables and green fruits. Only 22% eat enough red, 21% eat enough yellow/orange, 14% eat enough white/brown and finally, only 11% eat enough blue/mauve.
Reminder of some definitions
Vitamins are substances necessary for our body (for cell renewal, the fight against aging, the elimination of toxins…), but our body is not able to manufacture them, so we must provide them through food. Three vitamins act as powerful antioxidants: vitamin A/ beta-carotene, vitamin E and vitamin C.
Vitamin deficiency can lead to a decrease in immune functions (the body’s defence functions), and can lead to the development of age-related processes such as osteoporosis, dementia, atherosclerosis and cancer. Our diet must therefore be rich and varied to avoid any deficiency. Supplements are only necessary in case of a proven deficiency because attention, an excess of vitamins produces free radicals. Follow-up by a specialist is therefore recommended to keep an optimal contribution.
Like vitamins, minerals do not provide energy, but they are essential to the life of our cells. Our diet must provide sufficient quantities every day to compensate for urine loss. Mineral salts are present in all foods. To ensure adequate intake, simply vary your diet and eat a balanced diet. But be careful, the way food is prepared and cooked is important for the preservation of minerals. However, the refining of certain foods (sugar, flour, cereals, etc.) impoverishes them. These refined foods are devoid of nutritional value, are poorly digested and require the body to draw on its reserves of vitamins and minerals to metabolize them, causing demineralization and devitalization. As far as the cooking method is concerned, steaming or stewing practically does not alter the minerals. Other high-temperature cooking methods such as the pressure cooker destroy them.
The most important mineral salts are sodium (salt), potassium, calcium, iron, magnesium and phosphorus, which are necessary for all organs, including the brain, and for the functioning of enzymes. Their roles are vital. A blood test can determine a deficiency in either mineral and a possible intake of supplements can be recommended by your doctor or health professional.
Like vitamins, trace elements do not provide energy, but they are essential to the life of our cells. These trace elements are involved in the activity of enzymes and hormones. Trace elements are iodine, copper, fluorine, chlorine, zinc, cobalt, selenium and manganese. Trace elements cannot be synthesized by the body, which must draw them from food very regularly because stocks are limited. To ensure an adequate intake, simply vary your diet and eat a balanced diet. But be careful! As with minerals, the way to prepared and cooked food is important for their preservation.
Essential fatty acids
Essential fatty acids are those fatty acids (fats) that the body is not able to produce and that it must find in food or food supplements. They play a vital role in the proper functioning of cells, have a role in inflammation, immunity and blood coagulation.
For many years, researchers have been able to demonstrate the relationships that can exist between cardiovascular disease and diet. The first population to be studied was the Greenland Eskimos, which rarely have problems with myocardial infarction. Subsequently, Japanese researchers found that the people of the Okinowa Archipelago hold the world record for longevity. The common point between these 2 populations is a high consumption of fish rich in omega 3 (essential fatty acids).
Amino acids are essential nutrients for the body. The assembly of several amino acids forms the proteins that are the irreplaceable structural agents of our whole body: our muscles, our chromosomes, antibodies, hormones… are made of proteins. Daily needs are important because some molecules are very often renewed in our body (blood cells, digestive tract, dander…).There are essential amino acids that the body cannot produce and which must be taken by the diet.
Oxidative stress and its effects on health
Oxidative stress appears to be one of the central mechanisms of pathogenesis of cancer, cardiovascular disease and many other chronic diseases. Oxygen is essential to our survival, but its use by the body’s cells is not without risk.
A significant part (1-2%) of the oxygen we breathe is transformed into toxic derivatives called free radicals (1). Free radicals can react and damage cellular components such as proteins, lipids and DNA (2). Oxidation of biomolecules by free radicals is involved in several diseases such as cardiovascular diseases (arteriosclerosis), neurodegenerative diseases (Parkinson, Alzheimer), cancer and aging (3-7). Several enzymes and small molecules make it possible to eliminate free radicals, in particular vitamins E and C (8). As we get old, the generation of free radicals increases and their quantity becomes greater than the capacity of antioxidant defences. This imbalance, called oxidative stress, will lead the body to a pathological state (9). Consumption rich in antioxidant compounds can reduce the impact of this oxidative stress.
Antioxidants are biological substances found in foods that prevent oxidation reactions caused by free radicals. By definition, it is a substance with a low concentration compared to that of the oxidizable substrate, capable of delaying or stopping the oxidation of the substrate. In pictorial terms, the steel hull of a boat and the salt water that will certainly rust it. The antioxidant? The paint that covers the hull and prevents it from attacking the metal. The thicker and more protective the paint, the better the protection of the steel hull against rust. In the scientific field, antioxidants have been classified into three groups, namely:
During a balanced meal, these three groups of antioxidants are easily found, but the majority of dietary supplements contain synthetic antioxidants. On the other hand, it seems that antioxidants from food sources have a much higher bioactivity than supplements from synthetic extracts. This is due on the one hand to the fact that foods contain a greater heterogeneity of antioxidants and on the other hand, synthetic antioxidants are less well absorbed by the human body.
Antioxidants fall into 4 categories:
– trace elements
Classification of the main classes of antioxidants of food origin
Polyphenols are chemical compounds naturally present in the plant kingdom, especially in northern berries. There are more than 8000 different phenolic molecules, such as simple molecules, such as phenolic acids, much more complicated molecules (tannins) and others that can be complexed with sugars, proteins and even lipids. Among the polyphenols are flavonoids, which represent the main group in this series. Indeed, flavonoids are present throughout the plant kingdom, with the exception of fungi and algae. They are derivatives of water-soluble polyphenols (soluble in water), often colourless or yellow (with some exceptions, such as anthocyanins). Flavonoids in themselves constitute an extremely large family of compounds, playing important physiological roles (nutritional, medicinal, UV filters…). They are found in Quebec berries, are of particular interest to human health and are the subject of many medicinal claims, particularly for their high antioxidant capacity.
Flavonoids are themselves classified according to their degree of oxidation into subgroups such as:
– pro anthocyanidins
– anthocyanins (Ref 4 W)
Isoflavones are compounds found mainly in legumes (e. g. soybeans, whose phytoestrogenic properties are widely studied). Some isoflavone derivatives are powerful agents against certain bacteria. They have bacteriostatic properties and are specifically induced by infections with phytopathogenic organisms. In particular, many phytoalexins are found in legumes (e. g. bean phaseollin, soybean glycerolin)
Les proanthocyanes (particulièrement concentrés dans le cas de la canneberge/ macrocarpon).
Les proanthocyanes, aussi appelées proanthocyanidines sont des composés flavonoïdes présents dans de nombreux végétaux, en particulier dans la peau et les pépins de raisin, ce qui explique leur abondance dans le vin rouge.
Les anthocyanes (particulièrement concentrés dans le bleuet sauvage/ antigustifolium)
Les anthocyanes sont des flavonoïdes que l’on retrouve dans le règne végétal et qui donnent la couleur caractéristique des feuilles, des fleurs et des fruits. Ce sont des composés colorés (orange, pourpre à bleu) et généralement hydrosolubles. Contrairement aux autres flavonoïdes, les anthocyanes absorbent la plus part du temps dans le spectre de l’ultra violet. Elles participent largement dans la coloration des pétales, mais on les retrouve également dans de nombreux tissus végétaux. Leur synthèse dans les organes foliaires est souvent activée par le stress (froid, carences, sénescence…). Leurs composés sont très souvent utilisés comme colorants alimentaires et présentent des propriétés antioxydantes.
Les anthocyanes ont été étudiés d’après plusieurs activités biologiques incluant la capacité antioxydante, l’effet sur la perméabilité et la fragilité des vaisseaux capillaires, l’agrégation des plaquettes de sang et l’effet sur le collagène (Réf 5 W). La capacité antioxydante des anthocyanes est l’une des propriétés biologiques les plus importantes. La recherche épidémiologique et biomédicale suggère que les antioxydants contenues dans les petits fruits, tels que le bleuet, l’airelle et la canneberge, peuvent jouer un rôle préventif sur l’apparition de certaines maladies comme le cancer, les maladies cardiovasculaires et les maladies neurodégénératives telles que l’Alzheimer et le Parkinson. Les anthocyanes et les autres flavonoïdes apportent une contribution substantielle aux antioxydants totaux du régime alimentaire (Réf 6 et 7 W). Les anthocyanes seraient un antioxydant naturel 20 fois plus efficace que les vitamines A et C.
La consommation de petits fruits et ses effets sur la santé
On connaissait déjà les bienfaits d’une alimentation équilibrée en fruits et légumes pour le maintien d’une bonne hygiène de vie. Le Guide alimentaire canadien recommande de consommer entre 8 à 10 portions de fruits et légumes par jour. En effet, consommer ces quantités recommandées réduit les risques d’apparition de plusieurs maladies. La forêt boréale québécoise, qui compte plus de 850 espèces de plantes vasculaires (10), représente une source abondante de composés utiles pour le traitement et la prévention de différentes maladies. Plusieurs plantes de ce vaste écosystème contiennent une haute concentration en composés antioxydants. Le bleuet nain sauvage, la plaquebière la canneberge et sa proche cousine l’airelle rouge vitis-idaea sont réputés pour leur forte teneur en composés antioxydants et, par conséquent, sont souvent considérés comme des références à ce niveau. De nombreuses études démontrent que les antioxydants retrouvés dans les baies boréales possèdent des propriétés protectrices remarquables (10–58).
Plusieurs études ont aussi démontré que, pour une personne en santé, la consommation de fruits riches en antioxydants réduisait les risques d’apparition de maladie cardiovasculaire de cancer d’obésité et de diabète (Réf 2, 3 W). Bien que les petits fruits soient qualifiés de petits seulement selon des critères de masse ou de volume, les études montrent que ces petits fruits présentent généralement des concentrations beaucoup plus élevées que les autres fruits ayant des composés à haute valeur nutritionnelle, telle que les antioxidants, les vitamines C et E. Parmi ces petits fruits on note le bleuet sauvage, l’airelle rouge et la canneberge. Ces petits fruits présentent un intérêt particulier, d’un point de vue organoleptique et médicinal spécialement pour leur concentration élevée en antioxydants.