Hazelnut: understand everything in 2 min

The health effects of certain active compounds contained in hazelnuts (for example antioxidants, monounsaturated fatty acids and fibers) are well demonstrated. Moreover, the Food and Drug Administration (FDA) of the United States allows since 2003 to register on the label of food products the following allegation concerning nuts (nuts and oilseeds): “The scientific data suggest , but do not prove that consuming one and a half ounces per day of most nuts, on a diet low in saturated fat and cholesterol, can reduce the risk of coronary heart disease ” ¹ . However, this claim is not yet permitted in Canada.

Active ingredients and properties

For shelled and oilseed fruits in general

The hazelnut is a shelled fruit. Several epidemiological and clinical studies associate regular consumption of nuts and oil seeds with various health benefits such as a cholesterol-lowering effect ² , a reduction in the risk of cardiovascular disease ³ and type 2 diabetes ⁴ . Other studies have found a decrease in the risk of gallstones in men ⁵ , and a decrease in the risk of gallbladder removal ⁶ and colon cancer in women ⁷. The amount of shelled and oil seeds related to these benefits is most often equivalent to a weekly intake of about five one-ounce (30 g) servings.

For the hazelnut

The effect of hazelnut consumption has been evaluated in a few studies. First, the daily addition of approximately 70 g of hazelnuts to the diet for 30 days led to a reduction in total cholesterol and LDL-cholesterol (“bad” cholesterol) ⁸ . Similar results were also observed at the time of the partial replacement of the carbohydrates in the diet by monounsaturated fatty acids (coming from, among others, hazelnut), and this, for 30 days in diabetic subjects ⁹ . An increase in antioxidant activity in the blood was also observed when adding 70 g of hazelnuts per day ⁸. In animals, consumption of hazelnut oil would reduce the oxidation of lipids in the blood, without lowering blood cholesterol levels as previously observed in humans ^{10 , 11} . Remember that lipid oxidation is a risk factor for cardiovascular disease. The mechanisms involved in these effects are not yet fully understood. The replacement of polyunsaturated fatty acids by the monounsaturated fatty acids of hazelnut oil, as well as its high antioxidant capacity would be possible explanations.

• Monounsaturated fatty acids . Hazelnuts are distinguished from other shelled and oleaginous fruits by their very high content of monounsaturated fatty acids (almost exclusively in the form of oleic acid ) and rather low in polyunsaturated and saturated fatty acids. In general, replacing saturated fatty acids in the diet with monounsaturated fatty acids leads to a reduction in total cholesterol and LDL cholesterol (“bad” cholesterol), without reducing good cholesterol (HDL) ¹². Moreover, the consumption of olive oil, by its content in oleic acid (and antioxidants), was seen to play a role in the reduction of certain risk factors of cardiovascular diseases such as blood lipids, blood pressure arterial and glucose metabolism ¹³ . As the lipid composition of hazelnuts resembles that of olive oil, it can be assumed that such effects could also occur with frequent consumption of hazelnuts. Incorporating hazelnuts in the diet undoubtedly helps increase the intake of monounsaturated fatty acids.
• Antioxidants . Antioxidants are compounds that reduce the damage caused by free radicals in the body. These are very reactive molecules which are implicated in the onset of cardiovascular diseases, certain cancers and other diseases linked to aging ¹⁴ . Antioxidants hazelnut are found in the fruit itself, but also in appreciable quantities in the thin brown skin that surrounds ¹⁵ . For its total antioxidant capacity, the hazelnut is found in third place among ten shelled and oleaginous fruits, after walnuts and pecans ¹⁶ . Hazelnut contains different antioxidant compounds, including tannins ¹⁵, phenolic acids ¹⁷ , flavonoids ^{17 as} well as vitamin E ¹⁸
• Phytosterols . Phytosterols are compounds found in plants and whose structure is related to that of cholesterol. A meta-analysis of 41 clinical trials has shown that taking 2 g of phytosterols daily reduces LDL cholesterol by 10% (“bad” cholesterol) and that this reduction can reach 20% as part of a diet. low in saturated fat and cholesterol ¹⁹ . Even if hazelnut is one of the shelled and oleaginous fruits containing the least phytosterols, a portion of 30 g still contains 36 mg ²⁰. It is practically impossible to reach this quantity of 2 g per day by food alone and for the moment, Health Canada does not allow the marketing of foods enriched with phytosterols. However, even if the effects of phytosterols from hazelnuts or other nuts and oilseeds have not been directly evaluated, it can be assumed that phytosterols found naturally in food remain beneficial for cardiovascular health.

Other properties

Most important nutrients

See the meaning of the nutrient source classification symbols

 Manganese . Hazelnut is an excellent source of manganese. Manganese acts as a cofactor for several enzymes that facilitate a dozen different metabolic processes. It also participates in the prevention of damage caused by free radicals .

 Copper . Hazelnut is an excellent source of copper. As a constituent of several enzymes, copper is necessary for the formation of hemoglobin and collagen (protein used for the structure and repair of tissues) in the body. Several copper-containing enzymes also help the body’s defense against free radicals.

 Vitamin E . Hazelnut is an excellent source of vitamin E. A major antioxidant, vitamin E protects the membrane that surrounds the cells of the body, especially red and white blood cells (cells of the immune system).

 Magnesium . Hazelnut is a good source of magnesium for women and a source for men , their needs being different. Magnesium participates in bone development, protein construction, enzymatic actions, muscle contraction, dental health and the functioning of the immune system. It also plays a role in energy metabolism and in the transmission of nerve impulses.

 Iron . Hazelnut is a good source of iron for men and a source for women , their needs being different. Each body cell contains iron. This mineral is essential for the transport of oxygen and the formation of red blood cells in the blood. It also plays a role in the production of new cells, hormones and neurotransmitters (messengers in nerve impulses). It should be noted that the iron contained in food of vegetable origin is less absorbed by the organism than the iron contained in food of animal origin. However, the absorption of iron from plants is favored when consumed with certain nutrients, such as vitamin C.

 Vitamin B1 . Unblanched dehydrated hazelnut is a good source of vitamin B1 while dry roasted and unblanched hazelnut is a source . Also called thiamine , vitamin B1 is part of a coenzyme necessary for the production of energy mainly from the carbohydrates that we eat. It also participates in the transmission of nerve impulses and promotes normal growth.

 Phosphorus . Hazelnuts are a source of phosphorus (see our Phosphorus nutrient overview sheet ). Phosphorus is the second most abundant mineral in the body after calcium. It plays an essential role in the formation and maintenance of healthy bones and teeth. In addition, it participates among other things in the growth and regeneration of tissues and helps to maintain normal blood pH . Finally, phosphorus is one of the constituents of cell membranes.

 Zinc . Hazelnut is a source of zinc. Zinc is involved in particular in immune reactions, in the production of genetic material, in the perception of taste, in the healing of wounds and in the development of the fetus. It also interacts with sex and thyroid hormones. In the pancreas, it participates in the synthesis (production), the storage and the release of insulin.

 Pantothenic acid . Hazelnut is a source of pantothenic acid. Also called vitamin B5, pantothenic acid is part of a key coenzyme that allows us to adequately use the energy present in the food we eat. It also participates in several stages of the synthesis (production) of steroid hormones, neurotransmitters (messengers in nerve impulses) and hemoglobin.

 Vitamin B6 . Hazelnut is a source of vitamin B6. Vitamin B6, also called pyridoxine, is part of coenzymes that participate in the metabolism of proteins and fatty acids as well as in the synthesis (manufacture) of neurotransmitters (messengers in nerve impulses). It also contributes to the production of red blood cells and allows them to transport more oxygen. Pyridoxine is also necessary for the transformation of glycogen into glucose and it contributes to the proper functioning of the immune system. Finally, this vitamin plays a role in the formation of certain components of nerve cells and in the modulation of hormone receptors.

 Folate . Hazelnut is a source of folate. Folate (vitamin B9) is involved in the production of all cells in the body, including red blood cells. This vitamin plays an essential role in the production of genetic material (DNA, RNA), in the functioning of the nervous system and the immune system, as well as in the healing of wounds and wounds. As it is necessary for the production of new cells, adequate consumption is essential during periods of growth and for the development of the fetus.

Source  : Health Canada. Canadian Nutrient File , 2005.
* EPA, DHA and Alpha-Linolenic Acid

Roasting hazelnuts
Hazelnuts are often used roasted, whether in certain preparations (butter or hazelnut paste) or recipes, or even eaten as they are. Roasting hazelnuts can lead to a maximum decrease of 10% in their vitamin E content and 14% in phytosterols, depending on the temperature and the cooking time ²⁵ . This reduction is minimal and it is always better to eat roasted hazelnuts than not to eat them at all. As for the fatty acid composition of roasted hazelnuts, it does not differ much from that of raw hazelnuts.

Precautions

Allergy to nuts and oilseeds
In the list of the main allergens of the Canadian Food Inspection Agency (CFIA) ²¹ , we find “nuts”, which refer to all nuts and oilseeds. Some people may however be specifically allergic to hazelnuts or to several shelled or oil-bearing fruits. Moreover, it has been observed that hazelnuts, walnuts, pecans, coconuts, almonds, Brazil nuts and cashews form a group whose allergies are strongly associated ^{22 , 23,24} : a person allergic to one of these foods is thus more at risk of being allergic to the others. In addition, it is usually recommended that people allergic to peanuts also refrain from consuming other nuts and oil seeds (including hazelnuts), since they also have a high allergenic potential and are often handled and distributed. by companies specializing in peanuts. Symptoms of shell allergy and oilseed allergy can be severe and can even lead to anaphylactic shock .

Oral allergy syndrome
Hazelnut is one of the foods that can be implicated in oral allergy syndrome. This syndrome is an allergic reaction to certain proteins from a range of fruits, vegetables and nuts. It affects people with allergies to environmental pollens. This syndrome is almost always preceded by hay fever . When people allergic to birch pollen consume raw hazelnut (cooking usually degrades allergenic proteins), an immunological reaction may occur. Local symptomslimited to the mouth, lips and throat, such as itching and burning sensations, may then appear and then usually disappear a few minutes after consuming or touching the offending food. In the absence of other symptoms and hazelnut allergy, this reaction is not serious and the consumption of hazelnuts does not have to be systematically avoided. However, it is recommended that you consult an allergist to determine the cause of reactions to plant foods. The latter will be able to assess whether special precautions should be taken.

Urinary stones
It may be recommended that some people adopt a restricted diet of oxalates to prevent recurrences of kidney or urinary stones (also called urinary stones). Oxalates are compounds found naturally in several foods, including shelled and oilseed fruits in general, including hazelnuts. It is therefore preferable that these people avoid consuming it.

Hazelnut trees are native to the temperate zone of the northern hemisphere, particularly from regions that benefit from a relatively mild winter and a cool summer. This climate is characteristic of the seaside. This is where the main hazelnut crops are found: Turkey (Black Sea), Spain and France (Atlantic Ocean) and Oregon in the United States (Pacific Ocean).

There are several species of hazel, two of which are of commercial importance: the common hazel ( C. avellana ) and the hazel of Byzantium ( C. colurna ). Their domestication dates back to the prehistoric period and is believed to be the work of the Turks or another people of Asia Minor. The Romans introduce the varieties of C. avellana throughout the empire, but it will still wait for the XVII ^th or XVIII ^th  century before they are produced on a large scale in Europe.

Most of world production, around 75%, is supplied by Turkey, followed by Italy (15%). The United States is far behind, with 5% of production, which is entirely concentrated in the Willamette Valley in Oregon. In order to expand the hazelnut growing area, American and Canadian researchers have been working for several decades on the creation of hybrids. They want to create a tree that would produce the large fruits of the cultivated species of Eurasia, while benefiting from the cold and disease tolerance of the species native to North America.

Hazelnuts are available in the shell or shelled retail trade, or in powder form. However, almost 97% of world production goes to the processing industry (confectionery, pastry, oil).

To access other recipes, you can go to the CuisineAZ.com kitchen recipe site, which offers, among others, the following recipes: hazelnut cake, hazelnut paste

Choose well

The hazelnut is offered year-round, but it is at its best between October and February. Hazelnut powder can be found in delicatessens. Otherwise, grind them in small batches at a time in a coffee grinder.

Culinary dishes

• To roast the hazelnuts: put them for ten minutes in an oven set at 180 ° C (355 ° F). To vary, you can coat them with oil topped with garlic, herbs, spices, soy sauce, etc.
• An apple with a few hazelnuts is a healthy and satisfying snack .
• Hazelnut butter: roast the hazelnuts in the oven and pass them through the food processor with a little vegetable oil. If desired, add other oilseeds (sesame, pumpkin or sunflower seeds) as well as cocoa, lemon or orange juice, honey, etc. This butter can replace peanut butter or any other oilseed butter.
• Amuse-bouche with two cheeses: remove the crust of a brie and mix the dough with cream cheese; add a grated apple and roasted and chopped hazelnuts. Spread slices of bread, crackers or crackers with this mixture.
• Add them raw or roasted in a salad with: orange wedges, celery, green onions, small lettuces; spinach and mushrooms; lettuce, avocado, pepper, shrimp; cucumber, zucchini, red onion, garlic, carrot, avocado, yogurt and blue cheese; chicken or turkey; short pasta, carrot, green onions, broccoli; potatoes, radishes, apples, celery, endives; lamb’s lettuce and beetroot. They can also be added to fruit salads .
• Vegetable cream: prepare the vegetable cream of your choice and garnish with roasted and chopped hazelnuts.
• Sauce: place hazelnuts in a blender with oil (hazelnut, if possible), fresh herbs (parsley, basil, oregano, coriander, etc.) and dried apricots. Serve over grilled vegetables.
• In the sautéed vegetable dishes, add roasted and chopped hazelnuts at the end of cooking.
• Pilaf: dry roast rice, quinoa or another grain; brown minced onion in oil, add sliced ​​mushrooms, chopped hazelnuts, rice, broth and bake or on the stove for about an hour. Just before serving, garnish with grated cheese. You can stuff a poultry with this pilaf, omitting the cheese and adding raisins.
• Add chopped hazelnuts to the morning cereals , incorporate them into muesli, sprinkle with yogurt or ice cream.
• Stuff with hazelnut apples , raisins and honey and put in the oven.
• Add ground hazelnuts to pancake mixes, cakes , muffins, breads, etc.
• To coat a fish or a vegetable (eggplant slices for example), pass them successively in flour, a beaten egg and coarsely chopped hazelnuts. Then brown in olive oil.
• Or simply roll scallops in hazelnut powder before frying them for a few minutes over low heat.
• To decorate a poultry , slip some hazelnut powder under its skin before cooking it.

The inshell hazelnut keeps for several months in a cool and dry place in an airtight container. Although shelled hazelnuts also keep relatively well, it is best to buy small amounts at a time, as they are less well protected against rancidity. As it fears humidity, it is not recommended to keep it in the refrigerator, where it could soften and mold.

The hazelnut tree plays an important role in ecology. It is one of the first plants to colonize bare, dry and sandy places, retaining the soil thanks to a very developed root system. Planted at the edge of fields, it protects crops against drying winds, which has a positive impact on yields. In addition, it filters and purifies water in riparian areas, and retains snow on the ground, mitigating the effects of successive frosts and thaws. Its flowers provide abundant nectar to bees and other insects, while its nuts and buds are the food of choice for a host of wild animals that can also find refuge there if needed.