Table of contents
Walnut oil ( organic ) is obtained from ripe, partially roasted seeds of the common walnut ( Juglans regia ). It is characterized, especially when raw and cold-pressed, by a good fatty acid pattern with many unsaturated fatty acids.
Use in the kitchen
Good walnut oil has a pale greenish-yellow to straw-yellow color. When cold-pressed, it tastes and smells delicately nutty. In its unrefined state, walnut oil has a smoke point of between 130 °C and 160 °C, which is why it is particularly suitable for vegan cold dishes or for seasoning at the end of cooking. It is not suitable for frying or deep-frying, as overheating creates harmful substances. It is only partially heat-resistant.
A high-quality oil is obtained by cold pressing unroasted organic walnuts (after a dry storage period of approx. 2-3 months). Depending on the further processing, it can be purchased refined or unrefined 1 (see the Purchasing chapter). Refined walnut oil has different properties such as a more neutral taste or a longer shelf life.
Raw walnut oil is best known as a fine salad oil, e.g. in dressings for carrot salad, lamb's lettuce or chicory and fig salad with celery and avocados . Fruit or balsamic vinegar is an excellent addition here. Walnut oil is also used to refine vegan pasta dishes (such as walnut tortellini with red wine and mushroom reduction ), soups (e.g. green pea soup with leaf spinach ) or casseroles. A few drops are drizzled over the finished, cooked dish. The combination with asparagus, potatoes or sweet potatoes is also very popular. In addition to its savory use, this oil also complements raw fruit salads, ice cream or other desserts such as grilled/baked pears or peaches as a nutty seasoning. It is also used as an additive in drinks such as raw carrot juice .
In general, it is important to pay attention to the dosage of walnut oil, otherwise it will mask the taste of other ingredients.
Making your own walnut oil
To make 300-500 ml of raw walnut oil, you need at least two kilograms of organic walnuts. As with industrial production, the walnuts must be stored dry for more than two months before further processing. The hard shell is removed and the walnut kernels are mixed until a creamy mass is formed. This is pressed through a cloth (e.g. linen) and the oil is collected in a clean bottle or bowl. Pressing the mass again increases the oil yield. However, you should use a fresh linen cloth here. Repeat this process as often as you like until the mass is sufficiently separated from the oil. If you have collected the oil in a bowl during production, pour it into a clean, dark bottle. The walnut oil is therefore also suitable for raw food dishes. For the sake of sustainability, the press cake can be reused for cakes, cabbage rolls, patties, pesto, etc.
Vegan recipe for basil and walnut oil pesto
Ingredients (for 4 people): 2 handfuls of fresh basil (organic), 1 handful of fresh parsley (organic), 80 g pecans, 100 ml walnut oil, 1 organic lemon (raw), 1 date (Deglet Nour, pitted), 0.5 tsp salt ,black pepper (to taste).
Preparation: Squeeze the lemon. Put the juice into a blender with the other ingredients, except salt and pepper. Blend for a shorter or longer time depending on the desired consistency to obtain a coarse or fine pesto. Season with salt and pepper and mix again briefly.
Vegan recipes with walnut oil (raw) can be found under the note: " Recipes that have the most of this ingredient ".
| Not only vegans or vegetarians should read this: Vegans often eat unhealthily. Avoidable nutritional errors . |
Purchasing - Storage
In supermarkets (such as Coop, Migros, Spar, Rewe, Edeka and Billa ) and organic supermarkets (such as Denn's Biomarkt and Alnatura ), walnut oil can often be found all year round. Drugstores (such as DM and Müller ) and local, traditional oil mills (such as Fandler ) also offer the aromatic oil all year round. In discount stores (such as Aldi, Hofer, Lidl ) and smaller supermarkets such as Denner and Volg Walnut oil is more likely to be available during special promotions. You can buy walnut oil from roasted or unroasted kernels, with quality products mostly being cold-pressed. Depending on the retailer, oils are available in conventional or organic quality.
When buying walnut oil, make sure that it does not have streaks. These are a sign that the product is inedible. It is also advisable to choose cold-pressed oil, as the gentle production process preserves more of the positive ingredients (see: Industrial production).
The availability of walnut oil varies depending on the size of the store, catchment area, etc. Our recorded food prices for the DA-CH countries can be found above under the ingredient image - and by clicking you can see their development at various suppliers.
Cold-pressed oils (laws)
According to the Federal Department of Home Affairs ( FDHA ), in Switzerland an edible oil is considered cold-pressed (or may be referred to using synonyms such as extra virgin, virgin, unrefined, cold-pressed or natural) if it is obtained by pressing or centrifuging from raw materials that have not been heated beforehand, the temperature during pressing did not exceed 50 °C and it has not been subjected to any refining, i.e. no neutralisation, no treatment with adsorbents, bleaching earth or steaming . 18
In the EU and the USA, there does not appear to be a generally applicable temperature limit set by law for cold-pressed oils. In Germany, similar values apply to those in the EDI regulation in Switzerland. However, the guidelines in Germany do not specify a permissible maximum temperature for general cold pressing. They only refer to products whose labelling and composition are not conclusively set by law (e.g. not for olive oil, spreadable fats). 19
On the other hand, both the EU directives and the EDI regulation on foods of plant origin, mushrooms and table salt (and their amendments) provide for special rules for the labelling of olive oils . 21,22
The terms "raw food" and "raw" are not state-protected terms, such as "organic". Although the pressing temperatures in purely mechanical cold pressing do not usually exceed 40 °C, one should not naively assume that edible oils are raw food quality. There is a suspicion that the measuring method used does not indicate the temperature in the press cylinder, where the heating is highest. In addition, the pressing pressure and the pressing speed as well as the moisture content of the oilseed influence the pressing temperature. If the moisture content is too low, the temperature rises during pressing and can even exceed the maximum limit of 50 °C. 23
Storage tips
The shelf life of cold-pressed walnut oil is shortened by exposure to sunlight and depends on the temperature, as walnut oil is susceptible to photooxidation. 2 In addition, the unsaturated fatty acids in cold-pressed oils react with oxygen (air), thereby reducing the shelf life. 1 In transparent bottles, cold-pressed walnut oil will last for around 2 months at room temperature before it loses quality. 2 The manufacturer therefore fills it into dark bottles. If stored in a cool, dark place, the cold-pressed oil will last for around 6-12 months. Opened bottles should be kept in the refrigerator and used within 10-12 weeks, otherwise they will go rancid.
Ingredients - Nutritional values - Calories
What nutritional values does walnut oil have? Walnut oil contains a lot of calories (884 kcal/100g), which come exclusively from fats. There are no carbohydrates or proteins. 9.1 g of 100 g are saturated fats. 9 Based on a portion size of 10 g (approx. 1 tablespoon), this results in 88.4 kcal/portion or almost 5% of the recommended daily dose of saturated fats.
The oil provides 53 g of linoleic acid (omega-6 fatty acid ) per 100 g. Two portions of walnut oil (20 g, approx. 2 tablespoons) therefore cover the total daily requirement of linoleic acid (LA). Pumpkin seed oil contains comparable amounts with 49 g/100g and hemp oil with 54 g/100g. Grape seed oil contains slightly more at 70 g/100g. 9
The content of alpha-linolenic acid (omega-3 fatty acid ) is 10 g/100g, so two portions of walnut oil (20 g, about 2 tablespoons) also cover the need for alpha-linolenic acid (ALA). This value is comparable to rapeseed oil, which contains 9.1 g/100g. Linseed oil has about 5 times as much ALA at 53 g/100g. 9
The ratio of linoleic acid (omega-6) to alpha-linolenic acid (omega-3) in walnut oil 9 is just under 5:1 and can be considered healthy. A ratio of 1:1 would be ideal, but the current range for the Western diet is assumed to be between 15:1 and 20:1. 10 So we usually consume enough or too much linoleic acid - with alpha-linolenic acid, you should consciously ensure that you consume it regularly (see next chapter).
The vitamin K content in walnut oil is 15 µg/100g. A similar amount of vitamin K is found in raw cauliflower or raw cucumber (16 µg/100g each). Since we consume much less than 100 g of oil per day, we only absorb tiny amounts of vitamin K from it. Olive oil contains 60 µg/100g, four times as much. 9 Tocopherol (vitamin E ) has an antioxidant effect, among other things. 3,6
The complete ingredients of walnut oil, the coverage of the daily requirement and comparison values with other ingredients can be found in our nutrient tables. In the article Nutrients explained you will get a detailed insight into the topic.
Effects on health
How healthy is walnut oil? A good fatty acid ratio, such as in walnut oil, can counteract inflammation. 12 Its polyunsaturated fatty acids reduce the risk of cardiovascular disease. Omega-6 (linoleic acid; LA) works primarily by lowering LDL cholesterol. Omega-3 (alpha-linolenic acid; ALA) is converted in the body into DHA and EPA, which are supposed to maintain blood flow and heart and vascular function. In this way, ALA prevents thrombosis and inflammation.
LA and its derivatives are said to have a potentially inflammatory character. However, this depends on the amount consumed. The EEK ( Swiss Nutrition Commission ) recommends that consumers consume the following absolute amounts of polyunsaturated fatty acids: for Omega-6, approx. 20 g/2000 kcal and for Omega-3, approx. 1-4.4 g/2000 kcal. 11 In terms of the LA:ALA ratio, walnut oil with 5:1 performs very well compared to other vegetable oils such as olive oil (12:1) orsunflower oil (>999:1). 9
Regardless of whether you look at the ratio or the absolute numbers: Due to excessive use of cooking oils, vegans and vegetarians in particular get too many omega-6 fatty acids.
Please note: Despite the positive health effects listed here , walnut oil is a concentrated food that has undergone various processing steps. In general , whole, unprocessed foods such as nuts or seeds are preferable (and much healthier for losing weight!). Various American doctors and authors take an even stricter approach, rejecting oil on principle and recommending switching to nuts and seeds. We are talking about Dean Ornish, T. Colin Campbell, John A. McDougall, Michael Klaper, Caldwell Esselstyn, Michael Greger, Joel Fuhrman and Neal D. Barnard, who basically explain that a diet high in animal fats and proteins (like the standard American diet) is bad for your health. You can find details in the text " Vegans often eat unhealthily. Avoidable nutritional errors ".
A daily intake of 15 ml of walnut oil, as an addition to the diabetic diet, has a positive effect on the clinical picture of patients with type 2 diabetes and additional hyperlipidemia. It appears to reduce total cholesterol, LDL cholesterol and triglycerides as well as the ratio of the first two. 4 Type 2 diabetes mellitus often correlates with hyperlipidemia (also known as hyperlipoproteinemia). 5
Scientific studies on walnut oil (Oleum Juglandis) are rather rare; research is mainly interested in walnut kernels or other plant parts of Juglans regia. 20
Secondary plant substances
Many of the health effects of walnut oil can be attributed to the secondary plant substances it contains. Our article on secondary plant substances provides an overview of the classification of substance groups, their occurrence in foods and possible effects on humans. Walnut oil contains the following secondary plant substances, among others: 3
- Isoprenoids: Triterpenes: Steroids: Phytosterols (brassicasterol,beta-sitosterol, campesterol, stigmasterol, clerosterol, stigmastadienols, delta-5-avenasterol), squalene
- Polyphenols: Phenolic acids: hydroxybenzoic acids (syringic acid, gallic acid, sinapic acid); hydroxycinnamic acids (ferulic acid, a-coumaric acid, p-coumaric acid, chlorogenic acid, caffeic acid); flavonoids: flavonols (quercetin, kaempferol, rutin), flavanols (protocatechin, catechin), flavones (luteolin), flavanones (naringenin, pinocembrin), stilbenes (resveratrol)
- Other nitrogen-containing compounds: biogenic amines (melatonin)
- Other organic compounds: Phenylpropanoids (vanillin)
However, it should be noted that the composition of secondary plant substances in walnuts and products made from them can vary depending on the variety, time of harvest, growing conditions, recipe and manufacturing process. Therefore, quantities are only of limited use and should only be understood roughly.
Walnut oil exhibits anti-inflammatory, antitumor, antioxidant, immunomodulatory, neuroprotective, cardioprotective, antidiabetic and antihyperlipidemic activities. The data published in the literature suggest that walnut oil has many health benefits. 3
At least 16 phytosterols have been identified in walnut oil. The total content of phytosterols in walnut oil is 140-283 mg/100g.Beta-sitosterol, campesterol and delta-5-avenasterol are the most important phytosterols. Beta-sitosterol (121-252 mg/100g) is the highest, accounting for over 80% of the total phytosterol content. The total sterol content in walnut oil is higher than in almond, peanut and macadamia oil. Phytosterols competitively inhibit the absorption of cholesterol in the microvillus of the small intestine, promote the breakdown and metabolism of cholesterol and inhibit the biochemical synthesis of cholesterol. Sterols show promising therapeutic effects in Alzheimer's, atherosclerosis and Huntington's disease. Sterols also play an important role in hormonal signaling, tissue division, and embryonic patterning. 3
Squalene is a biochemical precursor for the synthesis of cholesterol and other sterols. Its synthesis takes place in the liver and skin and decreases with age. Walnut oil contains about 0.94 mg/100g squalene. Squalene has a positive effect on the skin and can enhance the activity of anti-cancer agents. Melatonin is a hormone of the pineal gland that transmits information about the daily light-dark cycle to the body's structures and easily penetrates most biological cell membranes and the blood-brain barrier. The average melatonin content in walnuts is 3.54 ± 1 ng/100g. Humans contain only 0.1-1 ng/100g. Therefore, consuming walnut oil is an effective method of melatonin supplementation. Melatonin is a radical scavenger with high lipid and water solubility. It interacts with oxidants, nuclear receptors and intracellular proteins and increases the levels of various antioxidant enzymes. Thus, melatonin protects cells from oxidative damage and regulates neuromedical, anti-cancer and anti-aging activities. 3
Polyphenols such as gallic acid in walnut oil have a strong antioxidant effect. They also enhance the antioxidant effect of other ingredients such as tocopherol. This effect prevents oxidative stress caused by excess reactive oxygen species (ROS). Oxidative damage is suspected of causing chronic diseases such as arteriosclerosis or cancer. Polyphenols and their conversion products in the cell also influence the health of the intestinal microbiome by promoting the growth of beneficial bacteria and reducing pathogens. 3
Dangers - Intolerances - Side effects
Walnut oil and other nut and peanut oils contain enough allergens (depending on the manufacturer and sensitivity) to trigger symptoms in people with a nut allergy. A study examined various production methods and their effect on the allergenicity of the oil. However, no definitive method has been found that makes consumption safe if you have a walnut allergy. 7 A walnut allergy manifests itself in different ways: Mild to moderate symptoms include isolated oral allergy symptoms, skin reactions, irritation of the eyes or the gastrointestinal tract. Severe symptoms include anaphylaxis, swallowing difficulties or cardiovascular symptoms. 8
Folk medicine - natural medicine
Various parts of the walnut (kernels, leaves, bark, green fruits, seed shell) are used in folk medicine. Depending on tradition, the walnut is said to help with diarrhea, cancer, skin diseases, fever, diabetes mellitus, heart disease and inflammatory diseases, among other things. 20
Ecological footprint - animal welfare
The CO 2 footprint of cooking oils for consumers in Germany is just over 3 kg CO 2 eq per kg of oil (e.g. olive oil : 3.2; rapeseed oil : 3.3;sunflower oil : 3.2); we are not aware of any directly comparable figures for walnut oil. The values for unprocessed seeds or nuts are significantly lower. For example, sunflower seeds, at 1.5 kg CO 2 eq/kg, cause around half the emissions of sunflower oil. According to the Institute for Energy and Environmental Research in Heidelberg, the ecological footprint of walnuts with shells is around 0.9 kg CO 2 eq/kg. 14
In general, the greenhouse gas emissions of a food depend not only on cultivation (conventional, organic) but also on other factors such as processing stages, transport and packaging. 24 If one of the latter steps is eliminated or reduced, the amount of contamination is reduced. Regionally produced walnut oil therefore has a better carbon footprint because fewer emissions are generated for transport.
Especially for family farms, the production of biofuel and the use of renewable energy for machines and processes has some potential. According to a 2022 study, this represents a good opportunity to reduce the CO 2 footprint of vegetable oils. 15
The water footprint of walnuts with shells is 4918 l/kg, and for shelled walnuts it is 9289 l/kg. 16 This value increases for walnut oil depending on the type and location of production. Here too, regional products should be preferred. The water footprint of cooking oils in general varies greatly. It depends, among other things, on where the raw materials are grown and the further use of the press residues. Olive oil has a significantly larger footprint of 900,000 liters of water-eq/kg than rapeseed oil with 800 liters of water-eq/kg. 14
For detailed explanations of various sustainability indicators (such as ecological footprint, CO2 footprint, water footprint), see our article: What does the ecological footprint mean?
Worldwide occurrence - cultivation
The walnut tree originally comes from Persia. The main cultivation areas extend from central and southern Europe through Central Asia, India, Nepal and China to California and Mexico. In Europe, walnuts are mainly found from France, Italy, Turkey, Greece and Iran. 1 Depending on the supplier, they also use local walnuts for walnut oil.
Cultivation - Harvest
The best place for a walnut tree is in a sunny, warm climate. 1 Walnut trees are susceptible to wet conditions, whereas they appear to be relatively resistant to drought. 13 For commercial purposes, they are planted in large, garden-like plantations, where harvesting begins after 6-8 years. From this point on, 4000 fruits are harvested per year for about a century. 1
Industrial production
In industry, walnut oil processing focuses on extraction with organic solvents or hot pressing. Compared to extraction, pressing the kernels is less productive, but more environmentally friendly. But even here, many manufacturers rely on refining: they often heat both the seeds and the press and add chemical additives to achieve the highest possible oil yield. Research is therefore currently working on special pretreatment and extraction methods with as little impact as possible on antioxidant activity and on the environment. 6 Smaller and ecologically oriented companies, on the other hand, sell natural oils that are made from gently dried kernels, cold pressed and without additives.
Further information
Walnut oil consists of real walnuts ( Junglans regia ), which belong to the walnut family (Juglandaceae). 13 Since walnuts grow on trees, they are classified as tree nuts like almonds or hazelnuts. Walnut oil also belongs to the group of tree nut oils. It should be noted here that walnuts are also called tree nuts in Switzerland, which can lead to inaccuracies.
Alternative names
In English, walnut oil is called walnut oil, walnut kernel oil or walnut seed oil. In Switzerland, it is also known as tree nut oil. The name for the medicinal drug is Oleum Juglandis .
Other uses
Walnut oil is not only used in the kitchen: In ancient Egypt it was used to embalm mummies. In France it was used as holy oil in the church in the 19th century. To this day, walnut oil is used to polish wood and wooden furniture. 13 It is also suitable for creating oil paintings. 17 Walnut oil is also often used to make skin creams. It is said to provide moisture and thus work against dry skin and wrinkles. 13
Bibliography - 24 Sources
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| 3. | Song H, Cong Z et al. Research progress on Walnut oil: Bioactive compounds, health benefits, extraction methods, and medicinal uses. Journal of Food Biochemistry. December 2022;46(12):e14504. |
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