Since we calculate the nutritional content of each ingredient we describe, we have made a distinction between raw lemon (Citrus limon) used without the peel and raw lemon in which the entire peel is used (for jam, for example). It should be noted that limes are quite different from lemons, for example, in that they are smaller and greener.
We use lemons either by squeezing them (often with a juicer or reamer) or by peeling them first (as for lemon slices). The sour taste of the flesh imparts a refreshing and citrus flavor to dishes and drinks. Lemon juice is also a natural antioxidant and a natural gelling agent as a result of the pectin it contains. Because of these qualities, the juice is often used to preserve food.
Lemon juice is particularly well suited for adding flavor to and seasoning desserts, sauces, soft drinks, liqueurs, pastries, salad dressings, marinades, preserves, and ice cream — as well as for producing syrup or jam and preserving cut raw vegetables. Lemon juice can also replace or compliment vinegar in salad dressings.
While we do not recommend eating lemon seeds, they are not toxic except in large quantities. See below under Dangers — intolerances — side effects.
You can find ideas for using lemons and recipes for lemon peel at this LINK. The finely shredded peel of organic lemons can impart a fresh lemon aroma and flavor to foods, savory dishes, desserts, and cakes.
Pour 1 liter boiling water over a sprig of fresh mint and a thumb-size piece of fresh ginger that has been grated. Let the mixture steep for 15 minutes and cool to room temperature before straining through a fine sieve. Add about 100 mL white grape juice and the juice of two lemons. Pour the finished beverage into large glasses filled with ice cubes and garnish with lemon slices and edible flowers such as violet, nasturtium, mallow blossoms (malva), or dandelion. The ginger and lemon iced tea is about enough for six glasses, depending on the size of the glasses.
First boil 250 mL water, 100 g sugar, a few mint leaves, and 2 g agar-agar (agar) for at least one to two minutes. Be sure to cook the mixture long enough that the agar-agar can form a gel. Hollow out six lemons, remove the seeds, and blend the flesh with an immersion blender until the consistency is even. Add the lemon puree to the sugar water and let it cool. Use an ice-cream maker to freeze the sorbet or put it in the freezer and stir it every hour.
Lemons are part of the basic assortment of produce found in western grocery stores of any size. Lemons can not only be found in large supermarket chains such as Walmart, Whole Foods Markets, Kroger, and Safeway (United States); Asda, Sainsbury’s, Tesco, Aldi, Lidl, and Holland & Barret (Great Britain); Metro, Extra Foods, and Goodness Me (Canada); Coles, Woolworths, and Harris Farm (Australia), but also in most small grocery stores and farmers markets. Since lemons are often exposed to high levels of pesticides, look for lemons from certified organic cultivation, especially if you want to use the peel as well. Organic lemons are often available at the shops named above, as well as organic markets and health food stores.
Lemons are in season year-round. In suitable climates, the trees produce flowers throughout the year and ensure a continuous harvest.
How big is a lemon? Lemons can take many shapes, including round, oval, and egg-, and spindle-shaped, and tend to be 4 to 8 cm wide, 5 to 12 cm long, and weigh 50 to 250 g.1
Lemons sold in Europe are usually treated so that the peel remains yellow and the fruit does not dry out. Antifungal agents are applied after the fruit is harvested to prevent them from becoming moldy quickly, and artificial wax and pesticides are supposed to prolong shelf life. Lemons that are labeled “untreated” did not come into contact with chemicals or wax after harvesting, but were quite possibly treated while they were still hanging on the tree. The regulations for organic lemons are much stricter, which is why consumer protection activists unequivocally recommend buying organic fruit if you want to consume the peel directly or use it in recipes.
Cut lemons should be consumed quickly or kept in the refrigerator for a few days. If you are going to store pieces of lemon in the refrigerator, wrap them in some paper towels to draw out the moisture and prevent them from molding. Lemons are very sensitive to cold, so the temperature of the refrigerator should not be less than 5° C. If you only need to use a small part of a lemon, cut a piece as small as you need from the fruit instead of cutting the lemon in half. If you only need a little juice, you can prick the lemon pulp with a fork or toothpick and then squeeze it. Paper towels are also a good option to protect fruits used in this way.
Be careful not to allow lemons to come into contact with aluminum foil, as the citric acid can dissolve the aluminum. Aluminum can cause various illnesses, including Alzheimer’s disease and cancer.
Another option for storing cut lemons is to freeze the juice; freezing juice in ice cube trays is an option to facilitate more convenient portioning.
Whole lemons can be stored for up to nine months at 10 to 12 °C and 85 to 95 % relative humidity.1 The high acid content of lemons protects not only the lemon juice itself from oxidizing, but also other fresh foods as well. For example, lemon juice can be used to keep sliced fruit and vegetables fresh. You can prevent the surfaces of cut produce such as apples, pears, bananas, avocados, celery, and chicory (endive) from browning by drizzling some lemon juice on them.
More than 300 volatile substances make up the aroma of lemons. One of these substances, called citral, is the main component.1 Citral and essential oils form the typical smell of the fruit. The organic acids (citric, malic, acetic, and formic acid) in lemons enhance the effects of both the ascorbic acid and vitamin C they contain. A lemon’s flesh also contains the flavonoid diosmin (venosmine), as well as hesperidin, a flavanone glycoside. The flesh and pith of the fruit contain pectin.1,2
While lemons are known for their rich vitamin C content, they contain an average of 51 mg of vitamin C per 100 g of fruit flesh, which is far less than bell peppers (183.5 mg), blackcurrants (181 mg), wild garlic (187.5 mg), or kiwis (93 mg).1,3 Nevertheless, lemons contain valuable nutrients and are a reliable source of vitamin C as a result of their availability year-round and their excellent shelf life. Calling lemons a superfood, however, would be an exaggeration since other fruits and vegetables contain significantly more vitamin C.
Detailed nutritional information can be found in the tables below the text at the bottom.3
How healthy are lemons? They contain flavonoids that protect against oxidative stress and cancer as well as protecting the capillaries. These flavonoids also have positive effects on arteriosclerosis, thrombosis, and edema. Vitamin C strengthens the immune system and improves the body’s ability to absorb iron from other plant foods.2
Epidemiological studies show that a higher intake of flavonoids correlates to a reduced risk for many diseases including cardiovascular mortality. Flavonoids affect the metabolism of arachidonic acid and blood coagulation.4,5 Several studies, including a dissertation from 2014, show that bioflavonoids such as quercetin may have therapeutic applications in treating cancer by affecting changes in cell morphology, specifically by blocking cell turnover in cancer cells and in preventing their "growing".6
Lemon seeds and lemon pith contain limonoids, which have been demonstrated at least in part to have qualities that promote health. These qualities include fever-reducing, antibacterial, and antiviral effects. Limonoids have also been investigated as a treatment for several types of cancer, but further clinical studies are needed to confirm these findings.7 Limonoids reduce the amount of cholesterol released by liver cells, which leads to a reduction in the blood levels of LDL cholesterol in animal experiments. Although we assume that limonoids may have antiatherogenic effects, there are no clinical studies available that suggest this.8
Is it a good idea to eat a whole lemon? You can in principle, but it’s a bit much. Citrus can even trigger an allergic response in some people. Possible effects include oral allergy syndrome (OAS), which is characterized by discomfort in the mouth and throat and a tongue that feels furry. Skin reactions can take up to two days to appear. In the event of a skin reaction, request a skin or allergy test with an allergist, and clarify whether the trigger was a fructose intolerance or a reaction to preservatives.
Are lemon seeds poisonous? Lemon seeds contain an insignificant amount of amygdalin, as do other foods such as almonds. The seeds should therefore not be eaten regularly in quantities of more than 100 g. Heating or drying lemon seeds releases the amygdalin, which is a precursor of prussic acid.9
Citric acid attacks tooth enamel both when it occurs naturally in food and when it is an additive (E330). Because of this effect on tooth enamel, you should not brush your teeth vigorously after eating or drinking acidic foods, as this would be excessively abrasive for the outer layers of the teeth. Instead, we recommend rinsing your mouth with water. This way you can dilute the acid and accelerate the replacement of the minerals that have been dissolved by the acid.10
The parts of the lemon indicated for therapeutic use include essential oil from the peel, lemon juice, and dried or fresh lemon peel.11 Lemon juice is often used for colds, minor skin injuries, insect bites, bleeding gums, and in skincare products.1
Lemon has diuretic, anti-inflammatory, and circulatory effects. When taken internally, lemon can help with varicose veins, kidney stones, hemorrhoids, mild febrile illnesses, and mucous-filled bronchial passages. External applications can be used to treat eczema, frostbite, sunburn, and toxic insect bites. Lemon can also be gargled to soothe a sore throat.12
Is lemon juice good for your skin? Although many cosmetics and other toiletries contain small quantities of lemon juice, it should not be applied to the skin on its own since the concentrated acids can cause skin irritation.
The Internet is also full of lemon juice diets that are supposed to help you lose weight, since lemons are said to help you burn fat, but there is no scientific evidence for this.14
The ancestors of all edible citrus fruits are believed to be on the southeastern slope of the Himalayas in northeastern India, Myanmar, and the Yunnan province in China. The Yu Kung (Yu Gong, “Tribute to Yu”), a section of the ancient Chinese classic Shu Ching (Shūjīng, Shu-king, “Book of Documents”) records payments of tribute with citrus fruits to the Chinese ruler Ta Yu around 2200 BCE.15 It was not until much later in 1805 that mandarins were imported to Europe from China.
Citrus fruits originated from a cross between bitter oranges (Citrus aurantium) and citrons (Citrus medica), and were probably first found in northern India.
Lemon trees can be planted as sources of food or as ornamental plants in your garden even in Central Europe. Lemon trees can grow outdoors as a potted plant in a sheltered place from mid-May until the first frost in early autumn. In winter, the temperature in which the plants grow must be adjusted according to the light conditions. If your lemons trees live in bright, cold conditions in the winter, the leaves still receive sufficient light for photosynthesis, but the roots are almost completely inactive at 12.5 °C and below. As a result, the roots will not sufficiently supply nutrients to the leaves, which will fall off (Winter Leaf Drop).
A suitable substrate for planting lemon trees is a mixture of peat (or coconut fibers as a peat substitute), compost, and loamy garden soil. The garden soil should be low in lime — ideally free of it altogether — and have a slightly acidic pH value. The water you use for watering lemon trees should likewise be free of lime; rainwater would be a good choice. Lemon trees can be fertilized once a month with a phosphate-based, low-nitrogen fertilizer.13
Scale insects are a common pest found on lemon trees. The plant can be propagated using cuttings or micropropogation.11
Lemon blossoms can self-pollinate, and insects and the wind can help with pollination as well. Although unfertilized flowers can develop into fruits, they will be seedless.13 Since lemon trees are self-fertilizing, they are ideal for sunrooms and greenhouses.
Lemon trees bloom and produce fruit throughout the year in warm, humid conditions, and they can produce up to four harvests. The trees need an evenly warm (at least 5 °C) and humid climate, and they are more sensitive to drought and cold than other commercially grown citrus fruits. The plants are often subjected to a period of stress, as in stopping irrigation, in order to allow for a more economically cost-effective harvest. A period of stress results in more blossoms and fruits that ripen simultaneously.
The most widespread lemon varieties are “Zagara Bianca,” “Lunario,” und “Feminello Santa Teresa," according to Wikipedia. Other important varieties include "Primofiori," “Verna,” “Interdonato,” “Feminello” and “Lisbon.” Eureka is the main variety found in California. These fruits are produced from the seeds of Sicilian lemons planted in California in 1858. The Eureka variety has dark green, round leaves and almost no thorns. The fruit also ripens early and has few to no seeds.11
“Meyer Lemons” (Citrus Meyeri, Cirtus limon “meyeri”, or Citrus jambhiri “Meyer”) originally came from China, where they were first derived from lemons and oranges. Meyer lemons contain less acid than Eureka lemons, and have become increasingly popular in the US since the 1990s.11
The name lemon comes from the Arabic ليمون, which is transliterated “laimūn” (lemon) according to the German oriental society (Deutsche Morgenländische Gesellschaft (DMG)). Lemons are the fist-size fruits of the lemon tree (Citrus limon) and are a member of the genus citrus (Citrus). A cross between bitter oranges (Citrus aurantium) and citrons (Citrus medica) gave rise to today’s lemon varieties. There is reliable evidence for the existence of lemons in China and the Mediterranean since about 1000 CE.11
In previous centuries, the designation “lemon” actually referred to what we call a citron today. Citron (Zitronatzitrone) remained the name for the fruit in German until the late Middle Ages, and is still in use in some parts of Austria. “Lemonade” is a designation that once only referred to drinks made with lemon. Today, the term is used in many countries to describe any number of drinks made from fruit juice or flavorings and carbonated water.11
1. aid Infodienst (Herausgeber). Exoten und Zitrusfrüchte. 4. Auflage. Bonn; 2014. Druckerei Lokay e. K. Reinheim.
2. Roger P. Heilkräfte der Nahrung: Ein Praxishandbuch. Zürich: Advent-Verlag; 2006:128-129.
3. USDA (United States Department of Agriculture). Nährstofftabellen.
4. Galati, E. M. et al. Biological effects of hesperidin, a citrus flavonoid. (Note I): antiinflammatory and analgesic activity. Farmaco. 1994; 40:709–712. PMID 7832973.
5. Watzl B, Rechkemmer G: Basiswissen aktualisiert: Flavonoide. Ernährungs-Umschau. 2001; 48/12.
6. Klappan A: Einfluss des Flavonoids Quercetin auf den mTOR-Signalweg von Zervix- und Mammakarzinomzellen. München 2014, DNB 1048361322 (PDF volltext).
7. Wikipedia Limonoide.
8. Ernährungsumschau. Limonoide in Zitrusfrüchten – Bitterprinzip und antikanzerogene Wirkung.
9. Fleischhauer S. G., Guthmann, J., Spiegelberger, R. Enzyklopädie. Essbare Wildpflanzen. 2000 Pflanzen Mitteleuropas. 1. Auflage; Aarau: AT Verlag; 2013.
10. Wetzel W-E, UGB-Forum Spezial: Von klein auf vollwertig, S. 19-20.
11. Wikipedia Zitrone.
12. Bown D.: Kräuter. Die grosse Enzyklopädie. Anbau und Verwendung. 2. Auflage. München: Dorling Kindersly; 2015.
13. Garten-wissen.com Zitronenbaum.
15. Legge J. Sacred Books of the East. Vol. 3: The Shoo King. Teil III, Buch I: The Tribute of Yu. London: Trübner; 1879: 68. sacred-texts.com/cfu/sbe03/sbe03013.htm.