What is a lemon?

The lemon is the fruit of an evergreen belonging to the Rutaceae family, Citrus limon. This tree, which can exceed 6 meters in height, is characterized by light green leaves and it’s oval fruit whose skin can take on shades of green and yellow that, contrary to the fruits of other species belonging to the genus Citrus, are produced in continuation.


What are the nutritional properties of lemon?

In 100 g of the edible part of the fruit there are 89.5 g of water and only 11 Calories. These correspond to 22% proteins and the remaining 78% carbohydrates (in particular, 2.3 g of soluble sugars and 1.9 g of dietary fiber called pectins), while lipids are virtually absent.

The most abundant vitamin is vitamin C, provided in doses of 50 g per 100 g of lemon.

There are also:

• niacin (vitamin B3 or PP, 0.3 mg per 100 g)

• thiamine (vitamin B1, 0.04 mg per 100 g)

• riboflavin (vitamin B2, 0.01 mg in 100 g)


Among minerals it provides:

• potassium (140 mg per 100 g)

• calcium (14 mg per 100 g)

• phosphorus (11 mg per 100 g)

• sodium (2 mg per 100 g)

• iron (0.1 mg 100 g)


The nutritional composition varies if you take into account the juice only: the energy coming from carbohydrates (87%) increases compared to that coming from proteins (13%), but you get only soluble sugars (1.4 g per 100 g of juice). So while consuming the whole fruit also includes the fibers, the lemon juice has none. Calories also decreased (6 to 100 g), while the proportion of water increases (92.1%). Regarding the micronutrients, 100 g of lemon juice make 43 mg of vitamin C, 0.2 mg of niacin, 0.02 mg thiamine, and 0.02 mg of riboflavin, 140 mg potassium, 14 mg calcium, 10 mg of phosphorus, 2 mg of sodium and 0.2 mg of iron.

In lemons there are also organic acids, carotenoids, flavonoids (especially abundant in the peel and albedo – the white part of citrus fruits), bitter limonoid and volatile compounds (which account for 2.5% of the peel). Among all, there are limonene, alpha-terpinene, alpha-pinene, citral, coumarins, mucilage and flavonoids eriocitrin and hesperidin.


When should you not eat lemon?

Lemon intake may be associated with decreased plasma concentrations of chloroquine. It also promotes the absorption of iron.


Seasonality of lemon

The Citrus limon is an evergreen that produces fruits during the whole year. A big part of the harvested crop is directed to the processes that allow you to extract the juice to be used as such or to obtain other citrus-based beverages. Even the peel, pulp and seeds may be used at industrial level, for example for the production of oils or pectins.


Possible benefits and drawbacks of lemon

Lemon juice has a long history of use as an astringent, diaphoretic (promotes sweating), diuretic, gargle, lotion and tonic. It is also used topically in the treatment of acne, mycosis of the skin (such as athlete's foot), the sunburn and warts. The alleged pairing utility of its application to sun exposure to erase the tattoos is instead denied.

To date, several epidemiological studies have found an association between consumption of citrus fruits and reducing the risk of various diseases. As for the lemon, from the pharmacological point of view the main benefits derived from its intake depends on its content in vitamin C and potassium. Among the benefits that have been an object of study there are included the antioxidant actions (which seems to be associated with the skin, to pectins and oils), anti-tumor actions (in particular, the consumption of citrus fruit has been associated with a protective effect against cancer of the oral cavity) and antimicrobial (oils exert bacteriostatic and antiviral action dependent on citral and linalool). It also seems that in cases of calcium nephrolithiasis hypocitraturia and in appropriate daily doses the consumption of lemon juice can reduce the formation of kidney stones.

Often lemon juice is accused of worsening gastroesophageal reflux, but these analyses seem to indicate that the problem is not dependent on its acidity or by a change of pressure on the lower esophageal sphincter. It is however certain that it can damage tooth enamel causing unevenness of the surface, loss of gloss and discoloration. There were also no reports of allergic reactions to soaps containing lemon supposedly associated with a cross-reactivity between the seeds of citrus fruits and the allergens in peanuts.