Lemons (Citrus limon) are among the world's most popular citrus fruits.

They grow on lemon trees and are a hybrid of the original citron and lime.

There are many ways to enjoy lemons, but they taste very sour and are usually not eaten alone or as a whole fruit.

Instead, they’re often a garnish with meals, and their juice is often used to provide a sour flavor. They are a key ingredient in lemonade.

A great source of vitamin C and fiber, lemons contain many plant compounds, minerals, and essential oils.

These yellow fruits also have many potential health benefits. Eating lemons may lower your risk of heart disease, cancer, and kidney stones.

This article tells you everything you need to know about lemons.

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Lemons contain very little fat and protein. They consist mainly of carbs (10%) and water (88–89%).

A medium lemon provides only about 20 calories.

The nutrients in 1/2 cup (100 grams) of raw, peeled lemon are (1):

  • Calories: 29
  • Water: 89%
  • Protein: 1.1 grams
  • Carbs: 9.3 grams
  • Sugar: 2.5 grams
  • Fiber: 2.8 grams
  • Fat: 0.3 grams

Carbs

The carbohydrates in lemons are primarily composed of fibers and simple sugars, such as glucose, fructose, and sucrose (2).

Fiber

The main fiber in lemons is pectin.

Soluble fibers like pectin can lower blood sugar levels by slowing down the digestion of sugar and starch (3).

Dietary fibers are an important part of a healthy diet and linked to numerous health benefits (3, 4).

SUMMARY Lemons contain approximately 10% carbs, which are mostly soluble fibers and simple sugars. Their main fiber is pectin, which may help lower blood sugar levels.

Lemons provide several vitamins and minerals.

  • Vitamin C. An essential vitamin and antioxidant, vitamin C is important for immune function and skin health (5, 6).
  • Potassium. A diet high in potassium can lower blood pressure levels and have positive effects on heart health (7).
  • Vitamin B6. A group of related vitamins, B6 is involved in converting food into energy.
SUMMARY Lemons are very rich in vitamin C. In addition, they’re a decent source of potassium and vitamin B6.

Plant compounds are natural bioactive substances found in plants, some of which have powerful health benefits.

The plant compounds in lemons and other citrus fruit may have beneficial effects on cancer, cardiovascular disease, and inflammation (8, 9, 10).

These are the main plant compounds in lemons:

  • Citric acid. The most abundant organic acid in lemons, citric acid may help prevent the formation of kidney stones.
  • Hesperidin. This antioxidant may strengthen your blood vessels and prevent atherosclerosis — the buildup of fatty deposits (plaque) inside your arteries (11, 12).
  • Diosmin. An antioxidant used in some drugs that affect the circulatory system, diosmin improves muscle tone and reduces chronic inflammation in your blood vessels (13).
  • Eriocitrin. This antioxidant is found in lemon peel and juice (13, 14).
  • D-limonene. Found primarily in the peel, d-limonene is the main component of lemon essential oils and responsible lemons’ distinct aroma. In isolation, it can relieve heartburn and stomach reflux (15).

Many of the plant compounds in lemons are not found in high amounts in lemon juice, so it is recommended to eat the whole fruit — excluding the peel — for maximum benefit (16, 17).

SUMMARY Lemons contain plant compounds that provide various health benefits. These compounds include citric acid, hesperidin, diosmin, eriocitrin, and d-limonene.

Citrus fruits, including lemons, are associated with numerous health benefits.

Their vitamins and fiber, as well as their powerful plant compounds, are likely responsible (18).

Heart health

Heart disease, including heart attacks and strokes, is the world's most common cause of death.

Intake of fruits high in vitamin C is linked to reduced heart disease risk (19, 20).

Low levels of vitamin C in the blood are also associated with increased risk of stroke, especially among those who are overweight or have high blood pressure (21, 22).

Intake of isolated fibers from citrus fruits has been shown to decrease blood cholesterol levels, and the essential oils in lemons can protect LDL (bad) cholesterol particles from becoming oxidized (23, 24).

Recent studies in rats show that the plant compounds hesperidin and diosmin may have beneficial effects on some key risk factors for heart disease (25, 26, 27).

Prevention of kidney stones

The citric acid in lemons may reduce your risk of kidney stones (28, 29).

Some studies have shown that lemon juice and lemonade can be effective at preventing kidney stones, but other studies have found no effect (30, 31, 32).

Anemia prevention

Anemia is often caused by iron deficiency and most common in pre-menopausal women.

Lemons contain small amounts of iron, but they are a great source of vitamin C and citric acid, which can increase the absorption of iron from other foods (33, 34).

Because lemons can enhance the absorption of iron from foods, they may help prevent anemia.

Cancer

Lemons may help reduce the risk of many types of cancers, including breast cancer. This is thought to be due to plant compounds like hesperidin and d-limonene (35, 36, 37, 38, 39, 40, 41, 42).

SUMMARY Lemons may help protect against anemia, prevent the formation of kidney stones, and reduce your risk of heart disease and cancer.

Many people drink lemon water — either hot or cold — a few times per day.

The recipe is usually freshly squeezed juice from 1/2–1 lemon in a cup (240 ml) of water.

Drinking water with freshly squeezed lemon may have some health benefits.

Lemon water is a rich source of vitamin C and plant compounds, which can enhance immune function, protect against various diseases, and increase your absorption of iron (5, 20, 34, 35).

The citric acid in lemons decreases your risk of kidney stones by diluting urine and increasing its citrate content (28).

Given that some pulp goes into the mix, pectins in the pulp can promote fullness and feed the friendly bacteria in your gut, therein promoting good health and decreased risk of disease (3).

To top things off, the lemon aroma derived from the essential oils might decrease stress and improve mood (43).

Lemonade should have similar health benefits — except for the frequently added sugar, which is unhealthy when consumed in excess.

SUMMARY Drinking lemon water may decrease stress, enhance immune function, help prevent anemia, reduce your risk of kidney stones, and protect against several diseases.

Lemons are generally well tolerated, but citrus fruit may cause allergic reactions in a small number of people (44).

They may also cause contact allergy and skin irritation in people with dermatitis (45).

Lemons are quite acidic, so eating them frequently may be harmful to dental health if your tooth enamel becomes damaged (46).

SUMMARY Lemons are usually well tolerated but may cause allergies or skin irritation in some people. Large amounts may be harmful to dental health.

Lemons are a refreshing fruit usually not eaten whole but rather as a garnish or flavoring.

They are an excellent source of vitamin C, soluble fibers, and plant compounds — all of which can provide health benefits.

If you’re interested in trying them out, lemons are sure to boost your health.