Lemons 101: A Complete Guide

Whether you associate lemons with lemonade, household cleaning, or a way to add flavor to dishes, there’s no mistaking these ubiquitous fruits. Despite their famously sour taste, lemons are one of the all-time most popular and versatile fruits.

Since you’re very unlikely to snack on them the same way you would a tangerine or a grapefruit, you may be wondering what you can do with lemons, and better yet, how they might benefit your health. Here, we break down the scientifically proven benefits of lemons according to research and nutrition experts.

What Are Lemons?

Lemons are a member of the citrus family, which also includes oranges, grapefruit, and limes. All citrus fruits contain some level of citric acid, the compound responsible for their famously tart taste. According to the Food and Agriculture Organization of the United Nations, citrus fruits like lemon are among the most popular — and widely grown crops — in the world.

Citrus limon, the evergreen bush that produces lemons, is part of the Rutaceae family, according to the Encyclopaedia Britannica. Though the fruit’s origins are unknown, it’s thought to have been introduced to Spain and North Africa between 1,000 and 1,200 A.D., before spreading throughout Europe and the Middle East by the late 1400s. Since then, lemons have thrived in tropical and subtropical climates throughout the world, and are now a staple food used to make juices and to add flavor to vegetables, fish, and poultry.

Aside from adding flavor to foods, different parts of lemons are also used to produce citric acid, a preservative and flavor; pectin, a soluble fiber used to thicken foods; and essential oils. These byproducts are used in a variety of food and skin care products, as well as certain medications.

As with other fruits, lemons are considered a low-calorie, low-fat food choice that provides a variety of nutrients.

Per the U.S. Department of Agriculture (USDA), one raw lemon contains:

• Calories: 18.8
• Protein: 0.72 grams (g)
• Fat: 0.2g
• Carbohydrates: 6.1g
• Fiber: 1.8g
• Sugars: 1.6g
• Calcium: 16.9mg
• Iron: 0.39mg
• Potassium: 89.7 milligrams (mg)
• Sodium: 1.3mg

“Lemons are high in vitamin C, which is an antioxidant,” explains Denison. “Vitamin C plays many roles in the body, including helping with immune function.” According to the National Institutes of Health (NIH), vitamin C-rich foods can supply the body with antioxidants needed to help fight disease-causing oxidative stress. The NIH notes that adult women need 75 mg vitamin C per day, while adult men should aim for 90 mg. The upper limit for all adults is 2,000 mg.

Another nutritional benefit of lemons: Their high vitamin C content also helps you absorb iron in your diet, Denison points out. Per the NIH, iron is a mineral that promotes growth and development; getting too little iron in your diet can cause anemia, leaving you feeling weak, lacking energy, and unable to concentrate. Pairing iron with vitamin C in your diet can help you better absorb this mineral.

Lemons are also a modest source of folate and magnesium. If you were to add lemons to plain water for flavor, you would also gain about 1 calorie and 1.2 mg vitamin C, according to the USDA.

While lemons are typically added to foods and beverages rather than eaten whole, there are still many potential benefits to consider with this citrus fruit. From boosted immunity to better digestion, here’s what the science says about lemons and health.

May Promote Better Immune Function

Vitamin C, which lemons naturally offer, is considered a crucial micronutrient in immune health. As one clinical review explains, vitamin C can boost your immune function, decrease inflammation, and possibly help fight infections. (That said, there’s no evidence that vitamin C can reduce your risk of catching the common cold, though taking vitamin C supplements regularly might help shorten your cold and lessen its severity, notes the NIH).

May Protect Against Chronic Diseases

According to the NIH, getting an adequate vitamin C intake from eating lots of fruits and vegetables may reduce your risk of developing chronic diseases, such as cancer and heart disease. It’s thought that vitamin C in foods like lemons may decrease oxidative damage throughout your body. However, it’s not clear whether vitamin C alone, whether in diet or supplemental form, directly reduces the risk of chronic disease development.

May Promote Better Digestion

While there’s no research suggesting that lemons alone can detox the body, drinking lemon water may promote better digestion overall.

“Adding lemon to your water may mean you actually desire to drink more and achieve your unique hydration needs,” explains Trisha Best, RDN, a consultant with Balance One Supplements based in Dalton, Georgia. “Lemon water has also been shown to support weight loss by improving insulin resistance and digestion.” One in-vitro study suggests that lemon extract may contain bioactive compounds, such as flavanones, which researchers found mimicked insulin resistance.

Best also notes that drinking warm lemon water in the morning may have a laxative effect. This could promote better digestive health if you experience constipation. While more research is needed on this end, one study found that lemon juice, when combined with prune juice, helped promote normal bowel functioning in patients who recently underwent orthopedic surgery.

May Decrease the Risk of Kidney Stones

Kidney stones are composed of calcium, uric acid, and oxalate, per Mayo Clinic. These start off as crystals, and then may grow larger until they turn into painful stones. Lemons may prevent kidney stones due to their citric acid content that may bind to calcium. According to Harvard Health, 80 to 85 percent of kidney stones are composed of calcium.

“Those prone to kidney stones may also see benefits from making lemon water a regular part of their drink rotation,” says Best. Harvard Health also notes that citrate in lemons and lemon juice may help reduce the incidence of kidney stones.

“Lemons can help reduce calories or sodium intake if they are used in place of a high calorie or sodium item,” says Denison.

One previous study in obese mice found overall decreases in body fat gains, cholesterol, and glucose in those that were fed a high-fat diet supplemented with lemon peel extract for 12 weeks. However, it’s important to note that the mice didn’t lose weight, and that such results haven’t been replicated in any human studies yet.

Drinking lemon water is another touted method of body detox and weight loss, though such claims are unsubstantiated. According to one clinical review, researchers found that drinking more water may help increase weight loss by reducing the number of overall calories you consume and also breaking down fat cells through a natural process called lipolysis. However, it’s important to note that the studies included in this review were also done on animals — not humans.

“The human body can effectively detox without the help of lemons,” says Kelsey Lorencz, RDN, nutrition advisor for Zenmaster Wellness. “The liver and kidneys help filter toxins out of your body and excrete it through urine. If these systems are not working effectively, you likely require medical attention. The science just isn't there that adding lemon to your diet will provide any substantial benefit to the detox process.”

“Also, foods do not target weight loss in certain areas of the body, so lemons will not reduce belly fat or help detox the body on their own,” says Julia Denison, RDN, the Pittsburgh-based owner of Running on Cupcakes.

What is true about lemon water, however, is that adding flavors to water may help you drink more of it and reach the recommended daily amount. Mayo Clinic recommends drinking at least 92 ounces (oz) of water daily for women, and 124 oz for men. This adds up to about 11.5 and 15.5 cups, respectively.

One more recent trend is adding lemon to coffee, supposedly as a beverage that boosts weight loss. Again, as with lemon water, any benefits you might gain are likely from filling up on liquids — not from the lemons themselves, notes the Cleveland Clinic.

Lemons are available year-round in grocery stores and at some farmer’s markets. However, not just any old lemon will do, and you’ll also need to store them properly when you get home. Here’s how to get started:

Selection 

As with other citrus fruits, you’ll want to choose lemons that are free of any bruises or brown spots that could indicate spoilage. The University of Nebraska in Lincoln also recommends selecting lemons that are smooth in texture, bright yellow in color, and heavier to hold.

Storage 

Depending on how soon you plan on using lemons, as well as the available space in your kitchen, you can choose to either store lemons at room temperature or in the fridge. Lemons will stay fresh at room temperature for up to two weeks, while refrigeration can extend their lifetime for up to six weeks. Wherever you store your lemons, consider washing them in cool water first to clean pesticides and bacteria from the surface, per the Academy of Nutrition and Dietetics.

Unlike other fruits, lemons aren’t typically eaten whole. Instead, you can use them to add flavor to water or foods, such as chicken, fish, pasta, or vegetables. You can also use lemons to make fresh lemon juice — just keep in mind that it takes about six lemons to get 1 cup of lemon juice.

If you’re looking for new ways to eat lemons, you may be surprised at how versatile this citrus fruit can be.

“My favorite way to eat lemons would be classic homemade lemonade,” says Denison. “If I'm feeling ‘fancy’ I'll make a lavender simple syrup to make it a lavender lemonade. I also really enjoy making a simple salad dressing with oil, vinegar, and lemon juice.”

If you’re looking to drink lemon water, Best offers a few rules of thumb:

“Lemon water can be consumed either hot or cold without negating its nutritional or health benefits,” says Best. “With that being said, it's best to drink lemon water in whatever method allows you to do so consistently and with enjoyment.”

She recommends drinking no more than 6 tablespoons of lemon juice per day. “This would be using one tablespoon in each 8-oz glass to equal around four to six glasses a day,” she says. “[You can drink] one with each meal and between meals.”

But before you experiment with lemons, here’s a word of caution on preparing them: The Academy of Nutrition and Dietetics still recommends that you wash them, even if you’re not eating the peel or using the zest. This is because when you cut into the lemon, any bacteria that may be on the outside of the fruit could be transferred to the inside flesh.

There are not many risks associated with eating lemons, says Denison, and they’re likely safe for most people to consume in moderation.

That said, this acidic fruit may lead to some unwanted side effects.

“Of course, there is always a chance someone could be allergic to lemons,” Denison points out. “Lemons are also a high acidity food, so someone who is sensitive to this or has any GERD or acid reflux issues may not want to consume large amounts of lemon.”

Side Effects

Lemons — and especially lemon juice — are highly acidic, which may gradually wear down tooth enamel. To help minimize tooth erosion, the American Dental Association recommends limiting the amount of acidic foods and beverages you consume, and to wait at least one hour before brushing your teeth so that your enamel may re-harden. You may also consider drinking lemon water with a straw to help reduce direct contact with your teeth.

Contrary to popular belief, lemon water will not help acid reflux — and could actually worsen symptoms. Lemons and lemon juice are among the many acidic foods that may cause acid reflux, such as nausea, heartburn, belching, and indigestion, per Mayo Clinic.

In addition to avoiding lemons and other acidic foods, Tufts University recommends talking with a doctor about taking antacid medications if you experience frequent acid reflux.

If you’ve recently increased your lemon intake, be on the lookout for the following symptoms:

• Tooth sensitivity or pain from worn down tooth enamel
• Burning throat, indigestion, heartburn, and other symptoms of acid reflux
• Nausea, diarrhea, and abdominal cramps from too much vitamin C

Is It Possible to Be Allergic to Lemons?

While a lemon allergy isn’t one of the more “common” food allergies, such as wheat, nuts, or cow’s milk, the American Academy of Allergy, Asthma, and Immunology (AAAAI) explains that it’s possible to be allergic to lemons if your immune system reacts adversely to pectin, profilin, and lipid transfer proteins. These most commonly cause allergic reactions in the mouth and face area within two hours of consumption, per the AAAAI.

Still, having an allergy to lemons doesn’t necessarily mean you’re allergic to all citrus fruits, notes the London Allergy and Immunology Centre. The only way to know whether you have a lemon allergy is through allergy or blood testing from a doctor.

It’s possible to grow citrus trees, including lemon trees, at home. But before you start digging holes in your hard, it’s important to know that lemon trees need quite a bit of space — they can grow up to 20 feet tall and 15 feet wide, according to The Spruce. They also grow best in subtropical climates. Lemon trees are not a good garden option if you have pets at home, as they can be toxic to cats and dogs, per the American Society for the Prevention of Cruelty to Animals.

If you have the space and live in the right climate, The Spruce offers the following tips for growing your very own lemon trees:

• Dig each hole about twice as wide and twice as deep as each root ball.
• Use well-draining, medium-textured soil that has a low acidity.
• Plant the trees in a spot where they will get full sun and minimal wind exposure.
• Water one to two times per week, but avoid making the soil too soggy.

Alternatively, if you’d prefer growing lemons in a container, consider using a seed from an organic lemon. The Farmers’ Almanac recommends filling a planter with moist soil up to one inch below the rim of the container. Then, place the seed about ½-inch into the planter before covering with soil. Covering the container with plastic wrap and poking holes at the top. As with lemon tree gardening, you’ll want to make sure the soil stays moist, but not too wet, either. Once it outgrows its pot, repot it in a planting pot and continue to water periodically to keep the soil moist.