Is lime peel healthy?

Lime peel, also known as lime zest, refers to the outermost layer of a lime fruit. It contains high concentrations of vitamins, minerals, and beneficial plant compounds compared to the lime juice and pulp. Lime peel has been used for centuries in traditional medicine, but modern research also indicates it may offer various health benefits. This article reviews the nutrition profile and potential health effects of lime peel.

Nutrients in Lime Peel

Lime peel is highly nutritious compared to other citrus peels. A 100 gram serving provides 1:

  • Calories: 112
  • Protein: 5.3 grams
  • Fat: 1.2 grams
  • Carbs: 25 grams
  • Fiber: 12.7 grams
  • Vitamin C: 129% of the Daily Value (DV)
  • Calcium: 10% of the DV
  • Iron: 11% of the DV
  • Magnesium: 7% of the DV
  • Potassium: 7% of the DV

Lime peel is particularly high in vitamin C, providing even more than the juice. It also contains an array of plant compounds, including 2:

  • Flavonoids: Eriocitrin, hesperidin, and naringin
  • Alkaloids: Synephrine
  • Polyphenols: Limonoids and coumarins
  • Volatile essential oils: Limonene, linalool, geraniol, and citral

These nutrients and plant compounds are responsible for the unique health benefits of lime peel.

Rich in Antioxidants

Lime peel is loaded with antioxidants, including flavonoids, polyphenols, and vitamin C 3.

Antioxidants help neutralize unstable molecules called free radicals, which can damage your cells if too many accumulate 4.

The main antioxidants in lime peel include:

  • Flavonoids: Hesperidin, eriocitrin, and naringin. These flavonoids possess antioxidant and anti-inflammatory activities 5.
  • Limonoids: Limonin and nomilinic acid. These powerful antioxidants are almost exclusively found in citrus peels 6.
  • Vitamin C: A strong antioxidant that is essential for immune health and collagen production 7.

The combination of flavonoids, limonoids, and vitamin C make lime peel one of the most antioxidant-rich parts of the lime fruit.

May Lower Cholesterol

Adding lime peel to your diet may help lower cholesterol levels and heart disease risk.

In one study, rats fed dietary lime peel extract for 6 weeks had significantly decreased blood cholesterol levels compared to a control group 8.

Researchers believe limonoids like limonin in the lime peel inhibit the activity of an enzyme that synthesizes cholesterol in the liver 9.

Other animal studies observe similar cholesterol-lowering effects, especially at higher doses 10, 11.

Human studies are needed, but research suggests lime peel extract may help lower cholesterol when consumed regularly.

Contains Anticancer Compounds

Lime peel extract has been shown to suppress the growth and spread of certain types of cancer cells in test-tube and animal studies.

For example, one test-tube study found it stopped the spread of human breast and lung cancer cells. Tangeretin and nobiletin, flavonoids present in lime peel, appeared to be responsible for these anti-cancer effects 12.

In another study, naringenin, the main flavonoid in grapefruit peel, blocked the growth of human colon cancer cells in a test-tube. It worked by inducing apoptosis, or programmed cell death 13.

Furthermore, test-tube studies indicate that limonene, a compound in lime peel oil, inhibits tumor growth and stimulates apoptosis in cancer cells such as melanoma, breast, lung, and stomach cancers 14, 15.

While promising, human research is needed before making conclusions.

May Boost Weight Loss

Preliminary evidence suggests lime peel may boost fat burning and help induce weight loss.

The main active compound appears to be polyphenols. In one study, polyphenol-rich lime peel extract prevented weight gain in mice on a high-fat diet. It appeared to work by increasing fat breakdown and suppressing blood sugar spikes 16.

Human research is limited, but results are also promising.

In a 4-week study in 17 obese people, taking lime peel extract significantly reduced body weight and body fat compared to a placebo group 17.

What’s more, 100 grams of lime peel provides over 12 grams of fiber, which can promote weight loss by slowing digestion and increasing fullness 18.

Overall, lime peel is rich in polyphenols and fiber that may induce weight loss seen in animal and human studies, but more extensive research is needed.

May Improve Heart Health

Lime peel may protect heart health in several ways. As discussed, it may reduce blood cholesterol levels and help prevent weight gain — two major factors for heart disease.

Test-tube and animal studies indicate citrus flavonoids can also help 19:

  • Reduce inflammation
  • Decrease blood pressure
  • Improve artery function
  • Inhibit platelet aggregation involved in clot formation

Further, a recent study in over 500,000 people linked higher intakes of flavonoids to a lower risk of heart disease. While citrus fruits and juices were included, the effects of citrus peels were not specifically examined 20.

Lime peel may promote heart health by reducing risk factors like cholesterol and inflammation. However, human studies on lime peel itself are needed.

May Reduce Kidney Stone Risk

Citrus peels may help prevent kidney stones from forming.

Kidney stones develop when small mineral crystals clump together in concentrated urine. They can grow large enough to cause severe pain and block urine flow 21.

Several rat studies show that citrus peel extracts help prevent calcium oxalate kidney stones from forming 22, 23.

Researchers believe citrus bioflavonoids like naringenin bind to stone-forming minerals and inhibit the growth of crystals 24. Other beneficial compounds in citrus peel, such as limonin, may also contribute to these effects 25.

While lime peel’s specific effects on kidney stones are unknown, it contains many of the same beneficial plant compounds as other citrus peels. More research is needed, but lime peel may aid in preventing this painful condition.

May Have Antimicrobial Properties

Lime peel may have powerful antimicrobial properties. Test-tube studies indicate its essential oils and organic compounds inhibit the growth of a variety of bacteria, viruses, and fungi 26.

For example, one test-tube study found lime peel essential oil killed or suppressed E. coli, S. Enteritidis, and shigella — bacteria that can cause foodborne illness 27.

Citrus flavonoids like hesperidin and flavones are thought to be responsible for the antibacterial effects 28.

Another test-tube study showed that lime peel extract combatted oral pathogens that contribute to cavities and gum disease 29.

Research in humans is limited, but regularly including lime zest in your diet could provide antimicrobial benefits.

May Aid Blood Sugar Control

Lime peel may aid blood sugar management in people with diabetes.

Human and animal studies indicate it may:

  • Improve insulin sensitivity
  • Suppress blood sugar spikes
  • Increase glucose uptake in muscle cells

For example, one study in rats with diabetes found that dried lime peel extract for 4 weeks decreased blood glucose by 64–71%, compared to vitamin C only decreasing it by 48–51% 30.

The combination of plant compounds in lime peel appears to be responsible for these effects, especially flavonoids like hesperidin 31.

Furthermore, a recent human study found that taking 1,500 mg of orange peel extract per day for 4 weeks reduced blood insulin levels in 17 obese people, compared to a placebo. This implied benefits for insulin sensitivity 32.

While promising, human research on lime peel and blood sugar management is lacking.

Other Potential Benefits

Here are other potential health benefits of lime peel:

  • May improve artery function. Rat studies show lime juice and peel relax blood vessels and improve artery blood flow and flexibility 33.
  • May relieve heartburn. Citrus peels may provide relief from acid reflux and heartburn symptoms by improving the function of muscles in the food pipe 34.
  • May promote wound healing. Test-tube studies indicate constituents in lime peel, especially limonene, stimulate skin cell production and collagen synthesis 35.
  • May strengthen immunity. The vitamin C content in lime peel boosts white blood cell function and immunity 36.
  • May benefit skin health. Applying diluted lime essential oil has been shown to protect skin from sun damage in human research 37.

Despite promising test-tube and animal studies, human research is lacking.

Adverse Effects and Precautions

Lime peel is considered very healthy and non-toxic at typical culinary doses, but you should take precautions:

  • Contact dermatitis (skin irritation) has occurred from applying undiluted lime oil directly to the skin 38.
  • While safe at low doses, extremely high oral doses of lime peel may cause stomach upset or toxicity 39.
  • Lime juice and peel may make your skin more sensitive to UV radiation. Be sure to use sun protection if applying lime to your skin 40.
  • If taking medications or supplements that interact with citrus, check with a healthcare professional before consuming lime peel 41.

Unless you have a specific sensitivity, lime peel is safe to consume in normal food amounts. But very high doses from concentrated extracts could potentially cause side effects.

How to Add It to Your Diet

Here are simple ways to add lime peel to your meals:

  • Add grated lime zest to guacamole, dips, salad dressings, marinades, baked goods, and yogurt.
  • Mix lime zest into your favorite smoothie or cold juice.
  • Bake fish with lime slices or zest on top.
  • Add lime peel powder to spices when making meat or vegetable dishes.
  • Use a zester or grater to add lime zest to oatmeal or overnight oats.
  • Dry excess lime peels to make a zesty seasoning powder.

The zesty flavor of lime peel pairs well with seafood, chicken, vegetables, smoothies, dips, dressings, baked goods, and more.

The Bottom Line

Lime peel is low in calories and rich in vitamin C, antioxidants, and fiber.

It contains unique plant compounds, such as naringenin, nobiletin, and limonin, that may provide anti-cancer, weight loss, cholesterol-lowering and other benefits.

At the same time, lime peel is considered very safe and can easily be added to various dishes to give them a nutritional boost.

While results from lab and animal studies are promising, human research into the specific effects of lime peel is needed.

Overall, lime peel makes an excellent addition to a healthy diet.

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