Although you might consider cucumbers to be a vegetable, they're actually a fruit and a member of the Cucurbitaceae family, which includes squash and melons. A cool, crispy addition to your summer salad, cucumbers are packed full of vitamins, minerals, fiber and antioxidants. But did you know that most of the nutrients are in the edible cucumber peel? So forgo peeling and get the maximum benefits of cucumber skin nutrition.
Cucumber Skin Benefits
One large cucumber, with peel — 8 1/4 inches long, weighing 300 grams — contains a mere 45 calories. Of the total calories, 83 percent or 10.9 grams come from carbohydrates, 6 percent or 0.3 gram from fat and 11 percent or 2 grams from protein. Cucumbers do not contain cholesterol.
Peeling your cucumber lowers the calories to 34 and decreases some of the carbohydrates and protein but, most important, you lose out on much of the vitamin, mineral and polyphenol content.
Read more: Nutrition in Cucumbers Without the Peel
Vitamins in Cucumber Peel
Cucumbers are a good source of many vitamins, a large portion of those nutrients residing just under the peel. The breakdown of the nutritional content in a large cucumber with peel is:
- Vitamin A: 316 IU or 6 percent daily value (DV)
- Vitamin C: 8.4 milligrams or 14 percent DV
- Vitamin K: 49 milligrams or 62 percent DV
- B Vitamins:
- Thiamine, 5 percent DV
- Riboflavin, 6 percent DV
- Niacin, 1 percent DV
- Vitamin B6, 6 percent DV
- Folate, 5 percent DV
- Pantothenic acid, 8 percent DV
Vitamin A in cucumbers keeps your skin and eyes healthy. You need the antioxidant vitamin C to help your immune system protect you from disease. Vitamin K is known best for its ability to clot blood. The B vitamins provide your body with the energy it needs for the proper functioning of your heart, brain and blood cells.
Mineral Content With Peel
The vast array of essential minerals contained in, or just under, the cucumber skin benefits your body by aiding in all functions of metabolism. One large 8 1/4 inch fruit contains:
- Potassium: 442 milligrams or 13 percent DV
- Manganese: 0.2 milligram or 12 percent DV
- Magnesium: 39 milligrams of 10 percent DV
- Phosphorus: 72 milligrams or 7 percent DV
- Copper: 0.1 milligram or 6 percent DV
- Calcium: 48 milligrams or 5 percent DV
- Iron: 0.8 milligram or 5 percent DV
- Zinc: 0.6 milligram or 4 percent DV
- Selenium: 0.9 microgram or 1 percent DV
If you peel the cucumber, a portion of each mineral is diminished. For example, a peeled cucumber contains:
- 61 milligrams less potassium
- 6 milligrams less magnesium
- 13 milligrams less phosphorus
- 9 milligrams less calcium
Read more: Benefits and Side Effects of Cucumbers
Cucumbers Keep You Hydrated
Cucumbers consist mostly of water — 96 percent, in fact. All the cells, organs and tissues in your body need water to help regulate temperature and carry out bodily functions. Eating cucumbers can help you replace the fluid lost through breathing, sweating and digestion.
Snacking on a sliced cucumber with the peel after your workout is a convenient, nutritious way to replenish your body with the electrolytes it needs to prevent dehydration.
Read more: Dehydration in Sports Performance
Keeps Your Digestive System Working
The water in cucumbers is also helpful to maintain digestive health. Dehydration is often a contributing factor if you have constipation. Without the water content, your stool may be hard and difficult to pass.
Cucumbers contain fiber, much of it in the cucumber peel. Fiber also helps to keep you regular. It is the part of the cucumber that your body cannot digest or absorb, so it adds bulk to your digested food and softens your stool so it can pass smoothly through your digestive system.
By keeping you regular, the fiber in cucumber and its peel may help with irritable bowel syndrome, hemorrhoids, diverticulitis and other gastrointestinal disorders, in addition to possibly reducing the risk of colon cancer.
Helps Control Your Weight
Perfect for your weight-loss plan, cucumbers are low in calories, have very little fat and are low in carbohydrates —10.9 grams per cucumber with the peel; 6 grams without the peel. The carbs in cucumbers are healthy, complex carbs that provide energy for your body. You should aim to eat 45 to 65 percent of your daily calories from carbs or between 225 and 325 grams.
A dietary strategy to reduce calorie intake while controlling hunger was the topic of a CDC research brief that confirmed the positive impact on satiety and body weight of eating low-energy-dense foods. Foods that are highest in water and fiber, such as cucumbers, are low-energy-dense. The review suggested that for the same number of calories, you can consume more food if it's lower in energy density.
Results of another analysis, published in Nutrients in 2016, included 13 trials and 3,628 people to conclude that eating low-energy-dense food is the most effective measure to manage weight when the aim is weight loss.
Read more: How to Calculate Energy From Foods
Keeps Bones Strong
According to the Better Bones Foundation, vitamin K aids in binding calcium to bone matrix, rather like glue, and is necessary for helping to heal bone fractures. Cucumber with its fruit peel provides 65 percent DV, but if you discard the peel, you lose 29 micrograms of vitamin K, which decreases its DV percentage to 25 percent.
Calcium is well-known for its contribution to bone density. A deficiency in calcium may result in low bone mass and the risk of osteoporosis and bone fracture. Eating the cucumber with the peel will provide 9 milligrams more calcium than if you peeled off the skin.
The symbiotic relationship of calcium and vitamin K was shown in a study published in Integrative Medicine: A Clinician's Journal in 2015. The findings reported that an intake of calcium in tandem with vitamin K benefits bone strength and density while circumventing the possibility of risk of heart disease from excessive calcium.
Retains Cognitive Function
Many nutrients in cucumbers are important to healthy aging of the brain and prevention of memory loss, including vitamin C, B vitamins and calcium. In addition, a flavonoid called fisetin, which is responsible for the pigment in cucumbers, has anti-aging and neuroprotective properties.
A study published in EBioMedicine in 2018 found that foods containing fisetin may help you live a longer, healthier life — by as much as 10 percent.
Fisetin, with its anti-inflammatory properties, can cross the blood-brain barrier and protect the brain against age-related neurodegenerative diseases, such as Alzheimer's. A 2013 animal study, published in the journal Aging Cell, showed that fisetin prevented the development of learning and memory deficits and lowered the rate of dementia.
- ITIS Report: Cucurbitaceae
- SELFNutritionData: Cucumber, With Peel, Raw
- SELFNutritionData: Cucumber, Peeled, Raw
- Nutrients: Contribution of Water From Food and Fluids to Total Water Intake: Analysis of a French and UK Population Surveys
- International Foundation for Gastrointestinal Disorders: Dietary Fiber
- Mayo Clinic: Mayo Clinic Q and A: Diet, Lifestyle Choices Can Lower Risk of Diverticulosis Developing Into Diverticulitis
- International Journal of Food Sciences and Nutrition: Dried Fruit and Public Health – What Does the Evidence Tell Us?
- Dietary Guidelines, 2015-2020: Appendix 7. Daily Nutritional Goals for Age-Sex Groups Based on Dietary Reference Intakes and Dietary Guidelines Recommendations
- Mayo Clinic: Carbohydrates: How Carbs Fit Into a Healthy Diet
- National Centers for Chronic Disease Prevention and Health Promotion: Low-Energy-Dense Foods and Weight Management: Cutting Calories While Controlling Hunger
- Nutrients: Link Between Food Energy Density and Body Weight Changes in Obese Adults
- Better Bones Foundation: Key Vitamins for Bone Health — Vitamin K1 and K2
- National Institutes of Health: Office of Dietary Supplements: Calcium
- Integrative Medicine: A Clinician’s Journal: Proper Calcium Use: Vitamin K2 as a Promoter of Bone and Cardiovascular Health
- Mercola: What Are the Benefits of Fisetin?
- EBioMedicine: Fisetin Is a Senotherapeutic That Extends Health and Lifespan
- Aging Cell: Modulation of P25 and Inflammatory Pathways by Fisetin Maintains Cognitive Function in Alzheimer's Disease Transgenic Mice
- Nutrients: Ascorbic Acid and the Brain: Rationale for the Use Against Cognitive Decline
- Nutrients: B Vitamins and the Brain: Mechanisms, Dose and Efficacy—A Review
- Cell Reports: Inhibiting the Mitochondrial Calcium Uniporter During Development Impairs Memory in Adult Drosophila