Nuts + Seeds: Pumpkin Seeds
By Anne Danahy, MS, RDN
Vol. 25 No. 3 P. 16
The Seasonal Treat With Year-Round Health Benefits
Many people think of pumpkin seeds as no more than the remnants of their Halloween jack-o’-lanterns. They either get tossed in the compost pile or roasted for a tasty fall snack. But pumpkin seeds are more than a seasonal treat. Like other edible seeds, they’re a nutritional powerhouse that can—and should—be enjoyed year-round.
History and Botany
Pumpkins are a member of the Cucurbitaceae family, which includes cucumbers, melons, and other types of squash. They’re likely native to Mexico, where archeologists found evidence of pumpkin seeds dating back as far as 7000 to 5550 BC.1
Cultivated pumpkins (Cucurbita pepo) are grown worldwide, but most of those bred for their seeds come from China. After the ripe fruit (yes, pumpkins are technically a fruit) is harvested, the seeds are mechanically separated from the pumpkin flesh to be washed, dried, and roasted. Their white outer shell or hull often is removed, but both the hull and the kernel inside are edible.
Some farmers grow oilseed pumpkins, a shell-less variety first cultivated in Styria, a region in southeast Austria. Through natural mutation, Styrian pumpkins evolved to have an abundance of shell-less seeds but largely inedible flesh. After harvesting the seeds from these pumpkins, farmers often return the flesh to the soil as compost, while the seeds are used whole or pressed for their dark green oil.2
Pumpkin seed kernels sold at supermarkets also are known as pepitas, short for pepita de calabaza, which means “little seed of squash” in Spanish. When roasted, the flat, green, oval-shaped seed kernels have a mild, nutty flavor and are a popular component of traditional diets worldwide.
“Pumpkin seeds have been invaluable sources of nutrition for many civilizations,” says Kelly LeBlanc, MLA, RD, LDN, director of nutrition at Oldways. “They’re nutritious, filling, and easy to carry and store. Plus, they’re a source of many important nutrients, especially heart-healthy fats,” she says.
The seeds are significant in Latin American diets. “Not only are they a popular snack in Mexico but they’re a central ingredient in mole verde, one of the seven classic mole sauces from Oaxaca, Mexico. Pumpkin seeds contribute to its characteristic green color,” LeBlanc says.
“Pumpkin (and other edible squash) seeds also are an important part of the Mediterranean diet,” LeBlanc adds. “Traditional Mediterranean cooks have a knack for using ingredients in their entirety, from seed to stem, which means these seeds may have certainly had a place on Mediterranean tables.”
Pumpkin seeds contain a wide range of micronutrients, including manganese, magnesium, iron, copper, zinc, and vitamin E. And they’re well-known for their healthful fat content, approximately 75% of which comprises mono- and polyunsaturated fatty acids.3 The kernels also are a good source of plant protein, providing all nine essential amino acids, although they’re low in tryptophan and methionine.3,4
Pumpkin seeds are sold as whole (shell and kernel) or as kernels or pepitas (hulled seeds); whole seeds have considerably more fiber than do hulled seeds. According to the USDA, pumpkin seeds in their shell provide 5 g fiber, whereas hulled seeds have 2 g fiber per ounce.5,6 See the table below for a breakdown of pumpkin seeds’ nutrient profile per 1 oz (28 g) serving.
Pumpkin seeds are notable for their flavonoids and phenolic compounds, which have antioxidant and anti-inflammatory properties.3,7 “Interestingly, roasting pumpkin seeds not only makes them taste better but it also increases the content of these health-promoting compounds,” says Laura M. Ali, MS, RDN, LDN, a culinary nutritionist and author of MIND Diet for Two, based in Pittsburgh. citing the fact that roasting the seeds releases bound phenols and flavonoids. Research on the effect of roasting found that the optimal roasting temperature to enhance total phenolics, total flavonoids, and antioxidant activity without degrading their protein is 160˚ C (320˚ F).7
With their wide range of nutrients, pumpkin seeds contribute to a healthful eating pattern, helping to boost beneficial fats, fiber, protein, vitamins, and minerals. Ali emphasizes that they’re higher in protein and fiber than many other seeds, so they make a filling and nutritious snack. Moreover, “allergies [to pumpkin seeds] are infrequent, so they’re safe for most people to eat,” she says. “But because they’re high in fiber, some people may experience gas or bloating if they eat too many.” Ali suggests 1 oz (approximately 1/4 cup) is an appropriate portion size for most people to get the nutrition benefits without problematic digestive side effects.
Medicinal Uses and Potential Health Benefits
Pumpkin seeds have a long history of use in traditional medicine. They’ve been used to treat various conditions, including bladder and prostate complaints, gastritis, enteritis, fevers, headaches, nerve pain, and parasites. The seeds have anti-inflammatory, antimicrobial, and analgesic properties.3,8,9
Most research on the specific health benefits of pumpkin seeds comes from lab and animal studies. Although more research is needed, studies suggest that pumpkin seeds may provide consumers with a wide range of health benefits.3,9
Both pumpkin seeds and their oil contain phytosterols, plant compounds that may help reduce cholesterol levels. Animal studies have found that pumpkin seed powder reduces total cholesterol, LDL cholesterol, and triglycerides while increasing HDL cholesterol.3,9,10
Pumpkin seed oil also has been clinically studied. In one small double-blinded, placebo-controlled study of 35 women, taking 2 g pumpkin seed oil in capsule form daily for 12 weeks increased HDL levels but didn’t significantly affect total or LDL cholesterol. However, researchers noted an improvement in the atherogenic index, suggesting fat from pumpkin seeds may reduce plaque development in the arteries. The researchers also assessed menopause symptoms and noted that the supplements reduced hot flashes, headaches, and joint pain in the participants.11
Both the seeds and oil appear to promote healthy blood pressure levels, although the exact mechanism is unclear. Researchers suggest the seeds’ combination of magnesium, arginine, and polyphenols contributes to improved endothelial function and nitrous oxide production, which relaxes blood vessels and reduces blood pressure.3,9,12
Various compounds in pumpkin seeds appear to have hypoglycemic properties. In rats with diabetes, pumpkin seed powder reduced fasting blood sugar.13,14 With their significant protein and healthful fat content, pumpkin seeds can help attenuate glycemic response when included with a carbohydrate-rich snack or meal.
Pumpkin seeds also may have anticancer benefits. Their flavonoid compounds have antioxidant properties, which may help protect cells against oxidative damage. In lab and rat studies, compounds extracted from pumpkin seeds induced colon cancer cell apoptosis (cell death) and blocked the spread of liver and colon cancer cells.3,9
Some researchers suggest pumpkin seeds possess possible antidepressant properties, potentially due to their tryptophan and magnesium content, which help support healthy neurotransmitter activity in the brain.3 As a tryptophan source, it can be inferred that pumpkin seeds also may help improve sleep quality.
Numerous Ways to Enjoy Pumpkin Seeds
Because of consumers’ ever-increasing interest in foods with functional health benefits, pumpkin seeds have grown in popularity over the past few years; the pumpkin seed market is projected to grow by 13% annually in the next few years.15
Roasted kernels or whole pumpkin seeds with shells are readily available in the snack aisle or where nuts and seeds are sold at the grocery store. You also can find the kernels as a common ingredient in many foods, such as the following:
• granola bars or bagged granola;
• artisan breads, muffins, and other baked goods;
• chips and crackers;
• toppings in premade salads; and
• pumpkin seed butter, a nut-free alternative to nut butters.
LeBlanc recommends using pumpkin seeds like any other nut or seed. They add texture to salads and can be used in healthful, potentially novel foods for clients, such as dukkah, a crumbly Mediterranean nut and seed mixture eaten with bread and olive oil, or served atop fish or chicken. LeBlanc also suggests clients try sikil pak, a Mayan pumpkin seed dip, an accessible recipe that can be found on Oldways’ website.
And, when pumpkins are in season, homemade roasted pumpkin seeds are a treat. Ali recommends the following easy, three-step process:
• Soak cleaned pumpkin seeds in water for 30 minutes, then drain.
• Place the seeds in a large pan of salted water and boil them for 10 minutes. Drain well and toss them with olive oil and seasonings.
• Spread them in a single layer on a sheet pan lined with parchment paper and roast them at 325˚ F until they’re browned, “popping,” and crispy.
The roasted seeds can be stored in an airtight container in the pantry or refrigerator for up to two or three months.
Pumpkin seeds are an excellent alternative or addition to nuts and other seeds, and they deserve a year-round spot in clients’ diets. RDs can suggest them as a healthful snack or ingredient to add some crunch to a salad or other recipe; not only do they satisfy but they also provide a wealth of potential health benefits.
— Anne Danahy, MS, RDN, is a Scottsdale, Arizona–based dietitian and freelance health content writer.
1. Oliveira R. 10 things you probably didn’t know about pumpkins. University of California website. https://www.universityofcalifornia.edu/news/10-things-you-probably-didnt-know-about-pumpkins. Published October 25, 2018. Accessed December 8, 2022.
2. Fruhwirth GO, Hermetter A. Seeds and oil of the Styrian oil pumpkin: components and biological activities. Eur J Lipid Sci Technol. 2007;109(11):1128-1140.
3. Dotto JM, Chacha JS. The potential of pumpkin seeds as a functional food ingredient: a review. Sci Afr. 2020;10:e00575.
4. Alfawaz MA. Chemical composition and oil characteristics of pumpkin (Cucurbita maxima) seed kernels. Food Sci Agric. 2004;2(1):5-18.
5. Seeds, pumpkin and squash seed kernels, roasted, without salt. FoodData Central website. https://fdc.nal.usda.gov/fdc-app.html#/food-details/170557/nutrients. Accessed December 8, 2022.
6. Seeds, pumpkin and squash seeds, whole, roasted, without salt. FoodData Central website. https://fdc.nal.usda.gov/fdc-app.html#/food-details/170188/nutrients. Accessed December 8, 2022.
7. Peng M, Lu D, Liu J, Jiang B, Chen J. Effect of roasting on the antioxidant activity, phenolic composition, and nutritional quality of pumpkin (Cucurbita pepo L.) seeds. Front Nutr. 2021;8:647354.
8. Ratnam N, Vandana, Najibullah M, Ibrahim M. A review on Cucurbita pepo. Int J Pharmacogn Phytochem Res. 2017;9(9):1190-1194.
9. Syed QA, Akram M, Shukat R. Nutritional and therapeutic importance of the pumpkin seeds. Biomed J Sci Tech Res. 2019;21(2):15798-15803.
10. Hussain A, Kausar T, Jamil MA, et al. In vitro role of pumpkin parts as pharma-foods: antihyperglycemic and antihyperlipidemic activities of pumpkin peel, flesh, and seed powders, in alloxan-induced diabetic rats. Int J Food Sci. 2022;2022:4804408.
11. Gossell-Williams M, Hyde C, Hunter T, et al. Improvement in HDL cholesterol in postmenopausal women supplemented with pumpkin seed oil: pilot study. Climacteric. 2011;14(5):558-564.
12. Patel S. Pumpkin (Cucurbita sp.) seeds as nutraceutic: a review on status quo and scopes. Med J Nutr Metab. 2013;6(3):183-189.
13. Adams GG, Imran S, Wang S, et al. The hypoglycemic effect of pumpkin seeds, trigonelline (TRG), nicotinic acid (NA), and d-chiro-inositol (DCI) in controlling glycemic levels in diabetes mellitus. Crit Rev Food Sci Nutr. 2014;54(10):1322-1329.
14. Sharma A, Sharma AK, Chand T, Khardiya M, Yadav KC. Antidiabetic and antihyperlipidemic activity of Cucurbita maxima Duchense (pumpkin) seeds on streptozotocin induced diabetic rats. J Pharmacogn Phytochem. 2013;1(6):108-116.15. Oller S. Pumpkin seeds shift beyond seasonal as their functional qualities shine. Food Dive website. https://www.fooddive.com/news/pumpkin-seeds-shift-beyond-seasonal-as-their-functional-qualities-shine/593902/. Published January 28, 2021. Accessed December 8, 2022.