What's New and Beneficial About Pumpkin seeds
• Pumpkin seeds have long been valued as a source of the mineral zinc, and the World Health Organization recommends their consumption as a good way of obtaining this nutrient. If you want to maximize the amount of zinc that you will be getting from your pumpkin seeds, we recommend that you consider purchasing them in unshelled form. Although recent studies have shown there to be little zinc in the shell itself (the shell is also called the seed coat or husk), there is a very thin layer directly beneath the shell called the endosperm envelope, and it is often pressed up very tightly against the shell. Zinc is especially concentrated in this endosperm envelope. Because it can be tricky to separate the endosperm envelope from the shell, eating the entire pumpkin seed—shell and all—will ensure that all of the zinc-containing portions of the seed will be consumed. Whole roasted, unshelled pumpkin seeds contain about 10 milligrams of zinc per 3.5 ounces, and shelled roasted pumpkin seeds (which are often referred to pumpkin seed kernels) contain about 7-8 milligrams. So even though the difference is not huge, and even though the seed kernels remain a good source of zinc, you'll be able to increase your zinc intake if you consume the unshelled version.
• While pumpkin seeds are not a highly rich source of vitamin E in the form of alpha-tocopherol, recent studies have shown that pumpkin seeds provide us with vitamin E in a wide diversity of forms. From any fixed amount of a vitamin, we are likely to get more health benefits when we are provided with that vitamin in all of its different forms. In the case of pumpkin seeds, vitamin E is found in all of the following forms: alpha-tocopherol, gamma-tocopherol, delta-tocopherol, alpha-tocomonoenol, and gamma-tocomonoenol. These last two forms have only recently been discovered in pumpkin seeds, and their health benefits—including antioxidant benefits—are a topic of current interest in vitamin E research, since their bioavailability might be greater than some of the other vitamin E forms. The bottom line: pumpkin seeds' vitamin E content may bring us more health benefits that we would ordinarily expect due to the diverse forms of vitamin E found in this food.
• In our Tips for Preparing section, we recommend a roasting time for pumpkin seeds of no more than 15-20 minutes when roasting at home. This recommendation supported by a new study that pinpointed 20 minutes as a threshold time for changes in pumpkin seed fats. In this recent study, pumpkin seeds were roasted in a microwave oven for varying lengths of time, and limited changes in the pumpkin seeds fat were determined to occur under 20 minutes. However, when the seeds were roasted for longer than 20 minutes, a number of unwanted changes in fat structure were determined to occur more frequently.
While antioxidant nutrients are found in most WHFoods, it's the diversity of antioxidants in pumpkin seeds that makes them unique in their antioxidant support. Pumpkin seeds contain conventional antioxidant vitamins like vitamin E. However, not only do they contain vitamin E, but they contain it in a wide variety of forms. Alpha-tocopherol, gamma-tocopherol, delta-tocopherol, alpha-tocomonoenol and gamma-tocomonoenol are all forms of vitamin E found in pumpkin seeds. These last two forms have only recently been discovered, and they are a topic of special interest in vitamin E research, since their bioavailability might be greater than some of the other vitamin E forms. Pumpkin seeds also contain conventional mineral antioxidants like zinc and manganese. Phenolic antioxidants are found in pumpkin seeds in a wide variety of forms, including the phenolic acids hydroxybenzoic, caffeic, coumaric, ferulic, sinapic, protocatechuic, vanillic, and syringic acid. Antioxidant phytonutrients like lignans are also found in pumpkin seeds, including the lignans pinoresinol, medioresinol, and lariciresinol.
Interestingly, this diverse mixture of antioxidants in pumpkin seeds may provide them with antioxidant-related properties that are not widely found in food. For example, the pro-oxidant enzyme lipoxygenase (LOX) is known to be inhibited by pumpkin seed extracts, but not due to the presence of any single family of antioxidant nutrients (for example, the phenolic acids described earlier). Instead, the unique diversity of antioxidants in pumpkin seeds is most likely responsible for this effect.
Plants that have a close relationship to the soil are often special sources of mineral nutrients, and pumpkin (and their seeds) are no exception. Our food rating process found pumpkin seeds to be a very good source of the minerals phosphorus, magnesium, manganese, and copper and a good source of the minerals zinc and iron.
Pumpkin seeds have long been valued as a special source of the mineral zinc, and the World Health Organization recommends their consumption as a good way of obtaining this nutrient. To get full zinc benefits from your pumpkin seeds, you may want to consume them in unshelled form. Although recent studies have shown there to be little zinc in the shell itself (the shell is also called the seed coat or husk), there is a very thin layer directly beneath the shell called the endosperm envelope, and it is often pressed up very tightly against the seed coat. Zinc is especially concentrated in this endosperm envelope. Because it can be tricky to separate the endosperm envelope from the shell, eating the entire pumpkin seed—shell and all—will ensure that all zinc-containing portions of the seed get consumed. Whole roasted, unshelled pumpkin seeds contain about 10 milligrams of zinc per 3.5 ounces, and shelled roasted pumpkin seeds (sometimes called pumpkin seed kernels) contain about 7-8 milligrams. So even though the difference is not huge, and even though the kernels still remain a good source of zinc, the unshelled version of this food is going to provide you with the best mineral support with respect to zinc.
Other Health Benefits
Most of the evidence we've seen about pumpkin seeds and prevention or treatment of diabetes has come from animal studies. For this reason, we consider research in this area to be preliminary. However, recent studies on laboratory animals have shown the ability of ground pumpkin seeds, pumpkin seed extracts, and pumpkin seed oil to improve insulin regulation in diabetic animals and to prevent some unwanted consequences of diabetes on kidney function. Decrease in oxidative stress has played a key role in many studies that show benefits of pumpkin seeds for diabetic animals.
Pumpkin seeds, pumpkin seed extracts, and pumpkin seed oil have long been valued for their anti-microbial benefits, including their anti-fungal and anti-viral properties. Research points to the role of unique proteins in pumpkin seeds as the source of many antimicrobial benefits. The lignans in pumpkin seeds (including pinoresinol, medioresinol, and lariciresinol) have also been shown to have antimicrobial—and especially anti-viral— properties. Impact of pumpkin seed proteins and pumpkin seed phytonutrients like lignans on the activity of a messaging molecule called interferon gamma (IFN-gamma) is likely to be involved in the antimicrobial benefits associated with this food.
Because oxidative stress is known to play a role in the development of some cancers, and pumpkin seeds are unique in their composition of antioxidant nutrients, it's not surprising to find some preliminary evidence of decreased cancer risk in association with pumpkin seed intake. However, the antioxidant content of pumpkin seeds has not been the focus of preliminary research in this cancer area. Instead, the research has focused on lignans. Only breast cancer and prostate cancer seem to have received much attention in the research world in connection with pumpkin seed intake, and much of that attention has been limited to the lignan content of pumpkin seeds. To some extent, this same focus on lignans has occurred in research on prostate cancer as well. For these reasons, we cannot describe the cancer-related benefits of pumpkin seeds as being well-documented in the research, even though pumpkin seeds may eventually be shown to have important health benefits in this area.
Possible Benefits for Benign Prostatic Hyperplasia (BPH)
Pumpkin seed extracts and oils have long been used in treatment of Benign Prostatic Hyperplasia (BPH). BPH is a health problem involving non-cancer enlargement of the prostate gland, and it commonly affects middle-aged and older men in the U.S. Studies have linked different nutrients in pumpkin seeds to their beneficial effects on BPH, including their phytosterols, lignans, and zinc. Among these groups, research on phytosterols is the strongest, and it centers on three phytosterols found in pumpkin seeds: beta-sitosterol, sitostanol, and avenasterol. The phytosterols campesterol, stigmasterol, and campestanol have also been found in pumpkin seeds in some studies. Unfortunately, studies on BPH have typically involved extracts or oils rather than pumpkin seeds themselves. For this reason, it's just not possible to tell whether everyday intake of pumpkin seeds in food form has a beneficial impact on BPH. Equally impossible to determine is whether intake of pumpkin seeds in food form can lower a man's risk of BPH. We look forward to future studies that will hopefully provide us with answers to those questions.
Pumpkin seeds—also known as pepitas—are flat, dark green seeds. Some are encased in a yellow-white husk (often called the "shell"), although some varieties of pumpkins produce seeds without shells. Pumpkin seeds have a malleable, chewy texture and a subtly sweet, nutty flavor. While roasted pumpkins seeds are probably best known for their role as a perennial Halloween treat, these seeds are so delicious, and nutritious, that they can be enjoyed throughout the year. In many food markets, pepitas are available in all of the forms described above—raw and shelled, raw and unshelled, roasted and shelled, roasted and unshelled.
Like cantaloupe, watermelon, cucumber, and squash, pumpkins and pumpkin seeds belong to the gourd or Cucurbitaceae family. Within this family, the genus Cucurbita contains all of the pumpkins (and their seeds). The most common species of pumpkin used as a source of pumpkin seeds are Cucurbita pepo, Cucurbita maxima, Cucurbita moschata, and Cucurbita mixta.
Pumpkins, and their seeds, are native to the Americas, and indigenous species are found across North America, South America, and Central America. The word "pepita" is consistent with this heritage, since it comes from Mexico, where the Spanish phrase "pepita de calabaza" means "little seed of squash."
Pumpkin seeds were a celebrated food among many Native American tribes, who treasured them both for their dietary and medicinal properties. In South America, the popularity of pumpkin seeds has been traced at least as far back as the Aztec cultures of 1300-1500 AD. From the Americas, the popularity of pumpkin seeds spread to the rest of the globe through trade and exploration over many centuries. In parts of Eastern Europe and the Mediterranean (especially Greece), pumpkin seeds became a standard part of everyday cuisine, and culinary and medical traditions in India and other parts of Asia also incorporated this food into a place of importance.
Today, China produces more pumpkins and pumpkin seeds than any other country. India, Russia, the Ukraine, Mexico, and the U.S. are also major producers of pumpkin and pumpkin seeds. In the U.S., Illinois is the largest producer of pumpkins, followed by California, Ohio, Pennsylvania, Michigan, and New York. However, pumpkins are now grown commercially in virtually all U.S. states, and over 100,000 acres of U.S. farmland are planted with pumpkins.
How to Select and Store
Pumpkin seeds are generally available in prepackaged containers as well as bulk bins. Just as with any other food that you may purchase in the bulk section, make sure that the bins containing the pumpkin seeds are covered and that the store has a good product turnover so as to ensure the seeds' maximal freshness. Whether purchasing pumpkin seeds in bulk or in a packaged container, make sure that there is no evidence of moisture or insect damage and that they are not shriveled. If it is possible to smell the pumpkin seeds, do so in order to ensure that they are not rancid or musty.
We recommend that you purchase certified organic raw pumpkin seeds and then light-roast them yourself (see next section on how to do so). By purchasing organic, you will avoid unnecessary exposure to potential contaminants. By purchasing raw, you will be able to control the roasting time and temperature, and avoid unnecessary damage to helpful fats present in the seeds. At the same time, you will be able to bring out the full flavors of the pumpkin seeds through roasting.
Pumpkin seeds should be stored in an airtight container in the refrigerator. While they may stay edible for several months, they seem to lose their peak freshness after about one to two months.
Tips for Preparing and Cooking
Tips for Preparing Pumpkin Seeds
While most stores sell pumpkin seeds, it is fun and easy to make your own. To do so, first remove the seeds from the pumpkin's inner cavity and wipe them off with a paper towel if needed to remove excess pulp that may have stuck to them. Spread them out evenly on a paper bag and let them dry out overnight.
You can, of course, purchase pumpkin seeds in the store. We would recommend purchasing organic raw pumpkin seeds and then light-roast them yourself.
Place the seeds (whether those you retrieved from the pumpkin or those you bought at the store) in a single layer on a cookie sheet and light roast them in a 160-170°F (about 75°C) oven for 15-20 minutes. This 20-minute roasting limit is important. In a recent study, 20 minutes emerged as a threshold hold time for changes in pumpkin seed fats. When roasted for longer than 20 minutes, a number of unwanted changes in fat structure of pumpkin seeds have been observed by food researchers. Roasting for no longer than 20 minutes will help you avoid these unwanted changes.
Interestingly, studies have shown that roasting temperatures of 194°F (90°C) or higher are often required to bring out the full nut-like aromas and flavors in pumpkin seeds. While we do not question this finding, we believe that the unsaturated fats in pumpkin seeds will be better preserved by roasting at this lower temperature—160-170°F (about 75°C)—and that you will still be delighted by the aromas and flavors of the roasted seeds.
How to Enjoy
A Few Quick Serving Ideas
Pumpkin seeds are not a commonly allergenic food and are not known to contain measurable amounts of oxalates or purines.
Pumpkin seeds contain a wide variety of antioxidant phytonutrients, including the phenolic acids hydroxybenzoic, caffeic, coumaric, ferulic, sinapic, protocatechuic, vanillic, and syringic acid; and the lignans pinoresinol, medioresinol, and lariciresinol. Pumpkins seeds also contain health-supportive phytosterols, including beta-sitosterol, sitostanol, and avenasterol. Pumpkin seeds are a very good source of phosphorus, magnesium, manganese, and copper. They are also a good source of other minerals including zinc and iron. In addition, pumpkin seeds are a good source of protein.
In-Depth Nutritional Profile
In addition to the nutrients highlighted in our ratings chart, an in-depth nutritional profile for Pumpkin seeds is also available. This profile includes information on a full array of nutrients, including carbohydrates, sugar, soluble and insoluble fiber, sodium, vitamins, minerals, fatty acids, amino acids and more.
Introduction to Food Rating System Chart
In order to better help you identify foods that feature a high concentration of nutrients for the calories they contain, we created a Food Rating System. This system allows us to highlight the foods that are especially rich in particular nutrients. The following chart shows the nutrients for which this food is either an excellent, very good, or good source (below the chart you will find a table that explains these qualifications). If a nutrient is not listed in the chart, it does not necessarily mean that the food doesn't contain it. It simply means that the nutrient is not provided in a sufficient amount or concentration to meet our rating criteria. (To view this food's in-depth nutritional profile that includes values for dozens of nutrients - not just the ones rated as excellent, very good, or good - please use the link below the chart.) To read this chart accurately, you'll need to glance up in the top left corner where you will find the name of the food and the serving size we used to calculate the food's nutrient composition. This serving size will tell you how much of the food you need to eat to obtain the amount of nutrients found in the chart. Now, returning to the chart itself, you can look next to the nutrient name in order to find the nutrient amount it offers, the percent Daily Value (DV%) that this amount represents, the nutrient density that we calculated for this food and nutrient, and the rating we established in our rating system. For most of our nutrient ratings, we adopted the government standards for food labeling that are found in the U.S. Food and Drug Administration's "Reference Values for Nutrition Labeling."