Squash, winter

This week we celebrate winter squash as our Food of the Week while it is in the peak of its season, has the best flavor and is the least expensive. Winter squash is one of the richest sources of plant based anti-inflammatory nutrients such as omega 3s and beta-carotene, which are important for a strong immune system to help protect against colds and flu. For more on the Food of the Week More About Winter Squash From Our Newsletter Cubed Buttenut Squash Why is the food of the week among the WHFoods?"> Healthy Eating with the Seasons What's New and Beneficial about Winter Squash Although winter squash has long been recognized as an important food source of carotenoids, only recently have research studies documented just how fantastic winter squash can be when it comes to these key antioxidants. For some groups of study participants, winter squash turns out to be the primary food source of alpha-carotene and beta-carotene in the entire diet! For lutein, zeaxanthin, and beta-cryptoxanthin (three other health-supportive carotenoids) winter squash also comes out among the top three food sources in several studies. Seeds from winter squash make a great snack food, just like pumpkin seeds. If you scoop the pulp and seeds from inside the squash and separate out the seeds, you can place them in a single layer on a cookie sheet and lightly roast them at 160-170°F (about 75°C) in the oven for 15-20 minutes. By roasting them for a relatively short time at a low temperature you can help minimize damage to their healthy oils. Linoleic acid (the polyunsaturated omega-6 fatty acid) and oleic acid (the same monounsaturated fatty acid that is plentiful in olive oil) account for about 75% of the fat found in the seeds. We think about winter squash as a very starchy vegetable—about 90% of its total calories come from carbohydrate, and about half of this carbohydrate is starch-like in its composition. However, recent research has made it clear that all starch is not the same, and the starch content of winter squash brings along with it some key health benefits. Many of the carbs in winter starch come from polysaccharides found in the cell walls. These polysaccharides include pectins—specially structured polysaccharides that in winter squash often include special chains of D-galacturonic acid called homogalacturonan. An increasing number of animal studies now show that these starch-related components in winter squash have antioxidant, anti-inflammatory, as well as anti-diabetic and insulin-regulating properties. Winter squash is a vegetable that might be especially important for us to purchase organic. Recent agricultural trials have shown that winter squash can be an effective intercrop for use in remediation of contaminated soils. Polycyclic aromatic hydrocarbons (PAHs), including pyrene, fluoranthene, chrysene, benzo(a)anthracene and benzo(a)pyrene are unwanted contaminants. PAHs are among the contaminants that can be effectively pulled up out of the soil by winter squash plants. When winter squash is planted as a food crop (as opposed to a non-food crop that is being planted between food crop seasons to help improve soil quality), the farmer's goal is definitely not to transfer soil contaminants like PAHs up into the food. But some of that transfer seems likely to happen, given the effectiveness of winter squash in mobilizing contaminants like PAHs from the soil. For this reason, you may want to make a special point of purchasing certified organic winter squash. Soils used for the growing of in certified organic foods are far less likely to contain undesirable levels of contaminants like PAHs. WHFoods Recommendations Our favorite way to prepare winter squash is to steam it as it takes such a short period of time. It's best to steam 1-inch cubes of squash. The preparation for this is described in the How to Enjoy section below. For most types of squash you only need to steam it for 7 minutes. So you save time and enjoy a host of more nutrients.

This chart graphically details the %DV that a serving of Squash, winter provides for each of the nutrients of which it is a good, very good, or excellent source according to our Food Rating System. Additional information about the amount of these nutrients provided by Squash, winter can be found in the Food Rating System Chart. A link that takes you to the In-Depth Nutritional Profile for Squash, winter, featuring information over 80 nutrients, can be found under the Food Rating System Chart.

• Health Benefits
• Description
• History
• How to Select and Store
• Tips for Preparing and Cooking
• How to Enjoy
• Individual Concerns
• Nutritional Profile
• References

Health Benefits

Antioxidant Support

While we've become accustomed to thinking about leafy vegetables as an outstanding source of antioxidants, we've been slower to recognize the outstanding antioxidant benefits provided by other vegetables like winter squash. But we need to catch up with the times! Recent research has made it clear just how important winter squash is worldwide to antioxidant intake, especially so in the case of carotenoid antioxidants. From South America to Africa to India and Asia and even in some parts of the United States, no single food provides a greater percentage of certain carotenoids than winter squash. (In the United States, a recent study that has determined winter squash to be the number one source of alpha-carotene and beta-carotene among Hispanic men ages 60 and older living within the state off Massachusetts. And we've seen studies ranking foods from this Cucurbita genus at the top of the carotenoid list in Cameroon, Sri Lanka, and the West Indies!)

The unique carotenoid content of the winter squashes is not their only claim to fame in the antioxidant department, however. There is a very good amount of vitamin C in winter squash (about one-third of the Daily Value in every cup) and a very good amount of the antioxidant mineral manganese as well. Recent research has shown that the cell wall polysaccharides found in winter squash also possess antioxidant properties, as do some of their phenolic phytonutrients.

Anti-Inflammatory Benefits

Most of the research to date on winter squash and inflammation has either been conducted using laboratory animals, or has been focused on laboratory studies of cell activity. Still, results in this area have been fascinating and also promising with respect to winter squash as an anti-inflammatory food. In some of the more detailed studies, specific inflammation-related molecules, enzymes, or cell receptors (for example, nuclear factor kappa-B, nitric oxide synthase, or cyclo-oxygenase) have been studied as targets for the activity of the cucurbitacin molecules found in winter squash. Cucurbitacins are glycoside molecules found in a wide variety of foods, including the brassica vegetables, some mushrooms, and even some ocean mollusks. But they are named for the gourd-squash-melon family of foods (Cucurbitaceae) due to their initial discovery in this food family. Cucurbitacins can be extremely bitter tasting to animals as well as humans, and they are considered to be part of the plants' natural defense mechanisms. Yet the same properties that make cucurbitacins potentially toxic to some animals and microorganisms also make them effective as anti-viral, anti-bacterial, and anti-inflammatory substances when we consume them in winter squash.

While winter squash should not be treated as a high-fat food, it does contain fats, including the anti-inflammatory omega-3s. One cup of baked winter squash will provide you with approximately 340 milligrams of omega-3 fats in the form of alpha-linolenic acid (ALA). While that amount is only about one-third as high as the concentration of ALA found in the "best of the best" omega-3 plant foods like walnuts, it is still a valuable amount being provided by a low-fat food. (Less than 15% of the calories in winter squash come from fat, compared with almost 90% of the calories in walnuts!). With winter squash, we have a fantastic anti-inflammatory food opportunity in which we can get a valuable amount of our anti-inflammatory omega-3s without much of a change in our total fat intake.

Promotes Optimal Health

It's the combination of antioxidant and anti-inflammatory compounds in winter squash that have shown this food to have clear potential in the area of cancer prevention and cancer treatment. Prostate cancer is the cancer type that has been of greatest research interest in this regard, followed by colon cancer, breast cancer, and lung cancer. We have yet to see cancer-related studies that involve everyday amounts of winter squash consumed in food form. Most of the studies in this area have involved extracts from foods in the Cucurbita genus, or isolated, purified substances (like cucurbitans) that can be obtained from those foods. Still, given the clear antioxidant and anti-inflammatory benefits of winter squash, we expect to see cancer studies in humans eventually identifying this food as a risk reducer for certain cancer types.

Potential Blood Sugar Regulation Benefits

A second area of high potential for winter squash and its health benefits is blood sugar regulation and prevention of type 2 diabetes. We've already seen evidence in animal studies that show improvement in blood sugar and insulin regulation following intake of cell wall polysaccharides from winter squash and other Cucurbita foods. Likewise, we've seen research pointing to other nutrients found in winter squash as beneficial for blood sugar control. These nutrients include the B-vitamin like compound d-chiro-inositol—a nutrient we expect to see moving up on the radar screen with respect to blood sugar regulation. It's also important to remember that blood sugar regulation is closely tied to our overall supply of B-complex vitamins, and that winter squash is unusual in its B-vitamin composition. This food provides a good amount of five B-complex vitamins! Those vitamins are B1, B3, B6, pantothenic acid, and folate.

Other Health Benefits

Finally, we believe that future research may underscore the health benefits provided by winter squash for prevention of cardiovascular disease. We already know that this food provides key antioxidant and anti-inflammatory benefits—two categories of nutrient support critically needed for reduced risk of most cardiovascular problems. But we also have preliminary evidence to suggest that there may be unique substances in the Cucurbita vegetables that partially block the formation of cholesterol in our cells by inhibiting an enzyme called HMG-CoA reductase. Coupled with its unique antioxidant and anti-inflammatory composition, winter squash may turn out to be particularly important food for inclusion in a heart healthy diet.

Description

Winter squash, members of the Cucurbitaceae family and relatives of both the melon and the cucumber, come in many different varieties. While each type varies in shape, color, size and flavor, they all share some common characteristics. Their shells are hard and difficult to pierce, enabling them to have long storage periods between one week and six months. Their flesh is mildly sweet in flavor and finely grained in texture. Additionally, all have seed-containing hollow inner cavities.

We are just beginning to discover the wealth of nourishment supplied by the mildly sweet flavored and finely textured winter squash, a vegetable that was once such an important part of the diet of the Native Americans that they buried it along with the dead to provide them nourishment on their final journey. Winter squash is available from August through March; however, they are at their best from October to November when they are in season.

The list presented below will give you more details about the fascinating food family of Cucurbitaceae. Here you can see the foods that are relatives of winter squash:

Cucurbitaceae Food Family

Cucurbita Genus

• winter squashes
• summer squashes

Cucumis Genus

• cucumbers
• casaba melons
• Crenshaw melons
• honeydew melons
• muskmelon

Citrullus Genus

• watermelon
• bitter apple

As noted in the lists above, both winter squashes and summer squashes can be found within the Cucurbita genus of this food family. Here are some key food species—including varieties of winter squash—that you'll find in this amazing Cucurbita genus of foods: Cucurbita Genus and Species of Foods (including Winter Squash varieties)

Cucurbita pepo* (variety melopepo)	Cucurbita pepo (variety pepo)	Cucurbita maxima	Cucurbita moschata	Cucurbita argyosperma*
zucchini (summer variety)	acorn squash (winter variety)	buttercup squash (winter variety)	butternut squash (winter variety)	cushaw squash (summer variety)
yellow crooknook squash (summer variety)	delicata squash (winter variety)	Hubbard squash (winter variety)	winter crookneck squash	cushaw squash
scallop squash (summer variety)	spaghetti squash (winter variety)	banana squash (winter variety)
		Boston marrow squash (winter variety)
		Turk's turban squash (winter variety)

As presented in the chart above, common varieties of winter squash include:

• Butternut squash: Shaped like a large pear, this squash has cream-colored skin, deep orange-colored flesh and a sweet flavor.
• Acorn squash: With harvest green skin speckled with orange patches and pale yellow-orange flesh, this squash has a unique flavor that is a combination of sweet, nutty and peppery.
• Hubbard squash: A larger-sized squash that can be dark green, grey-blue or orange-red in color. The Hubbard's flavor is less sweet than many other varieties.
• Turban squash: Green in color and either speckled or striped, this winter squash has an orange-yellow flesh whose taste is reminiscent of hazelnuts.
• Kabocha squash: A type of Japanese squash that is becoming more and more popular in the U.S., kabocha squash is very sweet in flavor. It has deep green skin and orange flesh.

Pumpkins are also members of the Cucurbitaceae food family, and also within the Cucurbita genus of these amazing foods. However, the word "pumpkin" can be confusing and it is used in different countries in different ways. In Australia, for example, the word "pumpkin" is often used to refer to the same category of foods that are called "winter squashes" in the United States. Since there are literally hundreds of pumpkin varieties grown worldwide, and since there are pumpkin varieties that can be found within each of the Cucurbita species presented in the chart above, pumpkins can be confusing from a botanical standpoint. Additionally, they are not always easy to categorize within a "summer versus winter" classification system (even though they are generally a warm weather crop). Pumpkins are not the least bit confusing, however, from a taste and texture standpoint! These delicious foods can be amazingly sweet tasting (as is the case with sugar pumpkin, also sometimes called pie pumpkin), and they are among the most versatile members of this entire gourd-squash-melon food family.

History

Modern day squash developed from the wild squash that originated in an area between Guatemala and Mexico. While squash has been consumed for over 10,000 years, they were first cultivated specifically for their seeds since earlier squash did not contain much flesh, and what they did contain was very bitter and unpalatable. As time progressed, squash cultivation spread throughout the Americas, and varieties with a greater quantity of sweeter-tasting flesh were developed. Christopher Columbus brought squash back to Europe from the New World, and like many other native American foods, their cultivation was introduced throughout the world by Portuguese and Spanish explorers. Today, the largest commercial producers of squash include China, Japan, Romania, Turkey, Italy, Egypt, and Argentina.

How to Select and Store

Winter squash is easily prone to decay, so it is important to carefully inspect it before purchase. Choose ones that are firm, heavy for their size and have dull, not glossy, rinds. The rind should be hard as soft rinds may indicate that the squash is watery and lacking in flavor. Avoid those with any signs of decay, which manifest as areas that are water-soaked or moldy.

Winter squash has a much longer storage life than summer squash. Depending upon the variety, it can be kept for between one week to six months. It should be kept away from direct exposure to light and should not be subject to extreme heat or extreme cold. The ideal temperature for storing winter squash is between 50-60°F (about 10-15°C). Once it is cut, cover the pieces of winter squash in plastic wrap and store them in the refrigerator, where they will keep for one or two days. The best way to freeze winter squash is to first cut it into pieces of suitable size for individual recipes.

Tips for Preparing and Cooking

Tips for Preparing Winter Squash

Rinse winter squash under cold running water before cutting.

All varieties of winter squash require peeling for steaming except Kabocha and butternut squash. You can peel winter squash with a potato peeler or knife.

Butternut squash has a unique shape that requires a special approach to cutting. To cut into cubes, it is best to first cut it in half between the neck and bulb. This makes peeling it much easier. Cut bulb in half and scoop out seeds. Slice into 1-inch slices and make 1-inch cuts across slices for 1-inch cubes. This is the best size and shape for steaming.

If you are baking your squash you don't have to peel it. Cut the ends off, cut the squash in half lengthwise down the middle, scoop out the seeds and bake. Alternatively you can leave the squash whole, pierce a few times with a fork or tip of a paring knife, bake and scoop out the seeds after it has been cooked. You can peel cooked squash easily with a knife and then cut into pieces of desired size.

Save those seeds that you scooped out! Seeds from winter squash can make a great snack food, and can be prepared in the same way as pumpkin seeds. Once scooped out from inside the squash and separated from the pulp, you can place the seeds in a single layer on a cookie sheet and lightly roast them at 160-170°F (about 75°C) in the oven for 15-20 minutes. By roasting them for a relatively short time at a low temperature you can help minimize damage to their healthy oils. Linoleic acid (the polyunsaturated omega-6 fatty acid) and oleic acid (the same monounsaturated fatty acid that is plentiful in olive oil) account for about 75% of the fat found in the seeds.

The Healthiest Way of Cooking Winter Squash

Our favorite way to prepare winter squash is to steam it as it takes such a short period of time. It's best to steam 1-inch cubes of squash. The preparation for this is described above. For most types of squash you only need to steam it for 7 minutes.

How to Enjoy

A Few Quick Serving Ideas

• Top puréed cooked winter squash with cinnamon and maple syrup.
• Steam cubes of winter squash and then dress with olive oil, soy sauce, ginger and pumpkin seeds.
• Top "strings" of spaghetti squash with pasta sauce.
• Add cubes of winter squash to your favorite vegetable soup recipe.

WHFoods Recipes That Feature Winter Squash

• 7-Minute Butternut Squash
• Braised Red Curry Lamb & Vegetables
• Golden Squash Soup
• Steamed Butternut Squash with Almond Sauce
• Steamed Butternut Squash with Red Chili Sauce

Individual Concerns

Winter squash is not a commonly allergenic food, is not known to contain measurable amounts of oxalates or purines and is also not included in the Environmental Working Group's 2010 report "Shopper's Guide to Pesticides" as one of the 12 foods most frequently containing pesticide residues.

Nutritional Profile

The amazing phytonutrient content of winter squash makes us realize that this food is not just a starchy vegetable. Carotenoids found in winter squash include alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein, and zeaxanthin. Pectin-containing cell wall polysaccharides found in winter squash are important anti-inflammatory nutrients provided by this food, as are its cucurbitacins (triterpene molecules). Winter squash is an excellent source of immune-supportive vitamin A (in its "previtamin" carotenoid forms) and free radical-scavenging vitamin C. It is also a very good source of vitamin C, dietary fiber, vitamin B6, manganese, and copper as well as a good source of potassium, vitamin B2, folate, vitamin K, pantothenic acid, omega-3 fatty acids, magnesium, and niacin.

For an in-depth nutritional profile click here: Winter squash.

In-Depth Nutritional Profile

In addition to the nutrients highlighted in our ratings chart, an in-depth nutritional profile for Squash, winter 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." Read more background information and details of our rating system.

In-Depth Nutritional Profile for Squash, winter

References

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• Much grattidtude to George Mateljan,and the George Mateljan Foundation for www.whfoods.com