The delicate flavor, soft shell and creamy white flesh of summer squash is a perfect addition to any summer meal. While especially plentiful in the U.S. marketplace during the summer months, summer squash is actually available through the year. Summer squashes, members of the Cucurbitaceae family and relatives of both the melon and the cucumber, come in many different varieties. While each variety may have a distinct shape, color, size and flavor, all varieties share some common characteristics. Regardless of variety, all parts of summer squash are edible, including the flesh, seeds and skin. Some varieties of squash also produce edible flowers. Unlike winter squash, summer squash are more fragile and cannot be stored for long periods of time unless frozen. For Native Americans, squashes were considered as one of the "three sisters" along with corn (maize) and beans.
As a general rule, summer squash has not been as thoroughly studied from a health benefit standpoint as many of the other World's Healthiest Foods. Much of the research evidence specific to summer squash and its health benefits comes from animal versus human studies, and these research studies often look at squash as an overall food group rather than examining specific benefits from summer (versus winter) squash. However, in spite of these research limitations, there are still well-documented health benefits that are offered to us by summer squash!
No category of health benefits from summer squash is better researched than the category of antioxidant benefits. As an excellent source of manganese and a very good source of vitamin C. summer squash provides us with a great combination of conventional antioxidant nutrients. But it also contains an unusual amount of other antioxidant nutrients, including the carotenoids lutein and zeaxanthin. These antioxidants are especially helpful in antioxidant protection of the eye, including protection against age-related macular degeneration and cataracts. While we often think first about carrots as providing us with antioxidant-related eye health benefits, we also need to start including summer squash in our list of antioxidant-rich foods that can provide us with health benefits in this area.
If properly handled and prepared, summer squash also provides us with special antioxidant advantages in terms of its antioxidant stability. Recent research has confirmed strong retention of antioxidant activity in summer squash after steaming. Research has also confirmed excellent retention of antioxidant activity in summer squash after freezing. These findings mean that the antioxidant benefits of summer squash are available to us under a wide variety of circumstances. We have the option of enjoying raw summer squash, briefly steamed summer squash, and previously frozen summer squash while still coming away with well-documented antioxidant health benefits.
To obtain full antioxidant benefits from summer squash, we need to eat not only the flesh, but also the skin and the seeds. Many valuable antioxidant nutrients are found in those portions of the food, and studies document their importance in the overall antioxidant activity of summer squash. Purchasing organic summer squash is your best way to lower risk of potentially unwanted contaminants (like pesticides) on the skin of this vegetable. While purchasing organic, it's still worthwhile to use a natural bristle brush and gently cleanse the skin of the summer squash under cold running water.
The list of nutrients in summer squash related to healthy blood sugar regulation is a long one. Metabolism of sugar in the body requires ample presence of many B-complex vitamins, and most of these B-complex vitamins are found in valuable amounts in summer squash. Included here are the B-vitamins folate, B6, B1, B2, B3, and choline. Also important in blood sugar metabolism are the minerals zinc and magnesium, as well as omega-3 fatty acids, and all of these nutrients are provided by summer squash.
A mainstay of dietary protection from type 2 diabetes—as well as a key step in food support of diabetes problems—is optimal intake of fiber. Summer squash not only provides a very good amount of dietary fiber at 2.5 grams per cup, but it also provides polysaccharide fibers like pectin that have special benefits for blood sugar regulation. The pectin polysaccharides in summer squash often include chains of D-galacturonic acid called homogalacturonan. An increasing number of animal studies now show that these components in summer squash help keep insulin metabolism and blood sugar levels in balance, and protect against the onset of type 2 diabetes.
While lacking extensive research documentation, there are several other areas of health benefits from summer squash that are definitely worth noting and that may eventually have strong scientific back-up. The first of these areas involves inflammation-related conditions. The presence of omega-3 fats in the seeds of summer squash, the presence of anti-inflammatory carotenoids like lutein, zeaxanthin and beta-carotene, and the presence of anti-inflammatory polysaccharides like homogalacturonan make this vegetable a natural choice for protection against unwanted inflammation. Several preliminary animal studies show potential anti-inflammatory protection from summer squash for the cardiovascular system and also for the GI tract. (Two special areas of digestive tract interest involve anti-inflammatory protection against gastric ulcer and duodenal ulcer.) Insofar as chronic, unwanted inflammation is also a risk factor for development of type 2 diabetes, the anti-inflammatory benefits of summer squash may play an important role in its protection against type 2 diabetes as well.
The seeds of summer squash and oils extracted from its seeds have a long history of use in botanical and folk medicine in two areas. The first area involves the anti-microbial properties of summer squash seeds, and especially their anti-parasitic properties. Interestingly, dried summer squash seeds are still used in some parts of the world for treatment of intestinal tapeworms or other intestinal parasites. We have not seen peer-reviewed studies focusing on the antimicrobial benefits of summer squash seeds, but from our perspective, these benefits are unlikely to come from a food approach to summer squash that includes this vegetable in modest amounts as part of a healthy, whole foods diet. Far more likely these benefits will come from a medicinal approach to summer squash that involves consumption of its dried seeds in non-food amounts or extract of oils from those seeds.
The second area of folk medicine use involves non-cancerous enlargement of the prostate gland known as benign prostatic hyperplasia, or BPH. Seeds of summer squash (and oils from those seeds) have traditionally been used to help lower frequency of urination that is commonly experienced in men diagnosed with BPH. Like the area of anti-microbial benefits, we have not seen peer-reviewed studies focusing on summer squash seeds and their potential benefits in lessening frequency of urination in BPH. But from our perspective, these benefits are also unlikely to come from a food approach to summer squash that includes this vegetable in modest amounts as part of a healthy, whole foods diet. Far more likely these benefits will come from a medicinal approach to summer squash that involves consumption of its dried seeds in non-food amounts or from seed oil extracts.
The combination of antioxidant and anti-inflammatory nutrients in summer squash is a very logical nutrient combination for providing anti-cancer benefits. The development of many cancer types depends on chronic, unwanted oxidative stress that can occur along with poor intake of antioxidant nutrients, and chronic, unwanted inflammation that can occur along with lack of anti-inflammatory nutrients. While we eventually expect to see well-documented anti-cancer benefits from summer squash in large-scale human studies, the anti-cancer research on summer squash is still in a preliminary stage.
Summer squashes belong to the Cucurbitaceae family of plants and are relatives of winter squashes (including pumpkins), melons (including watermelon), and even cucumbers. But summer squashes are typically much more delicate than their fellow Cucurbitaceae, and are more often eaten fresh and shortly after harvest. The list presented below will give you more details about the Cucurbitaceae food family and shows how exactly how summer squashes fit in.
In the United States, you'll generally find three types of summer squash:
For readers interested in the scientific classification of these amazing summer squashes, we've provided a list below that shows basic types of summer and winter squashes and their botanical genus and species:
Cucurbita Genus and Species of Foods (including Summer Squash varieties)
*This genus/species can also be referred to as Cucurbita mixta.
Amazingly, scientists have found squash seeds (from the genus-species Cucurbita pepo, which includes summer squash) preserved in Mexican caves for more than 10,000 years! It was that long ago when domestication of summer squash originated in Mexico and Central America. Cultivation of squashes (including summer squash) quickly became popular in North, Central, and South America, and Native Americans often referred to squashes as one of the "three sisters" alongside of corn (maize) and beans. Squashes were one of the North American foods that Columbus brought back to Spain from North America, and Portuguese and Spanish explorers introduced squashes to many parts of the world.
Commercial production of squash (including summer squash) now takes place on a worldwide basis, and the largest producers of squash including the United States, China, India, and Russia. The Pacific Islands region—including Papua New Guinea, Tonga, French Polynesia, Fiji, Hawaii, and New Zealand—is also an important area for squash production. Total global production of squash measures more than 5 billion metric tons, with over 500,000 acres planted. Florida, California, Georgia and New York are the top squash-growing states in the U.S., producing more than 650 million pounds of squash. The U.S. is also the world's largest importer of squash, importing nearly 300,000 metric tons per year. (Ninety-five percent of U.S. imported squash comes from Mexico.)
When purchasing summer squash, look for ones that are heavy for their size and have shiny, unblemished rinds. Additionally, the rinds should not be very hard since this indicates that the squash are over-mature and will have hard seeds and stringy flesh. Purchase summer squash that are of average size since those that are overly large may be fibrous, while those that are overly small may be inferior in flavor.
Summer squash is very fragile and should be handled with care as small punctures will lead to decay. It should be stored unwashed in an air-tight container in the refrigerator, where it will keep for about seven days.
While it can be frozen, this will make the flesh much softer. We don't recommend freezing as a routine storage method. Yet, it is a great process to turn to if you have amounts larger than you will be able to consume (for example, if you grow summer squash in your garden and have a bounty of it). The fact is that the freezing of summer squash can be an excellent storage process in terms of nourishment. A recent research study has shown excellent retention of the antioxidant activity in frozen summer squash.
Begin by slicing your summer squash and steaming for three minutes. Steaming is prefereable to the more traditional boiling method as it minimizes water contact and therefore minimizes nutrient loss. Remove squash from steamer and let cool thoroughly before placing in freezer bags and storing in the freezer.
Summer Squash, sliced, cooked 1.00 cup 180.00 grams Calories: 36 GI: very low | ||||
| Nutrient | Amount | DRI/DV (%) | Nutrient Density | World's Healthiest Foods Rating |
|---|---|---|---|---|
| copper | 0.19 mg | 21 | 10.6 | excellent |
| manganese | 0.38 mg | 19 | 9.5 | excellent |
| vitamin C | 9.90 mg | 13 | 6.6 | very good |
| magnesium | 43.20 mg | 11 | 5.4 | very good |
| fiber | 2.52 g | 10 | 5.0 | very good |
| phosphorus | 70.20 mg | 10 | 5.0 | very good |
| potassium | 345.60 mg | 10 | 4.9 | very good |
| folate | 36.00 mcg | 9 | 4.5 | very good |
| vitamin B6 | 0.12 mg | 7 | 3.5 | very good |
| vitamin K | 6.30 mcg | 7 | 3.5 | very good |
| vitamin B1 | 0.08 mg | 7 | 3.3 | good |
| zinc | 0.70 mg | 6 | 3.2 | good |
| omega-3 fats | 0.15 g | 6 | 3.1 | good |
| vitamin B3 | 0.92 mg | 6 | 2.9 | good |
| vitamin B2 | 0.07 mg | 5 | 2.7 | good |
| pantothenic acid | 0.25 mg | 5 | 2.5 | good |
| calcium | 48.60 mg | 5 | 2.4 | good |
| iron | 0.65 mg | 4 | 1.8 | good |
| choline | 14.22 mg | 3 | 1.7 | good |
| protein | 1.64 g | 3 | 1.6 | good |
| World's Healthiest Foods Rating | Rule |
|---|---|
| excellent |
DRI/DV>=75% OR Density>=7.6 AND DRI/DV>=10% |
| very good |
DRI/DV>=50% OR Density>=3.4 AND DRI/DV>=5% |
| good |
DRI/DV>=25% OR Density>=1.5 AND DRI/DV>=2.5% |