The delicate flavor, soft shell and creamy white flesh of summer squash is a perfect addition to any summer meal. Once only available in the summer, they are now available throughout the year; however, they are in season between May and July when they are at their best and most readily available.

Summer 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. The entire vegetable, including its flesh, seeds and skin, is edible. In addition, some varieties of the squash plant produce edible flowers. Unlike winter squash, summer squash are more fragile and cannot be stored for long periods of time.

Promotes Optimal Health

Although not as potent as root vegetables like burdock, garlic or onion, squashes have been found to have anti-cancer type effects. Although phytonutrient research on squash is limited, some lab studies have shown vegetable juices obtained from squash to be parallel to juices made from leeks, pumpkin, and radish in their ability to prevent cell mutations (cancer-like changes).

Supports Men''s Health

In research studies, extracts from squash have also been found to help reduce symptoms of a condition occurring in men called benign prostatic hypertrophy, or BPH. In this condition, the prostate gland becomes problematically enlarged, which can cause difficulty with urinary and sexual function. Particularly in combination with other phytonutrient-containing foods, squash may be helpful in reducing BPH symptoms.

Well-Rounded Cardiovascular Protection

The traditional nutrients provided by summer squash are equally impressive. Our food ranking system qualified summer squash as an excellent source of manganese and vitamin C and a very good source of magnesium, vitamin A (notably through its concentration of carotenoids, including beta-carotene), fiber, potassium, folate, copper, riboflavin, and phosphorous.

Many of these nutrients have been shown in studies to be helpful for the prevention of atherosclerosis and diabetic heart disease. Summer squash''s magnesium has been shown to be helpful for reducing the risk of heart attack and stroke. Together with the potassium in summer squash, magnesium is also helpful for reducing high blood pressure. The vitamin C and beta-carotene found in summer squash can help to prevent the oxidation of cholesterol. Since oxidized cholesterol is the type that builds up in blood vessel walls, these nutrients may help to reduce the progression of atherosclerosis. The vitamin folate found in summer squash are needed by the body to break down a dangerous metabolic byproduct called homocysteine, which can contribute to heart attack and stroke risk if levels get too high. Finally, summer squash''s fiber has been shown to lower high cholesterol levels, which can help to reduce the risk of atherosclerosis and diabetic heart disease.

A Disease-Fighting Food

The nutrients in summer squash are useful for the prevention of other conditions as well. High intakes of fiber-rich foods help to keep cancer-causing toxins away from cells in the colon, while the folate, vitamin C, and beta-carotene help to protect these cells from the chemicals that can lead to colon cancer. The antioxidants vitamin C and beta-carotene also have anti-inflammatory properties that make them helpful for conditions like asthma, osteoarthritis, and rheumatoid arthritis, where inflammation plays a big role. The copper found in summer squash is also helpful for reducing the painful symptoms of rheumatoid arthritis.

Summer 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. The entire vegetable, including its flesh, seeds and skin, is edible. In addition, some varieties of the squash plant produce edible flowers. Unlike winter squash, summer squash are more fragile and cannot be stored for long periods of time.

Varieties of summer squash include:

  • Zucchini: Probably the best known of the summer squashes, zucchini is a type of narrow squash that resembles a cucumber in size and shape. It has smooth, thin skin that is either green or yellow in color and can be striped or speckled. Its tender flesh is creamy white in color and features numerous seeds. Its edible flowers are often used in French and Italian cooking.
  • Crookneck and Straightneck Squash: Both of these summer squashes have creamy white flesh and generally have yellow skins, although sometimes you can find them with green skin. Crookneck squash is partially straight with a swan-like neck. It was genetically altered to produce its straightneck cousin that is shaped as its name implies.
  • Pattypan Squash: This small saucer-shaped squash features skin that can either be pale green or golden yellow in color. Its cream-colored flesh is more dense and slightly sweeter than that of zucchini.

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 squashes 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 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.

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 overmature 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 a plastic bag in the refrigerator, where it will keep for about seven days. While it can be frozen, this will make the flesh much softer. To do so, blanch slices of summer squash for two minutes before freezing.

For some of our favorite recipes, click Recipes.

Tips for Preparing Summer Squash:

Wash summer squash under cool running water and then cut off both ends. You can then proceed to cut it into the desired size and shape for the particular recipe.

A Few Quick Serving Ideas:

Sprinkle grated zucchini or other summer squash on top of salads and sandwiches.

Enjoy an easy to make ratatouille by healthy sautéing summer squash, onions, bell peppers, eggplant and tomatoes and then simmering the mixture in tomato sauce. Season to taste.

Serve raw summer squash with your favorite dips.

Add zucchini or other summer squash to your favorite muffin or bread recipe; decrease the amount of liquid in the recipe by about one-third to compensate for the moisture present in the squash.

Summer Squash and Oxalates

Summer squash is among a small number of foods that contain measurable amounts of oxalates, naturally-occurring substances found in plants, animals, and human beings. When oxalates become too concentrated in body fluids, they can crystallize and cause health problems. For this reason, individuals with already existing and untreated kidney or gallbladder problems may want to avoid eating summer squash. Laboratory studies have shown that oxalates may also interfere with absorption of calcium from the body. Yet, in every peer-reviewed research study we''ve seen, the ability of oxalates to lower calcium absorption is relatively small and definitely does not outweigh the ability of oxalate-containing foods to contribute calcium to the meal plan. If your digestive tract is healthy, and you do a good job of chewing and relaxing while you enjoy your meals, you will get significant benefits - including absorption of calcium - from calcium-rich foods plant foods that also contain oxalic acid. Ordinarily, a healthcare practitioner would not discourage a person focused on ensuring that they are meeting their calcium requirements from eating these nutrient-rich foods because of their oxalate content. For more on this subject, please see "Can you tell me what oxalates are and in which foods they can be found?"

Summer squash is an excellent source of manganese and vitamin C. It is also a very good source of magnesium, vitamin A, dietary fiber, potassium, copper, folate, and phosphorous. In addition, summer squash is a good source of omega-3 fatty acids, vitamin B1, vitamin B2, vitamin B6, calcium, zinc, niacin, and protein.

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

In-Depth Nutritional Profile

In addition to the nutrients highlighted in our ratings chart, an in-depth nutritional profile for Squash, summer 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

The following chart shows the nutrients for which this food is either an excellent, very good or good source. Next to the nutrient name you will find the following information: the amount of the nutrient that is included in the noted serving of this food; the %Daily Value (DV) that that amount represents; the nutrient density rating; and the food''s World''s Healthiest Foods Rating. Underneath the chart is a table that summarizes how the ratings were devised. Read detailed information on our Food and Recipe Rating System.

Summer squash, cooked, slices
1.00 cup
180.00 grams
36.00 calories
Nutrient Amount DV
(%)
Nutrient
Density
World''s Healthiest
Foods Rating
manganese 0.38 mg 19.0 9.5 excellent
vitamin C 9.90 mg 16.5 8.3 excellent
magnesium 43.20 mg 10.8 5.4 very good
vitamin A 516.60 IU 10.3 5.2 very good
dietary fiber 2.52 g 10.1 5.0 very good
potassium 345.60 mg 9.9 4.9 very good
copper 0.19 mg 9.5 4.8 very good
folate 36.18 mcg 9.0 4.5 very good
vitamin K 6.30 mcg 7.9 3.9 very good
phosphorus 70.20 mg 7.0 3.5 very good
vitamin B6 (pyridoxine) 0.12 mg 6.0 3.0 good
omega 3 fatty acids 0.15 g 6.0 3.0 good
vitamin B1 (thiamin) 0.08 mg 5.3 2.7 good
calcium 48.60 mg 4.9 2.4 good
zinc 0.70 mg 4.7 2.3 good
vitamin B3 (niacin) 0.92 mg 4.6 2.3 good
vitamin B2 (riboflavin) 0.07 mg 4.1 2.1 good
iron 0.65 mg 3.6 1.8 good
protein 1.64 g 3.3 1.6 good
tryptophan 0.01 g 3.1 1.6 good
World''s Healthiest
Foods Rating
Rule
excellent DV>=75% OR Density>=7.6 AND DV>=10%
very good DV>=50% OR Density>=3.4 AND DV>=5%
good DV>=25% OR Density>=1.5 AND DV>=2.5%