The World's Healthiest Foods
Squash, summer

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.


Health Benefits

Cancer-Preventive Effects

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).

Prostate 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. And the fiber content may be helpful for reducing the uncomfortable diarrhea or constipation of irritable bowel syndrome.


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 modified 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 the 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.

    How to Select and Store

    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 perforated 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.

    How to Enjoy

    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 any measurable amount 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. Oxalates may also interfere with absorption of calcium from the body. For this reason, individuals trying to increase their calcium stores may want to avoid summer squash, or if taking calcium supplements, may want to eat summer squash 2-3 hours before or after taking their supplements.

    Nutritional Profile

    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 (similar to other information presented in the website, this DV is calculated for 25-50 year old healthy woman); 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. For more detailed information on our Food and Recipe Rating System, please click here.


    Squash, Summer, All Varieties
    1.00 cup
    36.00 calories
    Nutrient Amount DV
    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
    phosphorus 70.20 mg 7.0 3.5 very good
    omega 3 fatty acids 0.15 g 6.0 3.0 good
    vitamin B6 (pyridoxine) 0.12 mg 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
    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%


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    This page was updated on: 2004-11-20 19:58:52
    © 2002 The George Mateljan Foundation