Editor’s Note: Each month, HerbalEGram
highlights a conventional food and briefly explores its history, traditional
uses, nutritional profile, and modern medicinal research. We also feature a nutritious
recipe for an easy-to-prepare dish with each article to encourage readers to
experience the extensive benefits of these whole foods. With this series, we
hope our readers will gain a new appreciation for the foods they see at the
supermarket and frequently include in their diets.
The basic materials for
this series were compiled by dietetic interns from Texas State University in
San Marcos and the University of Texas at Austin through the American Botanical
Council’s (ABC’s) Dietetic Internship Program, led by ABC Education Coordinator
Jenny Perez.
We would like to acknowledge Perez, ABC Special Projects Director Gayle Engels,
and ABC Chief Science Officer Stefan Gafner, PhD, for their contributions to
this project.
By Hannah Baumana
and Sarah Edwardsb
a HerbalGram Assistant Editor
b ABC Dietetics
Intern (TSU, 2013)
History and Traditional Use
Range and Habitat
Cucurbita moschata —
often referred to as winter or pumpkin squash — is a trailing annual with lobed
leaves that produces yellow flowers.1 Mature fruits that are peanut-
or bottle-shaped are harvested for their rich orange flesh and edible seeds. Native
to tropical and subtropical America, butternut squash requires warmer climates
for cultivation as it is intolerant of cold temperatures.1,2
Curcurbita moschata grows best in rich and well-drained soil in full sun.2
It can be stored for extended
periods and, in fact, has one of the longest shelf lives in the squash family.3
Phytochemicals and Constituents
Winter squashes, such as the butternut, are high in complex carbohydrates and
provide vitamin C, potassium, iron, riboflavin, and magnesium.3
Additionally, butternut squash is an excellent source of vitamin A and
carotenoids such as α-carotene, β-carotene, β-cryptoxanthin, lutein, and
zeaxanthin, which contribute to its claimed anti-cancer properties.3
While it is a low-fat food, butternut squash does contain some healthy fats in
the form of alpha-linoleic acid, a beneficial omega-3 fatty acid that the body
does not produce naturally.4 Omega-3s possess a variety of health
benefits, including anti-inflammatory properties.
The vitamin C retention in butternut squash after cooking is unusually high
compared to other vitamin C-containing vegetables, and this is thought to
contribute to its potential antioxidant activity.5 About 80% of the
vitamin C in butternut squash is retained after cooking the pulp for 30 minutes
at 95°C (203°F). For comparison, cooking degrades vitamin C content in potatoes
by 30%, and, after maintaining heat for one hour, levels decrease by another
10%.
Boiled butternut squash has an intermediate glycemic index value at 66 (compared
to the reference glucose reference of 100).6 Despite its relatively
high glycemic index value, butternut squash’s complex carbohydrate content
slows the breakdown of carbohydrates into simple sugars, thereby delaying the
release of insulin.
The edible seeds of the squash, which have nutritional value on their own, can
be roasted like pumpkin (C. pepo)
seeds. Roasting lightly for a short period of time preserves the healthy oils —
including linoleic acid, a polyunsaturated omega-6 fatty acid, and oleic acid,
which is plentiful in olive oil — that make up approximately 75% of the fat
found in the seeds.4 Cucurbita
moschata seeds contain a higher amount of carotenoids as well as α-, β-,
and γ-tocopherol than C. maxima and
other pumpkin seeds. The seeds are a good source of vitamin E, which also may
contribute to the plant’s antioxidant activity.7
Historical Uses
Cucurbita moschata
cultivation dates back more than 10,000 years to Central America.8 The
use of the plant spread to the north and south, with evidence of use from 4,900
BCE in southern Mexico and 3,000 BCE in coastal Peru.1 Centuries
later, Christopher Columbus and other European explorers brought squash from
the Americas to Europe.8
Squash were initially cultivated for their seeds; in early varieties, the
sparse flesh was bitter and inedible.8 Pumpkin or squash seeds have
been used for treating enlarged prostate glands and intestinal parasites.2,9
In Traditional
Chinese Medicine (TCM), squash seeds have been used since at least the 17th
century. TCM practitioners consider squash to be a warming food that aids
digestion,3,10 improves qi
(energy) deficiency in the spleen/pancreas,11 and alleviates pain.
Application of fresh squash juice may reduce inflammation and relieve burns,
and its slightly acidic nature led to its incorporation as an ingredient in
bone marrow or “longevity” soup.11 In Ayurveda, winter squash has a
history of use to reduce vata
(conditions that are dry and cold) and pitta
(conditions that are inflammatory and hot).3 Winter squash are considered
therapeutic foods beneficial for diabetics due to their complex carbohydrate
content.3
Modern Research
Butternut squash pulp produced as a byproduct of the manufacturing process is thought
to be a potential source for the production of prebiotics used in functional
food and nutraceutical products.12 In 2010, butternut squash pulp
oligosaccharides were analyzed to determine their potential for prebiotic
production.12 Prebiotics must withstand digestion to ultimately
reach the colon and stimulate growth of bacteria or microbiota. The
oligosaccharides demonstrated resistance to hydrolysis by artificial human
gastric juice and α-amylase when compared to inulin, a reference prebiotic.
These oligosaccharides also stimulated the growth of lactobacilli in comparison
to inulin.
Research on the therapeutic properties of butternut squash has been limited to
human cell studies and animal studies. Analyses of bioactive-compounds have
focused on cucurmosin, which has been isolated from the fleshy part of the fruit.13
Cucurmosin inhibits the proliferation of cancer cells by inducing apoptosis
(programmed cell death). A 2012 study showed that cucurmosin inhibits cell
proliferation in a time- and dose-dependent manner and induces apoptosis
specifically in human pancreatic cancer BxPC-3 cells. Cucurmosin
down-regulates, or decreases the quantity of, epidermal growth factor receptor
(EGFR) protein expression, which is associated with overexpression that may
promote pancreatic tumor growth and metastasis. Researchers also found that cucurmosin
inactivated the PI3K/Akt/mTOR signaling pathway in human pancreatic cancer cells.13
In a separate study, human liver carcinoma cells (HepG2 cells) were treated
with cucurmosin, which resulted in an increase of cell apoptosis in a
concentration-dependent manner.14 Additional studies, particularly
human clinical trials, are needed to assess the potential therapeutic potential
of butternut squash in greater detail.
Nutrient Profile15
Macronutrient Profile: (Per 1 cup raw butternut squash cubes)
Calories: 63 Protein: 1.4 g Carbohydrates: 16.4
g Fat: 0.14 g
Secondary Metabolites: (Per 1 cup raw butternut squash cubes)
Excellent source of:
Vitamin A: 14,882 IU (298% DV) Vitamin C: 29.4 mg
(49% DV)
Very good source of:
Manganese: 0.38 mg (19% DV) Potassium: 493 mg (14%
DV) Magnesium: 48 mg
(12% DV) Vitamin B6: 0.22 mg
(11%DV) Dietary Fiber: 2.8 g
(11% DV)
Good source of:
Folate: 38 mcg (9.5% DV) Thiamin: 0.14 mg (9.3%
DV) Niacin: 1.68 mg (8.4%
DV) Phosphorus: 46 mg (4.6%
DV) Vitamin K: 1.5 mcg
(1.9% DV) Riboflavin: 0.03 mg
(1.8% DV)
DV = Daily Value as
established by the US Food and Drug Administration, based on a 2,000-calorie
diet.
Recipe: Creamy Butternut Squash Soup Courtesy of Sarah Edwards
Ingredients:
- 1 whole head of garlic, cloves separated and peeled
- 2 medium butternut squash
- 2 medium carrots, peeled and chopped
- 1 medium onion, peeled and quartered
- 4 tablespoons of extra virgin olive oil
- 1 teaspoon salt
- 8 cups vegetable broth
- 2 teaspoons of freshly minced ginger
- 2 tablespoons coconut milk (or more, to taste)
- 1 bunch cilantro, chopped (for garnish)
Directions:
- Preheat
oven to 350°F. Slice butternut squash in half, peel, and scoop out the seeds.
- Cut off
the bulbous ends where the seeds have been scooped out and place peeled whole
cloves of garlic in each cavity. Place squash face down in a large baking dish.
- Peel
and cut the rest of the squash into large cubes and place in the baking dish
with onion and carrot. Drizzle with olive oil and season with salt. Roast for 1
hour until tender.
- Heat
broth in a large pot over medium heat. Add the butternut squash sections and
garlic into the saucepan along with the roasted vegetables and minced ginger,
then bring to a boil and simmer for 10 minutes.
- Stir in
the coconut milk and allow to cool slightly. Blend the soup in batches in a
blender or in the pot with an immersion blender until thick and creamy. Garnish
with cilantro or roasted butternut squash seeds.
References
- Van Wyk B. Food Plants of the World: An Illustrated Guide. Portland, OR:
Timber Press, Inc; 2006.
- Bown D. The Herb Society of America New Encyclopedia of Herbs and Their Uses.
New York, NY: DK Publishing, Inc; 2001.
- Wood R. The New Whole Foods Encyclopedia: A Comprehensive Resource for Healthy
Eating. Middlesex, England: Penguin Books Ltd; 1999.
- Mateljan G. The World’s Healthiest Foods. Seattle, WA: George Mateljan
Foundation Publishing; 2007.
- Roura SI, Del Valle CE, Aguero L,
Davidovich LA. Changes in apparent viscosity and vitamin C retention during
thermal treatment of butternut squash (Cucurbita
moschata Duch.) pulp: effect of
ripening stage. J Food Qual. 2007;30:538-551.
- Bahado-Singh PS, Wheatley AO,
Ahmad MH, Morrison EYSA, Asemota HN. Food processing methods influence the
glycemic indices of some commonly eaten West Indian carbohydrate-rich foods. Brit J Nutr. 2006;96:476-481.
- Veronezi CM, Jorge N. Bioactive
compounds in lipid fractions of pumpkin (Cucurbita
sp.) seeds for use in food. J Food Sci. 2012;77(6):C653-C657.
- Murray M. The Encyclopedia of Healing Foods. New York, NY: Atria Books; 2005.
- Khare CP, ed. Indian Herbal Remedies: Rational Western Therapy, Ayurvedic and Other
Traditional Usage, Botany. Berlin, Germany: Springer; 2003.
- Duke JA, Ayensu, ES. Medicinal Plants of China. Algonac, MI:
Reference Publications, Inc. 1984.
- Pitchford P. Healing with Whole Foods: Oriental Traditions and Modern Nutrition. Berkeley,
CA: North Atlantic Books; 1993.
- Du B, Song Y, Hu X, Liao X, Ni Y,
Li Q. Oligosaccharides prepared by acid hydrolysis of polysaccharides from
pumpkin (Cucurbita moschata) pulp and
their prebiotic activities. Int J Food
Sci. 2011;46:982-987.
- Zhang B, Huang H, Xie J, et al.
Cucurmosin induces apoptosis of BsPC-3 human pancreatic cancer cells via
inactivation of the EGFR signaling pathway. Oncol
Rep. 2012;27:891-897.
-
Xie J, Que W, Liu H, Liu M, Yang A, Chen M.
Anti-proliferative effects of cucurmosin on human hepatoma HepG2 cells. Mol Med Rep. 2012;5:196-201.
|