Foods That Fight Cancer


winter squashes

Squash (Winter)

True American natives, winter squash have hard skins unlike the soft-skinned summer squash. They also come in a wonderful variety of colors, textures and flavors. Names like buttercup, banana, turban and delicata may sound delightful and pique your interest, but if you’re like many Americans, their irregular shapes and textures have kept you from venturing beyond the convenient canned pumpkin. The most common varieties you’ll see in supermarkets are acorn, butternut, spaghetti and hubbard.

What's in Winter Squash?

Squash nutrition facts

Winter squash are excellent sources of vitamin A, good sources of vitamin C and dietary fiber. They are also a good way to get potassium.

Winter squash, including pumpkins, are rich in carotenoids, including:

  • beta-carotene and alpha-carotene: these carotenoids can act as antioxidants. Also, our bodies convert these to vitamin A, a nutrient important for immune function and maintaining healthy cells among other roles.
  • lutein and zeaxanthin: these yellow pigmented carotenoids help protect eye health by filtering high-energy ultraviolet rays that can damage our eyes’ lens and retina. They act as antioxidants here and possibly elsewhere in our bodies.

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The Cancer Research

Many of the phytochemicals and nutrients in winter squash are well studied in the laboratory. Winter squash also contain dietary fiber, which can act in several ways to lower cancer risk, including helping with weight control. Excess body fat increases the risk of 12 different cancers, and dietary fiber can increase the feeling of fullness.

Current Evidence: AICR/WCRF Expert Report and its Updates (CUP)

Squash is a starchy vegetable that contain fiber. After a systematic review of the global scientific literature, AICR/WCRF analyzed how these vegetables and dietary fiber affect the risk of developing cancer. This comprehensive review of decades of research concluded that there is strong – probable– evidence that:

- foods containing dietary fiber DECREASE the risk of colorectal cancer

Evidence categorized as "probable" means there is strong research showing a causal relationship to cancer – either decreasing or increasing the risk. The research must include quality human studies that meet specific criteria and biological explanations for the findings. A probable judgement is strong enough to justify recommendations.

Source: AICR/WCRF. Diet, Nutrition, Physical Activity and Cancer: A Global Perspective, 2018.

”… Supplements of beta-carotene in high-doses, especially in smokers, do not offer any cancer protection and seem to increase lung cancer risk.”

Open Areas of Investigation: Laboratory Research

Laboratory research is extensive on squash compounds such as beta-carotene and vitamin C .  

  • Lab research shows that vitamin C protects cells’ DNA by trapping free radicals and inhibiting formation of carcinogens.
  • Alpha-carotene and beta-carotene are related carotenoids. Lab research shows that both act as antioxidants that also promote cell-to-cell communication, helping control cell growth.
  • Lutein and zeaxanthin are concentrated not only in our eyes, but also in skin. A recent animal study suggests that dietary intake may decrease development of skin cancer related to sun exposure.
  • Lab research shows that dietary fiber reduces cells’ exposure to cancer-causing substances and gut bacteria use it to produce short-chain fatty acids that protect colon cells.

    Open Areas of Investigation: Human Studies

    Human studies related to winter squash and cancer risk compare groups of people who consume relatively high and low amounts of total vegetables, squash, and/or levels of carotenoids.

    Further research is underway in all the noted areas.

    • Population studies that compare people with high and low amounts of beta-carotene in their diet or their blood link beta-carotene with lower risk of esophageal cancer.
    • Both beta-carotene and lutein consumption are related to lower risk of renal cell cancer – a type of kidney cancer – in several large population studies.
    • One study, which included almost 15,000 adults, found those with higher blood levels of alpha-carotene suffered fewer deaths from cancers of the aerodigestive tract after almost 14 years. Aerodigestive cancers include cancers of the esophagus, stomach, colon, liver, and pancreas, and larynx.
    AICR-Supported Studies
    Grant Number Title
    09A020: Dietary Induced Sporadic Colon Cancer
    08A083: Transcriptional Attenuation Induced by Sodium Butyrate and Vitamin D3 in Colon Cancer Cells
    87A31: Dietary Antioxidants and Transplacental Carcinogenesis
    99A083: Effect of Antioxidant Vitamins on Radioimmunotherapy-Induced Normal Tissue Toxicity
    91SG16: Modification of Mutagen Sensitivity by Dietary and Chemopreventive Factors in Head and Neck Cancer in Vitro
    92A69: Chemopreventive Effects of Vitamin A
    85B70: solation and Identification of Anticarcinogenic Minor Dietary Component
    94A76: Modulation of Anticarcinogenic Activities of Vegetables by Thermal Processing
    89SG19: Effect of Soluble Fibers on Colonic Physiology
    95B089: Reversal of Apoptosis Resistance in Malignant Rat Lymphoma Cells and Human B-Cell Chronic Lymphocytic Leukemia by Butyrate, a Diet-Derived Fatty Acid
    95A27: Vitamin Intervention in Smokers
    84B05: Sinigrin as Anticarcinogen to Nitrosamines
    94A63: Carotenoid Effects on Transcription and Growth in Tumors
    86A45: Anticarcinogenicity of Dietary Flavonol Quercetin
    93B43: Dietary Antioxidants and Protein Kinase C Oxidative Activation in Tumor Promotion
    08A032: Metabolic Profiling of Plants for Health
    98A051: Metabolism and Pharmacokinetics of IP6 In Vivo
    98A075: Phytate Promotes Apoptosis in Coloncytes via Inhibition of the PI 3 Kinase/Akt Signaling Pathway
    00B113: Mechanisms of Anticarcinogenic Componentsfrom Cruciferous Vegetables
    94B02: Role of Dietary Carotenoids as Anti-Cancer Agents
    99A027: Diet, Oxidative DNA Damage and Breast Cancer Risk
    93SG02: Chemopreventive Potential of Oltipraz on BOP-Induced Ductal Pancreatic Carcinoma Development in Syrian Hamsters
    89B36: Factors Affecting Nitrosoproline Formation in Vivo
    03B043: Design and Feasibility of a Mediterranean Diet
    05A021: Lycopene, Vitamin E, Selenium and Prostate Cancer
    01B039: Antitumor Effects of Dietary Isothiocyanates on Prostate Cancer
    97B125: Mechanism of Inhibition by Isothiocyanates and Allyl Sulfides in Rat Esophagus
    91SG04: Effect of Inositol Hexaphosphate on the Growth of Transplantable Fibrosarcoma in Mice
    94B66: Mechanism of Action of Indole-3-Carbinol, a Dietary Chemopreventive Agent in Breast Cancer
    95A111: Mechanism of Dietary Indoles in Prevention of Papillomavirus Induced Cancers
    00B103: Molecular Analysis of Indole-3-carbinol (I3C) Signaling Events in Prostate Cancer Cells
    93A76: Nutritional Determinants of Breast Cancer
    90A52: Nutritional Determinants of Breast Cancer
    09A056: The Role of Dietary Fiber and Gut Microflora in Prevention of Colorectal Cancer
    91B36: Studies on In Vivo Nitrosation
    09A097: Adolescent Diet and Benign Breast Disease
    95A24: Mechanism of Fatty Acid Effects
    94A25: Fatty Acids, Mitochrondia and Molecular Genetics of Colon Cancer
    95B025: Short Chain Fatty Acid Metabolism and APC Initiated Colon Cancer
    91SG05: Azoxymethane-induced Colon Cancer in Rats Fed Varying Levels of Bean(Phaseolous vulgaris) Dietary Fiber
    92A05: Fatty Acids, Mitochondria, and Molecular Genetics of Colon Cancer
    95B029: Gene-Environment Interaction in Heterocyclic Amine Carcinogenesis
    91A19: Fat-Fiber Interactions: Effect on Colonic Cytokinetics
    89B48: Can Putative Preneoplastic Foci be Used to Evaluate Inhibitors of Colon Carcinogenesis
    97A106: Diet, Oxidative DNA Damage and Breast Cancer Risk
    84A06: Mechanisms of Anticarcinogenesis by Dietary Dithiothiones
    06A097: Diindolylmethane Improves Effectiveness of Paclitaxel for Breast Cancer Treatment
    92A47: Prevention of Esophageal Neoplasms by Novel Organosulfur Compounds in Alliums
    89B25: Prevention of Esophageal Cancer by Novel Organosulfur Compounds in Alliums
    90B49: Effects of Organic Sulfides on the Metabolism of Nitrosamines
    99B093: Dietary Isothiocyanates, Glutathione S-transferases, and Colorectal Neoplasia
    09A062: Role of oxGPCs/PAFR in BITC Mediated Suppresion of Melanoma
    00B016: Synergy Between Two Phytochemicals in Cruciferous Vegetables in the Prevention of Cancer
    89A25: Cellulose Structure and Inhibition of Colon Carcinogenesis
    91SG21: Colon Carcinogenesis: Nutritional Modulation of Biomakers
    87A23: Effect of Carotenoids on Mammary and Urinary Bladder Cancers
    94A55: Modulation of Colon Cancer Phenotype by Short Chain Fatty Acids
    96A078: Activation of a Tumor Suppressor Gene by Nutrient Derivatives
    00A066: Mechanism of Cancer Prevention by Fiber
    96A077: Regulation of Apoptosis in Human Colorectal Carcinoma Cells
    95A17: Butyrate-mediated Signal Transduction in Colonocytes: Role of cAMP-dependent Protein Kinase
    03A002: Role of Wnt Signaling in Butyrate-Induced Colon Carcinoma Cell Proliferation, Differentiation and Apoptosis
    09A002: Factors Determining the Apoptotic Response of Colorectal Carcinoma Cells to Butyrate, a Fermentation Product Derived from Dietary Fiber
    05B124: Mechanism of Cancer Chemoprevention by Constituents of Cruciferous Vegetables
    86B14: Bioflavonoid Inhibition of Carcinogenesis
    86A25: Dietary Fiber, Bile Acids and Colon Carcinogenesis
    87B62: Dietary Treatment for the Prevention of Cervix Dysplasias
    10A050: Anticancer Effects of Mixed Disulfide Conjugates of Allium Thiosulfinates and Cysteine/glutathione
    83B11: Type and Amount of Dietary Fiber in Experimental Colon Cancer
    squash cut open with seeds

    In the Kitchen


    • When selecting squash such as acorn, compare equal sizes and purchase the heavier one to get more edible flesh.
    • Inspect squash to find those with a hard rind and no soft spots.
    • For canned pumpkin, make sure you buy pure pumpkin and not high-sugar pumpkin pie mix.


    • Winter squash lasts two to three months at room temperature or slightly cooler. Refrigerating whole squash makes it spoil more rapidly.
    • Cut pieces of squash keep about two days tightly wrapped in the refrigerator.
    • You can freeze squash in uncooked chunks or as cooked purée.


    • For most winter squash, it’s easy to cut them in half, remove seeds and bake.
    • Butternut, delicata and spaghetti squash can be peeled and cut in cubes for stir-fries, casseroles, stews, pasta, soup, and even enchiladas.
    • Roast in the oven alone or with other vegetables, drizzled with a bit of olive oil.
    • Baked squash halves are perfect for stuffing. Try apples, raisins and cinnamon, or spinach or kale with soy and ginger.
    • Steam, microwave or bake winter squash and then purée. Enjoy it as a side dish or to thicken and flavor soups and stews. Or use canned or frozen squash or pumpkin that is already puréed.
    • Top "strings" of spaghetti squash with pasta sauce.
    • Seeds from winter squash and pumpkin make a great snack or salad topping. Rinse, air dry, add a touch of oil, and bake at 350°F for 15-20 minutes.

    Caramelized Carrots and Orange Squash

    • 1/2 cup raisins
    • 2/3 cup apple juice
    • 2 lbs. carrots, peeled and sliced diagonally, 1/4-inch pieces
    • 1 small butternut squash, peeled, and cubed, 1/2-inch cubes
    • 1 small acorn squash (about 1 lb), seeds removed, peeled, cubed, 1/2-inch cubes
    • 3 Tbsp. light olive oil
    • 2 1/2 Tbsp. date syrup/honey (or dark honey)
    • 1/2 tsp. ground cinnamon
    • Sea salt and coarsely ground black pepper, to taste
    • 1/2 cup apricot halves cut into small pieces

    Preheat oven to 400 degrees F.

    Soak raisins in apple juice.

    Line large baking sheet with two sheets of parchment paper.

    In large bowl, mix vegetables, oil, syrup, cinnamon and add salt and pepper to taste. Spread mixture on baking pan.

    Bake until carrots (the longest to bake) are just soft then add raisins and apricots. Bake about 10 minutes longer, until carrots are soft enough for fork to prick through. Serve immediately or, if refrigerating for several hours or more, pour 1/3 cup apple juice over vegetables to keep moist before reheating.

    Makes 10 servings.

    Per serving: 188 calories, 4 g total fat (<1 g saturated fat), 39 g carbohydrate, 3 g protein, 6 g dietary fiber, 70 mg sodium.

    More Recipes
    Below are answers to some of the most frequently asked questions we get asked.


    Which fruits and vegetables should I be eating?


    Eat as many different vegetables and fruits as you can. Variety is the key to obtaining the many protective phytochemicals. Each vegetable and fruit has its own profile of health-promoting substances.

    The phytochemicals found in cantaloupe are different from those in broccoli or leeks or cherries. Try to include a lot of colors on your plate. Aim to eat some bright red, green, orange, blue, purple and yellow vegetables and fruits each day.


    Should I buy organic foods whenever possible?


    There are many reasons to eat organic foods, but currently, there is no convincing evidence that shows a difference between organic and conventionally grown foods related to cancer risk. Studies show pesticide residues on conventionally grown foods are almost always within safety tolerance limits.

    If you are concerned about pesticide residues and can afford to spend more, organic produce may be a choice for you. Eating generous servings of a large variety of veggies and fruits - whether organic or not will benefit your health. The advantages of including more vegetables and fruits in your diet outweigh the potential risks from pesticides.


    Can grilled meats really cause cancer?


    Lab studies show that exposing meats to direct flame, smoke and intense heat (like when you grill or broil) can cause the formation of carcinogens (cancer-causing substances). Cooking methods that involve less heat, such as microwaving, baking, steaming and poaching, do not promote the formation of these substances.

    Several strategies you can use to cut carcinogen formation on meat include marinating, flipping frequently, removing excess fat from meat before cooking, and microwaving for part of the cooking time. So for delicious and healthful options, try grilling vegetables, veggie burgers and fruit slices and cut down on meat, fish and poultry.


    1. World Cancer Research Fund / American Institute for Cancer Research, Food, Nutrition, Physical Activity and the Prevention of Cancer: a Global Perspective, 2007: Washington, DC. p. 82-113.
    2. Astner, S., et al., Dietary lutein/zeaxanthin partially reduces photoaging and photocarcinogenesis in chronically UVB-irradiated Skh-1 hairless mice. Skin pharmacology and physiology, 2007. 20(6): p. 283-91.
    3. Kubo, A., et al., Dietary factors and the risks of oesophageal adenocarcinoma and Barrett's oesophagus. Nutrition research reviews, 2010. 23(2): p. 230-46.
    4. Musa-Veloso, K., et al., Influence of observational study design on the interpretation of cancer risk reduction by carotenoids. Nutrition reviews, 2009. 67(9): p. 527-45.
    5. Gallicchio, L., et al., Carotenoids and the risk of developing lung cancer: a systematic review. The American journal of clinical nutrition, 2008. 88(2): p. 372-83.
    6. Druesne-Pecollo, N., et al., Beta-carotene supplementation and cancer risk: a systematic review and metaanalysis of randomized controlled trials. International journal of cancer. Journal international du cancer, 2010. 127(1): p. 172-84.
    7. Lee, J.E., et al., Intakes of fruit, vegetables, and carotenoids and renal cell cancer risk: a pooled analysis of 13 prospective studies. Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology, 2009. 18(6): p. 1730-9.
    8. Li, C., et al., Serum alpha-carotene concentrations and risk of death among US Adults: the Third National Health and Nutrition Examination Survey Follow-up Study. Archives of internal medicine, 2011. 171(6): p. 507-15.