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The last blog in the series was about what we should not be eating. Now let’s discuss what foods we should be trying to eat more of. Let’s do that by seeing what foods would be best to help prevent cancer.

There are few things scarier than a diagnosis of cancer. This is a disease I’m sure most everyone knows someone close to them has dealt with. Cancer is the second leading cause of death in the U.S (1). I was first introduced to cancer at 8 years old when my grandfather died of colon cancer. And again, my best friend lost his younger sister to breast cancer several years ago. I also just had a patient that was diagnosed with prostate cancer. But what really got me interested in this topic was because a good friend of my wife started battling ovarian cancer. She was asking if we knew of any experimental trials or treatments.

When I investigated this, I discovered the best cancer prevention evidence was found in whole plant foods. Thus, I made her a document of how to eat to supplement her treatments. If foods can help prevent or fight cancer, then they must be overall healthy right? What I have found in studying nutrition is if a particular food can help one disease, it usually helps several others as well. However, focusing on one problem at a time is needed to produce convincing research. But before we can get to preventing and treating cancer we need to understand what causes cancer. Let’s dig in!

How Does Cancer Form?

First of all, what is cancer and what causes it? All of your body’s cells (except red blood cells) have a center portion called the nucleus. In the nucleus are the blueprints for making more cells and proteins to help that cell function. These blueprints are called DNA. When a cell divides in two, the DNA is copied. Your body is very good at dividing cells to replenish and repair and it copies the DNA perfectly most of the time. Sometimes mistakes happen, this is called a mutation. Sometimes the mutation is so small there is no effect on the cell. However, sometimes the mutation makes the cell want to keep copying itself more than intended. In people with a healthy immune system, all these cells with mutations are identified and removed very quickly. Your body causes that cell to kill itself in a process called apoptosis. A cancer forms if the cells continue to copy themselves uncontrollably. Cancer cells can grow if the immune system is not working properly, if there are so many mutations occurring the immune system can’t keep up, if the particular mutation makes the cancerous cells really good at avoiding the immune system or resisting apoptosis. Cancer is like a weed that invades the tissue; it steals nutrients and eventually causes the organ it is in to fail. For a cancer to continue to grow (proliferate) and wreak havoc, it needs to have a blood supply that it creates called angiogenesis. When a piece of cancer tissue breaks off and get into the main blood supply, it can be relocated to another area and continue to grow and this is called metastasis.

What can increase the risks for cancer?

Cancer risks are increased by increasing the amount of DNA mutations. DNA mutations can be caused by a buildup of normal metabolic byproducts that lead to oxidative stress or excess inflammation. In addition, DNA can be directly damaged by things like radiation, ingested chemicals or food. Substances that increase the risk for cancer are called carcinogens. An example of a carcinogen is the weed killer Round Up. So if increased DNA damage leads to higher cancer risk, decreasing DNA damage can reduce the risk. Some things that can reduce DNA damage are avoiding radiation, smoke inhalation, chemicals, processed meats (as we know from my last blog), etc. Some things can protect cells from DNA damage in the presence of carcinogens. Substances that do so by decreasing oxidative stress are called antioxidants and those that do so by reducing inflammation are called anti-inflammatory. Cancer can be treated with things that reduce the formation of cancer blood vessels (anti-angiogenics), slow down cancer growth (anti-proliferative), increase the rate at which cancer cells kill themselves (apoptotic), or prevent cancer from moving to new areas (inhibit cancer migration). Below we will discuss the foods that have substantial evidence to fight off or prevent cancer.

What foods can help prevent or fight off cancer?

Cruciferous Vegetables: broccoli, brussel sprouts, red cabbage, kale, cauliflower, collard greens, bok choy, arugula, radish, watercress, turnips, rutabaga and wasabi.

How: They are rich in vitamins, minerals and antioxidants. They have anti-inflammatory and antimicrobial effects as well. Cruciferous vegetables contain a group of compounds called glucosinoles that are responsible for the bitter flavors and aroma but also have anticancer effects. These chemicals protect cells from DNA damage and inactivate carcinogenic substances. They also can induce cancer cell death (apoptosis), inhibit cancer blood vessel formation (angiogenesis), and inhibit tumor cell migration (needed for metastasis) (2-4).
Three review studies have shown higher intake of cruciferous vegetables can lower the risks of colorectal, lung, and bladder cancers (5-7).

My recommendation: Eat cruciferous vegetables daily. Broccoli, brussel sprouts, red cabbage and kale may be the best of the group but eat which ones you like. You can eat them raw, steamed or cooked. Try to get at least 1 serving every day, but the more the better.

Green Tea:

How: Green tea has catechins that are polyphenols and they give Green tea its taste. EGCG (epigallocatechin-3-gallate) has the strongest anti-cancer activity. A recent review shows that green tea consumption can reduce the risks of prostate cancer (8).

My recommendation: have 1-2 cups of green tea on most days!

Berries: Blueberries, strawberries, raspberries, blackberries, grapes, cranberries, cherries, and pomegranates

How: Berries have a lot of antioxidants that scavenge free radicals, thus reducing oxidative stress and preventing DNA damage. Also, key phytochemicals in berries can induce cancer cell death (apotosis) and inhibit cancer cell growth (9). Another review showed that berries could help prevent colon cancer in those that are high risk (10).

My recommendation: Eat a variety of whole berries as a snack on most days, at least 1 serving but the more the better. I like to mix them in a smoothie. Blueberries are probably the best. When able, choose organic.

Citrus Fruits: oranges, lemon, limes, grapefruit

How: A recent review showed that intake of citrus fruits significantly reduced the risk of esophageal cancer (11).

My recommendation: Squeeze a fresh lime or lemon into drinking water on most days. Eat an orange or grapefruit several times a week, more if you like. If you are taking medications and you eat grapefruit then let you r doctor know because grapefruit can effect the metabolism of some medications.

Flax Seeds

How: Flax seeds have phytoestrogen lignans, α-linolenic acid (ALA), and other phytochemicals that have anti-cancer effects. They can decrease cancer cell proliferation and angiogenesis and increase cancer cell death (apoptosis). One review shows that they can reduce the risk of breast cancer as well as augmenting chemotherapy drugs (12). Another review showed decreased risk of colorectal cancer (13).

My recommendation: You have to grind the flax seeds to get the nutrients out. Freshly grind them right before serving or you can refrigerate the ground seeds a day or 2 in advance of using. Put a tablespoon on salads, oatmeal, soups and in smoothies. Try to get a tablespoon in on most days.

Mushrooms: White, reshi, shiitake, lions mane, cordyceps mushrooms

How: mushrooms can boost the immune system, reduce inflammation and have some anti-cancer effects. One review showed reduced risks of breast cancer in women with higher intake of white mushrooms and green tea (14).

My recommendation: If you like mushrooms, add to your soups or dinner dishes on a regular basis.

Apples

How: Apples have several phytochemicals, including flavonoids, phenolic acids, and anthocyanins. These compounds have been shown to have activities to reduce gene mutations, have antioxidant activity, are anti-inflammatory, and reduce cancer proliferation and can induce cancer cell death (apoptosis) (15).

My recommendation: Eat an organic apple including the peel on most days.

Spices: Turmeric, ginger, and allium herbs (garlic, onions, leeks, chives, and shallots)

How: Curcumin, the active component in turmeric, has been shown to help reduce DNA mutation, have antioxidant and anti-inflammatory activity, and can prevent and arrest cancer cell growth. In a review, turmeric was shown to help prevent and treatment of reproductive cancers, prostate cancer, blood cancers, brain cancer, and bone cancers (16). Ginger extract has been shown in a recent review to have antiproliferative, antitumor, and anti-inflammatory activities (17). Another review showed that allium herbs have anticancer properties due to various sulfur and organic compounds like S-allyl mercaptocysteine, quercetin, flavonoids, and ajoene (18).

My recommendation: Take a turmeric/curcumin supplement with bioperine (helps increase the bioavailability). Regenexx has a great supplement that also has been shown in the lab to help stem cell function and arthritis. Use curry, ginger, garlic, onions, leeks, chives, and shallots as much as you can in cooked dishes.

Beans and Legumes: Edamame, peas, green beans, soy, alfalfa

How: Phyates in beans and legumes (as well as other vegetables) have antioxidant, anti-inflammatory, and immune enhancing effects. One study showed that phyates enhanced the anticancer effect of conventional chemotherapy and helped control cancer metastases (19). Another study showed just a quarter cup of beans per day reduced colorectal precancerous lesions up to 65% (20).

My recommendation: Eat a small serving of bean or legumes on most days.

The Bottom Line

Cancer is a horrible disease that affects us all in some way. Our genes only account for 10-20% of the risk for the leading causes of death including cancer (21). Thus, the good news is that most cancers can be prevented with diet and lifestyle. Diet and lifestyle changes can also help aid conventional therapies for cancer for those who are battling this disease. The above foods are some of the top cancer prevention foods with scientific evidence of its efficacy. In addition to fighting cancer, they are staples of a healthy diet to prevent many chronic diseases. As much as you are able, try to find ways to incorporate these foods into your diet on a regular basis.  The key is consistency.  For more nutrition information read my book Nutrition 2.0.

References
1. https://www.cdc.gov/nchs/fastats/leading-causes-of-death.htm
2. Hayes JD, Kelleher MO, Eggleston IM. The cancer chemopreventive actions of phytochemicals derived from glucosinolates. European Journal of Nutrition 2008;47 Suppl 2:73-88. [PubMed Abstract]
3. Hecht SS. Inhibition of carcinogenesis by isothiocyanates. Drug Metabolism Reviews 2000;32(3-4):395-411. [PubMed Abstract]
4. Murillo G, Mehta RG. Cruciferous vegetables and cancer prevention. Nutrition and Cancer 2001;41(1-2):17-28. [PubMed Abstract]
5. Cruciferous vegetables and risk of colorectal neoplasms: a systematic review and meta-analysis. Tse G, Eslick GD. Nutr Cancer. 2014;66(1):128-39. doi: 10.1080/01635581.2014.852686. Epub 2013 Dec 16. Review.
6. Cruciferous vegetable consumption and lung cancer risk: a systematic review. Lam TK, Gallicchio L, Lindsley K, Shiels M, Hammond E, Tao XG, Chen L, Robinson KA, Caulfield LE, Herman JG, Guallar E, Alberg AJ. Cancer Epidemiol Biomarkers Prev. 2009 Jan;18(1):184-95. doi: 10.1158/1055-9965.EPI-08-0710. Review.
7. The association of cruciferous vegetables intake and risk of bladder cancer: a meta-analysis. Liu B, Mao Q, Lin Y, Zhou F, Xie L. World J Urol. 2013 Feb;31(1):127-33. doi: 10.1007/s00345-012-0850-0. Epub 2012 Mar 6. Review.
8. Anti-Cancer Effects of Green Tea Polyphenols Against Prostate Cancer. Miyata Y, Shida Y, Hakariya T, Sakai H. Molecules. 2019 Jan 7;24(1). pii: E193. doi: 10.3390/molecules24010193. Review. PMID: 30621039
9. Antioxidant and anticancer properties of berries. Baby B, Antony P, Vijayan R. Crit Rev Food Sci Nutr. 2018;58(15):2491-2507. doi: 10.1080/10408398.2017.1329198. Epub 2017 Aug 14. Review. https://www.ncbi.nlm.nih.gov/pubmed/28609132
10. Chemopreventive and Therapeutic Effects of Edible Berries: A Focus on Colon Cancer Prevention and Treatment. Afrin S, Giampieri F, Gasparrini M, Forbes-Hernandez TY, Varela-López A, Quiles JL, Mezzetti B, Battino M. Molecules. 2016 Jan 30;21(2):169. doi: 10.3390/molecules21020169. Review.
11. Intakes of citrus fruit and risk of esophageal cancer: A meta-analysis. Zhao W, Liu L, Xu S. Medicine (Baltimore). 2018 Mar;97(13):e0018. doi: 10.1097/MD.0000000000010018. Review.
12. Flaxseed and its lignan and oil components: can they play a role in reducing the risk of and improving the treatment of breast cancer? Mason JK, Thompson LU. Appl Physiol Nutr Metab. 2014 Jun;39(6):663-78. doi: 10.1139/apnm-2013-0420. Epub 2013 Dec 23. Review.
13. Flaxseed Bioactive Compounds and Colorectal Cancer Prevention. DeLuca JAA, Garcia-Villatoro EL, Allred CD. Curr Oncol Rep. 2018 Jun 5;20(8):59. doi: 10.1007/s11912-018-0704-z. Review.
14. Dietary intakes of mushrooms and green tea combine to reduce the risk of breast cancer in Chinese women. Zhang M, Huang J, Xie X, Holman CD. Int J Cancer. 2009 Mar 15;124(6):1404-8. doi: 10.1002/ijc.24047.
15. Cancer chemopreventive potential of apples, apple juice, and apple components. Gerhauser C. Planta Med. 2008 Oct;74(13):1608-24. doi: 10.1055/s-0028-1088300. Epub 2008 Oct 14. Review. PMID: 18855307
16. Curcumin mediates anticancer effects by modulating multiple cell signaling pathways. Kunnumakkara AB, Bordoloi D, Harsha C, Banik K, Gupta SC, Aggarwal BB. Clin Sci (Lond). 2017 Jul 5;131(15):1781-1799. doi: 10.1042/CS20160935. Print 2017 Aug 1. Review. PMID: 28679846
17. Protective and therapeutic potential of ginger (Zingiber officinale) extract and [6]-gingerol in cancer: A comprehensive review. de Lima RMT, Dos Reis AC, de Menezes APM, Santos JVO, Filho JWGO, Ferreira JRO, de Alencar MVOB, da Mata AMOF, Khan IN, Islam A, Uddin SJ, Ali ES, Islam MT, Tripathi S, Mishra SK, Mubarak MS, Melo-Cavalcante AAC. Phytother Res. 2018 Oct;32(10):1885-1907. doi: 10.1002/ptr.6134. Epub 2018 Jul 16. Review. PMID: 30009484
18. Allium vegetables for possible future of cancer treatment. Asemani Y, Zamani N, Bayat M, Amirghofran Z. Phytother Res. 2019 Aug 29. doi: 10.1002/ptr.6490. [Epub ahead of print] Review. PMID: 31464060
19. Protection against cancer by dietary IP6 and inositol. Vucenik I, Shamsuddin AM. Nutr Cancer. 2006;55(2):109-25. Review. PMID: 17044765 
20. High dry bean intake and reduced risk of advanced colorectal adenoma recurrence among participants in the polyp prevention trial. Lanza E, Hartman TJ, Albert PS, Shields R, Slattery M, Caan B, Paskett E, Iber F, Kikendall JW, Lance P, Daston C, Schatzkin A. J Nutr. 2006 Jul;136(7):1896-903. PMID: 16772456 
21. Balancing life-style and genomics research for disease prevention. Willett WC. Science. 2002 Apr 26;296(5568):695-8. PMID: 11976443