Micronutrients found in brightly colored produce could play a part in protecting you from cancer, a new review of studies suggests.

Researchers from Brigham & Women's Hospital and Harvard Medical School found that women who have higher levels of carotenoids circulating in their bloodstreams also seem to have a lower risk of developing breast cancer, particularly estrogen receptor-negative breast cancer types.

Specifically, the decreased breast cancer risk was tied to high blood levels of alpha-carotene, beta-carotene, lycopene, lutein and zeaxanthin, as well as overall levels of total carotenoids, the researchers found. Their findings are published in the Journal of the National Cancer Institute.

Researchers speculated that carotenoids may have anti-cancer effects because alpha-carotene, beta-carotene and beta-cryptoxanthin in particular because those compounds metabolize into retinol, the naturally occurring form of vitamin A in the blood, which in turn regulates the growth, development and death of cells. It does this by affecting gene expression, explained the researchers. Additionally, the compounds may improve communication between cells, cell defense and repair, they continued:

"Carotenoids also may be directly anticarcinogenic by several other mechanisms, including improved gap junction communication, enhanced immune system functioning, or antioxidant scavenging of reactive oxygen species; this may inhibit cellular dysregulation or DNA damage," they wrote.

The findings are based on the analysis of eight studies, which included a total of 3,055 people with breast cancer and 3,956 controls. TIME pointed out that produce like carrots, spinach and kale are particularly high in carotenoids.

This is certainly not the first time fruits and vegetables have been suggested to make a positive difference on breast cancer risk. Reuters reported on a 2008 study in the Journal of Clinical Oncology, showing that breast cancer recurrence risk goes down by going above and beyond with eating produce.

Also on HuffPost:

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  • Broccoli And Broccoli Sprouts

    Cruciferous vegetables, but broccoli in particular, make for anti-cancer powerhouses thanks in part to a compound called sulforaphane that actually helps the body fight the spread of tumors. Recent research revealed the underlying reason: sulforaphane may inhibit an enzyme, called an HDAC, that <a href="http://www.huffingtonpost.com/2012/02/29/broccoli-cancer-sulforaphane_n_1310634.html">works to suppress the body's tumor fighting ability</a>, as we've previously reported. And sprouts are even more potent: three-day old broccoli sprouts have 20 to 50 times the sulforaphanes as mature broccoli, <a href="http://www.hopkinsmedicine.org/press/1997/sept/970903.htm">according to Johns Hopkins research</a>. For more about the cancer fighting properties of <em>all cruciferous vegetables, check HuffPost blogger Dr. Joel Fuhrman's <a href="http://www.huffingtonpost.com/joel-fuhrman-md/cancer-prevention_b_1624965.html">analysis of cabbage, brussels sprouts, bok choy and more</a>.

  • Garlic

    Garlic is considered a cancer-fighting food for several forms of the disease, <a href="http://www.cancer.gov/cancertopics/factsheet/prevention/garlic-and-cancer-prevention#r12">according to the National Cancer Institute</a>. One French study found that women who regularly ate garlic had <a href="http://www.ncbi.nlm.nih.gov/pubmed/9928867">a significantly reduced risk of breast cancer</a>. Garlic's mild cousin, onions also had a protective effect, according to the study.

  • Pomegranate

    Pomegranates are known for their anti-cancer properties, thanks to a richness in anti-inflammatory antioxidants, polyphenols. But they may offer a specific benefit against breast cancer: research shows that a phytochemical found in abundance in pomegranates, called ellagitannins, interfere in the production of aromatase, an enzyme that, as HuffPost blogger Dr. Nalini Chilkov explained, "<a href="http://www.huffingtonpost.com/nalini-chilkov/pomegranates-cancer-fighting-_b_1078343.html">increases hormone production in breast tissue</a>." That's important because breast cancer is hormone-dependent, meaning that it feeds off of hormones like estrogen to grow and spread. "Hormone dependent cancers such as breast cancer are commonly treated with aromatase inhibitors, which block this enzyme," wrote Chilkov.

  • Walnuts

    Although preliminary, research in mice has found that <a href="http://www.sciencedaily.com/releases/2011/09/110901163921.htm">including walnuts in a healthful diet throughout the entire lifespan</a> reduced the risk of developing breast cancer by <em>half</em>.

  • Turmeric

    Curcumin, the compound in turmeric, may play a role in blocking the expression of a molecule called RANKL, <a href="http://www.huffingtonpost.com/nalini-chilkov/turmeric-health-benefits-_b_828856.html">which is found in the most deadly and aggressive breast cancer tumor cells</a>.

  • Flax Seeds

    Most research regarding flax's anti-cancer properties has been done in mice or in-vitro cell cultures, but what it shows could be profound: in one study, according to the American Cancer Society, <a href="http://www.cancer.org/Treatment/TreatmentsandSideEffects/ComplementaryandAlternativeMedicine/HerbsVitaminsandMinerals/flaxseed">the lignans found in flax slowed the movement and "stickiness" of breast cancer cells</a>, causing it to spread more slowly in a cell culture simulation.

  • Berries

    Berries have several powerful antioxidants, primarily anthocyanins and ellagic acid, which have been shown in cell culture studies to <a href="http://www.aicr.org/foods-that-fight-cancer/blueberries.html#research">reduce free radical damage to healthy cells</a>, according to the American Institute for Cancer Research. In separate research, they were shown to slow the growth and shorten the lifespan of breast cancer (as well as mouth, colon and prostate cancer) cells.

  • Green Tea

    Green tea is rich in the polyphenol EGCG (epigallocatechin-3-gallate), which has been shown to slow the spread of breast cancer cells, <a href="http://www.breastcancer.org/tips/nutrition/supplements/known/green_tea">according to breastcancer.org</a>.

  • Tomatoes

    Tomatoes are rich in the antioxidant lycopene, which is thought to <a href="http://www.msnbc.msn.com/id/39726407/ns/health-cancer/t/what-you-should-eat-avoid-beat-breast-cancer/#.UHNMJvmMG5M">slow breast cancer cell growth</a>.