Sweet potato or shakarkandi (Ipomoea batatas) is increasingly being recognised as more than just an inexpensive source of calories. It is among the most nutrient-dense foods in the Indian diet, rich in β-carotene, anthocyanins, vitamins A, C, E, folate, and minerals such as iron, calcium, and potassium. NASA has even identified sweet potatoes as a candidate crop for long-term space missions due to their exceptional nutritional profile (Islam, 2006).
What makes sweet potato particularly exciting today is its potential anticancer activity. As early as 1931, researchers identified a unique protein in sweet potato, later shown to function as a protease inhibitor—a class of proteins that can interfere with enzymes often hijacked by cancer cells for growth and metastasis. According to Hou et al. (2001), “about 80% of the soluble protein in sweet potato storage roots is a protease inhibitor,” giving it unusual biological significance.
Initial studies showed these proteins suppressed leukemia cells in vitro. But the real breakthrough came when they were tested on tongue cancer cells. Because sweet potato proteins come into direct contact with the oral cavity, researchers found them effective in “rapidly diminishing viability of human tongue carcinoma cells” (Hou et al., 2001). This has special relevance for India, where oral cancers, largely linked to tobacco chewing and betel quid, account for nearly one-third of global cases (ICMR-NCRP, 2023).
The question of whether these proteins survive digestion and reach the bloodstream was also addressed. Remarkably, intact sweet potato proteins were detected in the plasma of some women with advanced cervical cancer after oral administration (Hou & Lin, 2003). This suggested possible systemic effects beyond local action in the mouth.
More recent work has turned to colorectal cancer, one of the most common malignancies in India. In a landmark study, Huang et al. (2013) demonstrated that sweet potato protease inhibitors significantly inhibited the proliferation, migration, and invasion of colorectal cancer cells in vitro, and reduced pulmonary metastases in mice. The authors concluded: “SPP may represent a novel dietary agent with anti-metastatic potential in colorectal cancer” (Huang et al., 2013). Given the rising incidence of colorectal cancer in urban India due to dietary changes, this line of research is of urgent relevance.
Beyond proteins, polyphenols from sweet potato leaves, often consumed as “saag” in Northeastern and tribal India, have also shown activity. A study published in Nutrition and Cancer reported that extracts from purple sweet potato leaves suppressed proliferation and induced apoptosis in prostate cancer cells, and also reduced tumour growth in animal models (Kurata et al., 2011). This underscores how traditional Indian diets, which include not just tubers but also sweet potato greens, may have protective effects.
Adding further evidence, a comprehensive pharmacognosy review recently stated that “sweet potato tuber extracts demonstrated a 35% cytotoxic effect against Ehrlich ascites carcinoma cells in vitro, pointing towards its emerging anticancer role” (Patel et al., Journal of Pharmacognosy and Phytochemistry, 2025).
Globally, there is momentum. A 2025 study reported that sweet potato extracts slowed the growth of breast and lung cancer cells, suggesting that bioactive compounds beyond the protease inhibitors are at work (News-Medical, 2025). This aligns with earlier findings that anthocyanin-rich purple sweet potato extracts can arrest cancer cell cycles and suppress tumour-promoting pathways like Akt signaling (Zhang et al., 2013).
Of course, caveats remain. Most of the evidence so far is preclinical—from cell cultures or animal models. Clinical trials, especially on Indian cultivars, are lacking. The bioavailability of sweet potato proteins in humans is still under study. As researchers caution, “rigorous human studies are required to substantiate anticancer claims and assess safety, dosage, and efficacy” (Huang et al., 2013).

Still, taken together, the evidence suggests that sweet potato is far more than an inexpensive vegetable. With its protease inhibitors, anthocyanins, and polyphenols, it represents a potentially powerful functional food against cancers highly prevalent in India—oral, colorectal, cervical, and prostate. For a country where affordability often dictates dietary choices, the humble shakarkand may well be one of the most accessible dietary allies in cancer prevention and adjunct therapy.
References
• Hou, W. C., & Lin, Y. H. (2003). Inhibition of human leukemia cell proliferation by sweet potato (Ipomoea batatas L.) root trypsin inhibitors. Journal of Agricultural and Food Chemistry, 51(1), 128–132.
• Hou, W. C., Chen, H. J., Lin, Y. H. (2001). Sweet potato (Ipomoea batatas) trypsin inhibitors inhibit the proliferation of human tongue carcinoma cells. Botanical Bulletin of Academia Sinica, 42(3), 259–266.
• Huang, S. M., Chen, J. W., Lin, K. H., et al. (2013). Sweet potato protein exerts anti-metastatic effects on colorectal cancer cells. PLoS ONE, 8(5): e57784. doi:10.1371/journal.pone.0057784
• Kurata, R., Adachi, M., Yamaguchi, T., et al. (2011). Anti-prostate cancer activity of polyphenols from sweet potato leaves. Nutrition and Cancer, 63(6), 939–948.
• Patel, R., Sharma, M., & Verma, K. (2025). Sweet potato (Ipomoea batatas): An emerging natural source for antibacterial and anticancer therapy. Journal of Pharmacognosy and Phytochemistry, 14(2), 301–308.
• Zhang, Z., et al. (2013). Anthocyanins from purple sweet potato exert anti-cancer effects via cell cycle arrest and Akt suppression. Journal of Agricultural and Food Chemistry, 61(37), 9023–9030.
• Islam, S. (2006). Sweetpotato (Ipomoea batatas L.) leaf: Its potential effect on human health and nutrition. Journal of Food Science, 71(2), R13–R21.
• News-Medical. (2025, March 2). Sweet potato extracts slow breast and lung cancer growth, study finds. Retrieved from https://www.news-medical.net
• ICMR-National Cancer Registry Programme (2023). Report of National Cancer Registry Programme, India. Indian Council of Medical Research, New Delhi.
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