Quoted from The Hundred Year Lie:

“Every vegetable, every fruit, has literally hundreds of constituents—any protection is likely due to a combination rather than a single chemical,” observes Lee Wattenberg, an authority on human enzymes at the University of Minnesota. Marion Nestle, professor of nutrition at New York University, speaking to The New York Times, adds: “The evidence is pretty clear that foods work [in promoting health], but single nutrients don’t.”

Finally, we have this perspective from T. Colin Campbell, professor emeritus of nutritional biochemistry at Cornell University, who co-conducted a comprehensive study of nutrition in China that was published as a book in 2005. He identified some important principles linking nutrition and health: (1) Nutrition represents the combined activities of countless food substances, and the whole truly is greater than the sum of its parts. (2) Genes don’t determine diseases on their own but are activated or expressed as a result of nutrition. (3) Nutrition can substantially control the adverse effects of toxic chemicals that we ingest or absorb.

“There is enough evidence now that doctors should be discussing the option of pursuing dietary change as a potential path to cancer prevention and treatment,” writes Campbell. “A whole-foods, plant-based diet may be an incredibly effective anti-cancer medicine.”

Fitzgerald, Randall. The Hundred-Year Lie: How to Protect Yourself from the Chemicals That Are Destroying Your Health (p. 181). Plume. Kindle Edition.