Can eating beans prevent cancer, dementia, or stroke? No, that's not true: There is no evidence of dementia and stroke prevention and limited evidence about cancer.
The claim originated from a video (archived here) published by @livinggenius (archived here) on TikTok, on November 25, 2023, under the title "암 치매 뇌졸중도 막는 이것? - 이렇게 먹으면 암과 치매 예방! - 함께 먹어야 하는 3가지 - 미역국 먹는 방법 - 된장국 이렇게 만드세요" or "This food prevents cancer, dementia and even stroke - When you have it like this, you can prevent cancer and dementia! - three foods that should be eaten together - how to eat seaweed soup - Cook your Doenjang-guk like this." (Translation from Korean to English by Lead Stories staff). It opened:
This food prevents cancer, dementia and even stroke!
Beans are the best source of protein, and a food you should eat more often as you get older.
This is what the post looked like on TikTok at the time of writing:
(Source: TikTok screenshot taken on Thu Nov 30 01:24:50 2023 UTC)
The video promotes beans as a superfood that prevents cancer, dementia, and stroke all at once. However, there is no sufficient scientific evidence to support the claim. In fact, there is no evidence that beans can prevent dementia and stroke, and limited evidence for potential cancer prevention.
According to the CDC, risk factors for dementia and stroke are associated with healthy habits, rather than intake of certain foods. Some research shows a promising anticancer potential of saponins, glycosides abundant in soybeans. However, while the National Cancer Institute in the United States acknowledges that beans have been studied regarding their relationship to cancer risk (see the graphic in this resource), the institute has not confirmed that beans can automatically decrease cancer risk.
The TikTok video also suggested specific ways to cook beans:
Beans should be eaten with seaweeds. Even though saponin in the beans has an anticancer effect, it can cause hypothyroidism when you eat too much of it, since it discharges iodine in your body. At this point, it will be better if you have Miyeok or Kelp (Dashima), which have plenty of iodine.
The TikToker suggests adding some Doenjang (Korean Style Soybean paste) in the Miyeok-guk (seaweed soup) to prevent iodine discharge. However, this claim is even more groundless than the previous one. A search on Google Scholar conducted by Lead Stories on November 30, 2023, for "saponin discharges iodine" (archived here) found no results to corroborate the claim.
