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Salt & Cancer Risk
26 Nov 2020
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Dr Greger

At offset 2:45 of this video, Dr Greger mentions that the #1 risk factor for stomach cancer are salted fermented vegetables; he attributes the high incidence of stomach cancer in Korea to kimchi. In the article Are kimchi and sauerkraut harmful? (2012), Dr Greger explains:

Why Shouldn’t You Eat Kimchi?

Kimchi consumption potentially doubles one’s risk of breast cancer, and may increase the odds of getting prostate cancer ten-fold—from just a spoonful a day.

Habitual “consumption of pickled foods, salted fish and processed meat were [each] associated with” about a 25% greater risk of stomach cancer. The pickled foods may explain why Korea appears to have the highest stomach cancer rates in the world.

Why Shouldn’t You Eat Sauerkraut?

Red or purple cabbage is one of my favorite vegetables—packed with antioxidants, yet dirt cheap, and seems to last forever in the fridge. But, when you ferment it, not only do you add way too much salt, but you end up wiping out some of the nutrition. The antioxidant capacity of your bloodstream in the hours after eating fresh red cabbage is cut down by almost 30% if you ate the same amount in fermented form.

In the paras above, Dr Greger refers to three of his videos listed below:

(2010) Is Kimchi Good For You?

(1 min) Transcript. Dr Greger's summary: "Epidemiological evidence that kimchi consumption may significantly increase cancer risk."

(2017) Is Miso Healthy?

(4 mins) Transcript. Dr Greger's summary: "Miso is packed with sodium, which is linked to both stomach cancer and high blood pressure, so is it safe to consume?"

(2018) The Benefits of Kale & Cabbage for Cholesterol

(5 mins) Transcript. Dr Greger's summary: "Dinosaur kale and red cabbage are put to the test."

Dr Peter Rogers
(2 mins, 2022) Do Fermented Foods Increase Risk Of Cancer? Pickles, Kimchi, Sauerkraut
Guidelines by WCRF & AICR

WCRF (World Cancer Research Fund) / AICR (American Institute of Cancer Research) publishes its recommendations every 10 years or so: 1997 (1st report), 2007 (2nd report), 2018 (3rd report) — also available in HTML format). Collectively, these reports constitute a gigantic treatise on nutrition and cancer; very readable. Here are two documents relevant to salt and cancer:

  1. (2018) Matrix for All Cancers — one of the columns is titled "foods preserved by salting", explained in footnote #29. The footnote explains that such foods 'probably' cause cancer.
  2. (2018) Stomach Cancer Report, Section 7.3 ("Foods preserved by salting" summarizes the evidence so far; it's from observational studies. Dr Greger has a solitaroy video on this subject: Is Kimchi Good For You?

In the 2007 guidelines, one of the recommendations under Salt and Cancer Risk was

"Recommends that people avoid adding salt at the table or in cooking."

In 2018 guidelines, I couldn't find such a recommendation even though the overall nature of the evidence has not changed much. What is the explanation for omission of salt elimination guideline in 2018? This article explains:

"Stronger evidence: Whereas the best available evidence for many nutrients and cancers previously included a mix of case-control studies and scientifically stronger prospective cohort studies, the evidence base in the new report rests largely on cohort studies and randomized controlled trials. Mechanistic studies also are considered, since the criteria needed to support a recommendation include not only a strong association in epidemiologic research but also plausible evidence of a biological mechanism that could explain the association.

This has led to more emphasis on the importance of some recommendations, such as regular physical activity and limits on alcohol. In a few cases, it led to recognition that the evidence may not be as strong as researchers once thought, resulting, for example, in no longer including a recommendation specifically focused on salt or sodium. Growing recognition of the complexity of cancer also is reflected in the new report. Different types of cancers — of the breast, esophagus, and stomach, for example — may be influenced by different lifestyle choices."

WCRF / AICR evidence classification is into 3 categories: strong (either "convincing" or "probable"), limited (either "limited — suggestive" or "limited — no conclusion"), or "substantial effect on risk unlikely." In the 2018 report, salt is "probable" (in other words, the evidence is strong — not as strong as "convincing" though).

Stomach Cancer in India: Salt & Spicy Food?

Source: Cancer Rate Doubles in India (India Today, 2018).

As per this article in India Today (2018), stomach cancer is the leading cancer in South & Coastal India; it is also common in North East India. See Regions 1 and 3 in the photo.

What is stomach cancer in India attributed to? See the "Diet and Lifestyle" section in this research paper: Epidemiological review of gastric cancer in India by Dikshit, Mathur, Mhatre, and Yeole, Indian J Med Paediatr Oncol. 2011 Jan;32(1):3-11. Excerpts from this research paper:

"Pickled food,[23] high rice intake, spicy food, excess chilly consumption, consumption of high-temperature foods[24] smoked dried salted meat, use of soda[25] and consumption of dried salted fish[25] have emerged as significant dietary risk factors in various parts of India. These practices are prevalent in southern and eastern states of India where a higher frequency of gastric cases are also observed."

"Salt intake is a risk factor for gastric carcinoma as it damages the gastric mucosa, which results in gastritis and increased cell proliferation.[26] Salted tea, a peculiar beverage, is commonly consumed by a majority of population in Kashmir valley was observed to be a risk factor.[27] Indian studies have not observed salt intake as a separate factor but salted and processed products were taken into consideration."

Summary

The evidence for the relationship between salt and cancer (stomach cancer in particular) is not as strong as the relationship between smoking and cancer. But salt is problematic for many other reasons: Salt & Hypertension, Salt & Heart Disease and Salt: Asthma & Autoimmune Conditions. So I choose to forego added salt in my food plates.

© Copyright 2008—2025, Gurmeet Manku.