Though the most concentrated sources of the toxic metal cadmium are cigarette smoke, seafood, and organ meats, does greater consumption from whole grains and vegetables present a concern?
Cadmium & Cancer: Plant vs. Animal Foods
4.7/5 - (38 votes)
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
“Cadmium is known as a highly toxic metal that represents a major hazard” to human health. It sticks around in our body for decades, because our body has no efficient way to get rid of it, and may contribute to a variety of illnesses, including “heart disease, cancer, and diabetes.” Most recently, data suggests that cadmium exposure may impair cognitive performance even at levels once thought to be safe.
Recent studies suggest “cadmium exposure may produce adverse health effects at lower exposure levels than previously predicted,” including increased risk of hormonal cancers. For example, researchers on Long Island estimated that about 40% of breast cancer in the U.S. may be associated with elevated cadmium levels.
“Inhalation of cigarette smoke is one of the major routes for human [exposure to cadmium].” Seafood consumption is another “dominant route” of human exposure in this study—even more so than from cigarette smoke. The highest levels, though, are found in organ meats. But, you know, how many horse kidneys can you eat? Because people eat so few organs, grains and vegetables actually end up contributing the largest amount.
But, wait a second. “…[w]hole grains and vegetable[s]…are among the major dietary sources of fiber, phytoestrogens, [and] antioxidants” that may protect against breast cancer. And, indeed, even though the risk of breast cancer goes up as women consume more and more cadmium, even though on paper, most cadmium comes from grains and vegetables, breast cancer risk goes down, the more and more whole grains and vegetables women eat.
So, maybe the animal-sourced cadmium is somehow worse? Or, the benefits of plant foods just overwhelm any adverse effects of the cadmium? This study may have helped solve the mystery. It’s not what we eat; it’s what we absorb.
“[Cadmium] bioavailability from animal-based foods [may be] higher than…from vegetable-based foods.” There appears to be something in plants that inhibits cadmium absorption. In fact, if you add kale to your boiled pig kidneys, you can cut down on the toxic exposure. Just one tablespoon of pig kidney, and we may exceed the daily safety limit—unless we eat kale, in which case we could eat a whole quarter-cup. “[T]he pronounced effects of the inhibitory factors in kale…point[s] out the importance of vegetable foods in terms of prevention of health hazard[s] from [cadmium] ingested as mixed diets in a real situation.”
“Even if a vegetarian diet contains more lead and cadmium than a mixed diet, it is not certain that it will give rise to higher uptake of the metals…because the absorption of lead and cadmium is inhibited by [plant compounds such as] fibre and phytate.” And, it’s not just in lab animals. Having whole grains in our stomach up to three hours before we swallow lead can eliminate 90% of absorption—thought to be due to phytates in whole grains, beans, and nuts grabbing onto it.
So, vegetarians may have lower levels, even though they have higher intakes. “In fact, a significant decrease in the hair concentrations of lead and cadmium [was seen] after the change from [an omnivorous] to [a] vegetarian diet…, indicating a lower [absorption] of the metals.”
Here’s that study. They took folks eating a standard Swedish diet, and put them on a vegetarian diet. Lots of whole unrefined plant foods; no meat, poultry, fish, eggs, and junk food that was discouraged.
Here’s where they started out: a measure of their mercury levels, cadmium level, and lead levels in their bodies. Within three months on a vegetarian diet, their levels significantly dropped, and stayed down for the rest of the year-long experiment. But then, they came back three years later—three years after they stopped eating vegetarian. And, what did they find? Their levels of mercury, cadmium, and lead shot back up.
Since the cadmium in plants is based on the cadmium in soil, plant-eaters that live in a really polluted area, like Slovakia, which has some of the highest levels, the so-called “black triangle” of pollution, thanks to the chemical and smelting industries. Those who eat lots of plants there can indeed build up higher cadmium levels, especially if you eat lots of plants. It’s interesting. “In spite of the significantly higher blood cadmium concentrations as a consequence of a greater cadmium intake from [polluted plants], all the antioxidants in those same plants were found to help “inhibit [the] harmful effects of higher free radical production” caused by [the] cadmium exposure.
Still, though, in highly polluted areas, it might be an especially good idea not to smoke, or eat too much seafood or organ meats. But, even if we live in the Slovak Republic’s black triangle of pollution, the benefits of whole plant foods would outweigh the risks. In highly polluted areas, zinc supplements may decrease cadmium absorption. But, I’d recommend against multi-mineral supplements, as they have been found to be contaminated with cadmium itself.
Please consider volunteering to help out on the site.
- R Madeddu, G Solinas, G Forte, B Bocca, Y Asara, P Tolu, L G Delogu, E Muresu, A Montella, P Castiglia. Diet and nutrients are contributing factors that influence blood cadmium levels. Nutr Res 2011 31(9):691 – 697.
- T Ciesielski, D C Bellinger, J Schwartz, R Hauser, R O Wright. Associations between cadmium exposure and neurocognitive test scores in a cross-sectional study of US adults. Environmental Health 2013 12(1):13.
- M Krajvcovivcová-Kudlávcková, M Ursínyová, V Mavsánová, A Béderová, M Valachovivcová. Cadmium blood concentrations in relation to nutrition. Cent Euro J Public Health 2006 14(3):126-9.
- C M Gallagher, J J Chen, J S Kovach. Environmental cadmium and breast cancer risk. Aging 2010 1(11):804-14.
- T S Srikumar, G K Johansson, P A Ockerman, J A Gustafsson, B Akesson. Trace element status in healthy subjects switching from a mixed to a lactovegetarian diet for 12 mo. Am J Clin Nutr 1992 55(4):885 – 890.
- Y R Ju, W Y Chen, C M Liao. Assessing human exposure risk to cadmium through inhalation and seafood consumption. J Hazard Mater 2012 227 - 228:353 – 361.
- M F McCarty. Zinc and multi-mineral supplementation should mitigate the pathogenic impact of cadmium exposure. Med Hypotheses 2012 79(5):642 – 648.
- H Harmens, I Ilyin, G Mills, J R Aboal, R Alber, O Blum, M Coşkun, L De Temmerman, J Á Fernández, R Figueira, M Frontasyeva, B Godzik, N Goltsova, Z Jeran, S Korzekwa, E Kubin, K Kvietkus, S Leblond, S Liiv, S H Magnússon, B Maňkovská, O Nikodemus, R Pesch, J Poikolainen, D Radnovi'c, A Rühling, J M Santamaria, W Schröder, Z Spiric, T Stafilov, E Steinnes, I Suchara, G Tabors, L Thöni, G Turcsányi, L Yurukova, H G Zechmeister. Country-specific correlations across Europe between modelled atmospheric cadmium and lead deposition and concentrations in mosses. Environ. Pollut. 2012 166:1 – 9.
- A M Riederer, A Belova, B J George, P T Anastas. Urinary cadmium in the 1999-2008 U.S. National Health and Nutrition Examination Survey (NHANES). Environ Sci Technol 2013 47(2):1137 – 1147.
- C A Krone, E J Wyse, J T Ely. Cadmium in zinc-containing mineral supplements. Int J Food Sci Nutr 2001 52(4):379 – 382.
- A Ebert-McNeill, S P Clark, J J Miller, P Birdsall, M Chandar, L Wu, E A Cerny, P H Hall, M H Johnson, C Isales, N Chutkan, M H Bhattacharyya. Cadmium intake and systemic exposure in postmenopausal women and age-matched men who smoke cigarettes. Toxicol Sci 2012 130(1):191 – 204.
- V Vromman, N Waegeneers, C Cornelis, I De Boosere, M Van Holderbeke, C Vinkx, E Smolders, A Huyghebaert, L Pussemier. Dietary cadmium intake by the Belgian adult population. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2010 27(12):1665 – 1673.
- R Chunhabundit, S Srianujata, A Bunyaratvej, R Kongkachuichai, J Satayavivad, S Kaojarern. Cadmium bioavailability from vegetable and animal-based foods assessed with in vitro digestion/caco-2 cell model. J Med Assoc Thai 2011 94(2):164 – 171.
- B Julin, A Wolk, L Bergkvist, M Bottai, A Akesson. Dietary cadmium exposure and risk of postmenopausal breast cancer: A population-based prospective cohort study. Cancer Res 2012 72(6):1459 – 1466.
- YA Cho, J Kim, HD Woo, M Kang. Dietary cadmium intake and the risk of cancer: a meta-analysis. PLoS One. 2013 Sep 17;8(9):e75087.
- M Vahter, G Johansson, A Akesson, B Rahnster. Faecal elimination of lead and cadmium in subjects on a mixed and a lactovegetarian diet. Food Chem Toxicol. 1992 Apr;30(4):281-7.
- HM James, ME Hilburn, JA Blair. Effects of meals and meal times on uptake of lead from the gastrointestinal tract in humans. Hum Toxicol. 1985 Jul;4(4):401-7.
- F Pearce. Mosses Reveal Slovakia's Black Triangle of Pollution. The New Scientist. 15 Mar 1997. 2073.
Images thanks to NASA via Wikimedia
- air pollution
- animal products
- antioxidants
- beans
- breast cancer
- cadmium
- cancer
- cardiovascular disease
- chicken
- cognition
- diabetes
- eggs
- fiber
- grains
- heart disease
- heavy metals
- junk food
- lead
- meat
- mercury
- nuts
- organ meats
- oxidative stress
- phytates
- Plant-Based Diets
- poultry
- seafood
- smoking
- supplements
- turkey
- vegans
- vegetables
- vegetarians
- women's health
- zinc
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
“Cadmium is known as a highly toxic metal that represents a major hazard” to human health. It sticks around in our body for decades, because our body has no efficient way to get rid of it, and may contribute to a variety of illnesses, including “heart disease, cancer, and diabetes.” Most recently, data suggests that cadmium exposure may impair cognitive performance even at levels once thought to be safe.
Recent studies suggest “cadmium exposure may produce adverse health effects at lower exposure levels than previously predicted,” including increased risk of hormonal cancers. For example, researchers on Long Island estimated that about 40% of breast cancer in the U.S. may be associated with elevated cadmium levels.
“Inhalation of cigarette smoke is one of the major routes for human [exposure to cadmium].” Seafood consumption is another “dominant route” of human exposure in this study—even more so than from cigarette smoke. The highest levels, though, are found in organ meats. But, you know, how many horse kidneys can you eat? Because people eat so few organs, grains and vegetables actually end up contributing the largest amount.
But, wait a second. “…[w]hole grains and vegetable[s]…are among the major dietary sources of fiber, phytoestrogens, [and] antioxidants” that may protect against breast cancer. And, indeed, even though the risk of breast cancer goes up as women consume more and more cadmium, even though on paper, most cadmium comes from grains and vegetables, breast cancer risk goes down, the more and more whole grains and vegetables women eat.
So, maybe the animal-sourced cadmium is somehow worse? Or, the benefits of plant foods just overwhelm any adverse effects of the cadmium? This study may have helped solve the mystery. It’s not what we eat; it’s what we absorb.
“[Cadmium] bioavailability from animal-based foods [may be] higher than…from vegetable-based foods.” There appears to be something in plants that inhibits cadmium absorption. In fact, if you add kale to your boiled pig kidneys, you can cut down on the toxic exposure. Just one tablespoon of pig kidney, and we may exceed the daily safety limit—unless we eat kale, in which case we could eat a whole quarter-cup. “[T]he pronounced effects of the inhibitory factors in kale…point[s] out the importance of vegetable foods in terms of prevention of health hazard[s] from [cadmium] ingested as mixed diets in a real situation.”
“Even if a vegetarian diet contains more lead and cadmium than a mixed diet, it is not certain that it will give rise to higher uptake of the metals…because the absorption of lead and cadmium is inhibited by [plant compounds such as] fibre and phytate.” And, it’s not just in lab animals. Having whole grains in our stomach up to three hours before we swallow lead can eliminate 90% of absorption—thought to be due to phytates in whole grains, beans, and nuts grabbing onto it.
So, vegetarians may have lower levels, even though they have higher intakes. “In fact, a significant decrease in the hair concentrations of lead and cadmium [was seen] after the change from [an omnivorous] to [a] vegetarian diet…, indicating a lower [absorption] of the metals.”
Here’s that study. They took folks eating a standard Swedish diet, and put them on a vegetarian diet. Lots of whole unrefined plant foods; no meat, poultry, fish, eggs, and junk food that was discouraged.
Here’s where they started out: a measure of their mercury levels, cadmium level, and lead levels in their bodies. Within three months on a vegetarian diet, their levels significantly dropped, and stayed down for the rest of the year-long experiment. But then, they came back three years later—three years after they stopped eating vegetarian. And, what did they find? Their levels of mercury, cadmium, and lead shot back up.
Since the cadmium in plants is based on the cadmium in soil, plant-eaters that live in a really polluted area, like Slovakia, which has some of the highest levels, the so-called “black triangle” of pollution, thanks to the chemical and smelting industries. Those who eat lots of plants there can indeed build up higher cadmium levels, especially if you eat lots of plants. It’s interesting. “In spite of the significantly higher blood cadmium concentrations as a consequence of a greater cadmium intake from [polluted plants], all the antioxidants in those same plants were found to help “inhibit [the] harmful effects of higher free radical production” caused by [the] cadmium exposure.
Still, though, in highly polluted areas, it might be an especially good idea not to smoke, or eat too much seafood or organ meats. But, even if we live in the Slovak Republic’s black triangle of pollution, the benefits of whole plant foods would outweigh the risks. In highly polluted areas, zinc supplements may decrease cadmium absorption. But, I’d recommend against multi-mineral supplements, as they have been found to be contaminated with cadmium itself.
Please consider volunteering to help out on the site.
- R Madeddu, G Solinas, G Forte, B Bocca, Y Asara, P Tolu, L G Delogu, E Muresu, A Montella, P Castiglia. Diet and nutrients are contributing factors that influence blood cadmium levels. Nutr Res 2011 31(9):691 – 697.
- T Ciesielski, D C Bellinger, J Schwartz, R Hauser, R O Wright. Associations between cadmium exposure and neurocognitive test scores in a cross-sectional study of US adults. Environmental Health 2013 12(1):13.
- M Krajvcovivcová-Kudlávcková, M Ursínyová, V Mavsánová, A Béderová, M Valachovivcová. Cadmium blood concentrations in relation to nutrition. Cent Euro J Public Health 2006 14(3):126-9.
- C M Gallagher, J J Chen, J S Kovach. Environmental cadmium and breast cancer risk. Aging 2010 1(11):804-14.
- T S Srikumar, G K Johansson, P A Ockerman, J A Gustafsson, B Akesson. Trace element status in healthy subjects switching from a mixed to a lactovegetarian diet for 12 mo. Am J Clin Nutr 1992 55(4):885 – 890.
- Y R Ju, W Y Chen, C M Liao. Assessing human exposure risk to cadmium through inhalation and seafood consumption. J Hazard Mater 2012 227 - 228:353 – 361.
- M F McCarty. Zinc and multi-mineral supplementation should mitigate the pathogenic impact of cadmium exposure. Med Hypotheses 2012 79(5):642 – 648.
- H Harmens, I Ilyin, G Mills, J R Aboal, R Alber, O Blum, M Coşkun, L De Temmerman, J Á Fernández, R Figueira, M Frontasyeva, B Godzik, N Goltsova, Z Jeran, S Korzekwa, E Kubin, K Kvietkus, S Leblond, S Liiv, S H Magnússon, B Maňkovská, O Nikodemus, R Pesch, J Poikolainen, D Radnovi'c, A Rühling, J M Santamaria, W Schröder, Z Spiric, T Stafilov, E Steinnes, I Suchara, G Tabors, L Thöni, G Turcsányi, L Yurukova, H G Zechmeister. Country-specific correlations across Europe between modelled atmospheric cadmium and lead deposition and concentrations in mosses. Environ. Pollut. 2012 166:1 – 9.
- A M Riederer, A Belova, B J George, P T Anastas. Urinary cadmium in the 1999-2008 U.S. National Health and Nutrition Examination Survey (NHANES). Environ Sci Technol 2013 47(2):1137 – 1147.
- C A Krone, E J Wyse, J T Ely. Cadmium in zinc-containing mineral supplements. Int J Food Sci Nutr 2001 52(4):379 – 382.
- A Ebert-McNeill, S P Clark, J J Miller, P Birdsall, M Chandar, L Wu, E A Cerny, P H Hall, M H Johnson, C Isales, N Chutkan, M H Bhattacharyya. Cadmium intake and systemic exposure in postmenopausal women and age-matched men who smoke cigarettes. Toxicol Sci 2012 130(1):191 – 204.
- V Vromman, N Waegeneers, C Cornelis, I De Boosere, M Van Holderbeke, C Vinkx, E Smolders, A Huyghebaert, L Pussemier. Dietary cadmium intake by the Belgian adult population. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2010 27(12):1665 – 1673.
- R Chunhabundit, S Srianujata, A Bunyaratvej, R Kongkachuichai, J Satayavivad, S Kaojarern. Cadmium bioavailability from vegetable and animal-based foods assessed with in vitro digestion/caco-2 cell model. J Med Assoc Thai 2011 94(2):164 – 171.
- B Julin, A Wolk, L Bergkvist, M Bottai, A Akesson. Dietary cadmium exposure and risk of postmenopausal breast cancer: A population-based prospective cohort study. Cancer Res 2012 72(6):1459 – 1466.
- YA Cho, J Kim, HD Woo, M Kang. Dietary cadmium intake and the risk of cancer: a meta-analysis. PLoS One. 2013 Sep 17;8(9):e75087.
- M Vahter, G Johansson, A Akesson, B Rahnster. Faecal elimination of lead and cadmium in subjects on a mixed and a lactovegetarian diet. Food Chem Toxicol. 1992 Apr;30(4):281-7.
- HM James, ME Hilburn, JA Blair. Effects of meals and meal times on uptake of lead from the gastrointestinal tract in humans. Hum Toxicol. 1985 Jul;4(4):401-7.
- F Pearce. Mosses Reveal Slovakia's Black Triangle of Pollution. The New Scientist. 15 Mar 1997. 2073.
Images thanks to NASA via Wikimedia
- air pollution
- animal products
- antioxidants
- beans
- breast cancer
- cadmium
- cancer
- cardiovascular disease
- chicken
- cognition
- diabetes
- eggs
- fiber
- grains
- heart disease
- heavy metals
- junk food
- lead
- meat
- mercury
- nuts
- organ meats
- oxidative stress
- phytates
- Plant-Based Diets
- poultry
- seafood
- smoking
- supplements
- turkey
- vegans
- vegetables
- vegetarians
- women's health
- zinc
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Title
Cadmium & Cancer: Plant vs. Animal Foods
LicenseCreative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)
Content URLDoctor's Note
Other toxins in cigarette smoke are also found in food. See:
- Estrogenic Cooked-Meat Carcinogens
- Heterocyclic Amines in Eggs, Cheese, & Creatine?
- Fukushima & Radioactivity in Seafood
Toxic metals have also been found in dietary supplements. See, for example:
Mercury is also a serious problem. See:
- California Children Are Contaminated
- Mercury vs. Omega-3s for Brain Development
- Nerves of Mercury
- Mercury in Corn Syrup?
For more on pollution in seafood, see:
- Fish & Diabetes
- Diabetes & Dioxins
- Pollutants in Salmon & Our Own Fat
- Alkylphenol Endocrine Disruptors and Alleriges
- Dietary Sources of Alkylphenol Endocrine Disruptors
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