Nuts and seeds reduce cancer risk

February 23, 2022 by Joel Fuhrman, MD


Summary


Eating nuts and seeds regularly can help us live longer, healthier lives. New research links higher nut/seed consumption with a lower risk of cancer, especially breast cancer. In addition, nut/seed phytochemicals have anti-inflammatory and cholesterol-lowering properties, help maintain a healthy gut microbiome, and can lower your diet’s glycemic load.  

Related blog posts by Dr. Fuhrman:

Nuts and Seeds Help Keep Disease Away
Fight Breast Cancer with Flax and Chia seeds
Nuts: An Important Component of an Anti-Diabetes Diet 


 

With their relatively high calorie count, adding nuts and seeds to your daily food intake can seem like a counterintuitive move – especially if you’re focused on losing excess weight. But the truth is, these tasty plant foods are nutritional superstars: They supply important phytochemicals that have antioxidant and anti-inflammatory properties that protect against cancer, promote cardiovascular health, increase insulin sensitivity and support a healthy gut microbiome. 

Longer life

Eating nuts and seeds regularly is consistently linked to longer life in observational studies. Possible explanations for this association include lowering glycemic load and promoting cardiovascular health.1-4

Recently, researchers have been investigating connections between consumption of nuts and risk of cancer or death from cancer. Most recently, results from the Shanghai Breast Cancer Survival Study suggested that participants with higher than average nut consumption had a 52% lower risk of cancer recurrence, metastasis, or death from breast cancer.5

Sources:

Nut consumption on all-cause, cardiovascular, and cancer mortality risk: a systematic review and meta-analysis of epidemiologic studies

 Nut consumption in association with overall mortality and recurrence/disease-specific mortality among long-term breast cancer survivors

Lowered risk of cancer

There is abundant research now on intake of nuts and cancer incidence. Three different research groups  performed meta-analyses of the literature in 2020 and 2021, analyzing approximately 30-45 studies. All three concluded that higher nut consumption was associated with a lower risk of cancer, and all three found a dose-response association, meaning as nut intake increased, cancer risk decreased. Two of the three noted that only tree nuts (not peanuts or peanut butter) were associated with reduced risk of cancer. One analysis found that nuts were associated with reduced risk especially of cancers of the digestive tract.6-8

Direct anti-cancer effects

Some phytochemicals in nuts, like those in greens, berries, and other plant foods, have direct anti-cancer effects. For example, laboratory studies on cancer cells have found that phytochemicals present in nuts, such as polyphenols and fatty acids, promoted cancer cell death and inhibited cell proliferation, metastasis, and angiogenesis.7

The studies discussed here have focused on nuts, not seeds, but lignans in flax, chia, and sesame seeds have anti-estrogen properties and are linked to a lower risk of postmenopausal breast cancer.9

Related: Fight Breast Cancer with Flax and Chia Seeds

Sources:

Association of Total Nut, Tree Nut, Peanut, and Peanut Butter Consumption with Cancer Incidence and Mortality: A Comprehensive Systematic Review and Dose-Response Meta-Analysis of Observational Studies

Nut Consumption and Risk of Cancer: A Meta-analysis of Prospective Studies

Meta-analysis of the association between nut consumption and the risks of cancer incidence and cancer-specific mortality 

Meta-analyses of lignans and enterolignans in relation to breast cancer risk

Oxidative stress, inflammation, and insulin sensitivity

Oxidative stress and inflammation are driving factors in heart disease, cancer, and other chronic diseases. Phytochemicals in nuts and seeds also have antioxidant and anti-inflammatory actions, such as tocopherols and tocotrienols (vitamin E), omega-3 ALA, and polyphenols such as quercetin, resveratrol, anacardic acid, and ellagic acid.7

Using nuts as a major calorie source reduces the overall glycemic load of the diet compared to common high-glycemic calorie sources such as rice, pasta, bread, and potatoes. Evidence from randomized controlled trials has suggested that eating nuts regularly improves insulin sensitivity in patients with type 2 diabetes.10

Related: Nuts: An Important Component of an Anti-Diabetes Diet

Source:

The effect of nuts on markers of glycemic control: a systematic review and meta-analysis of randomized controlled trials

Cholesterol

Nuts have total and LDL cholesterol-lowering properties that have been supported by many randomized controlled trials.11 Although we usually think of cholesterol in relation to cardiovascular disease, cholesterol plays a role in cancer as well. Cancer cells use cholesterol to fuel their high level of proliferation, and cholesterol may also be an important player in cellular signals that promote the survival of cancer cells.12,13

Sources:

Effects of tree nuts on blood lipids, apolipoproteins, and blood pressure: systematic review, meta-analysis, and dose-response of 61 controlled intervention trials

The role of cholesterol metabolism and cholesterol transport in carcinogenesis: a review of scientific findings, relevant to future cancer therapeutics

Cancer chemoprevention with nuts

Gut microbiome

One of the three meta-analyses on nuts and cancer risk found that nuts were especially protective against digestive cancers. The researchers thought this could be because the fiber in nuts helps reduce intestinal transit time, which reduces the duration of the colon’s exposure to dietary carcinogens. It could also be because of beneficial effects of nuts on the microbiome. Randomized controlled trials on walnuts and almonds have found increases in the populations of beneficial gut bacteria.7

Source:

Nut Consumption and Risk of Cancer: A Meta-analysis of Prospective Studies

TAKE ACTION: Eat a variety of nuts and seeds

Nuts and seeds are health-promoting, whole-food calorie sources, each with its own individual nutritional profile; some are higher in certain polyphenols than others, and others are high in omega-3 fatty acids, lignans, plant sterols, or vitamin E.  Include a variety of raw, unsalted nuts and seeds in your diet, such as walnuts, flaxseeds, almonds, pecans, cashews, and macadamia nuts, and emphasize the high-omega-3 nuts and seeds (walnuts, flax, chia, hemp).

Products to explore:  Mediterranean Stone Pine Nuts, Organic Raw Sprouted Almond Butter, Organic Raw Cashew Butter

 
References
  1. Grosso G, Yang J, Marventano S, et al. Nut consumption on all-cause, cardiovascular, and cancer mortality risk: a systematic review and meta-analysis of epidemiologic studies. Am J Clin Nutr 2015, 101:783-793.
  2. Luo C, Zhang Y, Ding Y, et al. Nut consumption and risk of type 2 diabetes, cardiovascular disease, and all-cause mortality: a systematic review and meta-analysis. Am J Clin Nutr 2014, 100:256-269.
  3. Aune D, Keum N, Giovannucci E, et al. Nut consumption and risk of cardiovascular disease, total cancer, all-cause and cause-specific mortality: a systematic review and dose-response meta-analysis of prospective studies. BMC Med 2016, 14:207.
  4. Mayhew AJ, de Souza RJ, Meyre D, et al. A systematic review and meta-analysis of nut consumption and incident risk of CVD and all-cause mortality. Br J Nutr 2016, 115:212-225.
  5. Wang C, Gu K, Wang F, et al. Nut consumption in association with overall mortality and recurrence/disease-specific mortality among long-term breast cancer survivors. Int J Cancer 2021.
  6. Naghshi S, Sadeghian M, Nasiri M, et al. Association of Total Nut, Tree Nut, Peanut, and Peanut Butter Consumption with Cancer Incidence and Mortality: A Comprehensive Systematic Review and Dose-Response Meta-Analysis of Observational Studies. Adv Nutr 2021, 12:793-808.
  7. Long J, Ji Z, Yuan P, et al. Nut Consumption and Risk of Cancer: A Meta-analysis of Prospective Studies. Cancer Epidemiol Biomarkers Prev 2020, 29:565-573.
  8. Zhang D, Dai C, Zhou L, et al. Meta-analysis of the association between nut consumption and the risks of cancer incidence and cancer-specific mortality. Aging (Albany NY) 2020, 12:10772-10794.
  9. Buck K, Zaineddin AK, Vrieling A, et al. Meta-analyses of lignans and enterolignans in relation to breast cancer risk. Am J Clin Nutr 2010, 92:141-153.
  10. Tindall AM, Johnston EA, Kris-Etherton PM, Petersen KS. The effect of nuts on markers of glycemic control: a systematic review and meta-analysis of randomized controlled trials. Am J Clin Nutr 2019, 109:297-314.
  11. Del Gobbo LC, Falk MC, Feldman R, et al. Effects of tree nuts on blood lipids, apolipoproteins, and blood pressure: systematic review, meta-analysis, and dose-response of 61 controlled intervention trials. Am J Clin Nutr 2015, 102:1347-1356.
  12. Cruz PM, Mo H, McConathy WJ, et al. The role of cholesterol metabolism and cholesterol transport in carcinogenesis: a review of scientific findings, relevant to future cancer therapeutics. Front Pharmacol 2013, 4:119.
  13. Falasca M, Casari I, Maffucci T. Cancer chemoprevention with nuts. J Natl Cancer Inst 2014, 106.

Joel Fuhrman, M.D. is a board-certified family physician, seven-time New York Times bestselling author and internationally recognized expert on nutrition and natural healing, who specializes in preventing and reversing disease through nutritional methods. Dr. Fuhrman coined the term “Nutritarian” to describe his longevity-promoting, nutrient dense, plant-rich eating style.
 
For over 30 years, Dr. Fuhrman has shown that it is possible to achieve sustainable weight loss and reverse heart disease, diabetes and many other illnesses using smart nutrition. In his medical practice, and through his books and PBS television specials, he continues to bring this life-saving message to hundreds of thousands of people around the world.

 

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vaporz

03/14/2022 11:44 AM

Interesting, never knew that cholesterol is a cancer contributor.

CarolW2

04/30/2022 12:58 AM

I never knew that about cholesterol either, wow, this info will go in my "good-to-know" file.