Can a handful of nuts reduce lung cancer risk?
Tree nuts such as walnuts, pecans, pistachios, and almonds as well as peanuts (which grow in the ground and are legumes, but have nut-like health benefits), have been shown pretty definitively to decrease the risk of getting cardiovascular disease and death from cardiovascular disease. This is likely due to the favorable fatty acids found in nuts that decrease vessel inflammation and lower serum lipids. In fact, the fatty acids in nuts may also prevent diabetes and weight gain. As I often tell people, a healthy diet should NOT be devoid of healthy fats that should primarily come from nuts, fatty fish, and extra virgin olive oil (EVOO). Eating these fats in moderation promote health, and if consumed in moderation, should be eaten several times a week. Studies such as the PREDIMED, The Physician’s Health Study, The Nurse’s Health Study, and the Health Professionals Follow-up Study, all basically show that as nut intake increases, the risk of heart and cardiovascular disease, as well as death from any cause, decreases by about 15-40% depending on the study.
The monounsaturated fatty acids and polyunsaturated fatty acids lower blood cholesterol and seem to decrease damage to the blood vessel lining and stabilize cell membranes, which may explain the reduced risk of sudden cardiac death described in some studies. Also, nuts contain a good amount of naturally occurring Vitamin E which is an antioxidant that may contribute to the benefits.
Additionally, nuts contain numerous phytonutrients—the complex family of molecules that prevent or delay cancer growth. Some of these phytonutrients include ellagic acid, anacardic acid, genistein, resveratrol (also found in red wine!), and they basically act as antioxidants that may prevent cell and DNA damage which can lead to cancer. Phytonutrients can also block cancer cell proliferation and spread, induce cell death, and block blood vessel growth in tumors. It must be stressed, however, that taking an individual supplement of a specific phytonutrient probably is not of benefit. Indeed, most studies support the notion that it is the synergistic action of phytonutrients found in a variety of foods that likely imparts benefit.
The literature on nuts and cancer prevention is growing, mainly through population-based studies that assess dietary intake over time and the development of a certain cancer. For example, one study known as the PREDIMED study assessed risk of various chronic diseases in people who consumed a Mediterranean diet. This study showed a 40% reduction in cancer deaths for those who ate more than three nut servings per week, and a 54% reduction in cancer deaths among those who ate more than three servings of walnuts per week. This is consistent with ongoing studies and data and suggests that eating nuts regularly may decrease risk of some cancers.
In closing, there was an article entitled “Nut Consumption and Lung Cancer Risk: Results from Two Large Observational Studies” published in the January 2017 issue of Cancer Epidemiology Biomarkers and Prevention that prompted me to write this blog. The researchers assessed data obtained from the Environment and Genetics in Lung Cancer Etiology (EAGLE) study and the National Institutes of Health (NIH) American Association of Retired Persons (AARP) Diet and Health study. Both studies evaluated diet intake of certain foods via questionnaire and found that a higher intake of nuts was inversely associated with an overall reduction in lung cancer risk by 26% in the EAGLE cohort and 14% in the AARP cohort—regardless of smoking status. The most pronounced protective benefit of increasing nut intake was in those who smoked 1-20 cigarettes a day as they saw a risk reduction of 39%.
It seems prudent to eat a handful of nuts, unsalted ideally, several times per week, as this may benefit current smokers and non-smokers alike when it comes not only to cardiovascular disease prevention, but also to lung cancer.
Mark A. Marinella, MD, FACP