38.1 OVERVIEW
Diet and nutrition is a subject discussed extensively on the Internet though it receives relatively little attention in medical and scientific journals. Pass’s 2001 book, Lung Cancer, has over 1,100 pages and 66 chapter, but no chapter devoted to diet. Scientists have not been able to identify a diet which cures cancer or develop a clear link between food intake and lung cancer. Anatomically, it is not clear how particular foods would reach the lung tissue.
38.2 DIET AND CAUSES OF CANCER
There is a fair amount of evidence that vegetable and fruit consumption minimize risk, while meat and fat-based diets increase it. “Diet, particularly high fat consumption and low fruit and vegetable consumption, contributes (independent of cigarette smoking) to the excess lung cancer risk in African-American men,” one study found. (2).
38.21 Fruit
One European study found, “fruit intake was inversely related to lung cancer mortality. This association was confined to heavy cigarette smokers.” (3). A recent British study found, “fish liver oil, vitamin pills, carrots and tomato sauce decreased risk.”
38.22 Red Meat
“A significant increase in risk of lung cancer associated with red meat, beef and fried meat was observed. The increase in risk was more evident in squamous cell lung cancer. This association remained after controlling for total energy and saturated fat intake, suggesting a possible role of heterocyclic amines in lung carcinogenesis.”
38.23 Vegetables
“12 studies showed a decreased lung cancer risk as vegetable consumption increased.” Albert (8).
38.24 Beta-Carotene Supplements
With fruit playing a positive role in cancer prevention, some suggested beta carotene supplements (an important ingredient in certain fruits):
“Beta-carotene and retinoids were the most promising agents against common cancers when the National Cancer Institute mounted a substantial program of population-based trials in the early 1980s. Both major lung cancer chemoprevention trials not only showed no benefit, but had significant increases in lung cancer incidence and in cardiovascular and total mortality. A new generation of laboratory research has been stimulated. Rational public health recommendations at this time include: 1) Five-A-Day servings of fruits and vegetables, a doubling of current mean intake; 2) systematic investigation of the covariates of extremes of fruit and vegetable intake; 3) discouragement of beta-carotene supplement use, due to adverse effects in smokers and no evidence of benefit in non-smokers.” Omenn (5) (6).
Indeed, the clinical trial was stopped because of the adverse impact of the
Beta Carotene. The reasons are unclear. The author concluded that there must be an important difference between concentrated vitamin supplements and fruit or vegetables which contained that ingredient. Patients should consult knowledgeable physicians and not simply accept theories proposed on the Internet or elsewhere.
38.3 DIET FOR LUNG CANCER PATIENTS
These studies lead to the question of whether tumors can be inhibited through a particular diet.
38.31 Clinical Trials with Vegetable Supplement
In one study, use of a vegetable supplement led to a longer life span for a group of patients with advanced cancer:
“Daily ingestion of SV (selected vegetables) was associated with objective responses, prolonged survival, and attenuation of the normal pattern of progression of stage IIIB and IV NSCLC. A large randomized phase III clinical trial is needed to confirm the results observed in this pilot study. In the study, the selected vegetable supplement includes “soybeans, mushrooms, mung beans, red dates, scallion, garlic, lentils, leek, Hawthorn fruit, onion, ginsengs, angelica root, licorice, dandelion root, senegal root, ginger, olive, sesame seeds, and parsley. The mix was blended, boiled, and then stored frozen.” (1).
What is the difference between this study and the beta-carotene study? Here, the supplement was simply a group of vegetables given in concentrated form. There, two specific vitamins were given.
38.4 FAMILY HISTORY OF LUNG CANCER AND ITS ROLE
Systems of genetic repair play a role in cancer making some individuals particularly susceptible to gene damage from smoking:
“The major risk factor for lung cancer is exposure to tobacco smoke. Exposure to radon, heavy metals used in smelting, and asbestos also greatly increases risks for lung cancer. However, only about 11% of tobacco smokers ultimately develop lung cancer, suggesting that genetic factors may influence the risk for lung cancer among those who are exposed to carcinogens.... Epidemiological studies show approximately 14-fold increased risks for lung cancer among average tobacco smokers and approximately 2.5-fold increased risks attributable to a family history of lung cancer after controlling for tobacco smoke... common genetic variants or polymorphism are hypothesized to affect lung cancer risk. Environmental carcinogenesis resulting from tobacco smoke exposure is a complex process that can involve activation of procarcinogens that lead to abduct formation and subsequent failure of DNA repair, which should normally remove these abducts. Studies comparing DNA repair capacity among newly diagnosed lung cancer patients and age-matched controls indicate significant differences between the two groups. DNA repair capacity influences risk for lung cancer among individuals.”
While tobacco is the primary risk factor, family history plays an important but subsidiary role. Those with a family history of lung cancer may have less of a capacity to repair smoking related DNA damage, therefore leading to increased incident of lung cancer.
REFERENCES
1. Sun, Study of a Specific Dietary Supplement in Tumor-Bearing Mice and in Stage IIIB and IV Non-Small Cell Lung Cancer Patients, Nutrition and Cancer 39(1):85-95, 2001.
2. Pillow, Case-control assessment of diet and lung cancer risk in African Americans and Mexican Americans, Nutr Cancer 1997;29(2):169-73.
3. Jansen, Cohort analysis of fruit and vegetable consumption and lung cancer mortality in European men, Int J Cancer 2001 Jun 15;92(6):913-8.
4. Darby, Diet, smoking and lung cancer: a case-control study of 1000 cases and 1500 controls in South-West England, Br J Cancer 2001 Mar 2;84(5):728-35.
5. Omenn, Chemoprevention of lung cancer: the rise and demise of beta-carotene, Annu Rev Public Health 1998;19:73-99.
6. Omenn, Effect of a Combination of Beta Carotene and Vitamin A on Lung Cancer and Cardiovascular Disease, N Engl J Med 1996 May 2;334(18):1150-5.
7. Is there a genetic basis for lung cancer susceptibility: Recent Results Cancer Res, 1999, 151:, 3-12.
8. Albert, Epidemiology of Lung Cancer, Chest. 2003;123:21S 49S.