Whole foods bestow lung cancer protection and improve lung function

Gina L. Nick

“Functional foods,” “nutraceuticals,” “designer foods” and “medicinal foods” are terms that describe foods, and key ingredients isolated from foods, that have non-nutritive or tertiary functional properties. Researchers, healthcare practitioners, laypersons, and the popular media use these words interchangeably. The purpose of this article is to detail valid scientific information available on the physiologic actions of known constituents and combinations of constituents, as they naturally occur in apples, highlighting their medicinal and nutritive mechanisms of action in preventing lung cancer and optimizing lung capacity.


Apples contain well-recognized medicinal and nutritive constituents that offer profound benefit in protecting the health of, and optimizing lung function. These constituents include the antioxidants quercetin and vitamin C, along with other flavonoids and vitamins, pectins, tannins and fruit acids like malic acid.

Researchers are not entirely clear on why apples offer a scientifically documented benefit in protecting lung health and improving lung function, particularly in those individuals suffering from lung cancer and asthma. Most postulate that antioxidant protection may be a key mechanism of action. It has been proposed that the antioxidant flavonoid quercetin may play a major role. (1,2) Additionally, pectins and pectin-like rhamnogalacturonans found in apples have pronounced antimutagenic effects in vitro. (3) Pectin polysaccharides most likely interact directly with cells (Salmonella typhimurium) to sterically protect them from mutagenic attack.

As well, apple pectin decreases the incidence and number of dimethylhydrazine- and azoxymethane-induced colon tumors in rats. (4-6) It is also believed that pectin lowers [beta]-glucuronidase activity, a key enzymatic step in carcinogen activation and tumor initiation.

In the intestine, apple pectin is a bulk-forming agent similar to psyllium and prevents diarrhea and constipation by a similar mechanism. Pectin also may modify intestinal bacterial enzyme activity in favor of a reduction of toxic breakdown products in the gut. (7) This may contribute to an overall chemoprotective effect in lung carcinogenesis.

Research on Apples and Lung Cancer

Researchers (1) documented a statistically significant inverse relationship between lung cancer risk and food sources high in the flavonoid quercetin (onions and apples) after controlling for smoking and intakes of saturated fat and [beta]-carotene in a population-based, case-controlled study conducted in Hawaii (Table 1). This research, published in the Journal of the National Cancer Institute, found that increased intake of foods containing flavonoids, like those found in apples, have the potential to cut the risk of lung cancer in half.

This is the second study to link apple consumption to reduced risk of lung cancer. While it is well established that consumption of fruits and vegetables is linked to a reduced risk of lung cancer, this study, which builds on the results of an earlier study (8) published in the American Journal of Epidemiology, shows that the cancer protective effect largely stems from the flavonoid quercetin found in apples.

In 1997, researchers (8) reported on a 25-year study of 10,000 Finnish men that found that intake of antioxidant flavonoids, and in particular the consumption of the flavonoid quercetin (which provided 95% of the total flavonoid intake in the population studied), reduced the incidence of lung cancer. After adjusting for other fruits and vegetables in the diet, researchers noted an inverse association between consumption of apples and lung cancer risk. In fact, the likelihood of lung cancer among those who ate the most apples fell by 58% relative to those who ate fewer apples.

Research on Apples and Overall Lung Function

A long-term cross-sectional analysis (2) of a cohort of 2512 Welshmen aged 45-59 living in Caerphilly, Wales between 1979 and 1983 found that lung function was linearly associated with dietary apple intake (Table 2).

The researchers found that good lung function was associated with high intakes of vitamins C, E, and beta-carotene, citrus fruits, apples, and fruit juices. However, after they took into consideration factors such as body mass, smoking history and exercise, the only food that seemed to make a significant difference was apples.

In fact, eating five or more apples a week was linked to slightly better lung function. The lung capacity in those individuals who ate apples was 138 millilitres higher, as compared to those who did not eat apples. This study additionally found that the age-related decline in lung function over five years in these men was offset by consuming five or more apples per week during the study period.

Researchers from the University of Nottingham in the United Kingdom reported similar findings. A nine-year population study (9) of 2,633 adults found that apple eaters have better lung function and lower risk of respiratory disease such as asthma than non-apple eaters.

Research on Apples and Asthma

Apples also appear to play a significant role, along with pears, in offering protection against asthma. A recent cross-sectional study (10) designed to evaluate the relationship between diet and asthma found that among the wide variety of fruits and vegetables studied, apples and pears provided superior protection against asthma. The study, conducted in Australia, involved 1,607 young adults aged 20-44 and the results were published in the American Journal of Clinical Nutrition.

An earlier study, completed in 2001, demonstrated similar findings. This was a population-based case-control study (11) of 1,471 adults in the United Kingdom, conducted by researchers from London’s King’s College and the University of Southampton. The study examined the effects of dietary antioxidants on asthma risk and severity. The researchers discovered that people eating at least two apples per week resulted in a 22-32% decreased risk of developing asthma as compared to those that ate less than that. The medicinal properties inherent in apples also demonstrate benefit in preventing chronic obstructive pulmonary disease in long-term heavy smokers.

Research on Apples and COPD in Smokers

A preliminary case control study, (12) completed by researchers from the University of Groningen in the Netherlands offers some evidence that apples may also bestow protection against chronic obstructive pulmonary disease (COPD) in long-term smokers. These researchers reported that eating fruits and vegetables, and in particular an apple a day, may reduce smokers’ risk of developing COPD, based on their case-control study of long-term heavy smokers. This is the first known study to suggest smokers could benefit from increased apple consumption.

Final Thought

Researchers are still not clear on what the entire medicinal profile of an apple is and exactly how it functions to protect lung tissue and prevent lung-related health challenges. What we do know is that the fruit offers a simple and effective means of protecting the health of the lungs. After reviewing the available research on the conditions that benefit from increased apple consumption, including chronic obstructive pulmonary disease in heavy smokers, asthma, a general decline in lung function and lung cancer, the use of this inexpensive, readily accessible whole food turns out to be an important primary or complementary therapy for anyone battling the effects of compromised lung function.

Table 1. Odds ratio for lung cancer in the highest vs. the lowest

quartiles for apple intake in a Hawaiian population. An odds ratio of

1.0 indicates no difference (Q1). Parentheses indicate 95% CI. Other

foods high in isoflavones are shown for comparison. Of these, only

apples and onions are high in quercetin. Adapted from Le Marchand et al.



(lowest) Q2 Q3

Apple 1.0 0.9 (0.6-1.4) 1.0 (0.6-1.6)

Onion 1.0 1.4 (0.9-2.3) 0.9 (0.5-1.4)

Red wine (tertiles) 1.0 0.8 (0.4-1.8) 0.7 (0.4-1.2)

Soy products 1.0 1.6 (1.0-2.7) 1.2 (0.7-2.2)

Q4 Two-sided P

(highest) for trend

Apple 0.6 (0.4-1.0) 0.03

Onion 0.5 (0.3-0.9) 0.001

Red wine (tertiles) — 0.20

Soy products 1.0 (0.5-1.8) 0.28

Table 2. Cross-sectional analysis: Differences in forced expiratory

volume in one second (FEV1) in mL associated with increases in the

frequency of apple intake from baseline. Adapted from Butland et al. (2)

Difference in lung

function (95% Cl)

Frequency of (1) Adjusted for

apple N age, height, age,

consumption and height

None 645 0 (baseline)

1 270 97.1 (3.2-191.0)

2-4 753 159.9 (90.2-229.5)

[greater than or equal to]5 433 291.8 (211.2-372.4)

Test for trend p<0.001

Difference in lung

function (95% Cl)

Frequency of (2) Adjusted for (1),

apple body mass index,

consumption and smoking

None 0 (baseline)

1 75.7 (-15.7-167.1)

2-4 102.9 (34.6-171.1)

[greater than or equal to]5 185.7 (104.9-266.5)

Test for trend P<0.001

Difference in lung

function (95% Cl)

Frequency of (3) Adjusted for (2),

apple social class, work

consumption exercise, and leisure


None 0 (baseline)

1 49.3 (-40.9-139.5)

2-4 84.7 (17.2-152.1)

[greater than or equal to]5 146.6 (66.5-226.8)

Test for trend P<0.001

Difference in lung

function (95% Cl)

Frequency of (4) Adjusted for

apple (3) and total

consumption energy intake

None 0 (baseline)

1 44.5

2-4 88.0

[greater than or equal to]5 138.1

Test for trend P<0.001

Excerpts reprinted with permission from the book Clinical Purification: A Complete Treatment and Reference Manual by Dr. Gina L. Nick.


1. Le Marchand, L. et al. 2000. Intake of flavonoids and lung cancer. J Natl Cancer Inst 92(2): 154-160.

2. Butland, B. K. et al. 2000. Diet, lung function, and lung function decline in a cohort of 2512 middle aged men. Thorax 55(2): 102-108.

3. Hensel, A. and K. Meier. 1999. Pectins and xyloglucans exhibit antimutagenic activities against nitroaromatic compounds. Planta Med 65(5): 395-399.

4. Ohkami, H. et al. 1995. Effects of apple pectin on fecal bacterial enzymes in azoxymethane-induced rat colon carcinogenesis. Jpn J Cancer Res 86(6): 523-529.

5. Tazawa, K. et al. 1997. Anticarcinogenic action of apple pectin on fecal enzyme activities and mucosal or portal prostaglandin E2 levels in experimental rat colon carcinogenesis. J Exp Clin Cancer Res 16(1): 33-38.

6. Tazawa, K. et al. 1999. Dietary fiber inhibits the incidence of hepatic metastasis with the antioxidant activity and portal scavenging functions. Hum Cell 12(4): 189-196.

7. Mallett, A.. et al. 1987. Dietary modification of intestinal bacterial enzyme activities–potential formation of toxic agents in the gut. Scand J Gastroenterol Suppl 129: 251-257.

8. Knekt, P. et al. 1997. Dietary flavonoids and the risk of lung cancer and other malignant neoplasms. Am J Epidemiol 146(3):223-230.

9. American Thoracic Society, unpublished findings presented at the society’s Annual Meeting, May 2001, poster 618.

10. Woods, R. et al. 2003. Food and nutrient intakes and asthma risk in young adults. Am J Clin Nutr 78(3):414-421.

11. Shaheen, S. et al. 2001. Dietary antioxidants and asthma in adults: population-based case-control study. Am J Respir Crit Care Med 164(10):1823-8.

12. American Thoracic Society, unpublished findings presented at the society’s Annual Meeting, May 2001, poster 617.

by Gina L. Nick, PhD, ND

Chief Scientific Officer at Longevity Through Prevention, Inc. (1)

Phone: 866-587-4622 X702 * Fax: 866-587-4622 * E-mail: drgina@LTPonline.com

P.O. Box 6936 * Laguna Niguel, California 92677 USA


COPYRIGHT 2004 The Townsend Letter Group

COPYRIGHT 2004 Gale Group

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