Eat an apple a day. Doing that could help you remember to eat an apple a day.
It might also help keep your skin from wrinkling.
And apple consumption appears to promote hair growth.
In addition, scientific research continues to build more and more evidence that antioxidants in apples are protective against cardiovascular disease and cancer development.
Apples just make sense as a daily part of the human diet.
Our forebears instinctively came to that same conclusion and adopted the maxim, "An apple a day keeps the doctor away." They did not understand on a physiological basis why apple consumption was associated with health. Modern scientific studies are unraveling the reasons.
Some of the research is epidemiological. Large populations are studied for their dietary habits, and correlations between food intake and health consequences are identified. Researchers also have the tools now to study how particular constituents in foods react at the molecular level within our cells to do us ill or good.
Antioxidants
This line of research has led to the discovery of the benefits of antioxidants. Our cells can be harmed by free radicals-unavoidable substances in our bodies formed through natural living processes—but antioxidant compounds can reduce the damage and lessen the likelihood that disease will ensue. Fruits and vegetables as a whole contain a wide range of helpful antioxidants. Hence the advice to eat at least five servings a day of fruits and vegetables is so sound. Apples are not the only health-imparting food in that group, but they make a vital contribution. Wisdom based on up-to-date science says to eat a variety of fruits and vegetables—and include at least one apple within your daily intake.
Aging
We deteriorate with age. Our motor skills degenerate. We have trouble remembering things. Antioxidants to the rescue!
Studies at various research institutions around the world, particularly the U.S. Department of Agriculture's Jean Mayer Human Nutrition Research Center on Aging based at Tufts University in Boston, Mass., have linked the consumption of diets high in antioxidants with reduction in aging-related mental and physical degeneration. Oxidative stress (high incidence of free radicals) has been associated with such diseases as diabetic polyneuropathy (nerve damage in diabetics) and cardiomyopathy (heart muscle damage), according to an article in the May 2002 issue of Journal of Neural Transmission. Researchers at the James A. Haley Veterans Affairs Medical Center in Tampa, Fla., reporting in the July 15, 2002 issue of Journal of Neuroscience, noted that diets containing selected high-antioxidant foods actually reversed declines in particular physiological functions associated with aging-related mental deterioration. The Tufts scientists in collaboration with colleagues from Colorado and Pennsylvania, publishing in Brain Research in the June 2, 2000 issue, documented evidence that "age-related deficits in motor learning and memory can be reversed with nutritional interventions." They pointed out the relevance of these findings to rehabilitative strategies for victims of strokes.
The foods that have been touted the most for these positive factors are blueberries, strawberries and spinach. Apples are ranked as "intermediate" in this respect. British analysis from King's College in London, published in the February 2002 issue of Free Radical Research, listed various antioxidant components within the phenolic families of compounds found in fruits and vegetables. Darker foods like blueberries, strawberries and raspberries are rich in anthocyanins, which "demonstrated the highest antioxidant activities." Scientists at the UCLA Center for Human Nutrition in Los Angeles, Calif., included most apples in this category, stating in the November 2001 Journal of Nutrition that "red-purple foods contain anthocyanins, which are powerful antioxidants found in red apples, grapes, berries and wine." Apples also have flavonoid antioxidants, including catechins and quercetin, to add to their beneficial potency. The Tampa study showed that apples "significantly downregulated" an age-related inflammatory response in the brain that is thought to contribute to deterioration in mental processes.
As the level of understanding of the human brain and neurological system advances, a tendency grows to hype "miracle foods" as quick fixes for whatever ails us. A more moderate position is simply to recommend greater consumption of all fruits and vegetables on a consistent basis, including plenty of apples. They can all contribute something worthwhile. Apples and some other fruits and vegetables appear to be brain food. Apples can be savored simply because they are so delicious, but you may also achieve a side benefit—making your brain work better!
Wrinkles
An article published by Australian researchers in the February 2001 issue of Journal of the American College of Nutrition was titled "Skin wrinkling: can food make a difference?" The answer was a conditional yes. Elderly populations were monitored in Australia, Greece and Sweden as part of the International Union of Nutritional Sciences "Food Habits in Later Life" study. Dietary intakes were recorded, and the subjects' skin wrinkles were measured "using a cutaneous microtopographic method." The findings were that "a high intake of vegetables, legumes and olive oil appeared to be protective against cutaneous actinic [sun-caused] skin damage." Meat and butter and other dairy products appeared to have adverse effects. An Anglo-Celtic group of subjects consumed more apples, prunes and tea than other ethnic subjects did, and those foods apparently contributed to favorable results. As usual, the scientists qualified their findings as less than definitive, since it was only one research project. Their official conclusion: "This study illustrates that skin wrinkling in a sun-exposed site in older people of various ethnic backgrounds may be influenced by the types of foods consumed." Eating apples and vegetables is certainly cheaper than a bill for cosmetic surgery!
Hair Growth
Japanese researchers extracted a particular chemical compound from apples named procyanidin B-2 and studied its effect on hair epithelial cells in lab animals. Their conclusion, published in the January 2002 issue of British Journal of Dermatology, was that the compound promotes hair growth. The topic of whether or not it could do so on portions of the human male cranium that formerly boasted hair but currently do not was not addressed.
Cholera
Cholera, a scourge in the U.S. during pioneer days, has not been a problem here for more than a century. But outbreaks still occur elsewhere around the world. It's good to know apples can help. Japanese researchers, reporting in Microbiology and Immunology this year, administered a polyphenol compound extracted from immature apples to laboratory animal subjects and found it inhibited the effects of the cholera toxin in a dose-dependent manner—the more of the extract the animals ingested, the greater the control against symptoms. Apples appear to be good medicine—or, to use a more modern terminology, "effective nutriceuticals" (substances in plant foods that have protective and therapeutic values).
COPD
Chronic obstructive pulmonary disease (COPD) leaves its victims gasping for breath. Dutch scientists studied whether the flavonoid class of food compounds, including catechins, could improve symptoms in COPD patients. Tea and apples were the primary sources of the flavonoids. Results showed a positive association with improved lung function, including lowered incidence of coughing and breathlessness. The researchers stated in the July 1, 2001 issue of American Journal of Respiratory and Critical Care Medicine, "Solid fruit, but not tea, intake was beneficially associated with COPD. Our results suggest a beneficial effect of a high intake of catechins and solid fruits against COPD." That is, eating apples may very well help.
Bladder Cancer
Bladder cancer is a risk associated with the smoking of tobacco. French researchers, writing in the October 1996 issue of Carcinogenesis and the June 18, 1998 issue of Mutation Research, described their investigations into the inhibitory effects of dietary phenolics on the development of carcinogenic substances in the bladder. Their conclusion was that "overall, our study strongly suggests that smokers ingesting dietary phenolics, probably flavonoids, are partially protected against the harmful effects by tobacco carcinogens within their bladder mucosal cells." The foods cited as "important sources of dietary flavonoids which are probably responsible for the anti-mutagenicity associated with foods and beverages" were apples, onions, lettuce and red wine.
Lung Cancer
Scientists at the University of Hawaii's Cancer Research Center of Hawaii in Honolulu investigated possible relationships between flavonoid intake and lung cancer risk. They wrote in Journal of the National Cancer Institute in its January 19, 2000 issue that "we found statistically significant inverse associations between lung cancer risk and the main food sources of the flavonoids quercetin (onions and apples) and naringin (white grapefruit)." They concluded that "if replicated, particularly in prospective studies, these findings would suggest that foods rich in certain flavonoids may protect against certain forms of lung cancer." That is, quercetin may have a protective effect against lung cancer, and apples are among the richest foods in the beneficial quercetin.
Prostate
Belgian researchers from Antwerp, writing in European Urology in 1999, noted that the low-fat, high-fiber diets typical in Asia are associated with lower incidences of prostate cancer and prostate enlargement in comparison with rates in the U.S. and Europe. Phytoestrogens (estrogenic compounds in plants) have been proposed as the preventive agents. Flavonoids are among one class of phytoestrogens, and, the authors stated, "apples, onions and tea-leaves are excellent sources of flavonoids." Many plant compounds also help by inhibiting particular enzymes that are "crucial to cellular proliferation," which is a mechanism present in cancer.
Stroke
The U.S. Department of Agriculture scientists based at Tufts University noted in the September 15, 1999 Journal of Neuroscience that phytochemicals (chemicals found in plants) that are present in antioxidant-rich foods have for some time been known to have beneficial effects in relation to cancer and the cardiovascular system. Finnish researchers, writing in the May 2000 issue of European Journal of Clinical Nutrition, discussed a 28-year study of intake of the flavonoid quercetin by more than 9,000 Finnish men and women, about 9% of whom experienced cardiovascular disease during that period. Apples were the major source of quercetin for the study population. The researchers' conclusion was that "the results suggest that the intake of apples is related to a decreased risk of thrombotic stroke."
Heart Disease
Some of the same Finnish researchers conducted another long-term study on the association of dietary consumption of flavonoids and subsequent heart attack mortality. The primary sources of flavonoids were apples and onions. The scientists concluded, according to their report in the February 24, 1996 issue of British Medical Journal, that "the results suggest that people with very low intakes of flavonoids have higher risks of coronary disease." So eat apples for your heart's sake.
Dutch epidemiologists have made similar studies among their own populations, including a long-term monitoring of elderly residents in the city of Zutphen that began in 1985. Over the years a total of 11% of the men in the study died of ischemic heart disease. The key substance being studied was catechins, part of the flavonoid family, which were ingested mainly from apples, black tea and chocolate. The findings, reported in the August 2001 issue of American Journal of Clinical Nutrition, were that "catechin intake was inversely associated with ischemic heart disease." The conclusion: "Catechins, whether from tea or other sources, may reduce the risk of ischemic heart disease mortality." Eat apples, and wash them down with tea—sounds like a winning combination.
The Dutch researchers also did a study in 1998 to develop information on catechin intake by a representative population from very young to very old. Tea was the main source of catechins across all age groups, and apples and pears ran second for adults and the elderly. Smokers had lower catechin consumption than non-smokers, as did persons with lower socioeconomic status compared with those of higher socioeconomic status. The researchers noted in the February 2001 issue of European Journal of Clinical Nutrition that "catechins are quantitatively important bioactive components of the daily diet, which should be taken into account when studying the relation between diet and chronic diseases." And apples are rich in catechins.
Postmenopausal women would do well to eat plenty of apples, according to a Dutch-and-American study of nearly 35,000 Iowa residents from 1986 to 1998. A little over 2% of the subjects died from coronary heart disease during that period. An inverse association of catechin intake with risk of that disease was determined. The scientists wrote in the November 2001 Epidemiology that "of the major catechin sources, apples and wine were inversely associated with coronary heart disease death."
Cholesterol
Numerous studies over the past quarter century have shown that a diet rich in apples can help lower blood cholesterol. Pectin, a soluble fiber found in apples at a rate of .78 grams per 100 grams of edible fruit, is thought to play a significant role in that relationship. Other fruits and vegetables also contain pectin, but apples are a handy and excellent means toward cholesterol reduction.
How handy? Food scientists at the University of California at Davis studied the composition of apple juice, including phenols, anthocyanins and flavonols. They found that apple juice inhibits the oxidation of the harmful form of cholesterol (LDL, or low-density lipoprotein). That is, you can drink your apples, whether as cider or clarified apple juice, and help protect your circulatory system. The scientists wrote in Life Sciences in 1999, "Although the specific components in the apple juices and extracts that contributed to antioxidant activity have yet to be identified, this study found that both fresh apple and commercial apple juices inhibited copper-catalyzed LDL oxidation. The in-vitro antioxidant activity of apples supports the inclusion of this fruit and its juice in a healthy human diet." So drink up!
Cholesterol
And keep at it! Dutch scientists studied the bioavailability of quercetin—that is, how well the human body absorbs it and retains it. If it goes right through your system without getting into your crucial cells, you could ingest all the apples you want and not derive the full benefit. The news out of this study is good. As the researchers reported in the November 24, 1997 issue of FEBS Letters, peak levels of quercetin from apples were found 2 1/2 hours after ingestion. The half-life for apples was 23 hours. In other words, after that period the level was still at half the peak. The researchers wrote, "Because of the long half-lives of elimination, repeated consumption of quercetin-containing foods will cause accumulation of quercetin in blood."
Want to keep the levels of that beneficial antioxidant high in your circulatory system and your cells?
Eat (or drink) an apple a day!! Because science supports that flavorful advice!
© 1996, 1997, 1998, 1999, 2000, 2001 Michigan Apple Committee
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