(By Temitope Obayendo)
“An apple a day keeps the doctor away” is an adage that is proving increasingly true, as several studies have shown that a daily intake of apples and other vegetables will reduce the risk of cancer in humans.
Epidemiological studies, in particular, have linked the consumption of apples with reduced risk of some cancers, cardiovascular disease, asthma and diabetes. In the laboratory, apples have been found to have very strong antioxidant activity, inhibit cancer cell proliferation, decrease lipid oxidation and lower cholesterol.
Apples contain a variety of phytochemicals, including quercetin, catechin, phloridzin and chlorogenic acid, all of which are strong antioxidants. The phytochemical composition of apples varies greatly between different types of apples, and there are also small changes in phytochemicals during the maturation and ripening of the fruit. Storage has little to no effect on apple phytochemicals, but processing can greatly affect apple phytochemicals.
According to Professor (Mrs) Doris N. Onwukaeme, H.O.D, Pharmacognosy Department, Faculty of Pharmacy, University of Benin (UNIBEN), “Apples contain phytochemicals, including phenolics, flavonoids, carotenoids, antioxidants and vitamins, that build the body immune system, and thus prevent the onset of some ailments like cancer, diabetes, cardiovascular diseases and the likes.”
The professor, who spoke to Pharmanews during a telephone conversation, said studies have suggested that a diet high in fruits and vegetables may decrease the risk of chronic diseases, such as cardiovascular disease and cancer, and phytochemicals, including phenolics, flavonoids and carotenoids, from fruits and vegetables may play a key role in reducing chronic disease risk.
Also, a study conducted by the Department of Microbiology, Federal University of Technology, Owerri, Imo State, Nigeria, on the Microbiological Safety Assessment of Apple Fruits, attests to the health benefits of the apple.
The study states that the increasing understanding of the link between fruit intake and improved health, coupled with the newly found nutritional values of the apple, has increased its popularity and thus consumption rate. Whole fruits and juices of apple are extensively used as health foods because they are dependable sources of vitamins, minerals, electrolytes, antioxidants and fiber. The fruits are usually eaten fresh and raw, except for the seeds, making the nutritional values fully available for the body.
“Apples are rich source of phytochemicals that have been reported to reduce risk of cardiovascular diseases, asthma, diabetes, cataracts, Alzheimer’s disease/cognitive decline and pulmonary functions,” the study says.
Specific Health Benefits of Apple
1. Apples lower cholesterol: One medium-sized apple contains about four grams of fibre. Some of that is in the form of pectin, a type of soluble fibre that has been linked to lower levels of LDL or “bad” cholesterol. That’s because it blocks absorption of cholesterol, according to WebMD, which helps the body to use it, rather than store it.
2. They keep you full: The wealth of fibre an apple provides keeps you feeling full for longer, without costing you a lot of calories – there are about 95 in a medium-sized piece of fruit. That is because it takes our bodies longer to digest complex fibre than more simple materials like sugar or refined grains. Anything with at least three grams of fibre is a good source of the nutrient; most people should aim to get about 25 to 40 grams a day.
3. Apples may keep you slim: One component of an apple’s peel (which also has most of the fibre) is something called ursolic acid, which was linked to a lower risk of obesity in a recent study in mice. That is because it boosts calorie burn and increases muscle and brown fat.
4. They can help with breathing problems: Five or more apples a week (less than an apple a day!) has been linked with better lung function, most likely because of an antioxidant called quercetin found in the skin of apples (as well as in onions and tomatoes), the BBC reports. The breath benefits of apples extend even further: A 2007 study found that women who eat plenty of the fruit are less likely to have children with asthma.
5. Apples boost your immune system: While they do not quite rival oranges, apples are considered a good source of immune system-boosting vitamin C, with over 8 milligrams per medium-sized fruit, which amounts to roughly 14 per cent of your daily recommended intake.
6. Curb all sorts of cancers: Scientists from the American Association for Cancer Research, among others, agree that the consumption of flavonol-rich apples could help reduce your risk of developing pancreatic cancer by up to 23 per cent. Researchers at Cornell University have identified several compounds – triterpenoids – in apple peel that have potent anti-growth activities against cancer cells in the liver, colon and breast. Their earlier research found that extracts from whole apples can reduce the number and size of mammary tumours in rats. Meanwhile, the National Cancer Institute in the U.S. has recommended a high fibre intake, to reduce the risk of colorectal cancer.
7. They decrease the risk of diabetes: A 2012 study published in the American Journal of Clinical Nutrition found that apples, as well as pears and blueberries, were linked with a lower risk of developing type 2 diabetes because of a class of antioxidants, anthocyanins that are also responsible for red, purple and blue colours in fruits and vegetables.
8. They are good for your brain: Apples have been linked to a rise in acetylcholine production, which communicates between nerve cells. So, apples may help your memory and lower your chances of developing Alzheimer’s disease.
Though past studies have been divided on the issue, recent long-term studies suggest that people who have a diet rich in fruits that contain antioxidants – like apples – are 10 to 15 per cent less likely to develop cataracts.
Apple consumption was associated with decreased epithelial lung cancer incidence. This supported the findings of the previous studies discussed, where apples were significantly inversely associated with lung cancer, and may suggest that catechins alone do not help fight against lung cancers. Other data from the Zutphen Elderly study showed an inverse association between fruit and vegetable flavonoids and total cancer incidence and tumors of the alimentary and respiratory tract. Again, tea flavonoids were not associated with a decrease in cancer risk.
9. They reduce risk of cardiovascular disease: A reduced risk of cardiovascular disease has been associated with apple consumption. The Women’s Health Study surveyed nearly 40,000 women with a 6.9-year follow-up, and examined the association between flavonoids and cardiovascular disease. Women ingesting the highest amounts of flavonoids had a 35 per cent reduction in risk of cardiovascular events. Flavonoid intake was not associated with risk of stroke, myocardial infraction, or cardiovascular disease death. Quercetin did not have any association with cardiovascular disease, cardiovascular events, myocardial infarction or stroke. However, both apple intake and broccoli intake were associated with reductions in the risk of both cardiovascular disease and cardiovascular events. Women ingesting apples had a 13 – 22 per cent decrease in cardiovascular disease risk.
Apple and wine consumption was also inversely associated with death from coronary heart disease in postmenopausal women, in a study of nearly 35,000 women in Iowa. The intakes of catechin and epicatechin, both constituents of apples, were strongly inversely associated with coronary heart disease death. Although total catechin intake was inversely associated with coronary heart disease mortality, Arts et al (2001) found that tea catechins were not associated with coronary heart disease mortality in postmenopausal women. Apple catechins may be more bioavailable than the catechin and epicatechin gallates commonly found in teas.
10. They help with asthma and enhance pulmonary function: Apple consumption has been inversely linked with asthma and has also been positively associated with general pulmonary health. In a recent study involving 1,600 adults in Australia, apple and pear intake was associated with a decreased risk of asthma and a decrease in bronchial hypersensitivity, but total fruit and vegetable intake was not associated with asthma risk or severity. Specific antioxidants, such as vitamin E, vitamin C, retinol and β-carotene, were not associated with asthma or bronchial hypersensitivity. Previously, it had been found that apple intake, as well as selenium intake, was associated with less asthma in adults in the United Kingdom.
ICMSF, 1998 Total fungal count; FUTO: Federal University of Technology, Owerri
Nutrition Journal 2004
American Institute for Cancer Research