Apples are high in vitamins C, E, potassium, magnesium, fiber, and low in fats. A diet rich in fruits and vegetables may lower the risk of chronic diseases, and research studies suggest that apples may help to prevent cancer cell growth, increase heart health, and manage cholesterol levels, but how healthy are apples?
How healthy are apples?
Is it really true? Does an apple a day keep the doctor away? The answer actually involves phytochemicals— specific types of plant molecules that contribute to a reduction in cardiovascular disease, cancer cell growth, and inflammation, to name a few. Apples contain high amounts of phytochemicals, including flavonoids, carotenoids, and phenols. In comparison to other fruits, apples are the second-largest source of phenols, accounting for approximately 22% of dietary phenols.
Two of the leading causes of death in most developed countries are cancer and cardiovascular disease. Oxidative stress plays a key role in these two diseases by causing damage to DNA. Phenols are antioxidants, which means that they can help protect against damaging oxidative stress.
Cancer is a disease that results in uncontrolled cell division. Apples have the highest average anti-proliferative activity (prevent cell growth) in comparison to other fruits. In a study examining the effects of the consumption of fruits and lung cancer, researchers found that volunteers with the highest intake of apples (as well as onions and white grapefruit) had a 40-50% decreased risk of lung cancer.
Different types of apples have demonstrated various anti-proliferative activities in cell-based studies. The Red Delicious apple prevented cell proliferation of liver cancer cells by 57%, while the Fuji apple prevented cell proliferation by 39%. There is not enough research to conclude which variety of apple is better in the prevention of disease.
Heart health, antioxidants and anti-inflammatory factors
Diet and lifestyle choices can greatly impact overall body weight and cholesterol. Research suggests that eating apples can reduce the risk of cardiovascular disease. Flavonoids, a type of phytochemical found in apples, have a preventative effect against the major types of cardiovascular diseases. Researchers have reported reductions in the risk of stroke with increased flavonoid intake. One study found that older men who consumed flavonoids, had a reduced risk of mortality from cardiovascular disease. Another study showed that women who consumed the largest concentrations of flavonoids had a 35% reduced risk of cardiovascular disease.
Since apples are high in flavonoids, they may also help to prevent high blood pressure and bad cholesterol. Low-density lipoprotein (LDL) oxidation is suspected to cause atherosclerosis and heart disease. Antioxidants can contribute to a decrease in lipid oxidation. One study discovered that, apple peels prevented LDL oxidation by 34% while whole apples and apple flesh only contributed 34% and 21%, respectfully. The peel itself, provides a higher phenolic content than any other part of the apple. For these reasons, apple peels may likely have greater nutritional benefit.
Phytochemicals may contribute to anti-inflammatory activities, such as reduced colon and systemic inflammation. The expression of inflammatory cytokines—culprits of chronic inflammatory bowel disease, can be inhibited by apple pectin. Apple pectin can decrease tumor necrosis factor-alpha (TNF-α)—a gene responsible for inflammation. Other genes responsible for inflammation include, interleukin-1β, interleukin-15 and interleukin-16. Current research is exploring these findings.
Apple peels or apple skin contain a high number of antioxidants, especially Vitamin C. Approximately one serving of an apple is equal to 1500 mg of vitamin C. Vitamin C plays a role in preserving and maintaining a healthy immune system. Due to the presence of antioxidants, apples have been associated with healthy respiratory function and inhibition of asthma and chronic obstructive pulmonary disease.
Alzheimer’s, weight loss and bone health
How healthy are apples? Specifically, how healthy is apple juice? Apple juice may preserve acetylcholine, a chemical involved in memory and cognitive functioning. It also could prevent gene expression of the protein—amyloid β peptide. Alzheimer’s disease includes both a decline of acetylcholine and the production of amyloid β peptide. Although there is a long way to go, there is potential to investigate the effects of apple juice on Alzheimer’s disease.
Healthy weight loss management depends on a variety of different factors, but dietary fiber could help with reaching that weight goal. Apples have high amounts of fiber and low-energy density. Apples alone do not contribute to overall weight loss but their high fiber content may contribute to weight management.
Flavonoids, such as phloridzin found in apples, can contribute to overall bone health. In one lab study researchers gave phloridzin to rats over an 80-day period. After this period, the rats had a significant increase in bone mineral density. It was further discovered that the consumption of apple products decreases overall calcium loss.
How healthy are apples? —Whether you like apple slices, apple juice or the whole apple, it is safe to assume that apples are very nutritious and are a great choice of fruit to add to a healthy diet. Apples alone do not account for the prevention of disease, but the regular intake of various fruits and vegetables can maintain your overall health.
Follow your physician’s medical advice about which diet is best for you; consult your doctor if you have any medical concerns.
Berner Andrée Sandoval-Ramírez, Úrsula Catalán, Lorena Calderón-Pérez, Judit Companys, Laura Pla-Pagà, Iziar A. Ludwig, Ma Paz Romero & Rosa Solà (2020) The effects and associations of whole-apple intake on diverse cardiovascular risk factors. A narrative review, Critical Reviews in Food Science and Nutrition, 60:22, 38623875, DOI: 10.1080/10408398.2019.1709801
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