Apples: Autumn’s favourite functional food for bigger and stronger muscles19 September 2017
Apples are proving to be a functional food with benefits beyond basic nutrition. Synonymous with autumn harvests and back to school, apples provide amazing health benefits, with research showing promise in addressing the obesity epidemic and other chronic conditions and diseases. One of the most popular items to add to a lunch box, find out what the latest research is suggesting regarding the health and performance benefits of apples. From increased muscle size to decreased obesity, apples bring more than just flavour to the autumn season.
Obesity, Brown Fat, and Muscle Growth
Recent research from the University of Iowa (1) focused on the benefits of ursolic acid, a substance found in the skin of apples. Ursolic acid was shown to increase skeletal muscle mass and exercise capacity, along with the amount of brown fat- a metabolically active fat- in mice that were fed the supplement. Even on a high-fat, obesity-inducing diet, the group receiving ursolic acid gained less weight, maintained normal blood sugar levels, and had a reduced incidence of fatty liver disease when compared to a diet without ursolic acid. Additionally, the group receiving the ursolic acid had higher energy expenditure levels without increasing spontaneous activity, leading the researchers to hypothesise that the increased amount of brown fat and muscle provides a protective mechanism against obesity.
Reduced Disease and Chronic Conditions
Multiple epidemiological studies link apple consumption with reduced risks for cancer, cardiovascular disease, asthma, and diabetes. Apple consumption is also linked to reduced cholesterol levels and weight loss. The protective effect is connected to the oxidative protective phytochemicals that are found in apples, especially the apple skin. Phytochemicals help protect against oxidation and include a variety of flavonoids such as quercetin and catechins. Some studies on lung cancer have found an association with the dietary intake of foods rich in quercetin and a lower risk of the disease. Quercetin was also associated with a decreased risk for type II diabetes, asthma, and heart disease (2). Catechins have been associated with heart health maintenance, improved pulmonary function, and decreased risk of chronic obstructive pulmonary disease (COPD) (2, 3). Apple consumption can also decrease total cholesterol and LDL cholesterol levels, while increasing the beneficial HDL levels (2, 4).
Phloridzin, a polyphenol found in apples, may help protect postmenopausal women from osteoporosis (5). Apples also contain boron, a trace element linked to strong bones and lower incidences of arthritis (6, 7).
High in vitamin C, apples are great for healthy skin, hair, and nails. Topically, they remain a darling in the cosmetic industry showing up in eye-creams, cleansers, make-up, and hair products. Apple pectin oligogalacturonides have also been approved as an anti-aging active ingredient based on its ability to improve cell to cell interaction between the skin layers (i.e., wrinkle reduction) (8).
Which Variety to Choose?
Multiple factors, beyond personal taste, can play a role in choosing apples. Variety, growing conditions, time of harvest, storage, and preparation can all impact the “health” of an apple. Apples with higher flavonoid content include Fuji and Red Delicious. Quercetin and catechin levels are higher in Jonagold apples early in the season, but decrease as the season progresses, and to confound produce selection even more, the apples receiving more sun exposure on the tree will also have higher levels of quercetin. Storage does not seem to affect the quality of the phytochemicals, but processing does have a negative impact, especially when peels are discarded.
Raw or cooked, some varieties fit the bill better than others. Red Delicious are good for snacking, but don’t bake or freeze well. Looking for the best pie and baking apples also good for snacking? Try Granny Smith, Golden Delicious, Fuji, Jonagold, and Honeycrisp.
Serving size: 1 medium apple
Fibre: 4.4 grams
Vitamin C: 14% of DV
Interesting Apple Bites
Apples are part of the rose family. There are more than 7,500 varieties worldwide. The largest importers of apples are Russia, Germany and the UK. They float because they are made up of about 25% air, making them perfect for apple bobbing. Apple juice is said to improve mood and green apples help combat seasickness. The average person eats approximately 65 apples a year. The first record sale of “three Bramley apples for two shillings” was in 1862.
By Stacey Penney, MS, NASM-CPT, CES, PES, FNS
Content Strategist, NASM and AFAA
1) Kunkel SD, Elmore CJ, Bongers KS, et al. (2012) Ursolic Acid Increases Skeletal Muscle and Brown Fat and Decreases Diet-Induced Obesity, Glucose Intolerance and Fatty Liver Disease. PLoS ONE 7(6): e39332. doi:10.1371/journal.pone.0039332.
2) Boyer J and Rui HL. Apple phytochemicals and their health benefits. Nutr J 2004;3:5 doi:10.1186/1475-2891-3-5http://www.nutritionj.com/content/3/1/5.
3) Insel PM, Ross D, McMahon K, et al. Nutrition. 4th ed. Sudbury, MA: Jones and Bartlett; 2011.
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5) Puel C, Quintin A, Mathey J, et al. Prevention of bone loss by phloridzin, an apple polyphenol, in ovariectomized rats under inflammation conditions. Calcif Tissue Int Nov 2005;77(5):311-18. Epub Nov 16, 2005.
6) Newnham RE and Associates. Essentiality of boron for healthy bones and joints. Environ Health Perspect Nov 1994;102 Suppl 7:83-85. North Yorkshire, England. PMID: 7889887 [PubMed – indexed for MEDLINE] PMCID: PMC1566627 http://www.ncbi.nlm.nih.gov/pubmed/7889887.
7) What makes apples healthy? http://www.sharecare.com/question/what-makes-apples-healthy
8) Lebreton-Decoster C, Rousselle P, Laperdrix C, et al. Oligogalacturonides improve tissue organization of in vitro reconstructed skin. Int J Cosmet Sci Oct 2011;33(5):455-61. doi: 10.1111/j.1468-2494.2011.00655.x. Epub Apr 21, 2011. Inserm U989, Université Paris Descartes, Faculté de Médecine Necker, 156 rue de Vaugirard, 75730 Paris cedex 15, France.
9) 50 interesting facts about apples. Homefarmer. https://homefarmer.co.uk/facts-about-apples/
10) Top 10 facts about apples. The Express. http://www.express.co.uk/life-style/top10facts/375383/Top-10-facts-about-apples