Health Benefits of Navel Oranges
Navel oranges are one of the most common varieties of sweet oranges (Citrus sinensis). They are sweet, usually seedless, and have thick pebbly skins. Both the skin and the flesh of navel oranges are good for you. The numerous health benefits navel oranges offer are linked to their high concentration of antioxidants and other health promoting nutrients including vitamin C (ascorbic acid), hesperidin, limonene, narirutin and beta-cryptoxanthin. The health benefits of navel oranges range from anti-cancer and anti-asthma effects to the ability to support healthy collagen formation. Collagen is what gives skin a smooth, wrinkle-free appearance. All navel orange varieties provide more or less the same benefits (described in the following paragraphs), so pick the one that you think tastes best. Common navel orange varieties include Late Lane, Becks, Fukumotos, Cara Cara, Barnfields, Chislets, Washingtons, Newhall, Fisher, and Atwood.
Sweet Oranges May Protect from Cardiovascular Disease and Cancer
Almost all citrus fruits contain hesperidin, a health promoting flavonoid, but sweet oranges such as navel oranges are particularly rich in hesperidin. Hesperidin is known to act as a strong antioxidant, protecting the skin from free radical assault. People following an anti-cancer diet plan should also pay attention to this powerful flavonoid: it has also been shown to provide protection against some cancers, including human breast cancer and androgen-dependent prostate cancer, by suppressing cancer cell proliferation1.
Vitamin C — also abundant in navel oranges — shares many of the health benefits of hesperidin. For starters, vitamin C (also known as ascorbic acid) appears to reduce the risk of cardiovascular disease by raising the levels of HDL cholesterol while lowering blood pressure and reducing the conversion of fat into plaque in the arteries. Secondly, a lack of vitamin C has been shown to help tumors survive and grow more easily. Tumors with low vitamin C levels have also been found to contain more of HIF-12, a protein that helps cancer thrive and spread. Vitamin C is particularly concentrated in the thick skin of navel oranges.
In recent years, yet another citrus compound has gained attention because of its potential cancer and cardiovascular disease combating properties. Limonene, a natural compound that is most concentrated in the rinds and the white spongy inner parts of navel oranges, has been shown to produce anti-cancer effects in animals, prevent the spread of human breast cancer in cell cultures, and dissolve cholesterol.
Navel Oranges Offer Beauty Benefits
Benefits of navel oranges are not limited to pure health effects; they can also offer beauty benefits. Hesperidin in navel oranges works together with vitamin C to support healthy collagen formation. Collagen is what gives skin a smooth, supple, and youthful appearance. As part of the aging process, collagen production slows down, resulting in wrinkles and fine lines on the skin. Therefore, older men and women following an anti-wrinkle diet might reap extra benefits by eating plenty of navel oranges and other fruits rich in hesperidin and vitamin C.
In addition, hesperidin in navel oranges acts as a strong antioxidant, protecting the skin from free radical assault. Our skin is constantly bombarded with free radicals created by pollution, cigarette smoke, drugs, heavy execising, toxic wastes, stress, aging, and UV radiation. In addition to hesperidin and vitamin C, sweet oranges contain a number of other antioxidant compounds including the carotenoid beta-cryptoxanthin and the polyphenol narirutin.
Health Benefits of Navel Oranges for Asthma Sufferers
There is an increasing body of evidence that suggests that low consumption of fresh fruit rich in vitamin C, such as sweet oranges, is associated with decreased lung function. A study among British children found a positive association between fresh fruit consumption and the level of forced expiratory volume in one second (FEV1)3. The association was more pronounced in wheezers than non-wheezers. FEV1 refers to the amount of air that is forcibly exhaled from the lungs in the first second of a forced exhalation. FEV1 is commonly used by doctors to measure lung function.
An Italian study published in 2000 followed over 18,000 children aged 6-7 years and found that those eating the most citrus fruit (oranges, tangerines, and grapefruit), along with kiwifruit, had a reduced risk of wheezing4. The protective effect of citrus did not appear to be dose related. The authors attributed the lung health benefiting properties of citrus and kiwifruit to their high concentration of vitamin C.
Other studies have suggested that the potential anti-asthma effects associated with the consumption of oranges and other citrus fruits may also be partially linked to their high concentration of hesperidin. It is also possible that the flavonoid narirutin and the carotenoid beta-cryptoxanthin, both of which are abundant in navel oranges and sweet oranges in general, contribute to the anti-asthma benefits of oranges. For more information about asthma and nutrition, check out our in-depth article 10 Diet Tips for Asthmatics.References
1. Lee CJ, Wilson L, Jordan MA, et al (2010). Hesperidin suppressed proliferations of both human breast cancer and androgen-dependent prostate cancer cells. Phytotherapy Research, 24(1), Suppl 1:S15-9
2. Kuiper C, Molenaar IG, Dachs GU, et al. (2010). Low ascorbate levels are associated with increased hypoxia-inducible factor-1 activity and an aggressive tumor phenotype in endometrial cancer. Cancer Research, 70(14), 5749-58
3. Cook DG, Carey IM, Whincup PH, et al (1997). Effect of fresh fruit consumption on lung function and wheeze in children. Thorax, 52, 628-633
4. Forastiere, F., Pistelli, R., Sestini P., et al. (2000). Consumption of fresh fruit rich in vitamin C and wheezing symptoms in children. Thorax, 55(3), 283-288
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